APAN

hi to all of you,
the story goes like this :
i broke one of the valve springs of my beatifull 944 s2 convertible! , my mechanic started dismandling the engine, so far so good, but as soon as he reached the pistons he saw the light, i saw the light too. actually i almost had a stroke.
One of the pistons was F........ up.
propably something fell inside the enginet by the previous ******** that was servicing the car during another valve spring failure. greek mechanics aren't that reliable.anyway nikasil cylinders are OK so i am looking for a piston set and i need help.
The car wears right now MAHLE pistons, i checked at pelican parts, they can only give me porsche pistons around 2300 USD which is far too expensive.
what if i go for wiseco 750 for a piston set although i prefer using MAHLE which i can't find yet to buy.
I NEED HELP FROM THE EXPERTS!

931guru

Some of the dismantlers might have a piston to match what you need. There are some pretty reliable dismantlers around.

Chads996

If the cylinder is scored badly, it will need to be machined and then honed. Likely you will need oversized pistons in 104.5mm. If that is the case, there are not very many choices out there. While you are in there, I would also recommend going with forged pistons. The ones you are pulling are likely cast.

Possible examples out there:

JE pistons
Mahle
Wiseco

Take your time, there are some others out there too.

C.

APAN

thanks for your replies
my cylinders have no problem , i am just looking to by a new piston set and i don't know if Mahle work better on this car than wiseco or JE .I 've already found wiseco at a good price but i haven't found yet someone with Mahle .Does anyone know anything?

regards
Alex

V2Rocket

what happened to the pistons? got a pic?

gstein

For parts like this, I try to get a spare motor from somebody parting a wrecked car. I got my last motor for 250 bucks including all electronics etc.... Far cheaper than new pistons, plus some extra parts to sell if need be... good luck

Ben

APAN

i don't have a picture right now
my mechanic doesn't seem to like the idea of a used piston and to be honest this car is going to stay with me for a few decades so in that case i only wanna do once each repair

FRporscheman

I have a good set of used S2 pistons if you change your mind.

JET951

Hi Alex ,I have been working on the 944s and 944S2 twin cams since their inception and to this date have never seen a broken valve spring /springs on a 944S2 , I/we have many customers who race /compete with 944S2's with S2 & S cams and still have no problems at all with standard valves and valve springs , may I suggest that there may well be an underlying problem with the head on you re 944S2 particularly in relation to the preload of the springs ,excessive shims under the valve springs resulting in over compression of the springs (crush and break) or the springs are an inferior aftermarket copy , so do not just put back together without some one (machine shop) that has access to information in relation to the set up of the valve springs base shims ( its all in the manual )and buy a new set of factory springs or quality after market springs and start from there.

PS: I am not saying that its impossible for factory valve springs correctly set up to break , its just that I/we have never seen it , particularly when you state this is the second time its happened , something is not correct .
Regards .BB.

V2Rocket

clearly this is a sign from the porsche gods that you need to build a 3.0L turbo

APAN

Hi Sean
Porsche says that valve springs should be changed every 100.000 km.
my car has already 160.000km on the clock so in that case i find reseonable what happened
anyway i have bought already a new set of valve springs from porsche .
Arash
my other 3 pistons are OK , i will discuss your suggestion with my mechanic
if he agrees, do you consider on spliting your set
Spencer
the idea of having a 3.0 lt turbo is very interesting
my car is a 944 S2 convertible which unfortunately i don't drive at all because i live in greece ,
the car is on english registration and it's not allowed to be driven unless i change the registation (far to
expencive) and secondly i have 2 kids so i use a family car
So for the time being i spend a lot of money to bring the car to stock condition
Doesn't any of porscheholics have an idea on what works better on this car
Mahle
JE or
Wiseco

Makis

My S2 when I bought it had some running problems with the engine. I only found out the cause of the problem when one of the valves burned off and got damaged. The reason for the damage was a broken valve spring. The S2 valve springs are double springs. You have one stiff one and one softer one put together. The stiffer one will break causing the the valve not to work properly. You get a lot of valve float which after continuous use will burn the valve as the valve does not close properly and overheats.
I end up replacing all the valve springs as actually I had 2 valve springs broken. Luckily one of them was on a inlet valve so the valve did not overheat and burn.
But considering that the S2 valve springs are double type don't see how the piston will be damaged as there is no danger for the valve to drop into the cylinder.
So I think S2 valve springs are suspect. It also depends on how the driver treats the engine, thrashing it when cold may be not good for the springs who knows?

APAN

Maki
i bet you are GREEK
the piston is damaged from the valves
it's definitely a mistake by a previous mechanic
something fell inside the engine at a previous job and wasn't noticed up until now

Makis

I recon is not necessary a mistake by previous mechanic. I recon whats happened the timing belt snapped and the valves hit the piston destroying it in the process. The mechanic just fixed the head and valve problem but did not do the piston as that was getting expensive. If something fells inside the cylinder will destroy everything not just the piston.