Timing Belt Snapped

[dsp26]

Continuing on from here:
http://www.ozhonda.com/forum/showthread.php?t=101278&page=2



have fun gents scrap me off the list. timing belt snapped... asshole!! ggrrr hope nothing else broke


Ron, thats some bad luck man.. Hope it works out for you..

Did you change to a new belt when you did the new cams?


WTF

jeebus i hope you aint running a gatesor other aftermarket item.....Ron get it fixed asap and get out here !


i was sooo gee'd for tomorrow dammit.

oem Honda belt brand new when my motor was put together.

don't wanna hijack this thread further but a quick question on possible causes;

1)someone once replied to me on here that a ****ed dizzy bearing could snap belt from resistance.. how likely is this the case? coz the bearing sound did get worse and i didn't end up fixing it.

2)timing belt tensioner too tight??


next questions:
1) OEM Honda belt again
OR
2) "Performance" belt?

***EDIT***
don't worry benny i'll definitely be out next time you guys book a lane for some "WSID Stress Relief" after some more expenses on this :p


tensioner too tight/loose could prematurely snap belt
dizzy bearing - never heard of a seized one do this.mind you you can hear a bearing slowly die a long time before it probably seizes


Badluck Ron.


ill be there recording slow 1/4s
if anyone wants some in car footage just ask you can borrow the camera and ill youtube it laters


have fun gents scrap me off the list. timing belt snapped... asshole!! ggrrr hope nothing else broke


Ron, thats some bad luck man.. Hope it works out for you..

Did you change to a new belt when you did the new cams?


WTF

jeebus i hope you aint running a gatesor other aftermarket item.....Ron get it fixed asap and get out here !


i was sooo gee'd for tomorrow dammit.

oem Honda belt brand new when my motor was put together.

don't wanna hijack this thread further but a quick question on possible causes;

1)someone once replied to me on here that a ****ed dizzy bearing could snap belt from resistance.. how likely is this the case? coz the bearing sound did get worse and i didn't end up fixing it.

2)timing belt tensioner too tight??


next questions:
1) OEM Honda belt again
OR
2) "Performance" belt?

***EDIT***
don't worry benny i'll definitely be out next time you guys book a lane for some "WSID Stress Relief" after some more expenses on this :p


tensioner too tight/loose could prematurely snap belt
dizzy bearing - never heard of a seized one do this.mind you you can hear a bearing slowly die a long time before it probably seizes


Badluck Ron.


ill be there recording slow 1/4s
if anyone wants some in car footage just ask you can borrow the camera and ill youtube it laters


dunno maybe go the toda belt or apexi belt?


sorry to hear mann.. bad luck.... there irony in this though.. remember when i told you to get a performance belt for a peformance motor?? hopefully your valves are ok... maybe go toda or gates or is it worth trying the oem honda one again?


Nothing Beats OEM belt man. We use OEM belts only on our B16a and nothing is wrong. We even reuse second hand belts on our current b16a motor as it was the only belt that could be found before one of the supersprint rounds.

Gota make sure its tension properly and or ensure nothing can get into the timing belt area. A small rock can cause a belt to rip


when you say nothing can beat oem belt...? does that mean youve tried other good branded timing belts and they have done a worse job then the honda one?

IMO
oem belt for oem motor
performance belt for performance motor for higher revs etc lets just say the toda timing belt was the best investment i made for my motor... but each to there own opinion

[dsp26]

yeah find it odd.. going back to workshop now to check for further damage.

delsol9000rpms.. lol i knew you were gonna say exactly that :p i've always thought the same thing.. oem with oem and performance with performance... but i've never disputed the quality of oem honda parts though... i guess i just made a bad investment in this case.

what gets me though was this happened in the following circumstances:
- 4th gear @ 8okm/h
- ~4krpm off-load and off-vtec
- happily cruising along

so it can't be an oem thing.. may have been a bad batch... soooo, gonna try oem again depending on if the heads damaged or not. if i do need to get some valves i'll be getting flat-faced and toda belt.


gonna open up the motor today, can you guys make me feel better and tell me my motor is fine... when it happened:
- no loud noises or mechanical sounds, engine just shut off and i clutched in ASAP
- tried cranking after i stopped... sounded really clean and no restriction --> no compression --> no clanking noises
- wasn't on load or vtec


what are the chances of my head being in tact?

