Stock B20VTEC, danger inTorquing ARP ROD BOLTS and Revving to 8000rpm on stok block

[Chr1s]

Sam have you had overheating issues with your b20?

I've never seen a b20 yet thats run hot, unless the obvious with lack of water and shit working cooling system lol

[GSi_PSi]

Never had overheating issues, but without a breather setup the car would lose a bit of performance after giving it for a good hour or so

[tinkerbell]

wondering are there any dangers of torqueing arp rod bolts to the stock rods?.
How many people have managed to do this without any issues?

to add my experience to the extensive survey of people who have actually done it.

whilst knowing the risk, I have installed ARP rod bolts in two B20VTECs without checking for warpage of the big-end ID...

and after many hundreds of circuit racing laps, I am happy to say there did not appear to be any detrimental effects…

hence, in relation to installing ARP rod bolts without removing and checking the big-ends, I would suggest that you can probably "get away with it", but that is your own risk.

[GSi_PSi]

but the question is what is worse? and what is more likely to cause engine failure ?
Revving the b20 completly stock to 8000rpm or installing rod bolts in the block

[tinkerbell]

well, in my experience:

1. the bottomends were fine (no rod bearing issues)
2. i didnt throw a rod due to rod bolt stretch/failure

and

3. by not removing my rods & pistons i didnt have to worry about installing new rings and bearings (plus the added costs) and the issues that might be associated with new rings & bearings...

but again - it was a risk to not check the distortion potentially caused by the different rodbolts....

[JS2k]

The last of your worries are the conrod bolts when your revving an engine to 8k, only forced induction applications require ARP rod bolts etc

I can assure you Honda Engineers test these engines to extremes, much better that what you can

[Chr1s]

Funny you say that, naturally aspirated engines put more stress on rod bolts and rods.

Honda engineers also test their engines extensively, but only for what they are designed for. The B20/18 motors wern't designed to see 8000rpm onwards, they may be able to handle it no problem, they may not, nobody here obviously knows enough to put some hard fast facts down and Honda more than likely didn't test for it either. I personally think that standard rod bolts will be fine in stockish cam configurations.

[tinkerbell]

I can assure you Honda Engineers test these engines to extremes, much better that what you can

so Honda tested the B20B's to rev past 8000rpm for extended periods? wow, that is interesting information! what is your source?

[JS2k]

Tinkerbell and Chr1s - can you please show where i mention that Honda has tested these engines at extended periods at over 8000rpm??

What i said is Honda and other manufacturers do test there engines extensively at extremes, additionally manufacturers rev limit is normally a safe guard for the engine not a absolute maximum!!

I hope you didnt think Honda would hope nobody ever revved a B series engine above its limits and just hoped for the best! everything is manufactured with a safety net involved

I dare say, a decent set of conrod bolts is important in a engine rebuild for HP applications, although turbocharged or forced induction methods create more stress on the conrods and bolts than what an NA application would , but then again what would i know i have only been building engines for 15 years

We all have different opinions and ways of building engines, as good practice i would replace the mains and conrod bolts with new OEM items

anyways i wont get into this argument any longer, just my two cents

[GSi_PSi]

I dont think you understand that a B20's stock rev limit is 6500rpm, the engine was not designed to be constantly reach rpms of 8000rpm so they used D series 1.2L to 1.6 Litre rod bolts into the engine as it was the most practical to the cost/benefit analysis, and many people when first building B20's in the states have concluded that the rod bolt was the culprit of many blown engines. I can see the problem is you probably haven't come across or know anything about B20 Frankenstein or what is needed in building them so your probably just generalizing that most non turbo applications are safe without aftermarket rod bolts and you would most likely need them in forced induction applications, were most of the engine internals need to be forged or can withstand much more pressure

[Chr1s]

Well, this is a forum and everybody is open to an opinion, so here's mine.

In a forced induction motor, you have a condition where the engine is always under positive pressure. In a naturally aspirated engine, we often find a vacuum or an atmospheric condition present depending on how efficient the motor is.

So what? Well think of the process the rods and rod bolts see, the changing ingress of stresses is what i'm talking about in particular; Tension and compression.

