possible diesel head gasket failures

[handedyourhat]

I was workin on my build tonight and noticed a very important flaw that VW probably overlooked, and I dont know if anyone knows about this ? if you install your 1.6L stock turbo cast iron exhaust manifold on the studs on the head and center them (because the holes in the manifold are larger than the studs) and you torque the manifold nuts you will notice that the very bottom of the exhaust mounting surface on #1 and #4 ports are below the head face surface .... I now placed my cylinder head assembly on my block and noticed that the cylinder head is pivoting on #1 and #4 exhaust flandges.... :shock:  :shock:  :shock: . the head is actually sitting above the block with no head gasket in place about 1/8" :shock:  can you just imagine what would happen if you install the exhaust manifold more towards the head gasket surface and tighten the manifold nut, I bet you would be closer to 3/16" below the head surface...
I will have to take a grinder to the bottom of the exhaust flanges on #1 and #4 to correct this very over- looked and important VW problem...
just a little something to measure  the next time you rebuild your head off the engine ......who knows maybee this is why the head gasket failures occur ? :roll:  :roll:


Dan

[dillenger1]

Im not understanding what your saying.

[Turbinepowered]

I think he's saying he's been blowing headgaskets because the exhaust flanges on the manifold are long enough that they're keeping his head from sitting flat on the block.

Solution to this being, in his case, taking a grinder to the #1 and #4 flanges until they don't interfere anymore.

[jtanguay]

interesting... then wouldn't the head gasket blow early right from factory???  perhaps there needs to be a certain sequence such as install head, torque down, then install manifold, torque down?

[arb]

interesting... then wouldn't the head gasket blow early right from factory???  perhaps there needs to be a certain sequence such as install head, torque down, then install manifold, torque down?

That's how I've done every engine I've built... Never had this problem.

[Smokey Eddy]

I've always put the head on with the manifolds and turbo already on it. Maybe that is why my last HG only lasted a few months...  :roll:
I too will grind my manifold. 3/16ths you say?

[handedyourhat]

ya I would install the manifold on the head with a couple of nuts and put a straight edge on the head gasket surface and you will see the interferance between the straight edge and the manifold ....

Dan

[AudiVWguy]

This has to do with thousands of heating and cooling cycles on the exhaust manifold, some will warp over time. The Audi 5 cyl turbo had a lot of problems with this until they went to a two piece manifold. The 1 and 5 exhaust studs would pull themselves out of the head. (Don't ask me how I know this :cry: )
-JB