[dsp26]

this is such a damper.. i've had less problems with my sr20.... depending on how much this costs to repair i'll be leaving honda and follow in SHW7OY (Milads) footsteps and get a motorbike on the side :p

a del sol was a bad investment for track project to begin with... didn't realise it was 200Kg heavier than the Nissan NX i replaced with this and no torque :/

[grumpy rooster]

Different engine, but a TX3 I once owned snapped the timing belt and had exactly the same circumstances as yours. Had the exact same symptoms after it snapped as well. I had NO damage whatsover. So I'd say you may have escaped without too much drama.

Oh, and Milad's SR has a heap more in it if he wanted to. Remember, he is still using the OEM computer without any tuning. Its a good setup. :)

[dsp26]

Different engine, but a TX3 I once owned snapped the timing belt and had exactly the same circumstances as yours. Had the exact same symptoms after it snapped as well. I had NO damage whatsover. So I'd say you may have escaped without too much drama.

Oh, and Milad's SR has a heap more in it if he wanted to. Remember, he is still using the OEM computer without any tuning. Its a good setup. :)

good to know:thumbsup: although i clutched in straight away.. i was WOT'ing it before i realised the engine stopped.. no issue?


took it around to Joe's an hour ago... i was on low lift plus he notched my pistons so i'm hoping therewas no interference as you said... hopefully can troubleshoot the cause though as i don't need this happening again halfway to qld for work trip lol. i'm going to guess Joe will be sourcing the oem belt off you?

i'm still paying off my wisdom teeth which prevented me from getting the neptune off you... sux $3500 bill with $1400 to go :( one day when all is sorted i guess sorry about the hassle btw...


I had pretty much the same plans as Milads except I ordered JWT C2s and cancelled them that week my NX was written off (and sold off all the parts on my floor (clutch, par flywheel, imported vlsd box + hydro setup).... i didn't realise however that compression was that big a key on the SR... theres a few people now with 110-120wkw+ and still don't pull the same times as him... plus Milad has consistent times by the looks of it... good driver:thumbsup: i too had close to 11:1CR though on stock cams pulling 98wkw.. was a VERY strong motor

[panda[cRx]]

ouchies dude bad luck

we've got a lude vtir with a broken cambelt in our workshop at the moment. damaged all the valves and well yeh it's not pretty :(

on the other hand i've seen two civics in the last year have belts snap on them and all they've been up for is a new belt :)

[grumpy rooster]

good to know:thumbsup: although i clutched in straight away.. i was WOT'ing it before i realised the engine stopped.. no issue?

The engine would have stopped before you did that most probably. As soon as it snapped the shows all over, regardless of what you did.



took it around to Joe's an hour ago... i was on low lift plus he notched my pistons so i'm hoping therewas no interference as you said... hopefully can troubleshoot the cause though as i don't need this happening again halfway to qld for work trip lol. i'm going to guess Joe will be sourcing the oem belt off you?

Not me. I don't get into that stuff. I don't know who he uses.


i'm still paying off my wisdom teeth which prevented me from getting the neptune off you... sux $3500 bill with $1400 to go :( one day when all is sorted i guess sorry about the hassle btw...

Don't worry about it. These things happen. Nothing you can do about it.



I had pretty much the same plans as Milads except I ordered JWT C2s and cancelled them that week my NX was written off (and sold off all the parts on my floor (clutch, par flywheel, imported vlsd box + hydro setup).... i didn't realise however that compression was that big a key on the SR... theres a few people now with 110-120wkw+ and still don't pull the same times as him... plus Milad has consistent times by the looks of it... good driver:thumbsup: i too had close to 11:1CR though on stock cams pulling 98wkw.. was a VERY strong motor

This is getting off topic a bit but his car is just a well matched set of parts. Most people try to go too big with the cams or don't go for enough compression. The lightweight flywheel helps a lot as well. Practise and a good combo is the key on any car. Now he just needs some gears to make it go consistently into the 13's. :)

[fatboyz39]

You have more then likely bent some valves. Find the cause of the problem.

