What shop can bore out stock 94mm cylinders to .5mm or 1mm oversize?

[coolj30]

What shop can bore out stock 94mm cylinders to .5mm or 1mm oversize?
Any in Ohio?

I'm trying to put together a 2.0L type 4 for a project as cheap as possible.
I have a set of pistons and cylinders from a 2.0L 914 engine.
The pistons are fine and I found new rings for $19.50.
I honed the cylinders, but it was not enough and I still have some pitting.
I found that I can buy oversized rings in .5mm and 1mm.
So I am weighing the price of buying a set of new AA cylinders for $129.95 and getting $19.50 rings
OR boring out stock cylinders and spending $84.95 on rings....

I know I should just buy a set of 96mm slip-ins.... But I'm on a tight budget for this build. Thanks!

[Marc]

What are you planning to use for pistons? If you bore the cylinders, the pistons need to be oversize as well as the rings...

[Ol'fogasaurus]

Mark, isn't the 94 mm a bit thin to start with?

[Steve Arndt]

Mark, isn't the 94 mm a bit thin to start with?

Not in the type 4 forum Lee, they are THICK and strong. They are commonly bored to 96mm.

[Ol'fogasaurus]

thnx

[Piledriver]

Mark, isn't the 94 mm a bit thin to start with?

Not in the type 4 forum Lee, they are THICK and strong. They are commonly bored to 96mm.

T4 jugs are quite a bit beefier than any T1 jug, esp the factory/real OEM used ones.
They also don't have ~1/2" of unsupported and not really well cooled finless section jammed up in the head, more like 6mm.

Personally working on cutting that to ~zero and moving the head seal to the stupid thick shoulder of the jug, with a C ring.
The deck would be that much thicker,(a known weak point on T4 heads) and ~no material needs cut out of the head for huge bores, more strength and better cooling follows naturally.

Its too bad 105s are actually pretty thinwall...
But probably still as thick as T1 94s.

As to the original question, you are gambling a local shop has the proper torque plates and procedures down to bore jugs for a T4? EMW or RIMCO, pay for the postage..

I'd wager properly rebored used (heat cycled//aged iron) factory or old German OEM jugs will likely outlast the buttery soft Chinese cast iron many times over.

[coolj30]

What are you planning to use for pistons? If you bore the cylinders, the pistons need to be oversize as well as the rings...

Are you sure????
I thought for that small of an increase I could still use the stock 94mm piston and just go with the larger ring to seal it up? Maybe it can not be done? And that will answer my question/solve my problem.

[falcor]

No, oversize cylinders needs the correct oversize piston to match. Using just the larger rings and the rings wont get enough support from the grooves in the pistons and probably break, ruining both cylinders and pistons and perhaps more.

[Ol'fogasaurus]

I have to be more careful as I had missed that this was a 4 forever forum. It shows up in a small colored text on my tablet.

Lee

[Marc]

...Are you sure????
I thought for that small of an increase I could still use the stock 94mm piston and just go with the larger ring to seal it up? Maybe it can not be done? And that will answer my question/solve my problem.

Quite sure. Rings can handle maybe .010" of cylinderwall wear/taper. Pistons can also have their skirts "knurled" to take up a little extra clearance...but as far as an actual overbore, new oversize pistons are mandatory.

Mark, isn't the 94 mm a bit thin to start with?

Lee, that was my first thought when I saw the topic - but he's talking about 914 jugs and they can take it. 94mm Type I cylinders are all of .006" thicker than the oft-maligned slip-in 87s, so overboring those would be out of the question IMO.

[coolj30]

...Are you sure????
I thought for that small of an increase I could still use the stock 94mm piston and just go with the larger ring to seal it up? Maybe it can not be done? And that will answer my question/solve my problem.

Quite sure. Rings can handle maybe .010" of cylinderwall wear/taper. Pistons can also have their skirts "knurled" to take up a little extra clearance...but as far as an actual overbore, new oversize pistons are mandatory.


Well I feel dumb now.... lol But that solves my problem! I'll just buy a set of AA cylinders.
Thanks!