Low compression in one cylinder - what are the symptoms?

[nickk]

My car has low compression in 1 cylinder.

It tested:
1- 175psi
2- 125psi
3- 175psi
4- 175psi

Now with that much of a difference, should I be noticing poor performance and fuel consumption..? The only thing that I have noticed is a little bit of smoke when above 6500rpm.
Other than that it goes well and is still good on fuel.

[HondaPie]

can be oil ring in ur cylinder...

[dougie_504]

Crap power output

[DLO01]

Really depends on where your loosing compression. Could be rings, head gasket, who knows?

Power output, not as good fuel economy. Its prol not something that you would notice, but would affect in some way.

[dougie_504]

To put power output somewhat in perspective.

My friend made 100.7kw ATW in his B16A EF8 with I/H/E, stage 1.5 custom camshafts, skunk2 camgears, skunk2 valves/springs/retainers, port job, combustion chambers re-welded.

And I made 99.4kw ATW in my B16A EF8 with CAI, header and axle-back.

Turned out his compression was around the 180's and one cylinder around 140. Mine were 215, 210, 215 and 220.

Same dyno, within half an hour of one another.

[nickk]

hmmm might have to give it a dyno run. I've put an astra vxr and an ls2 to shame recently. whether their driving skills are poor and mine are good i do not know. i tried to drive my car as far as it would go on a tank and i reached 420km when it started surging. i dont drive like an idiot but i definately don't cruise everywhere. seems pretty good to be honest, i am really confused. I think a lot of questions will be answered when I crack open the motor at a later date.
p.s. dougie, you know i've met you recently?

[dougie_504]

You have?

At Garage Cafe?


Edit: Actually looking at your pic I'm pretty sure that's you lol

[nickk]

yeah man that's me. I'm stumped on what to do to my car, in terms of the motor man.

[dougie_504]

Bro you have a built B16A. You can keep running it while it's sick for a little while - just check your oil is the right colour etc.

I suggest either getting another bottom end for cheap (around $200) and reco'ing that and swapping them or just asking Andy Le (Jonny's brother) to fix it for you when he's available. He built Prima's motor, fixed up all that crap on Manny's, build Jonny's motor, built the other Nick's B20, building my B16 atm. He's pretty good and works very fast. RevZone does good work too.

Get it fixed mate. Don't go swapping your whole engine and stuff. Only upgrade your bottom if you want to, but before you put a new bottom on have that reco'd also so you know it's solid.


Stick to the B.

[bennjamin]

My car has low compression in 1 cylinder.

It tested:
1- 175psi
2- 125psi
3- 175psi
4- 175psi

Now with that much of a difference, should I be noticing poor performance and fuel consumption..? The only thing that I have noticed is a little bit of smoke when above 6500rpm.
Other than that it goes well and is still good on fuel.

Before listening to anyone else here

1. Was the test carried out properly ? IE. engine warm and WOT ?
2. please go get a LEAKDOWN test to verify exactly where you are loosing compression in that exact cylinder.

IE valves , rings , headgasket etc

then go from there

[nickk]

Before listening to anyone else here

1. Was the test carried out properly ? IE. engine warm and WOT ?
2. please go get a LEAKDOWN test to verify exactly where you are loosing compression in that exact cylinder.

IE valves , rings , headgasket etc

then go from there

Not sure if the comp test was done correctly or if the leak down was. I would assume that they (the mechanics) know what they are doing, they are from a reputable shop. It scored 80% in a leak down test on cylinder 2. The mech that did it said "I could hear the air escaping from everywhere, the rings are fcuked."

Bro you have a built B16A. You can keep running it while it's sick for a little while - just check your oil is the right colour etc.

Yeah don't get me wrong the car still drives well and pulls hard all the way to redline. It doesn't mix fluids, just eats a little oil.


I suggest either getting another bottom end for cheap (around $200) and reco'ing that
Where the fcuk can you find a short b16a for $200!? I'll buy two... ahah



RevZone does good work too.
I'm definitely going to take my car there for a tune but their prices on a rebuild are far too high.
I got quoted $1500 for machine work, just to rebuild.
Flowcraft (one of the best in the business) quoted me $700 and that is to suit a stroker kit.


Get it fixed mate. Don't go swapping your whole engine and stuff. Only upgrade your bottom if you want to, but before you put a new bottom on have that reco'd also so you know it's solid.
I'm keeping my head either way, I already have itr cams, dual valve springs and diff retainers. The head was recently reco'd.

My budget of 6k must include a built bottom end, vrs kit, a new clutch and flywheel, new engine mounts, consumables, all labour and tuning. I'm sure more things will come up while in the process of it all. Really $6k is streching it to do everything with top quality parts.

I am leaning towards a B16B at this stage, I can get a long motor with no accessories, unopened, guaranteed, less than 80,000k's for $3500. Put that in and sell off what I have.

[dougie_504]

Why do you need to build the bottom end? Do you want more power than what the stock one offers? A reco'd block makes awesome power compared to your average 20-year-old thrashed one.

Why do you need a new clutch/flywheel? If they're on their way out you can replace them while the block's out, but otherwise it might just be wasted cash.

Why do you need new engine mounts? If your current ones are stuffed fair enough. You can get D series to B series mounts for like $400 from shops like Innovative or HASport.

VRS kit isn't a bad idea, but you may as well just get a new head gasket instead. A good quality VRS kit is $400-600.

[nickk]

Yeah the whole point of the build is to get more power and to build something that can take a bit more of a beating.

New clutch and flywheel is standard when rebuilding or dropping in a new motor, unless it was recently changed. That's how I always do things.

As for engine mounts, I broke the stock one within two weeks of owning the car. Maybe it was old and brittle, or maybe I should double clutch more often when downshifting at high speeds and try not to 'chirp' 3rd LOL.

I can buy an oem vrs kit for less than 300, nothing wrong with oem seals, except for the cam seal :)

The way I see it is to do something once and do it properly, there's no point cutting corners just to save money.

If I can find a healthy B16B for a reasonable price, I'll go down that path... Less hassle
If not, it's a fresh build with mixture of oem and good quality aftermarket parts.

I don't want an 18 or 20 block because I'm not going to the effort of obtaining engineer's certs and doing it all 'by the book' so to speak.

At the end of the day, it's my daily, so as long as it can take a thrashing I'll be more than happy.

[dougie_504]

Fair enough.

Where can you get an OEM VRS kit for $300? I want to know for my build.

[nickk]

depends how long u wanna wait, jdm concept have them for about $300-$330 shipped from memory, they in nsw. Can get cheaper off a mate of mine. Where can you get the b16a blocks for $200 from lol?

[dougie_504]

Have seen them for sale in the private sales section, as low as $130 (probably without internals, of course). I reckon I can find one locally and maybe stock internals also if you want me to try.