jderimig

Going to try and remove the triplesquare bolt tonight. I set the engine at 90 BTDC and installed the flywheel lock to avoid a valve piston collision if I slip the wrench on the collar.

But I was thinking....why not leave the belt on and remove the flywheel lock during this operation? Then there would be no risk of a valve collision if I slip. Once and if the bolt is cracked then I can rotate back to TDC and install the lock.

V2Rocket

I really doubt you'd be able to bend a 944 valve by hand force, even multiplied through a breaker bar.
Done a lot of these, never give it a thought about cam slip. 32mm or 1.25" wrench on the "collar nut", whack the triple-square into place with a hammer a few times, long breaker bar with a good stable grip and start cursing.
A helper to counterhold the 32mm/1.25" wrench is really nice though.

jderimig

Thanks Spencer, last time I tried this, 7 years ago, I couldn't budge it, but I didn't have a buddy around, had one hand on the wrench and other on the triplesquare, even tried a electric impact wrench. I slipped once and freaked and gave up, but car runs fine with good compression after the event.

There is a TINY (I mean tiny) bit of play between my triplehead bit and the bolt with the driver I have.

StoogeMoe

You have about a 30% chance of getting that bolt out. Be prepared to drill it out. It's not that big of a deal.

Otto Mechanic

Maybe I don't understand the proposal? Leave the belt on since it will arrest motion of the crankshaft, then remove the flywheel lock, which arrests the crankshaft?

Why place the flywheel lock at all? Just rotate the crank to TDC, figure you won't put too much torque on the cam, and go for broke?

The lock needs to be in place to remove the crank bolt. It needs to remain in place until that bolt is replaced. Near as I can tell, it's more work to remove the lock, then replace it, than it is to leave it there.

Scott.

Otto Mechanic

The crankshaft bolt? Drilling it out would most likely destroy the crankshaft? You mean the camshaft bolt?

I must have missed part of this. The cheeshead (triple-square) bolt on my cam came right out. No arguments. Came out willingly and with a certain reserved glee. You can counter hold the cam bolt.

The crank bolt on the other hand was a true cast iron daughter of a newt.

Scott.

jderimig

I have seen some suggest to rotate 90deg BTDC (to move pistons away from valves) and install the flywheel lock to allow the timing belt to help (in addition to the collar wrench) hold the camshaft sprocket while torquing the cheesehead.

V2Rocket

I think the likelihood of stripping the cheesehead depends on how the last person put the bolt in (impact gun?) and how the current mechanic seats the tool.
I've never stripped one, they can be a bitch to get out but they always unscrew. Never had to drill one yet.

Really, make sure the tool is seated, give it 5-6 good whacks with a metal hammer, this will also "shock" the threads of the bolts a little.

jderimig

Bolt came right off. My 24" HF breaker bar had some good flex in it but the bolt loosened with a nice CRACK!

Otto Mechanic

I strongly support Spencer's (V2 Rocket's) analysis in this example. The cam bolt should not present a problem. It may be removed using a 27mm counter hold open end wrench and the appropriate cheeshead (triple square, 12 point) tool.

This is hardly rocket science. But it really is, isn't it? It really is rocket science. And that, in a nutshell, is why we do it.

Welcome aboard.

Seriously,
Scott.

jderimig

Actually I have rocket experience also. Rockets are easier.

Otto Mechanic

Sandbagger!

I'm also a former rocket scientist and have no excuse...

V2Rocket

this is perverted German science...