Head Gasket Question [Archive] - Duramax Diesels Forum

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Lonnie
01-14-2008, 01:06 PM
GM lists 3 head gaskets for the LLY engine......
Grade A, B & C.

What is the stock replacement?

What is the difference? My parts guy isn't real helpful.

Thanks,
Lonnie

mvnvltn
01-14-2008, 01:58 PM
Just get Grade C. They are the thickest.

If you want what you had, then you can use the holes on the end of the gasket to give you what grade they were.

Turbo Buick 6
01-14-2008, 03:10 PM
Good question. So what are the diff thickness of the 3? Did they use all 3 on trucks or just one of them? Just kind of curious because it seems like a good way to drop the compression a little.

Kat
01-14-2008, 03:46 PM
Here is the info I found. Hope it helps a little :D

http://www.mcratracing.com/forum/showthread.php?t=1741&highlight=head+gaskets

Turbo Buick 6
01-14-2008, 06:52 PM
Not sure if this is Kat or Pat, but either way thanks :hug:

Kat
01-14-2008, 07:02 PM
Not sure if this is Kat or Pat, but either way thanks :hug:

It's Kat :hug: But, Pat gave me the info :rofl:

Turbo Buick 6
01-14-2008, 07:04 PM
always a team effort :hug:

Lonnie
01-14-2008, 09:15 PM
Thanks for all the info. I was worried that I could not find any info & the dealers selling the stuff always seem to know the least.

I was only buying 1 side & needed to match the other.

I did find some info on the "grade" of the gasket
It goes as follows:

1 is Grade A
2 is Grade B
3 is Grade C
4 is for a .010-.030 overbore
5 is for a .010-.030 overbore with deck milled .008

You can see what you have by the following markings:
On the Left front (Dr. Side) or Right rear, there are 2 oval slots showing at the end of the head. The top slot shows this type.

A round hole at the top of the oval slot means it is a "1"
in the middle is a "2"
at the bottom is a "3"
if the oval is completely open, it is a "4"
if there is an oval at the top, it is a "5"

The bottom oval slot shows the side it is made for:
hole at bottom is left.
hole at top is right.
They also have an "L" or "R" at the end as well.

I'll post pictures when I get a chance.

I have no thickness or volume info for the gaskets, but this is a start.

Lonnie
Hope this helps.

Lonnie
01-17-2008, 08:46 PM
Something else to think about....

My engine has a "B" gasket on 1 side & a "C" on the other.

I spoke with a dealer mechanic that said the gaskets are sometimes different on the same engine. They must hand select them based on the deck clearance for each side on the engine.

Anyone else see this on their motor?

Lonnie

Kat
01-17-2008, 09:08 PM
Something else to think about....

My engine has a "B" gasket on 1 side & a "C" on the other.

I spoke with a dealer mechanic that said the gaskets are sometimes different on the same engine. They must hand select them based on the deck clearance for each side on the engine.

Anyone else see this on their motor?

Lonnie


IIRC Maxfarmer had that on his engine.

Kat
01-17-2008, 09:12 PM
Ok I found it. See post 23

http://www.mcratracing.com/forum/showthread.php?p=32408&highlight=head+gasket#post32408

Lonnie
01-17-2008, 09:42 PM
Kat,
Thanks for all your help.

I keep learning more things everyday.... even stuff I never thought I would be involved in.

For example:
1. How weak the oil pans are...
2. How the flywheel has to come off to remove the oil pan (another reason I think automotive engineers should have to work on vehicles before they are allowed to design car parts)...
3. How expensive the little GM tubes of silicone for the oil pan are (I'm also betting there will not be enough left in the tube to put my intake manifolds back on)...
4. How that little lower valve cover gasket can cost $50...
5. Never saw an engine with 2 different head gaskets on it intentionally (until this engine)...
6. Whoever designed the PCV & EGR system should be tar & feathered with the stuff that accumulates in the intake...
7. How you can bend a 3/4 drive breaker bar tightening flywheel bolts the proper amount...
8. How everything on a Duramax engine has cost me roughly twice what it would on a big block Chevy engine...

Lonnie

sweetdiesel
01-17-2008, 10:35 PM
Kat,
Thanks for all your help.

I keep learning more things everyday.... even stuff I never thought I would be involved in.

For example:
1. How weak the oil pans are...
2. How the flywheel has to come off to remove the oil pan (another reason I think automotive engineers should have to work on vehicles before they are allowed to design car parts)...
3. How expensive the little GM tubes of silicone for the oil pan are (I'm also betting there will not be enough left in the tube to put my intake manifolds back on)...
4. How that little lower valve cover gasket can cost $50...
5. Never saw an engine with 2 different head gaskets on it intentionally (until this engine)...
6. Whoever designed the PCV & EGR system should be tar & feathered with the stuff that accumulates in the intake...
7. How you can bend a 3/4 drive breaker bar tightening flywheel bolts the proper amount...
8. How everything on a Duramax engine has cost me roughly twice what it would on a big block Chevy engine...

Lonnie


uh yes Dont you love the duramax Diesel:rofl: I agree Lonnie
that PCV WTF where they thinking:confused:

Kat
01-17-2008, 10:44 PM
8. How everything on a Duramax engine has cost me roughly twice what it would on a big block Chevy engine...

Lonnie

Welcome to my world. I thought racing our corvette was expensive :eek:

Lonnie
01-18-2008, 08:31 AM
I build those Z06's all the time. They are about 1/2 the price.

