Like I was saying above the pistons came coated from socal so they may be cut already. I will reassure this evening and post my numbers for you guys to see. It would be really nice if I could run a thinner gasket. Thanks for the info
Piston to deck clearance and head gaskets
- Thread starter RPEVEHOUSE
- Start date
SoCal uses mahle race cast which are already cut, they are not having a specific piston made for them.
Ok, so I remeasured and this is what I got measuring above the piston pin and pulling the piston front to back. 2468 .010 .010 .010 .011
1357- .013 .013 .013 .014
That changes everything,lol. I’m gonna study the documents you guys posted and see if I can come up with a plan for the headgaskets. Thanks to everyone of you. Would have been way off base without you
By the book you'd need a B and a C, if it were my truck I'd run A and a B. One thing I'll note based on everyone's experience is to avoid the gold GM gaskets. Depending on what is in stock and your desired time frame, C grade might be all you're able to get
I have 2 sets of Mahle wave stopper grade Cs. I will do some checking around and see what I can get my hands on. Not in a really big rush but would like to get it back together in a fairly reasonable time frame. What’s the thinking behind the thinner gaskets? Is it to keep the compression ratio closer to advertised or just a better seal?
Sealing will be the same. Yes there is the advantage of a higher CR, which will help with a larger cam. Does it really make that much of a difference? Probably not in a diesel, it's good practice to get the quench tight as possible, within reason and not pushing the limits. Lots of shops will just slap a set of C gaskets on a head job and call it good, 99% of guys would never know any different.
How many old school gassers had the pistons -.025 plus a composite .040 gasket? The last sbc I put together had the pistons down about 020, the old man said to just run a Felpro SD composite which is like 045". I said F that it's getting a .015 steel shim haha
Quench is a large reason as well as piston growth (not a huge deal on cast but must be considered) plus valve overlap.
Your going to have alot of quench area with valve reliefs in the Pistons. Not real sure a tighter piston to head clearance is gonna help you much due to that but it certainly can’t hurt. You just don’t wanna go too tight
Just FYI, quench is the area in which the flame does not reach and unburnt fuel starts to accumulate and no longer be a vapor, which does not burn as well as it should once the area between the person and the head starts to open on the firing stroke. It’s not a massive amount, but it does lead to a little worse MPG.
Your going to have alot of quench area with valve reliefs in the Pistons. Not real sure a tighter piston to head clearance is gonna help you much due to that but it certainly can’t hurt. You just don’t wanna go too tight
Just FYI, quench is the area in which the flame does not reach and unburnt fuel starts to accumulate and no longer be a vapor, which does not burn as well as it should once the area between the person and the head starts to open on the firing stroke. It’s not a massive amount, but it does lead to a little worse MPG.
Ok, I see what you guys are saying. I may go the A B route. With that in mind, what gaskets are you guys getting the best service out of?
Mahle or victor reinz
Awesome, Thank you
I second this.
I will report back on what gaskets I use and how everything turns out. I appreciate the help from everyone. Thank you
While I got you guys here and I’m about to start running beads, what is your guys go to as far as sealant goes? For like the front and rear covers and oil pan?
GM OEM gray sealer. That shit is like glue.
lol, awesome. Thanks
I’ve had great luck with both of those. Back when I was at gm all we used was the gray gm stuff. In the independent market we use a lot of ultra gray and ultra black. Just wasn’t sure what the duramax group was using
Gm sealant, Ultra grey or right stuff.
I've used both Permatex and Loctite grey with no issues. Most leaks are from poor prep and application
Amen on that brother. I work with guys that will stick an oil pan and never even wipe of the rails. I’m more of the surgical type. All parts are spotless and wiped down with brake cleaner before anything is applied. I follow all torque specs. That’s the way I have done every single job for the 36 years I’ve been a tech. I never have comebacks because of it.