Are 97mm pistons available for 3.0SC

[derm.1785]

Hi, I’m thinking of rebuilding my euro 3.0sc 930/02 engine and was looking to use the original cylinders re bored and re coated to take a 97mm piston. I know that you can’t go bigger due to the sealing ring so 97mm is the maximum I can go. I have read that there may be some 97mm ( 70.4 ) rod pistons around but I can’t see them anywhere. I’m in the UK so parts are limited and shipping is expensive hence using original cylinders etc. I’d be interested to see what the power gain would possibly be or opinions on wether a 97mm piston is worth the effort, I can go 95mm standard JE/wossner/Carrillo etc which are easily available and possibly just as good on the HP. Any advice is appreciated, thanks

[Dpmulvan]

Turbo pistons are 97mm and readily available.

[Mark Henry]

I'd look for a set of 3.2 jugs to bore and plate, 1mm off the wall gets too close to the sealing ring for my comfort.

[derm.1785]

Would these fit, wrist pin diameter, compression??? I’ll look into it now.

[john walker's workshop]

Not a lot of cylinder to head sealing surface left after boring to 97. Suggest using carrera 3.2 cylinders without the o-ring groove if you do. Replaced a set of them last month that had the groove and it was sketchy.

[Mark Henry]

Originally Posted by derm.1785

Would these fit, wrist pin diameter, compression??? I’ll look into it now.

The 3.2 Jugs? Only the cylinders work, you would have to fit a 3.0 JE (etc) piston. It's the same jug, just no ring grove. If re-plating you can use alusil jugs.

[Dpmulvan]

What’s plating cost these days for a set $1700 ish??

[Steve G]

Originally Posted by derm.1785

Hi, I’m thinking of rebuilding my euro 3.0sc 930/02 engine and was looking to use the original cylinders re bored and re coated to take a 97mm piston. I know that you can’t go bigger due to the sealing ring so 97mm is the maximum I can go. I have read that there may be some 97mm ( 70.4 ) rod pistons around but I can’t see them anywhere. I’m in the UK so parts are limited and shipping is expensive hence using original cylinders etc. I’d be interested to see what the power gain would possibly be or opinions on wether a 97mm piston is worth the effort, I can go 95mm standard JE/wossner/Carrillo etc which are easily available and possibly just as good on the HP. Any advice is appreciated, thanks

97mm gives you a 3.1, if you're adamant then its best to use turbo barrels and custom pistons.
There is a guy in the states who sells 3.1 kits.
In the UK, if you want to bore and coat, i used Poeton in Gloucester, they had a good service.
If you're after more CC best to use old 3.2 barrels and have them bored to 98mm, pistons are easily available in many compression ratios, second hand cylinders are easily found. Then you have a 3.2 short stroke!

[derm.1785]

Originally Posted by Steve G

97mm gives you a 3.1, if you're adamant then its best to use turbo barrels and custom pistons.
There is a guy in the states who sells 3.1 kits.
In the UK, if you want to bore and coat, i used Poeton in Gloucester, they had a good service.
If you're after more CC best to use old 3.2 barrels and have them bored to 98mm, pistons are easily available in many compression ratios, second hand cylinders are easily found. Then you have a 3.2 short stroke!

I’ve been looking for some 3.2 Mahle barrels for a while now but haven’t see any at a good price, hence the reason for asking about my 3.0 bored out, I’ll keep looking.

[Dpmulvan]

If you have the cash you can get a set from LN Engineering.

[Steve G]

I made an inquiry with EBS in the states a couple of years ago.
You're looking at around $1100 for pistons and rings, $1050 for rebore and replate and they could supply a set of 3.2 barrels for around $850.
I paid just over a £1000 in the UK to have my barrels plated and honed to match the pistons as i couldn't find another set.

