2.2 or 2.0? Options

[cooper951]

I bought my 914 on eBay (I know, stupid, but let's move on) and the owner said it had a Big Bore Stroker 2.2L engine, upgraded from stock 2.0L, freshly rebuilt. The mechanic who went over it, adjusted the carbs, and fixed some other issues said that because the compression was 140# in the cylinders, it could not be a 2.2. He said it would need to be 180# or higher in order to be a 2.2, and he couldn't say for sure unless the engine was torn apart, which of course I'm not going to do. I've taken different PCars there for over 20 years, and they have a very good rep in the St. Louis with the Porsche crowd, so I trust him. Any thoughts on this issue?

[Chris H.]

Hmmmm.... I'm no expert, but a "stroker" engine is an engine that has been built to increase power by adding more to the stroke (different crank resulting in piston travel increase) rather than the bore (piston size). It's possible that you have stock P's and C's and a longer stroke crank, which would mathematically take you higher than stock, to 2.2. The compression ratio doesn't have to change when the engine is stroked. Shorter rods can be used, the deck height can be adjusted, etc. As you said, there is no way to know without tearing it apart, but DON'T (IMG:style_emoticons/default/biggrin.gif) !!!

['73-914kid]

I'm not sure your mechanic knows what he's talking about.
Compression check numbers have nothing to do with the displacement of an engine, everything to do with quality and condition of sealing parts within the engine (valve seats, rings, etc.) Valve timing, and engine compression ratio.

140 psi does seem low for a fresh engine, but again. Just because it's a "stroker" motor, doesn't mean much about compression test values, or the compression ratio of the engine.

If it ain't broke, don't fix it. Drive it and enjoy it.

[era vulgaris]

Did the seller offer any receipts from the shop that did the engine build? If you still have his contact info, it'd be worth it to ask.

[pete000]

I was wondering if there is a way to determine the engines displacement with out disassemble? I know my car is bigger than a 1.8 by the seat of the pants method, but would love to know just what it is. Previous owner said it was rebuilt to bigger bore. I am guessing a 2056 rebuild but not fully sure.

I know racing inspectors have a way to tell displacement in post race inspections, any idea how they do it?

[Dave_Darling]

The motor is "pumped". That's about all I know for certain, but I believe that it involves pushing a measured amount of air into the intake and turning the engine through one complete four-stroke cycle. You see how much air gets used, and that is a decent approximation of the displacement.

Ah, a quick Google search mentions a tool that gets threaded into the plug hole, and has a floating piston to measure how much air is going in.

http://www.speedtalk.com/forum/viewtopic.php?t=1237

--DD

[porschetub]

Hmmmm.... I'm no expert, but a "stroker" engine is an engine that has been built to increase power by adding more to the stroke (different crank resulting in piston travel increase) rather than the bore (piston size). It's possible that you have stock P's and C's and a longer stroke crank, which would mathematically take you higher than stock, to 2.2. The compression ratio doesn't have to change when the engine is stroked. Shorter rods can be used, the deck height can be adjusted, etc. As you said, there is no way to know without tearing it apart, but DON'T (IMG:style_emoticons/default/biggrin.gif) !!!

Deck height lowered by barrel spacers perhaps,if the compression is dead on 140 even that could be the reason with a fresh motor......