Porsche 964 engine reseal questions.

[John McM]

Thanks for the lead. I have bought a set of cylinders and pistons from Autobahn. Very reasonable at USD 999 the set. They are the same height group and tolerance as my existing ones, but slightly heavier pistons. It future proofs my engine choices if there are issues later on.

[John McM]

Another question.

Are 964 cylinder surfaces treated in any way prior to fitting new rings e.g. de-glaze?

[Catorce]

Originally Posted by John McM

Another question.

Are 964 cylinder surfaces treated in any way prior to fitting new rings e.g. de-glaze?

If they look good, then just wipe the barrels down on the inside with carb cleaner and kim wipes. I would need to see what they looked like prior to giving advice; I am assuming they are good cylinders with bores that don't need to be honed or replated.

[John McM]

Originally Posted by Catorce

If they look good, then just wipe the barrels down on the inside with carb cleaner and kim wipes. I would need to see what they looked like prior to giving advice; I am assuming they are good cylinders with bores that don't need to be honed or replated.

I'm hoping they're good, or at least two of them are. The eBay add says they came out of a motor being upgraded to 4.0. Sounds like they were from a Singer conversion.

[John McM]

Originally Posted by Catorce

If they look good, then just wipe the barrels down on the inside with carb cleaner and kim wipes. I would need to see what they looked like prior to giving advice; I am assuming they are good cylinders with bores that don't need to be honed or replated.

I'm hoping they're good, or at least two of them are. The eBay add says they came out of a motor being upgraded to 4.0. Sounds like they were from a Singer conversion. Porsche 911 964 3.6 OEM Set of Early MAHLE Pistons & Cylinders GREAT CONDITION!! | eBay

[superninety]

Call Mike Farrell at Autobahn and discuss it with him. Thus far he has always been very forthcoming when I have purchased from them. Then you can buy through Ebay and they will box them up.

http://www.autobahnparts.com/EbayStores.aspx

[John McM]

Another question.

When fitting the piston with rings into the cylinder is there a preferred entry direction? I ask as the P fix it DVD has the piston inserted down from the top of the cylinder and Pcarworkshop inserted it up from the bottom of the cylinder. Does it matter?

[Walt Fricke]

If you are taking the "insert piston in cylinder, then attach rod" approach, it can't matter as long as there is no lip at the top of the cylinder - which you don't want and won't have if cylinders are new or the equivalent. And if you install pistons on rods, then cylinders the question never arises.

[John McM]

Cylinders and pistons arrived from Autobahn. Beautifully packed and based on visual exactly as described. However now I need to make some decisions.

The Autobahn cylinders and pistons are a matched set. I weighed the pistons and they are within 2 grams across the set. Remarkable. However, they are 11 grams heavier than my existing set.

I have the following choices:

1. Install the Autobahn set in full with new rings.

2. Install two of the Autobahn set to my existing set and leave the pistons 11 grams heavier than their counterparts.

3. As #two, but get the Autobahn pistons lightened to match the existing pistons

The advantage with keeping my existing cylinders and pistons is that they have sealing rings machined into them so less possibility of leaks and they are off a known engine with rings that don't need replacing.

[John McM]

The pistons have cylinder numbers stamped on the crown. Unfortunately, three of them were packed on top of cylinders that didn't correspond to the number. To make sure I didn't a problem I had them all measured. It would appear that any piston could go in any cylinder. Is that a reasonable conclusion?

[jamesjedi]

I have a 964 engine. It is on the engine stand. In order to prevent any corrosion on the inside I have poured some non detergent engine oil in it. I also rotate the engine at the crank and on the stand. It leaks a fair amount. I am not sure how much is related to my having the engine upside down, but I will figure it out.

As a result I will eventually have to do what you are doing. Thanks for the effort of sharing your work. I am following with interest.

[John McM]

Originally Posted by jamesjedi

I have a 964 engine. It is on the engine stand. In order to prevent any corrosion on the inside I have poured some non detergent engine oil in it. I also rotate the engine at the crank and on the stand. It leaks a fair amount. I am not sure how much is related to my having the engine upside down, but I will figure it out.

As a result I will eventually have to do what you are doing. Thanks for the effort of sharing your work. I am following with interest.

Good luck with your rebuild. It helps to have these forums to provide advice.

As for corrosion, after cleaning I coated my parts in fresh engine oil, put them in zip lock bags and covered the lot with a plastic sheet (on the table area marked with a green circle. The engine bores have a light coat of oil and the case has a plastic sheet around it. I have weeks away from home with work so my rebuild is stop / start. The major work will start soon.

Btw I have learned that cleaning is by far the most time consuming part of this work. Lots of cans of degreaser, carb clean and brake clean.

[John McM]

I have decided to fit the ex Autobahn early Mahle cylinders as is (no gaskets or mods to the cylinders or the heads).

The question I have is whether the early cylinder/head joint is left dry or whether some use Curil T to help sealing?

[John McM]

I'm writing a list for the case seal.

The first thing I notice is that Wayne's book and the P fix it DVD start with the through bolts whereas the workshop manual says to lightly tighten the case perimeter nuts first.

The manual makes sense from a sealing perspective as it won't leak from the through bolt area so getting the perimeter sealed early must be best, however equally important are bearing clearances.

So why are there two perspectives and what are the relative merits of each approach?

[porschetub]

Wow nice garage,hope you get your rebuild sorted ,Iam from down your way have a 914/6 build going on for last 2 yrs,good luck on your engine,bloody hard to do this in NZ as you would know.

[John McM]

Originally Posted by porschetub

Wow nice garage,hope you get your rebuild sorted ,Iam from down your way have a 914/6 build going on for last 2 yrs,good luck on your engine,bloody hard to do this in NZ as you would know.

Thanks, I'm very lucky to be able to fit three cars in the garage albeit one has to sit outside now that I have a scissor lift taking up floor space.

Yes, it is harder to do these things in NZ e.g. I was about to close the case and noted that a stud was cross threaded. It took two goes to get the right replacement and set me back two weeks and I ended up with a lot of parts I didn't really need but ordered to make the most of shipping costs.

[John McM]

For the record I learned that a 48mm stud means that 48mm is protruding when inserted. It doesn't mean that the entire stud is 48mm long. That cost me one week and about $200 in shipping and parts I didn't really need.

[mikedsilva]

REally??? that surprised me... I honestly would have thought a 48mm stud was 48mm end to end!!

[mikedsilva]

As for your head to cylinder mating, I didn't use any sealant in that area.. what I did do, was lap each head to the corresponding cylinder using valve grinding compound to get a perfectly flat surface...

Engine has done a couple thousand kms so far, and no leaks whatsoever.

[John McM]

Originally Posted by mikedsilva

REally??? that surprised me... I honestly would have thought a 48mm stud was 48mm end to end!!

Glad I wasn't the only one not to know this. Look up 90006010401 and you will see it's a 8x32mm stud, yet it is 48mm long.