Yet Another 3.0 Head Gasket Thread

[andrewwynn]

I had similar happen in aluminum block push mower. I bumped up from 1/4 to 5/16" bolt.

I would use a helicoil and I would do it without removing and replace the chain cover.

10 N·m maths out to just shy of 2000# clamp force. The block just age/heat cycle weakened and couldn't handle the force anymore.

[ahlem]

I'd do it without changing the cover as well.
I have used copper spray gasket sealer in similar situations on other motors very successfully, especially when everything is new and you just decided to double check something so you could sleep at night.

[Russianblue]

that's the plan. plenty of M6 1.0 heli-coil kits available locally. still doesn't help with the gasket though. I gotta figure that out...whether I'm good re-using the brand new one that's been torqued down once. I really don't want to do all this and end up with a drip drip drip.

[Russianblue]

Originally Posted by andrewwynn

I had similar happen in aluminum block push mower. I bumped up from 1/4 to 5/16" bolt.

I would use a helicoil and I would do it without removing and replace the chain cover.

10 N·m maths out to just shy of 2000# clamp force. The block just age/heat cycle weakened and couldn't handle the force anymore.

you think i can get the helicoil tool in that far?

https://www.autozone.com/test-scan-a...tem/516472_0_0

the original bolt was 62mm. i'll go to the store and take a look. i'd love to be able to do it with the cover still on.

[andrewwynn]

I think the donut is just for setting the depth.

Most of the bolt holes on the m62 I've worked on were much bigger than 6mm so I would not have a problem either using helicoil or tapping to a bigger size. Like mentioned I've used 5/16 in place of 1/4 in S.A.E. that would mean 8mm in metric.

10 N·m on an m8-1.0 will get you just about identical clamping force

[Russianblue]

Well, I probably overthought that one. The heli-coil fix worked great. Hell of a lot less trouble than timeserts. The only issue was trying to judge the depth. I didn't want to drill too deep into the block because I believe I could have (theoreticall anyway) pierced the water jacket on CYL 1. As with anything else, the first time takes a long time. if this happened again it would be a 20 minute detour rather than a day of research.

Got the Jesus bolt on with the timing pin, 1/2 breaker, 4 foot cheater (jack handle), a piece of webbing (to pull on at the designated mark) and a luggage scale. Then for good measure I hit it lightly a couple of times with the stubby impact and that Jumbo harmonic balancer socket (which is strangely satisfying to use for some reason). It's in the 300-330 range. Good enough for government work.

With that buttoned up, it looks like I'll be making a go at lowering the head on today. If his schedule works out, our very own OVERBOOST has tentatively agreed to drive over and give me a hand.

Trying to remember all the stuff on the head that might be easier to install/arrange before it goes on. All those O2 sensor wires etc. I'm sure I will forget something.

[Overboost]

Running the Karmann Ghia over to Cars and Coffee here at the lake early this AM for about an hour. I am available from 10:00.

[Russianblue]

I thought I would report it here first. The head is ON, torqued and holding fast!

Overboost came over and after surviving a incident involving the hood crashing on his head, he expertly assisted me in lowering the head in. I absolutely could NOT have done this without his help. So...three (cheers or) beers for Overboost!! He's also one of those folks who is like "we hit a snag, no big...we'll figure something out!" That was helpful when we were having trouble getting the gasket to sit flat due to the fact that I had buggered an alignment dowel. That is a TIGHT, precision fit into the gasket. And I couldn't get the dowel to pass thru the gasket. It was EVERY SO SLIGHTLY out of round and had a small burr on it. Ultimately I took the dowel and the gasket to the workbench and used a rubber mallet to tap the dowel thru. I hope we didn't scar up black seals on the gasket too badly. it had a couple of marks but was still in tact.

I have come to the conclusion that there is no possible way to do this (at home, with the exhaust attached) without incurring a bit of risk to the head, block and head gasket. it's just too heavy and unwieldy, engine bar or crane notwithstanding. I cut a custom piece of wood to serve as a guard, and it did a good job. But who knows, there could be some sawdust or splinters in the combustion chamber. There may be an aluminum shard or two or three in the engine somewhere from the heli-coil and timesert process. I may have nicked the cyl head surface when we were lowering it on the dowels. The cats were rammed against the block dozens of times trying to wedge them in. Hopefully my piece of wood did it's job. Impossible to say really. You just can't SEE anything.

As much as I would like every single part of this to be clean-room precise...it's not. I can only hope (and do think) that given the successes of some people on this board and elsewhere, that there IS some room for error. I suppose we will find out in the not so far off future.

Here's my luggage scale 'damn near tree hunnid' torque wrench - btw, I would be PERFECTLY happy using the flywheel pin again for this. it was rock solid. I think the torque on this bolt is a little bit less than some other engines where it deforms the pin and/our housing.


This was actually a trial run. I strapped it a bit differently this morning.


All torqued up with no place to go!

[Overboost]

A second set of eyes knows we never scuffed or marked either surface or the gasket for that matter. It was a clean, methodical cylinder head mount with zero issues. Nobody could have done it better, well done Paul.

[oldskewel]

Congrats on the progress.

On the crank bolt - I think the way you did it was the safest = super-short impact wrench for removal, without using the alignment pin, considering the bolt may be really stuck and requiring a ship ton of torque. Then for reassembly, the alignment pin should be expected to not need a ridiculous amount, just the spec., and held just fine.

On the pics - I see the camshafts are still out. It might have been easier to put those in on the workbench. Did you change the valve stem seals? These M54s don't have the seal problems the V8s do, but I found mine to be pretty hard at 186k miles, so replaced them.