higher compression requires better head sealing

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Jennings wrote:
"stock aluminum gaskets are almost certain to fail, being a bit weak at ambient temperatures anyway -and impossibly frail at the temperatures to which they will be subjected. Copper is a better material, for while it is nearly as soft as aluminum at ambient, its hot-strength properties are better. Copper is soft enough to make a good gasket in the annealed state, but hardens in use, and must be re-annealed frequently to keep it soft and thus retain its properties as a gasket."

I believe that the stock aluminum gasket is only barely adequate with the low cranking pressure of 90psi (given the head is not the slant plug head) and that higher cranking pressures need a better gasket. I had good luck just cutting out my own gasket from hi temp gasket material. I'm sure there are plenty of people who think their aluminum gasket works just fine but I'm sure they completely ignore the fact that upon disassembly they can see that blackened areas of the gasket was telling then that they were losing compression, and therefore losing power.
Also I believe that every time the head is removed that a new gasket needs to be installed if the gasket is aluminum. That is because it conforms only once to the irregularities of the surfaces.
 
keep preaching.

teflon is far superior in all regards, costs sweet F all, and well...it works. no cutting, no trimming, just twist some tape up, and tighten down. of course, it is absolutely useless if you have a warped head/sealing surface...

even cranks the CR up a few points by removing 1mm of material between head and cylinder. bonus.
 
I strongly agree with both of you.
I easily got 5 uses out of stock aluminum headgaskets, especially at stock pressures.
I was careful to not over-torque it and filed and sanded both surfaces smooth.
My largest problem is with the stock head warping in a front-back axis.
I have to sand the stock head a few thou every time to assure flat.

The teflon tape trick has been a godsend Headsmess, eternally thankful.
Be careful of your squish gap when you do it folks, and it needs to be flat.
Here is what a blown headgaasket looks like:
55284-156a3de05e256e05d56433e4c72293f9.jpg

Note that it happened in the fore/aft axis.
Most of mine are.
 
I remember when I was a wrench fetching kid seeing the older wrench turners paint head gaskets. They said it helped them seal better. Makes me wonder if maybe some VHT might help. Also seems like wrapping a exhaust gasket with tef. tape could save a lota scraping at replacement time.
 
Yup, silver paint I bet.
The aluminum (or lead in other colours) acted as a filler and sealant.
It was messy and of negligible help in difficult situations.
I like the teflon exhaust gasket idea. Count on me to try it.

Been steady rain here. I am getting bicycle withdrawal.

Steve
 
Since first speaking of how I build my engines, and listening to the feed back to the point that I had to test the heads myself IE volumes and compression at different deck heights my school of thought has completely changed. Now the only ones I deck are those getting performance heads. I still haven't done the solder test. I did check the radius of the piston and degree cut of the perf. heads and think with the jug decked to where the piston is just noticeably below the deck the .7mm head gasket gets very close to the sought squish.
 
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Yup, silver paint I bet.
The aluminum (or lead in other colours) acted as a filler and sealant.
It was messy and of negligible help in difficult situations.
I like the teflon exhaust gasket idea. Count on me to try it.

Been steady rain here. I am getting bicycle withdrawal.

Steve
What do you think about spraying down the mag. coil with flex seal to water proof it?
 
Teflon tape?the plumbing type?
That's what their talkin about. I suppose if you got it to seal the head with no alum. gasket a guessed boost of 20 to 25 lbs. of extra compression pending on how much the tape squishes down.
 
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