Engine/Transmission (1994 - 1998) Loss of boost after head gasket replacement

[Matthug]

I just don't see how . 020'' thicker headgasket can drop compression a full point. I know I'm used to working with gas engines all my life before this, and I know diesel's have like no combustion chamber so that makes a difference... . but I just can't see it. I'm pretty tired after working a 12 hour day so I don't feel like doing all the math, can someone post up the compression equation with numbers in there?

 

[Matthug]

OK I stopped being lazy and did the math. It is true, . 020'' thicker headgasket lowers compression a full point, and it is because of the fact that there isn't much of a combustion chamber volume. I stand corrected!

 

[JRS]

Spoke with the service advisor at Cummins. He swears they didn't adjust/tweak anything. The guy at TST suggested I check everything they would have removed to get the head off.

 

[Matthug]

Does it say what the part number head gasket they used in the bill?

 

[JRS]

Not that I could find

 

[JRS]

Still no luck, here's what I've tried so far:



1) re-adjusted and re-alinged all the intercooler boots and other intake track clamps

2) Multiple (15) pressure-up's of the intake track, including soaping everything down.

3) Checked the spring height on my brand new overflow valve (spot on)

4) changed the fuel filter (old one only had 3k miles)

5) changed the pre-filter

6) changed the air filter (old one only had 5k miles on it)

7) checked the boost gauge and tubing for leaks

8) checked and soaped the poly line running from the AFC to the head



Any other ideas?



Nothing has made a bit of difference. I called a local tuner and he recommended just pushing the TST plate more forward to make up for the lost boost.

 

[JRS]

Finally found the problem, wastegate was opening up too soon. ordered a new one from Banks.