compression results

[polobai]

here they are-i thought i hada bhg for sure, but i guess maybe not?
1-175psi
2-170psi
3-167psi
4-170psi
5-167psi
6-173psi

they all seem good, the test was done with no spark plugs in and throttle @ 100% what do you guys think, the #s seem like a normal healthy engine right?

 

[Bishop92t]

Looks healthy.

 

[polobai]

ya thats what i figured, if there was a bhg, the #s for some cylinders would be a good bit different than the others in the other cylinders correct?

 

[TONY!]

I never believed that a compression test was the ideal way to check for BHGs. It can't diagnose intermittent BHGs at all, which is how most of them start in the first place!

...Temperature spikes with the temperature gauge are an indication of an intermittent leak. This is a leak that happens on & off. As hot combustion gasses leak into the system, the gauge will read the scorching combustion gasses leaking from the cylinders. Being that the gas is hotter than the temperature of the coolant, you will see the gauge skyrocket towards HOT. If you let off of the gas, you will notice that the temperature will decrease since little pressure & combustion occur at closed throttle.

Some do test this leak with a compression tester as well. Keep in mind that a leak may not show up until higher pressures occur, such as the pressures that are produced with combustion. Keep in mind: combustion pressure>>>>>compression pressure...

IF you like what you just read, here's more: http://supramania.com/forums/showthread.php?t=251
It was an attempt to reduce the repetitive "do I have a BHG!?" threads a bit.

 

[souprat]

my numbers were 180, 180, 182, 179, 180, and 181. but then i pulled the heads and i had a slight BHG. do a coolant leakdown test.

 

[polobai]

thanks guys for the replys, i am going to napa tommorow to get a block tester to see if there are any gases in the coolant to make sure. tony, i already checked that thread, it has some great info-but i figured compression check would let me know if the leak was really bad or not. im going to find out for sure tommorow when i pick up the block tester, i have a feeling that the results are going to come back with a bhg though. :icon_frow thanks again guys!

 

[IJ.]

I agree with the guys the head while running/boosting can and does move around quite a bit!

The coolant test that checks for hydrocarbons/gases in the cooling system would be a good early warning system.

 

[polobai]

i just did the block test from napa, and i believe the test came back with a leak. the fluid in the bottle was originally blue, and the instructions say that if the fluid turns yellow, then there is a leak, but if the fluid says blue, then there is no leak. my fluid turned green-so what does that mean its a slight leak? anyways, i think imma pull the head and do the machine work and replacethe gasket. man, i guess the mghs can blow after all even when torqued down properly- i guess the machine work was not up to par. thanks for the help guys!