madisonRX7

Has anyone ever heard of one of those long bolts that holds the engine stack together coming loose? One of the upper driver side bolts on my engine is totally backed out. It would fall on the ground if the flywheel were not in the way.

I was lucky to notice it when I removed the little sheet metal cover on top of the engine between the engine and trans. I could barely see it in there, and obviously I can't get access to it. I've been chasing a small coolant leak that seems to be coming from between the engine and trans. Could this be the cause?

Most importantly, can I just tighten that bolt? Or does the engine need to be rebuilt now?

Thanks a lot,
-Andre

1990 RX7 GTU red 70k miles, intake, exhaust, wheels, rebuilt trans
Many MCSCC "track records" for CStock RX7

tinvestor

Have not seen that one. wait for an answer from one of the big dogs. However I think the least amount of work that could be done is to losen all 18 and retorque them in the appropriate order.

rx7se88

im pretty sure thats where your coolant leak is from...when i tore apart my engine i had a little bit of coolant left in the engine and it leaked out of those bolts as i took them out

RETed

Hope it didn't snap...
Has the even been overreved or abused?
This can cause the tension bolts to back out.

Also, has the engine been rebuilt?
Poor rebuild would explain it also.

Yes, majority of the tension bolts also close up coolant passages, so your coolant leak is most likely from the loose tension bolt.


-Ted

tinvestor

Ted is it possible to just tighten one or would the safe bet be to back them out and retorque all?

RETed

If possible, I would remove it, replace the "stat-o-seal" underneath, and then put it back.

Don't redo any of the others unless they are leaking.

The stat-o-seal is a one-use sealing washer.
Once you break the seal, there is no guarantee it'll reseal.


-Ted

drago86

Its most likly snaped,..

Boostmaniac

That would be quite impressive.

drago86

It's quite common in aircraft. Sustained highish rpm creates a harmonic vibration in the bolts because they are only supported on teh two ends, breaking them off at the threads. There are special competition tension bolts with rubber sleeve in the middle to stop this but they are $$$. Alot of people either use a carefully selected piece of tubing, or heatsink, or even just a spiril bead of silicon on the midle of the bolt to stop this.

drago86

http://fc3spro.com/TECH/HOF/hof.html


^ ted's sheared e-shaft is much much more impressive.

HeffBoost

^That's great. It must have really been wound up when it lost it's oil.

Turblown

iTrader: (12)

Thats one of the reasons the " racers " buy studs from us..

HAILERS

First gain access and try to screw the thing in to see if it sheared or not. Sheared....remove engine and take it apart.

madisonRX7

Thanks to all of you for your helpful comments!

I haven't taken it apart yet. I'll let you know what I find.

Thanks again.