Cometic HG question

[wheming]

OK, could someone reassure me with a difference between the Cometic headgasket and a stock one with regard to a blocked port?

On the Cometic in the front middle next to #1 headbolt, there are two blocked ports. One is an oil return, but what is the other smaller port?
44417

And looking at the label I see this:
44416

Please tell me I'm just overthinking again and that I have the correct gasket and I didn't just block a pressurized oil port....

[GLHNSLHT2]

I would say the second picture answers your question. My Maserati 16v Cometic has the larger port open but the smaller port blocked.

[wheming]

I ordered this through a vendor here and at the time it came in, I looked quickly at it but didn't notice dohc.
I guess I figured it was the same gasket.
So what is that little port? Any idea?

[wheming]

#$@%!
OK, my blood is starting to bubble...
I just checked my order, to make sure I wasn't the one who boo-boo'd the order.
2 x 8-Valve Chrysler Cometic Head Gaskets (CmticHG8V) = $268
Head Gasket Thickness 0.084"

This is going to set me back several weeks. I've got a whole lot I could say but I better not and just say this: WTF!!!

[GLHNSLHT2]

is it just the one that's wrong or both of them?

Looking at the pic of my 8v head the smaller hole is for oil drainback too????

[wheming]

For the most part yes.
Those two holes in front near #1 headbolt, one larger one smaller both are covered over with the Cometic. Also there was one rivet that was in contact with the head (but not the block) in the front driver side corner. But it didn't appear to be a big issue.
The main difference I noticed were those two ports.
I've emailed the vendor I purchased from. These were drop-shipped from Cometic.

[wheming]

Forget i had a "spare" head to see. Looking at the head that will go on MeanMini, it appears that smaller port goes up high, just over the height of the headbolt hole.
44418

[GLHNSLHT2]

interesting. I've never looked at where it goes. Wonder if it's like a bleeder for air pressure so the oil doesn't get backed up. Just looked at the bottom of my Masi head and it doesn't have the smaller port either. I would guess the T3 doesn't have those ports at all?

[BadAssPerformance]

FWIW, this is the 2.2L 8V Cometic Gasket I used on my last 2.2L in the Z

44421

[wheming]

Thanks JT.
I was looking at TU's website and the picture of both the 8v and the 16v used the same image ( and the image was of the 8v gasket). And it is what you have there in your pic.
Sadly that is not what I received.

Now, I am severely bummed out due to all this wasted time, and of course money, after installing an incorrect gasket. I took vacation days to try and get Slug all finished up too.
This was were I was at after yesterday:
44422

So now I need to figure out what I should really do now.
I could remove this Cometic and install a MP "006", or I can wait until the headsaver copper shim comes in and install it with the 006 to put the compression where I wanted it.
I guess if Kelly says the FSM states you can reuse headbolts (after a check) I should be good to reuse these even after being torqued once? They've obviously never been heat cycled yet, just cold torque. I do have a second set of new bolts I have for Mini's build.

Anyone know how those Victor Reinz MLS gaskets are? Wonder how quick I could get one of those.

I'll call the vendor tomorrow and see what he recommends, and what he can do.

[speedfreek500]

Sorry to see your hard work wasted, Was the head and deck sent out to be machined? How much was taken off. I would use the mopar HG and ditch the shim if the head and deck have not be plained. Head bolts..... I have reused them a few times on past engines (torqued @ 90Ft/p), I always used Spray Tack on the HG. Never had a problem with leaks @20 psi. My last 2.2 the head had 60thou removed and did not use a shim, But did install a adj cam gear to keep the cam timing in order.

[wheming]

Nothing was taken off the block or head. As far as I know, they have never been cut.
When I removed the head during engine removal, I found there was only a factory type headgasket. No copper shim on Slug. (Mini had both a factory gasket and the shim.)

With today's tuning ability, I could probably be fine with just the factory gasket, but I wanted a bit of safety factor as Slug will be pushing nearly 30 psi, and these JE pistons bumped the compression a bit. Also it will probably be old school for a while until I learn or get instructed on MP Tune.

When torquing these headbolts after the 2nd 65 ft-lbs I bump the wrench up to 90 when I did the 1/4 turn. Some were right at 90 ft-lbs and some went over 90 to get the quarter turn.
Do we think it is best to torque them to the same rating, or is it better to get 1/4 turn?

[speedfreek500]

I was not aware that the Je pistons bumped up the compression, I use arp studs, Je pistons and have been to 30psi a few times on pump gas. I took some timing out and use 72Lb injectors with a 10.8-11.2 afr.

If the head bolts are made with torque to yeild in mind i would do what they say for install. I have always done them at 90Ft/p just to make sure the head was set with the same clamping force at all bolts. I had Rob made a cal for me and i did very very minor tweeks to fine tune it, pretty good for a mail order cal.

The mopar Hg might be a day or two away, Call the dealer in the morning just to make sure they can get one for ya. I think they are only $19 to $25.00

[wheming]

I've got 5 of them here at the house.

Stock compression was like. 7.8:1 or something I thought. The JE's were 8.1:1, not a big difference I know but with the shim Gus had it made it like 7.4:1 or something like that. He wrote it in the back of Mini's owners manual.