Compression occurs when the piston is "pushing" down on the rod, this induces stress in the rod near the wrist pin, this kind of stress will lead to a bending type of failure. There is no stress on the rod bolts at this point, if anything, this is where the importance of oil pressure between the bearing and journal is needed to avoid contact. For an increase in BMEP (power) there is the requirement for an increase in oil pressure. But this is another story.

Tension occurs as the piston is "pulling" on the rod and peaks in stress when the crank changes direction, imagine sprinting as fast as you can and then stopping and trying to change direction as fast as you can, the inertia would be huge. As mentioned earlier, a failure at this point would typically yield a rod split in two. What has rod bolts got to do with this stress? Well when the rod is under tensile stress, the bottom half of the rod cap is resisting this force due to the oil pressure again between the bearing and the journal. This resistant force is transmitted to the rod bolts which results in, you guessed it, tensile stress. Now we've realised that this kind of motion isn't present on the compression stroke, hence the term compression, the rod is subject to compressive stress, when the power stroke is occuring, the compressive stress is releived and the rod is in a happy state, so this rules HP out of the equation for stresses implied on rod bolts. Obviously the rod has to have a suitable second moment of inertia to sustain large compressive stresses. Although I will guarantee you that the tensile stress acting on the rod is much greater than the compressive.

It should be common sense now to see how a rod is affected now by the greater pressure differential as it sweeps from TDC on the intake stroke (overlap, MAP, tensile) in a naturally aspirated motor.

Why HP has nothing to do with how strong a rod bolt is? Because the tensile stress present on the rod bolt is what kills them, and the faster you spin the engine, the greater this becomes. THIS is why I say, RPM kills rod bolts.

Generally speaking, higher HP engines require a greater RPM to make this higher HP, this is why items fail in this manner and people just resort to "oh it's because of the power" mentality. Remember your simple Physics.

Oh by the way, you may have been building engines for the past 15 years, which no offense, means jack all to most educated people, although keep in mind you might be talking to an ex F1 engine developer one day.

[tinkerbell]

Tinkerbell and Chr1s - can you please show where i mention that Honda has tested these engines at extended periods at over 8000rpm??

well, right here:

I can assure you Honda Engineers test these engines to extremes

got a dictionary handy?

A S S U R E

–verb (used with object), -sured, -sur·ing.
1.
to declare earnestly to; inform or tell positively; state with confidence to: She assured us that everything would turn out all right.
2.
to cause to know surely; reassure: He assured himself that no one was left on the bus.
3.
to pledge or promise; give surety of; guarantee: He was assured a job in the spring.
4.
to make (a future event) sure; ensure: This contract assures the company's profit this month.
5.
to secure or confirm; render safe or stable: to assure a person's position.
6.
to give confidence to; encourage.

http://dictionary.reference.com/browse/assure

T E S T

–noun
1.
the means by which the presence, quality, or genuineness of anything is determined; a means of trial.
2.
the trial of the quality of something: to put to the test.
3.
a particular process or method for trying or assessing.
4.
a set of questions, problems, or the like, used as a means of evaluating the abilities, aptitudes, skills, or performance of an individual or group; examination.
5.
Psychology . a set of standardized questions, problems, or tasks designed to elicit responses for use in measuring the traits, capacities, or achievements of an individual.
6.
Chemistry .
a.
the process of identifying or detecting the presence of a constituent of a substance, or of determining the nature of a substance, commonly by the addition of a reagent.
b.
the reagent used.
c.
an indication or evidence of the presence of a constituent, or of the nature of a substance, obtained by such means.
7.
an oath or other confirmation of one's loyalty, religious beliefs, etc.

http://dictionary.reference.com/browse/test

E X T R E M E

–adjective
1.
of a character or kind farthest removed from the ordinary or average: extreme measures.
2.
utmost or exceedingly great in degree: extreme joy.
3.
farthest from the center or middle; outermost; endmost: the extreme limits of a town.
4.
farthest, utmost, or very far in any direction: an object at the extreme point of vision.
5.
exceeding the bounds of moderation: extreme fashions.
6.
going to the utmost or very great lengths in action, habit, opinion, etc.: an extreme conservative.
7.
last or final: extreme hopes.
8.
Chiefly Sports . extremely dangerous or difficult: extreme skiing.

http://dictionary.reference.com/browse/extreme


so yeah, whatever, and particularly in the context of a B20/VTEC hybrid engine - maybe you just need to keep in check your use of words? which might be easily misinterpreted?