[delsol9000rpms]

ye yur valves most likely are fukked... honda engine equals interference design.. plus yuve milled yur head and got bigger cam profiles......

who tensioned the timing belt? is that the cause of the problem?.... could it have been a faulty timing belt?

[TODA AU]

You have more then likely bent some valves. Find the cause of the problem.

Jimmy's right,
It's unlikley the exhaust valves will all be straight.
Honda's often break the valve guides when they bend valves too.

Belts generally don't just snap for no apparent reason.
Carfully check everything.
It could be a dodgey tooth on a cam pulley or crank pulley.
It could be something wrong with the water pump...
But you you need to figure out why it happened as well as fix it.

Good luck with it,

[dsp26]

Thanks blokes!

hopefully find out soon....

sad news though... i was hoping being on the low cam and having notched pistons would save me.

Adrian, quick question though.. you mentioned waterpump? in what way does it contribute to belt death?

[destrukshn]

anything with a damaged gear on it.
so cam, crank, water pump.

[bennjamin]

would any other contributing factors lead to this Ron ? The last install was cams right ? Has to be relative to it. Something too tight or too loose..

[dsp26]

just heard back from Joe.. cams/tensioner/water pump aren't seized... the timing belt stripped at the teeth at a section.

he won't be removing the head till friday so i won't find out till then but most likely cause was a bad timing belt batch coupled with dual valve springs

bad news is all 4 exhaust valves are gone as per your hunches... hopefully the cast pistons survived.

looks like the heads coming off either way.. may as well dump in flat faced exhaust valves at least and maybe the Toda belt...

dual valve springs were Toda A's though.. didn't think they were that much more seat pressure than ITR duals???


now i know what you guys are probably thinking.. i wasn't thrashing when it happened.... weird

[fatboyz39]

just heard back from Joe.. cams/tensioner/water pump aren't seized... the timing belt stripped at the teeth at a section.



Timing belt stripped at the section? Could it be either tension loose or tight?

Those cast piston should survive.

[dsp26]

^^^yeah i hope.. will find out more tomorrow when head comes off and i give it an inspection.

Officially over Honda and any boy racer car now.. just pulled out a loan to get it fixed properly...

gonna trade it up for an auto na subaru liberty.. that way no modding or spirited driving... last 4 cars including this has been a very bad bank account of mods.. coulda moved out by now...

[vinnY]

bad go ron, hope the damage isn't too major

boo auto liberty, scooby auto boxes are shocking in my experience
manual or go home

[Benson]

IMO, if it gonig to cost like 2k to fix, get yourself a B18c or B18c7 motor and whack it in. At least the resell valve is better than a b16a..

Just a thought

[IEVAQ8]

good luck with it all, but i had same prob in my da3 integra, cruzing at 60kms in 4or 5th gear and the belt just snapped, leaving me with bent exhuast valves............

unless the mottor is a free spinning motor (which u have discovered isnt), hence the bent valves.............its gonna be a costly fix.

good luck again.............dont let this dishearten you, get back out there...........

[dupac->]

good luck again.............dont let this dishearten you, get back out there...........


:thumbsup::thumbsup::thumbsup::thumbsup:


Hopefully this doesnt happen to me.. but if it did.. just an excuse to go harder on the setup.

its a never ending money pit a car will never be "complete"

[Limbo]

gezz really bad luck mate.
hope it works out for you.
Is the mechanic giving any warranty on any of the work?
or did you end up doing it by yourself?

[omgzilla]

Dam dude! Now you're making me rethink my priorities - i'll get my dizzy overhauled asap!

Bad luck mate. Sorry to hear.

[dupac->]

shan, like someone said earlier when ur dizzy is about to seize.. you will hear the sound way before then..

starts to get noisey much earlier prior to seizing.

so should be okay

[omgzilla]

Thanks Du.

Mine just seems to get a tad noisy on the occasional start-up but goes away after a minute. Do they usually get constantly noisy/louder before seizing?

Any more news Ron? Pistons ok?

