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3.5 Yes or No?

I am on the verge of rebuilding my 1980 3.3 turbo. I have a set of 3.5 Mahle cylinders that are brand new. I am going with an EFI system on the engine. Here is the question. Do I go with the 3.5 cylinders? I have heard quite a few arguments against this modification, mainly boring the spigots and potential cylinder sealing problems. I do not plan on running more than 1.0 bar with a 8.1 compression ratio. So what do you think?
Thank you.

Old 03-02-2008, 10:19 PM
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You already have the P&C so your concern is to use or not to use. I'm not a fan of the 3.5 conversion on a 3.3 , better to go 3.4 ........Is your 3.5 from andial ?
Old 03-02-2008, 10:25 PM
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I have heard rumors of slip fit 3.5's. Can't remember who was making them though. Doing a search may bring back some results.

I personally stuck with the 3.4 upgrade. I didn't like the idea of machining the case, and once its done, there is no going back. If it was good enough for the yellowbird it is good enough for me...
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Old 03-02-2008, 10:39 PM
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Hi Richard, that's the upgrade I started....and yes, first of all, you must consider that the engine case will have to be machined carefully....as you can see here....
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I got MAHLE 3.5/7.5/1 and 962 twin plugs heads....
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Old 03-03-2008, 12:16 AM
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Is there a possibility of getting the spigots machined for O-rings like the 993GT2 utilizes? I would think that this would be optimal.
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Old 03-03-2008, 09:48 AM
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Is there anything wrong with machining 1mm off the outer diameter of the 3.5 barrels so that you don't need to machine the case?
It should not weaken the barrels anymore than the 3.4 since it is only 0.5mm on the radius or wall thickness....at least it seems negligible.
Just a thought.
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Old 03-03-2008, 02:38 PM
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Quote:
Originally Posted by fredmeister View Post
Is there anything wrong with machining 1mm off the outer diameter of the 3.5 barrels so that you don't need to machine the case?
It should not weaken the barrels anymore than the 3.4 since it is only 0.5mm on the radius or wall thickness....at least it seems negligible.
Just a thought.

Don't know if it's a better solution....?......






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Old 03-03-2008, 03:30 PM
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Quote:
Originally Posted by A.Wayne View Post
You already have the P&C so your concern is to use or not to use. I'm not a fan of the 3.5 conversion on a 3.3 , better to go 3.4 ........Is your 3.5 from andial ?
Wayne,
At this point I only have the cylinders. I am going to have a set of pistons made. I purchased the cylinders and they came with 11.5 to 1 Cosworth pistons. I got a great deal so the pistons are extras. I do agree with you on the 3.4 prefrence. I just hate to spend the extra money on 3.4's when I already have the 100mm.
Old 03-03-2008, 06:39 PM
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If you are going to have pistons made , then i would go back to cosworth for a lower comp version.
Old 03-03-2008, 07:34 PM
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Quote:
Originally Posted by Richard Buckner View Post
Wayne,
At this point I only have the cylinders. I am going to have a set of pistons made. I purchased the cylinders and they came with 11.5 to 1 Cosworth pistons. I got a great deal so the pistons are extras. I do agree with you on the 3.4 prefrence. I just hate to spend the extra money on 3.4's when I already have the 100mm.
How about selling the cylinders?

Les
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Old 03-03-2008, 08:11 PM
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Originally Posted by A.Wayne View Post
If you are going to have pistons made , then i would go back to cosworth for a lower comp version.
Why Cosworth and not JE?
Old 03-04-2008, 07:33 PM
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Are you interseted in the cylinders?

Old 03-04-2008, 07:35 PM
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