I was going to try a Cal from Rob in Mini but the build specs I gave him have changed, so I'll need to see about fixing that.

[wheming]

Cometic is building two new gaskets and I'm told I should have them for the weekend. But the conscensus was to use studs with it, and I don't have those.
The copper shim I ordered last week will be here Weds.
Or I could just install the 006 without the copper shim today.

What to do???

I was surprised that there was no shim when removing the head for the rebuild, and that I have had the car for 10 years now and that headgasket was fine. I think it was an 006 also.

I may as well prepare for removing the head again by disconnecting all the stuff preventing lift off....

[wheming]

I myself wrote:

Stock compression was like. 7.8:1 or something I thought. The JE's were 8.1:1, not a big difference I know but with the shim Gus had it made it like 7.4:1 or something like that. He wrote it in the back of Mini's owners manual.


OK, let me rethink this...
Maybe 8.1:1 was factory compression ratio with the 782 head?
Then the 7.8:1 or so was with the 287 head...
And the 7.4:1 or so was 287 head+ 0.020" copper shim.
I can't check the manual, it is in Mini elsewhere.

[Pat]

on a 2.5, I think stock was 7.8 with the 782 head. 8.1 or 8.2 was the stock '86+ 2.2 compression with a 782 head.

My guess is that Gus ran a 287 with stock 2.5 pistons, which would drop the compression way down. If the JE's you have in there have a slightly smaller dish, you'll pick up some compression, but likely still be well below the factory 7.8 if you're still running the 287 head.

What head is going on it now? Do you know the dish volume of the pistons? Has the head or block been decked?

[wheming]

Head and block are uncut.
JE pistons from FM were I thought 8.1:1 was the lowest I could order.
Dish volume is 22cc.

Yes, Gus and I both used stock cast Mahle pistons, none of our engines were ever bored until now.

The MP 287 head was freshened up and is going to be reused.

I'm at the point ready to lift off the head, if I had two extra arms it would be off right now.

[Pat]

Stock Mahle 2.5 pistons had a 24cc dish, with a 50 cc chambered swirl head to give a 7.8 to 1 compression ratio.

By going to a 22 cc dish piston and a 56 cc chambered g head, assuming all is equal you'll have a 7.5 to 1 compression with the MP gasket (.065 thick). If you use the thicker cometic, you'd be about 7.3 to 1.

If it were me, I'd just put the MP gasket on it and run it. I don't think I'd want to go lower than the 7.5 to 1 you're looking at with that combo, especially with the cal options that are out there now.

Pat

[wheming]

OK, cool. Maybe that is why there was no copper shim on Slug, it might have had this MP gasket.

One last question, copper spray or no on the MP gasket?

I was just about to install without, but figured there is no sense in rushing at this point to regret it again later.

She's ready to lift off, only one bolt keeping her from flopping backwards...

And thanks for the advice and comments Pat, I appreciate it. :beer:

[Pat]

I use the copper spray on my head gaskets. I figure them may not all need them, but it definitely doesn't hurt. :-)

You'll pick up a bit of compresison with the piston change from what it used to be but it's still very low. Good luck with the project!

[wheming]

Thanks Pat!
Boost will correct that low compression... :D

And as a bonus, I could run cheap gas on a trip if I can control boost creep! However I don't think I ported the wastegate hole enough. We'll see. It will just be nice to see both of these cars back at full strength.

[BadAssPerformance]

+1 to Permatex "Copper Headgasket in a can" on stock type gaskets

Cometic MLS doesn't need it when new (cuz it is Viton coated) but good idea if you re-use it

[wheming]

To finish totally flogging this horse to death for all time....
I see now where i made an error. I was trying to get the compression ratio where Gus had it when he was running 28psi boost. And I knew we both ran the stock HG and the 0.020" copper shim. What I didn't realize is the gaskets I had here, the MP "006" were thicker than the original 2.5 HG. So when I was sizing the thickness of a Cometic I added the 0.020" to that and rounded to the closest flavor Cometic, 0.084". So as it turns out, this may be too thick with an uncut 287 head. I guess the 0.065" or 0.074" would have been the better choice. So I probably shouldn't use it in Mini now if that would put the compression too low.
And that would explain why everyone was questioning using that copper shim with the MP gasket.

So I think I am finally up to speed on headgaskets! ;)

Now should I bother to ask if I should reuse these headbolts that I've already torqued once? I kind of decided I was going to use the second set of new bolts I bought for Mini since I decided to get studs for her.

[Pat]

Dont forget you lost 2cc's of piston dish going to the JE's from the Mahles Gus ran. Your compression will be a bit higher than what it used to be, but still low.

[black86glhs]

Me personally, I would get new bolts for 30 psi. The rest of us running 12-14 psi can reuse them.

[wheming]

Me personally, I would get new bolts for 30 psi. The rest of us running 12-14 psi can reuse them.

My thoughts too! I'm sure they'll be someone out there who will jump at 1/2 price headbolts that were torqued but never even got a drop of oil on them or heat cycled.