[dsp26]

***EDIT***

OK got to see the car and drive it... feels exactly the same before it shat itself but it is now 10wkw less at peak and less everywhere and the AFRs are uniformly rich across the board... the entire AFR richened up about 3:1 across the board.

the only 3 things that changed between first and last rebuild are:
- CROME chip
- 65mm intake manifold
- 68/65mm TB


ideas? i would have thought the addition of IM/TB would have made me leaner....

[TODA AU]

***EDIT***

OK got to see the car and drive it... feels exactly the same before it shat itself but it is now 10wkw less at peak and less everywhere and the AFRs are uniformly rich across the board... the entire AFR richened up about 3:1 across the board.

the only 3 things that changed between first and last rebuild are:
- CROME chip
- 65mm intake manifold
- 68/65mm TB


ideas? i would have thought the addition of IM/TB would have made me leaner....

Assuming she's been strapped together spot on,
Your problem more than likley stems from how rich it is running.
When you say 3:1 richer, is that .3 of 1 point A/F
Or 3 pionts.
ie: 13.0:1 down to 12.7:1 (this is ok - the problem is not the fuel so much)
Or 13.0:1 down to 10.0:1 (This would be the root of all evil)

In either case, you'll need to get the chip tuned to your car rather than a generic burnt chip.
With the larger throttle & manifold, without tuning for then, generally a B16A will loose power by simply addind these parts.
Eg: Stock B16A + Type R intake manifold + Type R throttle = -4hp @ wheels without tuning.
NB: The ECU runs MAP & is a pressure system, if you fit a larger throttle & shorter, thicker runner intake, the actual pressure in the intake will be slightly higher when the manifild vacuum colapses @ WOT.
This will result in more fuel being added unless it's tuned to suit the new manifold.
Airspeed plays a part too.

[dsp26]

^^^yep it is down 3:1.. will post dyno soon.

but when my build finished the first time it was 102wkw now its back down to 92wkw.

If the CROME was retuned would it give me back more than 10wkw? or is it fair to say my IM/TB combo just wasn't designed for B16?

[Benson]

i dont think you can get 10kw from tuning.

I think the manifold setup might be too big for the set-up.

[dsp26]

i dont think you can get 10kw from tuning.

I think the manifold setup might be too big for the set-up.

so better to just sell the IM/TB setup and not lose out on tuning costs?

this is the last time i'm listening to stupid honda-tech advice

[TODA AU]

If the A/F's are 10.0:1 @ WOT...
10kw is not really a huge ask from a B16A as far as power gains go...
There is most certainly 5 of those KW right there...

The other issue could be the cam timing is different now if the head has been shaved.
This can cause a general loss of power accross the rev range.
Retarded tends to lose power everywhere but still have a good curve.
Too far advanced tends to increase mid range at the expense of top end.

To see a benifit from the use of the manifold & throttle,
You will likley need to have the ECU tuned to suit your car.

Re A/F's
Are they rich everywhere else also?
That being the case, a change in fuel pressure could sort things out.
If it's only overly rich at WOT, the problem is likley what I said in previous post.
With change in manifold absolute pressure due to larger throttle & manifold.

[dsp26]

here tis...
http://img.photobucket.com/albums/v281/dsp26/img-Z041634-0001.jpg

[fatboyz39]

It does not look right at all.

[dsp26]

i've turned fuel pressure down to 32psi from 40psi for now but thats not worth 10wkw....

every post from america says the aebs makes power even on itr cams on a b16.....

i'll switch the IM and TB next cloudy day and redyno....


what i hope didn't happen is the head shop replacing the cams with oems by accident by i doubt it as it wasn't on the invoice.......

[TODA AU]

Looking at the 2 graphs layed over each other,
Yes, it's way richer which can be partly attributed to less manifold vacuum @ WOT,
The amount that's richer by if corrected would bring the power up to near where it was,
But without any other changes, it's unlikley to beat it.
Of note,
The charateristic of the power has changed. (Almost like the Vtec point has moved)
Though the original output is a little leaner than it needs to be through most of the graph,
That aside, it has the charaterisic of advanced cams & a long pipe style CAI,
The current output has the charateristic of retarded cams & short ram intake.
If there was no change to the intake system leading to the throttle,
You need to confirm the cam timing...
Ideally you should have the car tuned with both intakes & use the best.