Example:
Head studs $250
Head gaskets under $100
Cam under $400
CNC ported heads under $2500 with all new valves & springs.

Makes Corvettes seem like economy builds.

SmokeShow
01-18-2008, 08:57 AM
Kat,
Thanks for all your help.

I keep learning more things everyday.... even stuff I never thought I would be involved in.

For example:
1. How weak the oil pans are...
2. How the flywheel has to come off to remove the oil pan (another reason I think automotive engineers should have to work on vehicles before they are allowed to design car parts)...
3. How expensive the little GM tubes of silicone for the oil pan are (I'm also betting there will not be enough left in the tube to put my intake manifolds back on)...
4. How that little lower valve cover gasket can cost $50...
5. Never saw an engine with 2 different head gaskets on it intentionally (until this engine)...
6. Whoever designed the PCV & EGR system should be tar & feathered with the stuff that accumulates in the intake...
7. How you can bend a 3/4 drive breaker bar tightening flywheel bolts the proper amount...
8. How everything on a Duramax engine has cost me roughly twice what it would on a big block Chevy engine...

Lonnie

I love the humor in your posts Lonnie. Thanks for sharing your experience(s) with this build with us. I appreciate it. :hug: :cool2:

Here's to having the rest of the build be trouble free! :beer



C-ya

Lonnie
01-18-2008, 07:09 PM
Thanks Mitch.

I set the engine in tonight & got it bolted to the trans. Now I have to make a crossmember for the motor mounts as they sit very low in the frame. All the clearances seem OK for the exhaust & surprisingly the oil filter clears as well. I still need to install all the top end components, but it is a major step toward completion. Getting everything positioned for height & will set the final front to rear position after I set the cab in place.

Lonnie

02freighttrain
01-19-2008, 10:13 PM
Kat,
Thanks for all your help.

I keep learning more things everyday.... even stuff I never thought I would be involved in.

For example:
1. How weak the oil pans are...
2. How the flywheel has to come off to remove the oil pan (another reason I think automotive engineers should have to work on vehicles before they are allowed to design car parts)...
3. How expensive the little GM tubes of silicone for the oil pan are (I'm also betting there will not be enough left in the tube to put my intake manifolds back on)...
4. How that little lower valve cover gasket can cost $50...
5. Never saw an engine with 2 different head gaskets on it intentionally (until this engine)...
6. Whoever designed the PCV & EGR system should be tar & feathered with the stuff that accumulates in the intake...
7. How you can bend a 3/4 drive breaker bar tightening flywheel bolts the proper amount...
8. How everything on a Duramax engine has cost me roughly twice what it would on a big block Chevy engine...

Lonnie
I don't think you have to take the flywheel/flexplate off to remove the oil pan. I have one on the stand right now with the oil pan off and the flexplate on. fwiw........

Lonnie
01-20-2008, 07:49 AM
Two rear bolts are behind the flywheel/flexplate ring gear & it's too close to get a socket or wrench in there. Did you remove the pan or did someone else? Please elaborate on how you did this as it could help others in his situation.

Lonnie
01-25-2008, 07:45 PM
I just found this info concerning the gasket selection on an Isuzu bulletin. I do not have actual dimensions, but I would assume based on the following info, that the gaskets are in order of increasing thicknesses of approx. 0.002"

Cylinder Head Gasket Selection

Grade------Right Side----Left Side------Piston Protrusion
Grade A----97288223----97309562-----.0088 to less than .0108
Grade B----97288224----97309563-----.0108 to less than .0128
Grade C----97309561----97288228-----.0128 to less than .0148

A USED Grade B gasket by my measurements is 0.039" thick at the main portion & 0.043" across the fire ring. Please remember that this is based on the somewhat irregular black gasket coating that is on the USED gasket, so do not take this as an absolutely perfect measurement.

Anyone have the "correct" dimensions for this gasket or for any of the other grades?

Hopefully this info will help someone in the future.

Lonnie

MaxFarmer
01-25-2008, 08:41 PM
The only thing I could find to add right now from my scribbles is that a compressed A gasket is supposed to be .035-.039 inches and a C gasket is supposed to be .039-.043 inches.
That doesnt sound right though b/c I dont know where the B should be in there. Maybe something in between?

Cobra#3747
01-25-2008, 08:47 PM
Gasket Grade..................Compressed Gasket Thickness

A............................0.0354-0.0394


B............................0.0374-0.0413


C............................0.0394-0.0433


2 other gaskets listed in service manual

Block Over-Bored 0.010-0.030 in ...............0.0394-0.0433


Block Over-Bored 0.010-0.030 in and Deck Milled 0.008 in....0.0492-0.0532

MaxFarmer
01-25-2008, 08:51 PM
I was close! Thank you!

dieselson
01-25-2008, 09:54 PM
How much is a head gasket set from the dealer?

Lonnie
01-26-2008, 09:28 AM
Depending on the discount you can work with your dealer, gaskets are approx $90-110 each side. Took me almost 2 weeks to get one from GM.
Bolts are about $40-50/side.
Copper injector washers (LLY) about $2.25 each.
Injector o-rings (LLY) about $8 ea. (ripoff considering a normal o-ring costs about $0.75)
Lower valve cover gasket (LLY) is $80 (be careful when you remove yours as it can be reused).
Upper gasket can be reused as well.


Lonnie

WolfLLY
05-06-2008, 12:39 AM
Thank you Lonnie. You just answered my question about the valve cover gaskets.