Specific Question - ARP Head Studs on 2.7 Magnesium case - Insane?

[Lapkritis]

Good advice - I was very careful to hold square while seating the cover plate but I'll inspect more thoroughly from the back side to make sure I don't have a fold or tear. Gave it a quick glance after and it looked as intended.

The cam plate was flat boarded with 1000 grit to clear off gasket remnants and wiped clean with brake parts cleaner a half dozen times before fresh gloves and applying the tacked gasket(holding from the sides so not touching the surface), pushing the bolts through carefully and installing into the housings.

[E Sully]

I may be a bit late on this, but I was wondering if you had seen this regarding the cooling tin.
Pelican Technical Article: 911 Engine Tin Cooling Modification

[KTL]

As long as you installed the gasket with care, you should be good. Especially since you made sure the cover plate was surfaced. I surfaced mine the same way with fine grit wet-sand paper and it took a considerable amount of time to true the surface. Time well spent but I should have just had my machinist buddy put them on the surfacing table.....

[Lapkritis]

Originally Posted by E Sully

I may be a bit late on this, but I was wondering if you had seen this regarding the cooling tin.
Pelican Technical Article: 911 Engine Tin Cooling Modification

Hi Ed,

Thanks for the pointer. I have seen the tin mod before. It may not be striking to the eye but you can see the modified tin tops here:



One contributor here seemed to think the cylinders cooled better with full tins when they are cast iron. I will only be running the modified tins on this engine.

Regards,

[Lapkritis]

Originally Posted by KTL

As long as you installed the gasket with care, you should be good. Especially since you made sure the cover plate was surfaced. I surfaced mine the same way with fine grit wet-sand paper and it took a considerable amount of time to true the surface. Time well spent but I should have just had my machinist buddy put them on the surfacing table.....

Yep - seems I have hours upon hours just cleaning gasket surfaces by hand which I figure is part of the right of passage doing a quick refresh on these. I normally use the 3M Roloc to clean engine surfaces and it does an amazing job. Then you barely need to use any chemicals and you can't damage the surface unless you fall asleep on the same spot for 20 seconds. Just have to watch for studs in the way so you don't ruin the tool. There are other grits available but here's the general idea:

Scotch-Brite Roloc Bristle Disc, Ceramic, 25000 rpm, 2" Diameter, 80 Grit, Yellow (Pack of 10): Amazon.com: Industrial & Scientific

[Lapkritis]

KTL- pretty sure I owe you one.



Probably Going back in after it rather than hoping the tiny grip it has behind the plate will hold... pretty sure I should only see the edge profile than most of the face.

[KTL]

Yeah that looks like the gasket is misaligned. Mine was only slightly misaligned and it had a steady drip. Ended up having to take the engine out and re-do it since it would drip on the exhaust and also make a mess of the rear of the car (oil mist). Yours would probably leak pretty hard the way it looks there.

[Lapkritis]

Went back in over the lunch hour. It was holding by about 2mm but you can see it slipped it out of round. Tricky little bugger. Found a gasket locally and giving it another try tonight with a different substance. I have the loctite 574 and curil t on hand but haven't decided. I know 574 is nasty when cured so would like to avoid it if possible. The permatex should have done the trick but I think it softened the paper. Definitely sticky enough as it tore the paper apart during removal.

[KTL]

Guys that work on these a lot seem to favor the 574. I'm not a big fan because I don't like the cleanup of the hardened goop. Used Curil T last time I had my leak and was cautioned using the Curil T for that gasket

Another gasket sealing question

However, local fellow racer friend cstreit who's built quite a few 911 engines swears by using the Curil T for the cam gasket and has never had a leak. Since I got skunked by the copper spray, I went with Chris' recommendation and no leak thankfully.

[Henry Schmidt]

Originally Posted by Lapkritis

Some of this problem may also be due to the low quality Victor Reinz gasket if used.
There are also two different gaskets (one for the 47mm and one for the 49mm journal) and I've seen the late gasket used in early and late gasket sets from VR.