[dsp26]

^^^sooo.. if i'm only gonna go back to the same power output with tuning bigger IM/TB then it's fair to say that i may as well put the original b16 stuff back on coz realistically i've lost 15wkw peak?

102wkw --> 107wkw setup:
- BC3+ cams
- head shave + BC 0.5mm head gasket = 10.88:1CR
- Cam gears at +2 +2 to bring cams back to spec from less head/hg thickness
- an additional +2 Intake as per buddy clubs specs for the cams
- Ign timing at 14* (17* made 99wkw due to pulstar plugs)
- 98ron
- Stock airbox with 3in SRI pipe from TB to airbox + K&N panel + no reso equipment + bottom of box is entirely cut out
- Stock IM/TB
- JDM P30-J02 rom from jap B16a2 with 5785 vtec x-over
- Then CROME tuned to 107wkw with 6000rpm x-over (BC recommended is 6200rpm)

Current Setup (92wkw)
- BC3+ cams
- Head shave an bit more + oem head gasket = ~10.9:1CR
- Cam gears left the same
- SRI with velocity stack pod
- aebs 65mm IM
- aebs 68mm tapered to 65mm TB
- Using same CROME tune
- LX91 Crane Cams external coil re-installed


Sooo its unrealistic for me to expect gains from the IM/TB addition to the vicinity of 110-115wkw, ie 18-23wkw gain with tuning? a 3:1 dip everywhere i don't think will account for anywhere near that much power even with ign maps modified

[fatboyz39]

Get it retune Ron and see how that goes. From the mods listed it should make over 110kw atw thats if everything is working 100% correctly.

[grumpy rooster]

I think your comparing apples with oranges. The first graph your comparing it to was before you got the car tuned (ie without CROME). Now your trying to compare the current setup (with CROME tune) to that graph. Without getting it retuned I think the comparison is just confusing. Your comparing 2 different setups with 2 different tunes and trying to tie it down to 1 thing. And, the tune was done on a different dyno which again makes it impossible to compare numbers.

Maybe I'm missing something but to me, until you get it retuned, any comparison with some sort of relevance is not possible.

I'm happy to be proven wrong. :)

[dsp26]

OK i'm gonna swap out the IM/TB tomorrow morning and get a redyno with both chips...

i know honda's are sensitive to air but not 15wkw sensitive on a mild setup...

also i know my dizzy is somewhat screwed with bearing issues right before belt snap but even then the graphs don't indicate to me any ign issues either

damn IM swap is such a pain in the arse job, so tight and so shit in hot weather......

[delsol9000rpms]

man leave the IM & TB

yu left the cam gears when you took abit more off the head which would mean it would be little bit retarded with the cam timing... the afr's would be one cause of lost power.. howeever i reckon the cam timing could also be aswell as causing the change in chracteristic of the curve as adrian pointed out...

also take in mind if your car was tuned and then yu added the coil pack it could not be functioning properly and therefore not be burning the fuel correctly causing your afr's to be the way they are?? take all of these into consideration... you said yourself when you installed the IM & TB it felt a whole lot faster... so y would it be the problem now??? i rekon it hasnt got anything to do with that soo dnt waste your time pulling it off etc... also the retardation of the cam timing would cause a change in the afr's? could be lots of things

try resetting the cam gears... and also try your stock coil setup.. and get it re tunedd correctly at the correct afr's

[dsp26]

Maybe... I did consider the coil and pulstar plugs but the curve doesn't indicate ignition issues with the usual serrated knife edge look but hopefully i can test a few things on the dyno.....

Cam gears are still fine though... i only had it shaved an additional amount equivalent to going back from 0.5mm to the oem size head gasket... plus the workshop used those cam calipers to reset cam timing properly and then just add the BC3+ +2INT recommendation.

How did you go with your IM/TB?

[ZeForce]

Get it retuned and see how it goes.... dont get caught up with dyno figures as they can vary quite a bit from day to day in my experience

[delsol9000rpms]

i havnt put on my inlet and tb just yet...

[dsp26]

OK i'm going to recap

1) Built engine
2) Belt snaps 5000KMs later
3) Put back together


Setup is exactly the same EXCEPT the following changes from Step 1 to 3...

