.20 over head gasket?? Do I need it??

wpeschel

wpeschel

Psyko
Joined
Aug 4, 2007
Messages
872
Ok I just recieved the .20 over marine head gasket from Pure Diesel Performance for my 12 valve... I am waiting on the head to get here on Wed and I was wondering if I made a mistake by getting the 20 over marine head gasket?? I am only looking around 350-400hp to tow with... The mods are going to be ddpIII sticks, and a 62/14 turbo later on.. I was wondering if I wasted my time getting the 20 over gasket?? Should I send it back for a stocker?? Thanks Wesley
 
wpeschel said:
Ok I just recieved the .20 over marine head gasket from Pure Diesel Performance for my 12 valve... I am waiting on the head to get here on Wed and I was wondering if I made a mistake by getting the 20 over marine head gasket?? I am only looking around 350-400hp to tow with... The mods are going to be ddpIII sticks, and a 62/14 turbo later on.. I was wondering if I wasted my time getting the 20 over gasket?? Should I send it back for a stocker?? Thanks Wesley
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Are you o-ringing the block or head and has anything been machined on both aswell.

Brett
 
Lower compression will lower throtle responce when the engine is not making much boost (below 20 psi).

Once boost is built, the low compression does not contribute to any real noticeable drop in throttle responce. This is nice since my truck makes 10 psi @ 70 mph, tickle the throttle, and zing, 30 psi. What I am saying is build the whole engine to deal with the drop in static compression.

On average with a + .02 head gasket and +.02 ISB300 pistons I average 16-17 MPG unloaded. The stock motor NEVER made more than 19 MPG

If the truck sees a lot of unloaded running down the road, a drop in fuel economy will result.

Full load with twins making over 65 psi, the drop in thermal efficiency by going from 17:1 to 15:1 is almost moot, and the higher in boost you go, the change approaches zero.
 
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I installed a pdr cam several years ago. It was a nice boost to my bottom end. When I had my head o-ring I went to a .020 over gasket. It took away the bottom end improvement I got from the cam. I went to a .010 over gasket on a new head. If I was to do it over, I would have put a stock thickness gasket back in.
 
if your not going nuts with it, I would go with a regular headgasket, just my opinion
 
I would say that if the head is new, and only a thousandth or two is milled to make it perfectly flat, stick with a stock gasket, especially on a truck like yours.

I had my head o-ringed just recently. Had a local shop do the decking, Triple D Performance did the o-ringing. The local shop that did the decking took .010 off to get it flat. I had no choice but to go to a .010 over gasket to make up for it. Only other thing would have been to recess the valves.
 
I just talked to Garret.. The head was decked 8 thousanths.. I think I will just go with the gasket I got cause I wanna get this thing backtogether asap... I might try to get a 10 over if I can get one from southern plains cummins...
 
Smokem said:
Decking the head has no effect on the compression or requires a thicker headgasket, only if you have material removed from the block altering piston protrusion should you change the gasket thickness.
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So what do you think??? Should I run a stock, 10, or 20 over??? thanks Wesley
 
Smokem speaks the truth!

I would only use a stock gasket... I actually only have a stock gasket and I have firerings and soon should be looking for 550-600hp...
 
I ran a .020 head gasket for over a year. Put it on when i had the head ported/ringed/valves, etc. I noticed an instant loss of bottom end response and a lot more haze at idle and when cold, even with high dollar injectors (II flies/ddp4's). It was suggested so often to run this thicker gasket when building power, lower drive pressures, cylinder pressure, etc, so i did.

I never really liked the way the truck responded down low and the hazing was annoying, even with multiple timing settings (18-22) I spent a lot of time trying to tune the truck to be clean, at least during low boost/town driving. I left it that way for more than a year because i thought it was easier on the engine?

About a month ago, maybe two, i switched back to the stock thickness gasket, mostly to cure the hazing, but it brought back all my bottom end as well. I would compare the difference as similar to switching from a sps66 to sps62 in response down low, or a cam swap. Oh, and no more idle haze. My truck is a daily driver, and i like the way it acts much better with the stock thickness gasket.

Dave
 
Smokem said:
Decking the head has no effect on the compression or requires a thicker headgasket, only if you have material removed from the block altering piston protrusion should you change the gasket thickness.
Click to expand...


So in my case, I was told wrong by Triple D? The other gasket cost me another $130 over the stock upper engine gasket set I had gotten. This absolutely sucks balls.
 
Well after all of this I ordered a stock gasket from Haisley cause they had one in stock and sent it second day air... Luckily I have a friend that is building a race truck and will need this gasket for his rig... Thanks for setting me straight... Wesley
 
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