There's a set for sale on eBay UK right now for £420

[derm.1785]

Originally Posted by Steve G

I made an inquiry with EBS in the states a couple of years ago.
You're looking at around $1100 for pistons and rings, $1050 for rebore and replate and they could supply a set of 3.2 barrels for around $850.
I paid just over a £1000 in the UK to have my barrels plated and honed to match the pistons as i couldn't find another set.

There's a set for sale on eBay UK right now for £420

Thanks for this. I’ve just messaged them for better pictures, not too worried about wear to the bores but need to know if ask the fins are there.

[HaroldMHedge]

Search the internet and you'll find that the 911SC could be obtained as a 3.1L which made about 210 HP.

Excellence - Point One This forgotten 911 SC variant packs a punch.

Silodrome Gasoline Culture - The Unusual Porsche 911 SC 3.1 – The Car With The Secret Engine Option

Henry Schmidt at SUPERTEC PERFORMANCE has a thread on this build recreation: Remanufactured 911SC 3.1L pistons & cylinders

[derm.1785]

3.2 cylinders are on the way to me from Germany, additional import duty to add to the cost but still a good buy. They have worn bores but I’m opening them up so I don’t mind. The next thing is to open up the opinions on which pistons to go for, JE, Carrillo, Wossner, Wiseco etc.

[mikedsilva]

Originally Posted by derm.1785

Hi, I’m thinking of rebuilding my euro 3.0sc 930/02 engine and was looking to use the original cylinders re bored and re coated to take a 97mm piston. I know that you can’t go bigger due to the sealing ring so 97mm is the maximum I can go. I have read that there may be some 97mm ( 70.4 ) rod pistons around but I can’t see them anywhere. I’m in the UK so parts are limited and shipping is expensive hence using original cylinders etc. I’d be interested to see what the power gain would possibly be or opinions on wether a 97mm piston is worth the effort, I can go 95mm standard JE/wossner/Carrillo etc which are easily available and possibly just as good on the HP. Any advice is appreciated, thanks

The 930/02 is a rare engine case. Belongs to the 76 and 77 Carrera 3 right?
So it should have the 6 bolt crank.

I rebuilt mine with stock crank and rods, and kept the 95mm bore but consulted with @KNIGHTRACE (William Knight) on this forum, who specced and ordered some Carrillo pistons for me. He also helped me choose a camshaft to better suit my needs. If you keep CIS you have limits, but if you have carbs or itbs, then there is a LOT more performance sitting waiting for you.

I wish I had done what you did, by getting some 3.2 cylinders opened up to 98mm but I was trying to be dollar conscious.
I believe William is fairly busy, and there is a long delay on pistons (I'm still waiting!) but if he has the time, it's definitely worth reaching out.

Mike.

[derm.1785]

Originally Posted by mikedsilva

The 930/02 is a rare engine case. Belongs to the 76 and 77 Carrera 3 right?
So it should have the 6 bolt crank.

I rebuilt mine with stock crank and rods, and kept the 95mm bore but consulted with @KNIGHTRACE (William Knight) on this forum, who specced and ordered some Carrillo pistons for me. He also helped me choose a camshaft to better suit my needs. If you keep CIS you have limits, but if you have carbs or itbs, then there is a LOT more performance sitting waiting for you.

I wish I had done what you did, by getting some 3.2 cylinders opened up to 98mm but I was trying to be dollar conscious.
I believe William is fairly busy, and there is a long delay on pistons (I'm still waiting!) but if he has the time, it's definitely worth reaching out.

Mike.

Mike. Thanks for this, keeping engine rebuilds to a reasonable budget is difficult, Luckily I bought the engine at the right price and you are correct it’s a rare case, very clean casting and strong. Im think I’m going to go with PMO as this will suit me more. Pistons are the next purchase issue with so many claiming to be the next best thing etc, that’s why I’m reaching out to those that have experience in running and rebuilding with different makes and types.
Hopefully this thread will give others like me a chance to get up to date info on this size of engine. I have rebuilt a few stock early engines 2.0T and a few 2.2E but always replaced like for like.

[Henry Schmidt]

911 SC 3.1 pistons and cylinders