- Idle Fuel Pressure (Vacuum line on) from 40psi to 34psi
- Dizzy timing from 14* now retarded ALL THE WAY?!?!
- All valves replaced
- Valve seats cut again (Again)
- cyl compression went down from 230psi to 200psi

Now ive seen 2 engines lose power before from having the valve sinking in the seat (a 4age20v and sr20) and i was discounting that memory until recently 2 separate people/workshops reminded me that B-series engines make power in the head and that a sunk seat will lose power... my valve seats were reseated twice and chances are its beyond the Honda limit of 10 thou...

So tell me is the below powerband loss a result of valve seating? Plus the fact that dizzy timing had to be retarded aaaaaaalllll the way....
i'm losing my patience. Had i known this was going to happen I would have just sourced a head from here....

These are the justifications i was given:
*230psi to 200psi cyl pressure drop
- Non oem valve replacements.. "may have a bit more of a dish"...
- Fair enough but 30psi is ****ing huge

* Valves sinking in seat
- "Had to be done"
- Which is fair enough... but Honda specs limit it to 0.010" otherwise needs to get re-seated. and that minute amount won't look "sunk in"

* Different powerband on second pic)
- "The manifoldand throttlebody you put on isn't designed for it, if you take it off you get it (power) back"
- OK I did that.. made less power... was 91wkw but the curve changed back to how it was

Now i'm not ****ing stupid... i'm getting irritated because:
- I refuse to believe a reputable workshop would try to justify these as so...
- "tinkering" the dizzy and fpr to gain 2wkw additional peak doesn't equal the 5-8wkw i've lost from 2000-7000rpm.... and the fact the dizzy had to be retarded all the way is a ****ing huge diference.




http://img.photobucket.com/albums/v281/dsp26/Dyno%20Sheets/B16a2_BC3plus_vs_Stock-1.jpg
http://img.photobucket.com/albums/v281/dsp26/Dyno%20Sheets/img-Z041634-0001.jpg
http://img.photobucket.com/albums/v281/dsp26/Dyno%20Sheets/DelSol_20081216.jpg

[fatboyz39]

why isnt your air/fuel last time was 10:1 ? and now back to where it was?

[TODA AU]

These are the justifications i was given:
*230psi to 200psi cyl pressure drop
- Non oem valve replacements.. "may have a bit more of a dish"...
- Fair enough but 30psi is ****ing huge

* Valves sinking in seat
- "Had to be done"
- Which is fair enough... but Honda specs limit it to 0.010" otherwise needs to get re-seated. and that minute amount won't look "sunk in"

* Different powerband on second pic)
- "The manifoldand throttlebody you put on isn't designed for it, if you take it off you get it (power) back"
- OK I did that.. made less power... was 91wkw but the curve changed back to how it was

Now i'm not ****ing stupid... i'm getting irritated because:
- I refuse to believe a reputable workshop would try to justify these as so...
- "tinkering" the dizzy and fpr to gain 2wkw additional peak doesn't equal the 5-8wkw i've lost from 2000-7000rpm.... and the fact the dizzy had to be retarded all the way is a ****ing huge diference.

You seem to know the answers to your own questions but you’re just not putting it together.
Get back to basics & think of it in simple terms.
You’ve got larger than std cams,
If the cam timing is out,
this affects the dynamic compression of the engine & therefore what it shows on a compression test…
So, check/set the cam timing.

Valve seat sinking,
You know this is an issue…
It may not be perfect but it works.
If you want to fix it, pull it down & use 0.5mm oversize valves.
This will allow you to reclaim the seat.
Worse than sunken valves is core shift…
Hopefully you don’t have that…

Going back to your original intake manifold you can see plain as day…
The cam timing is retarded.
Lack of low end, then coming to life in the last part of the rev range.
Again check/set cam timing.
Once cam timing is sorted together with a good tune, you’ll probably make some decent power.

Dizzy being full whack one way or the other is not right…
Cam manufacturers aren’t complete retards rarely ever machine the distributors drive in the end of the cam, in a position when the timing cannot be effectively set.
If the dizzy is near the middle chances are the cam timing is near right, if it have to go full whack one way or the other.
Mate, you know the answer…
Check/set the cam timing.
Hope that helps

[dsp26]

You seem to know the answers to your own questions but you’re just not putting it together.
Get back to basics & think of it in simple terms.
You’ve got larger than std cams,
If the cam timing is out,
this affects the dynamic compression of the engine & therefore what it shows on a compression test…
So, check/set the cam timing.

