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Author Topic: Effect of A Too Thick Head Gasket??  (Read 594 times)

April 05, 2018, 10:47:52 am

thomas m

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Effect of A Too Thick Head Gasket??
« on: April 05, 2018, 10:47:52 am »
Re: 1.6 Non-Turbo Diesel

Does anyone have an idea of how much putting the wrong size (too thick) head gasket in place would effect the compression? Some commentary has suggested that a hasty mechanic could do that to expedite the job.

For this hypothetical, let's say that the correct size would be the "two hole" thick gasket. So, instead, a "three hole" is installed.

Apparently, it would run, but would it be noticeable to a non-performance driver???

« Last Edit: April 05, 2018, 10:51:24 am by thomas m »

Thomas, Original owner since new:
1991 MK2 Jetta Non-turbo 1.6 diesel, Engine Code ME, 5 speed 020 AWY 04120 transmission, Hydraulic Lifters,
310,000 miles
Location: Vancouver, WA

Reply #1April 05, 2018, 01:16:45 pm


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Re: Effect of A Too Thick Head Gasket??
« Reply #1 on: April 05, 2018, 01:16:45 pm »
Thomas M,

I very much doubt that a non-performance driver would notice any difference with a thicker gasket.  It might sound a little less like a diesel but the compression on those last few millimeters won't change much.  Now that is assuming that you have also changed the rings to be sure that all the compression is above the cylinder anyway.  But how many do that when they blow a gasket?  Most of us are more interested in getting it back to a running condition and it is only if we see cylinder scoring, have a huge carbon ridge on the top of the cylinder or note other problems with the pistons that we are tearing into it farther.

Look at the difference in thickness between the two gaskets you mentioned.  A two holer for anything after 1981 is 1.50 mm and a 3 holer is 1.6mm  Not a lot of volume involved with a cylinder that is as round as the piston but only .1 mm high. I have no idea if that equates to 2 or 5 or 10 or more PSI change in pressure. 

Sometimes it is suggested to change the gasket if it is hard to start but I think that is an excessive recommendation as there are other easier ways to get the hard start problem fixed.  Like bump the timing a few mm instead. 
Now Own 1981 Caddy as the NEW DISTRACTION to all that is around me.  Project Away!


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