[Lapkritis]

I'm not so much hung up on the brand of things but more the materials. Does this gasket come in anything besides paper or cork? This would be a perfect spot for an MLS gasket type given the awkward pressures.

[Henry Schmidt]

Originally Posted by Lapkritis

I'm not so much hung up on the brand of things but more the materials. Does this gasket come in anything besides paper or cork? This would be a perfect spot for an MLS gasket type given the awkward pressures.

The key to sealing this joint is a high quality paper gasket. (not all paper is created equal).
A multi-layer steel gasket would probably offer challenges to setting chain parallelity.
Might work but first someone would have to make it.
I didn't notice the method you used to check chain parallelity.
We made a tool that makes this process simple and almost fool proof.

[Lapkritis]

Straight edge and a caliper. Couple things make me think the method is a bit of an art is the case half steps on the intermediate shaft face. I took many measurements and had it down where I had a consistent result with the same shims as prior to my teardown on the engine. Visually inspecting the sprocket shown light wear on the outward face at that time. It was in spec with those shims by my measurement but sprocket wear and the chain slightly catching in the test rotations tell me the measurement is BS and the previous builder achieved the same measurement some 22yrs prior.

Unsure of gasket material on parallel position of chain with MLS. If anything, I would think it to be more uniform even though the crown sprocket that rides the woodruff key is snug on the cam to hold the chain sprocket square. Axial movement of the crown sprocket from the cam would be extremely difficult although not impossible. The 71ft lbs to squeeze the cam nut down is quite a force. MLS wouldn't poop out with higher torque on the 3 cap fasteners Likely my real problem is being a tough guy with my fasteners and showing them who's boss and the gasket crapping out with nowhere to go.

Spoke for awhile with Mark at Exotech ( http://WWW.exotechpower.com ) when I picked up the new gasket tonight. New paper is going in dry with the same brake clean preparation on the surfaces. Also putting my tough guy attitude towards fasteners torque in check.

[Lapkritis]

Ended up replacing the sandwich gasket for both banks to be safe. They sit quite nicely with no dressing, stayed in place but was careful to check alignment from the backside before tightening down and seating against the housing. All timed up and ready for the rest of the rockers and covers...

[Lapkritis]

Wrapped the clock around out there last night with rockers and a few other gaskets. I have a few commitments that are taking my away from playing in the garage but hoping to be back at it Sunday for a start-up on Monday.

[Walt Fricke]

The pressure fed tensioners kit includes two brackets, sort of like Adel clamps but very small, which attach one each to the 6mm studs which hold the chain housing cover on. They are to support the small steel tube leading to the tensioner. Early on, vibration caused leaks due to cracking in the lines (at its banjo I think), or so Porsche thought. Hence the addition of the clamps.

Can't say as I have ever had a leak due to a crack here, even after one of my clamps itself broke, but worth thinking about.

[Henry Schmidt]

Originally Posted by Walt Fricke

The pressure fed tensioners kit includes two brackets, sort of like Adel clamps but very small, which attach one each to the 6mm studs which hold the chain housing cover on. They are to support the small steel tube leading to the tensioner. Early on, vibration caused leaks due to cracking in the lines (at its banjo I think), or so Porsche thought. Hence the addition of the clamps.

Can't say as I have ever had a leak due to a crack here, even after one of my clamps itself broke, but worth thinking about.

Good catch Walt, I've seen more than a few failures do to missing supports.

[manbridge 74]

OP, do you plan on using E85 for fuel?

[Lapkritis]

Yep, kit I received was without the clamps but they will be added.

E85 - not planned at this time. 93 pump with the PMO carbs.

[manbridge 74]

Do you plan on some sort of total loss cooling system if detonation occurs?

Water vapor cooled 911 - the Rubbermaid Solution