Valve seat sinking,
You know this is an issue…
It may not be perfect but it works.
If you want to fix it, pull it down & use 0.5mm oversize valves.
This will allow you to reclaim the seat.
Worse than sunken valves is core shift…
Hopefully you don’t have that…

Going back to your original intake manifold you can see plain as day…
The cam timing is retarded.
Lack of low end, then coming to life in the last part of the rev range.
Again check/set cam timing.
Once cam timing is sorted together with a good tune, you’ll probably make some decent power.

Dizzy being full whack one way or the other is not right…
Cam manufacturers aren’t complete retards rarely ever machine the distributors drive in the end of the cam, in a position when the timing cannot be effectively set.
If the dizzy is near the middle chances are the cam timing is near right, if it have to go full whack one way or the other.
Mate, you know the answer…
Check/set the cam timing.
Hope that helps

Thanks for the details Adrian:thumbsup: just wanna clarify some things though...

- I discounted the dynamic CR issue because the BC3+ low lobe wasn't that much bigger than stock.. 30psi difference between first build and now.... sooo.... so your suggesting i loosen LSA on the cams to reclaim some CR?
- Cam timing, you mentioned its retarded, currently setup at +6 +4, each marker on the gears = 2*@crank. i'm guessing the +4 +4 is to account for my head shave to reset to TDC.. the additional +2INT is as per Buddy Clubs recommendation. (those are rough observations btw, they were dialled on a degree wheel/tool)
- Is there any guideline I can use to somewhat gauge P2V clearance while i play with my cam gears with head still on? jack the car up and rotate wheels?
- does the graph indicate to you sunk valve seats? i just know it creates a powerloss due to the shrouding but i don't know the resulting curve characteristic and how much. Does this also mean cam gears have to be adjusted to account for the sunk amount? is this contributing to retard?

- i'm going to estimate that my head is shaved 0.040" / 1.016mm all up. rough guide from research says that every 0.040" removed = roughly +1 on cam gears or 2* crank.
- Written down on one of my papers was LATDC.... INT = 0.93mm/4.5*A + EXH = 1.04mm/1.5*
- so cam gear correction is roughly +2 +1 for head shave
- To loosen LSA is to advance int + retard exhaust? but this decreases V2V clearances right? but since i have sunk valves its less of a risk?
- wouldn't this mean +6 +4 is too far advanced already?
- Should i try +7 +5 to advance them more? or should i +8 +4 to loosen LSA some more? or since the top end is fine now +6 +2??

- relative to TDC (assuming 0 0) does the P2V clearance increase/decrease for the below scenarios:
Adv Int =
Ret Int =
Adv Exh =
Ret Exh =

- can you please explain "Core Shift". Is this something that should be obvious to a builder/head specialist?

- On a side note... how come i'm the only loser that lost power with an ITR (copy, aebs) manifold and 65mm TB?

- How did my AF change between Pic 2 and 3 from leaning FPR (i thought this would cause linear movement) + retarding dizzy all the way?

- Why are there so many drastic/extreme changes just to get me back to similar peak power + nowhere near the same midrange because i snapped a timing belt and had valves replaced?? when the engine was first put together cam gears were in the vicinity of +4 +2 and dizzy timing at 14* and fpr at 40psi??

- With some of the above info (especially cam timing so far advanced and dizzy so far retarded) does this still look like a case of cam timings retarded? or its powerloss from head failure?



But i'll be honest.. i can't afford to screw my own engine a 2nd time... my expense so far has already far exceeded a b18c7 motor :/ Are you able to have a look at it for me and do the fiddling? PM me?

[delsol9000rpms]

adrian speaks the truth...

[Benson]

losing 30psi is heaps!

Probably those cheapo valves you got in it now. Or something isnt sealing right.

Like Dave said the other night, the engine just feels lazy

[TODA AU]

Thanks for the details Adrian:thumbsup: just wanna clarify some things though...

