Cylinder Head Gaskets, what happened ???

donporfi · 12-08-2016, 01:55 PM

Recently rebuilt a 3.2 engine.
While testing it after a few miles started to hear a sound like an exhaust leak.
Found out that the leak was not from the exhaust but the leak was between the cylinder and the cylinder head. The compression leak is in cylinders 4 and 6.
This is what we found after disassembling the heads.
Please let me know what happened and how to correct this.

TibetanT · TibetanT's Garage

If that is what I think it is….copper gasket ?

Those copper gaskets do not go between the Heads and the Cylinders.

Those copper gaskets are supposed to placed between the engine case spigot and the cylinder base.

Good luck with that.

Flat6pac · 12-08-2016, 02:13 PM

Amature build, Carrera head to cylinder is a taper on the cylinder top with high torque to seal.
Bruce

gtc · gtc's Garage

Uh oh. Hopefully the heads weren't damaged.

donporfi · 12-08-2016, 03:26 PM

Mechanic claims the gasket kit had 12 copper gaskets.
Also he torqued the heads according to specs.

OK, now what we need to correct this error ?

Do we need other gasket? I see in pictures that there are two types of gaskets, the copper ones that go between the cylinders and the block and others that look like steel that I suppose go between the heads and the cylinders.
Or the 3.2 engines do not use gaskets between the heads and the cylinders and need to be torqued to seal.
Thanks for your answers.

Jeff Alton · 12-08-2016, 04:00 PM

The 3.2 does not use a gasket between the cylinder and the head. Like others have said, that gasket in your pictures goes between the cylinder and the case.

Did you pay someone to rebuild this motor?

VFR750 · 12-08-2016, 05:45 PM

The heads don't look too bad. Clean them first, then look closely to see if the sealing surface is still smooth

What you should be worried about is small trenches or erosion where the hot gas escaped between the cylinder and the head. Also look at the top surface of the cylinder. Same concern. Erosion from hot gas cutting little trenches.

As said above, for a 3.2 there isn't a gasket. The head clamps directly onto the cylinder. The copper gaskets gave up pretty fast.

Usually you only need one copper gasket, 0.25mm thick between the case and the cylinder. Must have had 6 spares.

Sad to see. But as I said earlier, it looks like the heads are ok.

john walker's workshop · 12-09-2016, 06:14 AM

I'd be a bit concerned about the rest of the engine job after finding that gross error. Never seen that trick before.

MotoSook · 12-09-2016, 06:22 AM

Quote:

Originally Posted by john walker's workshop

I'd be a bit concerned about the rest of the engine job after finding that gross error. Never seen that trick before.

I'm with John on this. It's apparent the assembler has never done this before.

Sorry to see this. Once the copper is cleaned off, you might find the surface is just fine. If not, a machine shop can "kiss" them to clean up the mating surface. Worst case is they need to take more off, but you can them use a thicker base shim (that copper gasket) to get proper piston to head clearance.

Trackrash · Trackrash's Garage

Quote:

Originally Posted by MotoSook

I'm with John on this. It's apparent the assembler has never done this before.

Sorry to see this. Once the copper is cleaned off, you might find the surface is just fine. If not, a machine shop can "kiss" them to clean up the mating surface. Worst case is they need to take more off, but you can them use a thicker base shim (that copper gasket) to get proper piston to head clearance.

+1
I guess the "builder" thought it was a type 4! Amazing, really. Did he even look at a manual?

I would be very concerned about the tops of the cylinders. They have a slight taper, and it is critical for head to cylinder sealing.

I wonder what other surprises there are inside the case?

Steve@Rennsport · 12-09-2016, 11:54 AM

Quote:

Originally Posted by john walker's workshop

I'd be a bit concerned about the rest of the engine job after finding that gross error. Never seen that trick before.

Totally agree.

This one reminds me of a DIY client who forgot to install bearings into his newly rebuilt rods. That lesson sure didn't save him any money.

tocobill · 12-09-2016, 12:02 PM

Quote:

Originally Posted by Steve@Rennsport

Totally agree.

This one reminds me of a DIY client who forgot to install bearings into his newly rebuilt rods.

How does that even happen? I can see the base shim that happened above but one would think having the rods clank around on the crank would seem errrr wrong?

Cevan · 12-09-2016, 12:33 PM

Quote:

Originally Posted by Trackrash

+1
I guess the "builder" thought it was a type 4! Amazing, really. Did he even look at a manual?

I would be very concerned about the tops of the cylinders. They have a slight taper, and it is critical for head to cylinder sealing.

I wonder what other surprises there are inside the case?

Ha ha! Type IVs don't use a gasket there either.

MotoSook · 12-09-2016, 12:36 PM

I overlooked this picture with the arrow. Once can use spray die penetrant to verify if it is a crack. If it is cracked, it's done for.

donporfi · 12-09-2016, 01:52 PM

Thanks for all your answers, we really appreciate them.

Yes we are rookies in Porsche engines rebuilds, this is our first one. Yes we read manuals, Wayne´s book, Bentley , How to rebuild 911, PET etc.

The problem down here (Mexico) there are no experienced Porsche mechanics, there are not that many early Porsches here, you could not buy a Porsche here until a couple of years ago. Now you can import early Porsches 30 years or older or buy a new one at the few distributors.

We needed to start to rebuild engines and this was it, we know we all make mistakes because of the lack of experience but we are learning. To send an engine to a qualified mechanic in the USA
would be very expensive.

Cevan, Type 4 engines use a sealing ring p/n 021 101 343 between the head and the cylinder.

faapgar · 12-09-2016, 02:55 PM

Actually there is a head gasket repair kit for a 3.2.Grady Clay was a friend & fellow shop owner & we discussed this repair in our many talks.I am in C.R. right now but the part # is 930-104-381-01.It is 0.5mm thick I think.My machinist would open up the inside of the shim to 97mm,98mm & 100mm for a bullet proof head gasket.You lap the cylinder to the head with valve grinding compound then check with Prussion Blue.I did more than 100 Turbo engines and ran them at 1.0 bar with no leaks or sweat.I run 3 ENGINES 2.8 on a 76 Turbo case with early 3.6 heads with the stud spacing narrowed at 14:3 to 1 with no leaks running the engine to 9300 RPM.Some other shop must know this.Thanks for the rant.I get a little frustrated at the lack of good response.Ask Jerry Woods or Peter Dawe as these guys are smart. Thanks Fred

Trackrash · Trackrash's Garage

In hindsight, what was Porsche thinking making a cylinder base gasket that fits inside the head?

Hopefully there wasn't any real damage to your motor. Good luck.

donporfi · 12-09-2016, 03:56 PM

Thanks again for your answers.

MotoSook, thanks for your comment regarding what appears to be a crack. We checked it and it is not, we use Magnaflux spotcheck penetrants.

Steve@Rennsport · 07:18 AM

Quote:

Originally Posted by tocobill

How does that even happen? I can see the base shim that happened above but one would think having the rods clank around on the crank would seem errrr wrong?

Its a long story, but apparently he didn't notice that it was "unusual".

Lack of experience and certainly some hubris since he failed to ask questions before he buttoned things up.

boosted79 · 12-10-2016, 04:49 AM

"Actually there is a head gasket repair kit for a 3.2."

Can you elaborate some more? You say you lapped the head/cylinder. I'm assuming you cut the heads by 0.5 mm to keep the deck height? Tough to make up for a 0.5 mm head gasket by using a thinner base gasket when the base gasket is 0.25 mm.

Where in CR do you go? I've been to Tamarindo, nice but too damn hot for me.