head gasket suggestions?

cumminsontheroc

cumminsontheroc

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Joined
Oct 11, 2007
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i finally took my head off this morning and need some suggestions on a head gasket!*bdh* i have arp 12mm studs,370 injectors 191 dvs, 4000gsk, 0 plate and a hx52. only want to do this once so i want to start with a good one!
 
Good lord dude. Is your truck big enough? LOL Check the head for flatness and then have it o-ringed and studded. As far as the gasket goes, it depends on how much you take off the head when you have it flattened.
 
BgBlDodge said:
As far as the gasket goes, it depends on how much you take off the head when you have it flattened.
Click to expand...

Shaving head has nothing to do with gasket selection. Our heads are flat.
.020 over gasket reduces compression/cyl pressure for going with big boost.
I put the +.020 gasket in, although it's probably not necessary as I'm stuck at 32psi with my hx40 for some reason.
I didn't oring, but mines mostly a daily driver and didn't feel the expense was worth it for me. 12mm ARPs should hold what I want out of it. If you have the money, do the orings.
 
Ridemywideglide said:
Shaving head has nothing to do with gasket selection. Our heads are flat.
.020 over gasket reduces compression/cyl pressure for going with big boost.
Click to expand...
I beg to differ!
If your cylinder head is warped and the removal of 10 thousandths is needed to get it flat again, a head gasket thickness of at least 10 thou over stock is needed for proper clearance.
 
Ridemywideglide said:
Shaving head has nothing to do with gasket selection.
Click to expand...

Actually it has everything to do with gasket selection. When you shave the head it effects the protrusion of the injector into the piston bowl. If you don't shave the head and put a .020" gasket on it will effectively pull the injector tip out of the bowl which affects the static timing. Also, if you shave too much and use the thinner gasket it is possible for the valves to smack the pistions.

A more accurate statement would have been to say that shaving the head has nothing to do with an engine's compression ratio.
 
Ken in AZ said:
If you don't shave the head and put a .020" gasket on it will effectively pull the injector tip out of the bowl which affects the static timing.

This is why you use thinner injector washers.
I just went through this whole ordeal. .020 over Head gasket unmilled head=lower compression. If you use .020 injector washers, you are back to stock injector tip depth.
Click to expand...
 
Ridemywideglide said:
Shaving head has nothing to do with gasket selection. Our heads are flat.
.020 over gasket reduces compression/cyl pressure for going with big boost.
I put the +.020 gasket in, although it's probably not necessary as I'm stuck at 32psi with my hx40 for some reason.
I didn't oring, but mines mostly a daily driver and didn't feel the expense was worth it for me. 12mm ARPs should hold what I want out of it. If you have the money, do the orings.
Click to expand...

I was referring to the valve to piston clearance.
 
Milling the head doesn't do anything for compression and when it is done correctly they sink the valves in deeper to keep the appropriate clearance. A thicker gasket is only needed to run super high boost and/or to compensate for the block being resurfaced. And if you shave the head the injector does get deeper but it can't be hit due to the bowl location of the piston and it will let you run more timing without overspraying the bowls.
 
Muddin_dude06 said:
Milling the head doesn't do anything for compression and when it is done correctly they sink the valves in deeper to keep the appropriate clearance. A thicker gasket is only needed to run super high boost and/or to compensate for the block being resurfaced. And if you shave the head the injector does get deeper but it can't be hit due to the bowl location of the piston and it will let you run more timing without overspraying the bowls.
Click to expand...

Wow, sounds remarkably like what I said.. And read all over the place.
Sooooo.. Shaving the head has nothing to do with gasket selection.. :hehe:

Thanks Muddin_dude.. :rockwoot:
 
My stock injectors use .020" washers so when I put the thicker headgasket in I did effectively pull the injector tip out of the piston bowl.

I guess I could have used no washers to keep them at the stock depth huh? LOL
 
Ken in AZ said:
My stock injectors use .020" washers so when I put the thicker headgasket in I did effectively pull the injector tip out of the piston bowl.

I guess I could have used no washers to keep them at the stock depth huh? LOL
Click to expand...

Sorry,
But your wrong.
MOST Stock injectors use .040" washers. I have read that some 215s came with .020" washers. Not sure though.
WE PUT .020" washers on our trucks to get the injector farther into the bowl, so we can run more timing and to reduce Idle Haze.:welcome:

This Info. was from Smokem, and I believe him when it comes to these things.
Here is a thread I started awhile back about all of this stuff.

http://www.competitiondiesel.com/forums/showthread.php?t=21279
 
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Now that I think about it, When I replaced my injectors with marine 370s, I called Cummins to get new washers and they said STOCK was .040", I told them that I thought .020" washers were stock, they said no.
I then called Bosch and they ran my CPL# and verified .040" washers were stock for my 215 injectors.
 
I know a handfull of guys running some good twins with stock thickness gaskets.... any gain to run a oversized?

I had a +0.010 in my 01 but it blew out the front so shes on the trailer currently :bang
 
IC-Smoke said:
I know a handfull of guys running some good twins with stock thickness gaskets.... any gain to run a oversized?

I had a +0.010 in my 01 but it blew out the front so shes on the trailer currently :bang
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Dont know. This is wht was recommended by Garrett from Pure Diesel Power. I know ALOT of people use the .020" gasket. Its probably because its just thicker and harder to blow.
 
Tony is right stock washers for our 215 injectors are .040" and that is according to my local cummins dealer.

IMO if you o-ring a head or firering a head and use studs (the bigger and/or higher quality the better) you should use a standard gasket unless the block was resurfaced. You will lose HP and TQ because of less compression.

Now if you are going for 1000hp on N2o then sure lower the compression to relieve stress off of parts but if you are going for something to drive often and make good useable power try to keep it stock compression IMO.
 
Ken in AZ said:
My stock injectors use .020" washers so when I put the thicker headgasket in I did effectively pull the injector tip out of the piston bowl.

I guess I could have used no washers to keep them at the stock depth huh? LOL
Click to expand...

This is the reason for running 020" washers.. You run 020 gasket, so you go from 040 to 020 washers to keep the injector the same distance from the bowl. 0 gasket + 040 washers = 40thou.. 020 gasket + 020 washers = 40thou... So by using the 020's Ken you kept your injectors at the stock location compared to the piston if you used a 020 gasket. What you did was effectively lose what you gained by running the 020's before the thicker gasket.

Initial point was about shaving the head and that changing compression or clearance. As muddin stated, with a good head guy doing the job, the only change will be injector depth, thus making a gasket selection based on "I shaved the head and now I need a thicker gasket" just plain WRONG.

Running the 020 gasket will lower compression, allowing, as muddin also stated, higher boost/nos with less chance of blowing it.
I have noticed that with the 020 gasket on mine, it is a bit more tempermental on cold starts. There is no more half-crank and fire like before. It's close when it's warmer.

Running 020 washers does just what Tony says (believe Smokem on whatever he says, even if he says the sky is green.. lol), puts the spray deeper into the bowl allowing more timing.

I'm wondering if anyone has ever machined the injector holes say 020 or 040 to get even deeper...?
 
ok i ended up with a cometic gasket and had the head resurfaced and checked! i wanted to have it fire ringed but i waited too long. i have to have it all back together before monday! im going out of town next thursday.. thanks for the help guys!
 
Have you checked out the threads on the cometic?
You may want to read up before you put that on...
 
cummins sells a complete, top-end gasket kit for about $120. I got one myn and it seemed pritty good.
 
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