- I discounted the dynamic CR issue because the BC3+ low lobe wasn't that much bigger than stock.. 30psi difference between first build and now.... sooo.... so your suggesting i loosen LSA on the cams to reclaim some CR?
- Cam timing, you mentioned its retarded, currently setup at +6 +4, each marker on the gears = 2*@crank. i'm guessing the +4 +4 is to account for my head shave to reset to TDC.. the additional +2INT is as per Buddy Clubs recommendation. (those are rough observations btw, they were dialled on a degree wheel/tool)
- Is there any guideline I can use to somewhat gauge P2V clearance while i play with my cam gears with head still on? jack the car up and rotate wheels?
- does the graph indicate to you sunk valve seats? i just know it creates a powerloss due to the shrouding but i don't know the resulting curve characteristic and how much. Does this also mean cam gears have to be adjusted to account for the sunk amount? is this contributing to retard?

- i'm going to estimate that my head is shaved 0.040" / 1.016mm all up. rough guide from research says that every 0.040" removed = roughly +1 on cam gears or 2* crank.
- Written down on one of my papers was LATDC.... INT = 0.93mm/4.5*A + EXH = 1.04mm/1.5*
- so cam gear correction is roughly +2 +1 for head shave
- To loosen LSA is to advance int + retard exhaust? but this decreases V2V clearances right? but since i have sunk valves its less of a risk?
- wouldn't this mean +6 +4 is too far advanced already?
- Should i try +7 +5 to advance them more? or should i +8 +4 to loosen LSA some more? or since the top end is fine now +6 +2??

- relative to TDC (assuming 0 0) does the P2V clearance increase/decrease for the below scenarios:
Adv Int =
Ret Int =
Adv Exh =
Ret Exh =

- can you please explain "Core Shift". Is this something that should be obvious to a builder/head specialist?

- On a side note... how come i'm the only loser that lost power with an ITR (copy, aebs) manifold and 65mm TB?

- How did my AF change between Pic 2 and 3 from leaning FPR (i thought this would cause linear movement) + retarding dizzy all the way?

- Why are there so many drastic/extreme changes just to get me back to similar peak power + nowhere near the same midrange because i snapped a timing belt and had valves replaced?? when the engine was first put together cam gears were in the vicinity of +4 +2 and dizzy timing at 14* and fpr at 40psi??

- With some of the above info (especially cam timing so far advanced and dizzy so far retarded) does this still look like a case of cam timings retarded? or its powerloss from head failure?



But i'll be honest.. i can't afford to screw my own engine a 2nd time... my expense so far has already far exceeded a b18c7 motor :/ Are you able to have a look at it for me and do the fiddling? PM me?


Re the compression test result.
If there is less than 5% difference between the cylinders,
Don’t worry about this at the moment. It’s not really an issue…

Regarding sunken valve seats,
No not really.

Re cam timing…
Written down on one of my papers was LATDC.... INT = 0.93mm/4.5*A + EXH = 1.04mm/1.5*
This is what the target is…
Ignore all other recommendations & setting per the gears…
Use a dial indicator & set the timing precisely.

Re core shift…
Drop in & I can show you on a head.
Or I can type out an explanation tonight.

Re the only loser…
This isn’t the case,
But when cams, compression & intake are changed,
The existing tune program is generally no good.
When you have other issues it gets worse.
Once your cam timing is right, the power should return.
Then you can add the manifold & throttle & tune the missing power back into it.
There is no magic pudding though…

I can have a look at it… I’ll PM you later when I get home.
Cheers

Adrian

[dsp26]

^^^what time do you close up shop tonight Adrian... wouldn't mind dropping by in the arvo for a quick chat before i drive my slug up to qld....




losing 30psi is heaps!

Probably those cheapo valves you got in it now. Or something isnt sealing right.

Like Dave said the other night, the engine just feels lazy
still does mate... all sound and no go.

i'm sure its ****ed.. its noticable on partial throttle.

ni don't mind too much the powerband now... it picks up from 7k rpm now which is fine for drag i guess as each shift lands me just over 6k rpm if i redline it to 9k rpm.... but this thing feels like crap on incline roads... ie m7 on-ramp :(



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