S 2 Heads warning

[SUSIT]

Just found an issue in replacing the Head on my S2, some of you may be aware of this already but worth saying I think.

The head I sourced had no cams or more important cam bearing caps. Not a problem I thought either use the old ones or buy some new caps.

So found out today the caps are matched to the head and are in theory non interchangable. So having bought a ok head and had it recond I cant use the bloodything that easily (if at all)

Have now bought a second head complete with cams (having bought 2 new cams)

I need to get the car up and running, its been off the road 3 months and now my mate has it on his ramp in bits he wants to get the job done ASAP Its also my daily driver[]

I will strip the first head i bought down and trial fit the cams (old ones, new ones going in 2nd replacement head) using the caps from my original head assembly. I may be lucky and it will go together with no sticking once all torqued down correctly. If not then I am told line boring might work.

Watch this space! and all because a £25 chain broke. If you dont know when your cam chain was replaced then I woulod seriously consider having it changed sooner rather than later.

Two steps forwards 3 back[]

Ps if anyone has cam bearing caps lying about I may like to relieve you of them

 

[bertelli_1]

Unfortunately you've found out the hard way that head and caps are machined as an assembly. As you point out you 'may' be ok with another set of caps (a machine shop should be able to measure them for you if in doubt).

I have a set of caps if you would like them - much cheapness!

 

[SUSIT]

ORIGINAL: sc0tty


Just out of interest, what mileage was your 944 at when the cam roller chain snapped? (I had mine replaced at 98,000 miles in 2007 for the first time, so mine had lasted 18 years)

134,000 miles on the clock. dont think the chain ever been done

 

[Super_Marv]

IIRC, Barry at Hartech recommends the chain is replaced every 45,000 miles, as the chain stretches as it gets older and causes additional wear to the teeth on the inlet cam.

 

[bazhart]

Also as the cams wear a change even sooner is preferential.

Cam caps are matched but can be re-line bored.

The biggest weakness in the S2 head is at the rear where the oil hole is drilled to take the oil feed up from the block to the valve area. The casting is very thin where the two drilled holes meet and eventually it can metal fatigue due to the pressure fluctuations and start and stop cycles and crack - feeding oil under pressure into the coolant system - similar looking to the same problem of the oil feed pipe to the oil filter housing leaking on older 944's (with the orange o rings) but less of a problem with later 944's with green o rings and all S2's and 968's that should have been fitted with them.

Baz.

 

[sulzeruk]

I don't think there is a massive issue with the cam caps as the car is a low production volume and there are no shells within the head. If you line bore them, you would then to put shells in. I have used other caps before in different engines with no ill effects so don't see what the concern is about. All you have to do is measure them with a bore gauge for concentricity. All cams will be finished to the same outside diameter so all of the caps should be to the same inside diameter. they are also pegged as well so there really should be no variance between caps. As long as you keep the same numbers to each one, what is the problem?

 

[SUSIT]

ORIGINAL: sulzeruk

Hi Gavin, it would be a problem if they made 3 million of them but they made about 6000 cars alll in and it is Porsche we are talking about so the engineering tolerances would be a bit better than your average. I have every confidence that your cams will fit, as I said, check with a bore guage and I am sure you will find they are ok. They are also pegged into the head so cannot have any lateral movement, just make sure you keep 1 to 1 and 2 to 2 and the writing to the correpsonding stamp on the head and you will have no bother. I don't know what Steve in Inverness is on about in the post, I would be giving it a try before getting yet another head!
Alasdair

I will give it a try but dont have the time. I have spoken to a number of people and companies and not one are convinced i wont run into problems.

Once the car is running I will take my time and sort out the other head but 3 months down the line I need my car back.

Its my daily driver and the garage it is at is a 45 minute drive (34 miles) away so cant just nip down to sort these things out.

 

[sulzeruk]

Tis dead easy to check and takes about 5 minutes to see! Put the cams in the head with the caps and see if they turn! I would be very surprised if they did not and would even put money on it that they would! Even better f the head is bare and hasn't been rebuilt yet,
Alasdair

 

[SUSIT]

ORIGINAL: sulzeruk

Tis dead easy to check and takes about 5 minutes to see! Put the cams in the head with the caps and see if they turn! I would be very surprised if they did not and would even put money on it that they would! Even better f the head is bare and hasn't been rebuilt yet,
Alasdair

Fraid the head is fully built up, The chaps at Promax and EMC did not think I would be able to tell unless it was stripped down again and both felt I would be lucky to get away with it.

I have spend more than I paid for the car sorting this out and wont take any chance of it going to rat shit on me. It i had known this from the begining I would have tried it all before having the head recond.
My own fault for not having done my research as fully as I needed too. hence my post.

If when i get the time to trial fit cams using my old head cam caps and it works I will post here.

 

[tref]

Out of interest, have you used the "special tools" for lifting the cams from the head, or have you just gradually slackend off each of the caps to allow them to lift? It isn't a loaded question - having to lift the cams in mind I just want to know if the spacial tool is really necessary or not!

Regards,

Tref.