they're taking my engine apart again!!!!!

[Boosted]

Forgot to add, I hope the collets are seated properly

[kismetcapitan]

so did I, and everything else checked out. I ran in the engine at 9000rpm. So I imagine if there were other gremlins, surely they would have shown up at 9000rpm and 1.8 bar boost?

It was an "intentional" error - where the pins were specifically sized to 0.001mm clearance. They were measured, because they were custom made and balanced! What he didn't know until after the engine was built was that that clearance is too big for an HKS piston, due to the expansion characteristics of the alloy that HKS uses.

He'll get it right, even if he has to buy me another engine, and the work is obviously unconditionally guaranteed - I haven't paid a dime over the original price for the build, which happens to include unlimited Dynapack time. £2000 all inclusive. Does your garage provide the same service and guarantee?

Originally Posted by Boosted

That's fair enough, but why didn't he measure all the clearances between piston and pin beforehand?

Actually, I would have thought/hoped/expected that he would have measured every single component and made sure it was all spot on before any rebuild was commenced anyway. After all, if he builds race engines then all that is second nature, surely.

Also, if he has made that mistake, what other gremlins are potentially lurking about?

[paul cawson]

Originally Posted by kismetcapitan

It was an "intentional" error - where the pins were specifically sized to 0.001mm clearance.

0.001= 0.000039 thou I think 0.0005 thou is a good clearance size

[kismetcapitan]

Originally Posted by paul cawson

0.001= 0.000039 thou I think 0.0005 thou is a good clearance size

the difference is indeed miniscule. I talked with him again last hour and it can't be all six pistons IMHO, because then we'd be hearing 1100 clicks per second at idle if it were one piston, and it wasn't that fast, maybe 15-20 clicks a second at 1100rpm idle. I have to take the recording of the sound and analyze it to get the exact click frequency. It could be just one piston clicking on the power stroke, all we know now is that it's from the rear of the engine, #6 probably (it's always that damned sixth cylinder causing mayhem ). If it's one cylinder clicking only on one particular stroke the recording should have 46 clicks per second.

So it may not be all the pins after all, or maybe one is shifting around. We won't know until the engine is apart and they get measured. It's true that they were not measured when they redid my head; they were focused on measuring all the shells to insure they were still within the clearances they wanted.

[kismetcapitan]

Originally Posted by Boosted

Forgot to add, I hope the collets are seated properly

which collets?

[tweenierob]

Originally Posted by kismetcapitan

He'll get it right, even if he has to buy me another engine, and the work is obviously unconditionally guaranteed - I haven't paid a dime over the original price for the build, which happens to include unlimited Dynapack time. £2000 all inclusive. Does your garage provide the same service and guarantee?

I really hate to say this Toby, whereas i may not include unlimited dyno time.
I do read all of your threads and ask the same question, if your engine builder is so maticulous (sp) why the **** is your engine apart again dude.
It sounds very much to me like he has some good tools which looks nice to you when you see what he is up to, but on the flip side he is missing out some of the less specialist procedures which means less seat time for you.

Something isnt right

Rob

[kismetcapitan]

yep, hard pill to swallow, but it's really the only quality game in town. I think the idler failure was just outright bad luck, and I've run my car hard and finished mapping it, yet that ticking sound means that something was overlooked.

[GarethK]

When he says 0.001mm 'undersize', what is he talking about exactly?

Standard pistons have a bore of 20.987/20.993 which is a tolerance band of 6um. The pin is 20.989/20.995, again 6um. This means the resultant fit can be from 8um interference to 4um clear.

I don't know the exact tolerances for HKS pistons, but 1um is not enough to suddenly cause a problem if all other parts are within tolerance.

When you say the difference between what you are Paul Cawson are saying is miniscule, it is 10x the tolerance! Assuming Paul, that by '0.0005 thou' you mean 0.5thou as in 0.0005 inch. 0.0005 thou is not even measurable with normal equipment.

My point is 0.001mm is a very small amount, no matter how accurately someone wants to claim they work. Measurements of the same sample piece will go up and down 0.001mm or more without serious temperature control and expensive equipment.

You might want to ask exactly what the 0.001mm is that he's talking about - what is the mating tolerance etc before taking you whole engine apart for some measurement that is 1/12th of the standard fit band!

[kismetcapitan]

maybe he meant 0.01mm, there have been a lot of translation errors. From the sound, it's definitely one (not all six) of the reciprocating mechanisms. I'll find out more tomorrow when they've finished the teardown.

I think I'm cursed, the R34 he built ran sweet as a nut from the get go and two years later is still running strong. But that's one possible source of error - his FSM is for the R34, my engine is a mix of R32, R33, and R34 bits. Theoretically the basic longblock of the RB26 hadn't changed, but now I'm not so sure.

[paul cawson]

Originally Posted by GarethK

When he says 0.001mm 'undersize', what is he talking about exactly?

Assuming Paul, that by '0.0005 thou' you mean 0.5thou as in 0.0005 inch. 0.0005 thou is not even measurable with normal equipment.

Yes a sensible clearance for a piston pin is 0.0005 inch, I was pointing out 0.001mm = 0.000039 thou which most shops would not be able to machine to.

[kismetcapitan]

so he wasn't too far off by doing a 0.00039" clearance. Why he's second-guessing that now, I don't know.

The night before I visited the shop, I finally ticked off a good launch and logged 0-160kph in 7.41 seconds, the 0-100kph mark coming in at 3.44 seconds. That's on 100% pump gas, I haven't even gotten into mapping the ignition for toluene, which I hope bumps the 0-160kph time down a tenth or two, maybe a little more if I raise the boost another 0.15bar, assuming I can get another sub-3.5 second launch. This is definitely a car worth being patient for, although it is a long suffering process.