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Eccentric shaft end play

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Old 02-09-17, 07:29 AM
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Eccentric shaft end play

So I recently bought a large street port S4 T2 engine that had cracked a rear iron while on the dyno. I had the engine take apart, inspected and the rear iron replaced. Everything else was okay. This was sort of a rush job as I had to make it to track the weekend after. The engine runs great and I have no issues with it at stock boost.

My concern is that when we measured the E shaft end play, it was just barely out. Spec is 0.04mm to 0.07mm and mine was measured at 0.074mm. Should I be concerned? I want to raise boost to 12psi but don't want to at the expense of another engine. The rotor housings on this engine are pretty much brand new.

thanks for your time fellas!
Old 02-11-17, 10:47 AM
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Did you take this measurement during assembly?

That is only barely out of spec, but it won't ever get tighter from there, only looser. Will probably run for YEARS like that however with zero consequence. Likely forever.

If it was me and I had just gone through all the work to assemble everything in the engine bay, I'd just leave it and wait for a weekend when I was very bored and could go in there and replace the bearings and spacer.
Old 02-11-17, 11:07 AM
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If the clutch doesn't chatter, who cares?
Old 02-11-17, 12:19 PM
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the measurement you get depends how you measure it, if you were using a big prybar and were .004mm on the loose end, i think its fine. if you were just pulling it by hand and its out by .004mm it is more worth looking into, but i still wouldn't be in a hurry.

its freeplay, literally, so if you're using a big prybar, you're going to get a bigger measurement, than if you just go by hand.
Old 02-11-17, 12:21 PM
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i probably wouldn't worry too much about it, though it could be a sign that the thrust plate is shedding.
Old 02-11-17, 10:23 PM
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Originally Posted by Aaron Cake
Did you take this measurement during assembly?

That is only barely out of spec, but it won't ever get tighter from there, only looser. Will probably run for YEARS like that however with zero consequence. Likely forever.

If it was me and I had just gone through all the work to assemble everything in the engine bay, I'd just leave it and wait for a weekend when I was very bored and could go in there and replace the bearings and spacer.
Correct, measured during assembly. Replaced the rear iron, that's it. I figured that whoever rebuilt the engine set the endplay already but there's so many opinions on end play that I wasn't sure what to think of it. I guess some people like it on the tighter end and some people like it on the looser end.

I may do just that actually, probably when I have the car painted, might as well do the engine bay too.

Originally Posted by peejay
If the clutch doesn't chatter, who cares?
Doesn't chatter! Looks like I'm in the clear, haha

Originally Posted by j9fd3s
the measurement you get depends how you measure it, if you were using a big prybar and were .004mm on the loose end, i think its fine. if you were just pulling it by hand and its out by .004mm it is more worth looking into, but i still wouldn't be in a hurry.

its freeplay, literally, so if you're using a big prybar, you're going to get a bigger measurement, than if you just go by hand.
18" pry bar with moderate pressure. Was pretty consistent with the pressure and got 0.074mm three times in a row.

I figured it wouldn't matter much but again, there's so many opinions on end play that I wasn't sure what to think of it. I guess some people like it on the tighter end and some people like it on the looser end.

Originally Posted by RotaryEvolution
i probably wouldn't worry too much about it, though it could be a sign that the thrust plate is shedding.
Will do, gonna check it next time I have the engine out!

Thanks for the replies fellas, now I can sleep soundly at night




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