metal head gasket thickness.
- Thread starter ronniek
- Start date
the deck hasn't been touched and cylinder head has just been skimmed.
I put in titan metal head gasket coated with copper cement ,but i still put low compression.Average 120 psi.
I have heard that cometic head gasket might be better.Is this a metal head gasket and what makes it a better gasket.
Ronnie.
I put in titan metal head gasket coated with copper cement ,but i still put low compression.Average 120 psi.
I have heard that cometic head gasket might be better.Is this a metal head gasket and what makes it a better gasket.
Ronnie.
Did you have a valve job done while head was off???
How many miles on the bottom end??? That's low compression you've got there. :icon_conf
How many miles on the bottom end??? That's low compression you've got there. :icon_conf
what is the bore diameter of your HG? When selecting a HG you should measure all parameters of your engine. You cant really go by what somebody else used...
like p5150 said, there are a number of factors that can make a differance. I have a titan on mine and have no problem. on thing though, did you remove the one side rivet form the gasket? the rivet could be your problem. I dont know if Titan had the design changed to move the rivet out further so that it is not inbetween the head and block. but either which way, there could be a number of other things that can contribute to the problem. You should really do a leak down test and not a compression test to determine what or where the problem is.
head gasket is 86mm bore,which is correct.Also I had a 1.2mm hks gasket for 5 years and it started leaking a month ago.The coolant grooves on cylinder head had corroded to thr combustion ring area.The hks gasket was still intact.
That was with no. 6 cylinder and I had good compression on all other cylinders.So I am thinking that the bottom end should be ok.it has done just over 100,000 kms.
I did get the valve job done.
thanks for info on rivet,I will have a look.
Ronnie.
That was with no. 6 cylinder and I had good compression on all other cylinders.So I am thinking that the bottom end should be ok.it has done just over 100,000 kms.
I did get the valve job done.
thanks for info on rivet,I will have a look.
Ronnie.
Finally I sorted out why My car had low compression.I bought a compressor and did a leakdown test and found air leaked from all intake ports and 3 of exhaust ports.I also removed a rivet from one of the titan head-gasket.
Hopefully by next week,the supra will be back on the road.
Ronnie.
Hopefully by next week,the supra will be back on the road.
Ronnie.
You need a leakdown tester and a air compressor. The leakdown tester can be picked up at any Napa or Snap-on dealer. They are not to badly priced. If I recall, mine was around $60 at Napa....
They are fairly simple to use. They are a unit that is a block with 2 gauges on it. One is the in or test pressure. the other is a precentage gauge representing the lose of pressure within the tested cylinder. The unit has 2 hook-ups on it. one is the compressor hook up and the other is just like a compression tester hook-up and threads into the spark plug hole just as the compression tester. To use, you turn the motor over to TDC compression stroke for the cylinder that you are testing. hook the unit up to that cylinder and hook up your shop air. Most units have an adjuster knob to set the test pressure. I usually use 100 to 120 PSI as the test pressure. If it seams like the motor is turning over, make sure that the motor is perfectly at TDC, and or lower the pressure slightly. Once hooked-up and pressurized, look at the percentage gauge and see what it is at. O to 5% is typicaly a good cylinder, 5 to 10% could use attension. Anything over 10% needs attension. If you find a cylinder that has a high % of leakdown, listen in the intake, exhaust, oil cap opening and remove the radiator cap.
Air heard from intake = leaking intake valve
Air heard from exhaust = Leaking exhaust valve
Air heard from oil cap oplening = bad rings and or problem with cylinder wall also possibly a crack in the block.
bubbles seen in radiator = leaking headgasket and or possibly a crack in the head or block
They are fairly simple to use. They are a unit that is a block with 2 gauges on it. One is the in or test pressure. the other is a precentage gauge representing the lose of pressure within the tested cylinder. The unit has 2 hook-ups on it. one is the compressor hook up and the other is just like a compression tester hook-up and threads into the spark plug hole just as the compression tester. To use, you turn the motor over to TDC compression stroke for the cylinder that you are testing. hook the unit up to that cylinder and hook up your shop air. Most units have an adjuster knob to set the test pressure. I usually use 100 to 120 PSI as the test pressure. If it seams like the motor is turning over, make sure that the motor is perfectly at TDC, and or lower the pressure slightly. Once hooked-up and pressurized, look at the percentage gauge and see what it is at. O to 5% is typicaly a good cylinder, 5 to 10% could use attension. Anything over 10% needs attension. If you find a cylinder that has a high % of leakdown, listen in the intake, exhaust, oil cap opening and remove the radiator cap.
Air heard from intake = leaking intake valve
Air heard from exhaust = Leaking exhaust valve
Air heard from oil cap oplening = bad rings and or problem with cylinder wall also possibly a crack in the block.
bubbles seen in radiator = leaking headgasket and or possibly a crack in the head or block
7M-GTE said:
here ya go, from the reference section:
http://www.supramania.com/forums/showthread.php?t=2229
-shaeff
ok just to clearify for my own info. with turbos, lower compression is better because we can run higher boost with less ping? so a 2mm gasket will lower the compression more than a 1mm gasket? is this correct?
Joel: Correct.
It all depends on the octane of the fuel you'll run.
Best combination is as much cylinder pressure as you can run without detonation.
X:1 static + XX psi boost + XXX octane you just need to juggle the numbers to get the safest result allowing a margin in case you get a dud load of Gas.
It all depends on the octane of the fuel you'll run.
Best combination is as much cylinder pressure as you can run without detonation.
X:1 static + XX psi boost + XXX octane you just need to juggle the numbers to get the safest result allowing a margin in case you get a dud load of Gas.
so for example on my car with stock block for now and with my mods and run with the best pump gas, what would be the prefered thickness of gasket? any idea?
Stock!
I think it compresses to 1.27mm or maybe 1.4mm someone will jump in shortly.
Again this all depends on if the block and head have ever been surfaced and by how much as this will bump the comp ratio up.
Main thing is to keep out of detonation as nothing kills these motors faster.
I think it compresses to 1.27mm or maybe 1.4mm someone will jump in shortly.
Again this all depends on if the block and head have ever been surfaced and by how much as this will bump the comp ratio up.
Main thing is to keep out of detonation as nothing kills these motors faster.
i took .006 off the head when it was surfaced to remove warp and the gravel imbedded in the head and i think thats the only time the head was off.