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Fri Nov 27, 2015 3:31 pm

I have three 914 motors. 2in pieces on the bench being evaluated and the third in RevWife's 914.
1) 1.7 that sat since '93, water and oil in case eroded the cam gears, but all else looks fine. Stock l-jet.
2) 2.0l dropped a seat #3 take. All else looks good.
3)2.0l running/driving-daily driver set for stck d-jet, but running hmx 44
Plan
1) use the 94mm from the 2.0 Ito build the 1.7 into an 1832 for se in a 74 standard type 1
Question:
a) will the 94mm pistons work? Is there any issue with the difference in stroke?
b) what max rpm is permissible for a stock non-counterweight 66mm stroke TiV crank?
c)what cam? (40-44hpmx/idf )
d) opening heads up to 42mm intake 36mm exaust

2) stock 71mm crank with 96mm p/c to make a 2056 for use in 74 914 daily driver (though RevWife wants to see what she can do at the drag strip.)
a) 44 carbs possibly a resurrected D-Jet?
b)what's the rpm max on this crank?
c)what cam
d) 42/36 heads or larger?

3) motor coming out of the 914 to become 2800+
a)??? Cross this river when we get closer.

Thanks for the thoughts, input and direction
Rev.

Sat Nov 28, 2015 7:21 am

I wouldn't worry about the cranks limitations. The rods or rod bolts are the weak spot. My experience is that they let go before the crank.

Sat Nov 28, 2015 8:42 am

Thanks for the reply- I'll add ARP bolts to the parts list.

Sun Nov 29, 2015 2:33 pm

Any difference in 96mm pistons for a 66mm and those for a 71mm crank?

Sun Nov 29, 2015 3:17 pm

Pin height is different between the two to compensate for the stroke.

Sun Nov 29, 2015 6:49 pm

Thanks, Joseph. That's the first I've seen a distinction between the 66 and 71 strokes, but I'm just wandering into the type 4 world. Can you point me in a direction where I would find what that difference is?

Sun Nov 29, 2015 7:01 pm

the 1.7 and 1.8 have different rods (length and journal size) compared to 2L.

BASICALLY the 1.8 was changed to 2.0L with an offset grind of the crank to a smaller rod journal, and a different length rod. And pin height in the piston.

1.7/1.8 differ in the bore size, and the cylinder head bore (1.7 is smaller). There are slip in kits for the 1.7L, but they suck. So they work "OK" if you get them for a 1.8, but also bore the 1.7L head to the 1.8/2.0L size.

Sun Nov 29, 2015 7:44 pm

Okay, maybe I'm comparing apples and oranges and coming up peaches.

What I've been reading from Raby is that one can take a 1.7 case and I at all 2.0 crank, rods, and 94p/c's to come up with a 2.0L wth no machining required.
that lead me to belive/think/assume that they were the same bore diameters.
What am I missing?
I realize this is an aside from the 96mm pin height question. Sorry for the diversion.
Rev.

Sun Nov 29, 2015 7:47 pm

Mike,
There is a site called Shop Talk Forums that has a section on type 4 engines.
On it is a lot of info you may be interested in.
The differences between a 66mm and 71mm stroke as John says is the offset grinding of the crankshaft.
The 1.7/1.8L rod journals are 55mm and the 2.0L are 50mm.
Also the connecting rod length are different. 1.7/1.8 are 126mm and 2.0L are 131mm. Both use 24mm wrist pin diameter.
John sells parts on his site aircooled.net and George at http://www.europeanmotorworks.com/ specialize in type 4 parts and machine work.

I have a type 4 2056cc (71x96) that been in several vehicles over the years.

Sun Nov 29, 2015 8:14 pm

You can take a 1.7 engine and make it a 2.0L by using the 2.0L crank, rods, pistons, and heads. The block (case) is virtually the same.

Sun Nov 29, 2015 8:36 pm

MY type 4 engine started out as 1700cc engine from a 1971 Porsche 914 that I bought in 1976. I installed a NPR 96mm big bore kit to make it a 1911cc. John is correct in that top of the cylinders are too thin. On mine the cylinders cut grooves in the heads. It was then enlarge to a 2.0L with the use of used parts from work that were take off from other engines. It is now the 2056cc with the cylinders that European sells. 2.0L and 96mm cylinder slip right into case without machine work.
I am still using the 1.7L heads that came with the engine. I had them machine to fit the 2.0L size cylinders.
Yes all the engine cases are basically the same. Some have the place for the oil filler tube opened up. The 914 case does not. Early cases had a second relief valve on the side by the push rod tubes.
Later cases out of Buses usually have ran hard.
The oil galleys soft plugs need removed, drilled and tapped for pipe plugs as they fall out on there own. It is quite common even with the stock oil pump.

Mon Nov 30, 2015 7:39 am

turns out, the motor is a 1.8- that explains much of my confusion.

Now that what I'm reading matches with what I'm seeing :idea:

Thanks guys for hanging in there. Much appreciated.
Rev.

Mon Nov 30, 2015 2:54 pm

I wouldent waste the money on rod bolts just put in a set of H beam rods.

Mon Nov 30, 2015 3:16 pm

Oh, my. This is a whole subject into itself.

See sig below for my bus motor build - It might have a few bits of useful info.

Tue Dec 01, 2015 7:55 am

Thanks for the link, Clatter. Enjoying the read. It's going slowly, it enjoying it.
The plan for the motor formerly known as 1.7, from here out to be referenced as 1.8- was for it to be asswmbled from those pieces I've got on hand, namely crank, rods, cylinders/Pistons, and heads.
With respect to the p/c's - pin height is notably different between the 93 x66 and the 94 X 71 Pistons. Can that difference be made up by shaving the barrels (yes would make a narrower motor- what are the drawbacks of this?)
Can it be made up by Purchasing longer rods? Do they make (did they make) longer rods for the 66 cranks? Or would that entail grinding the journals?

Or- do I swap in the 2.0 crank and rods to go with the 94p/c - and save the machining and purchases for the 2.0?

Also- regarding heads- should I keep the 2.o heads with the larger motor? Or the 1.8 heads (with larger valve seats cut) in the larger motor?