I'm in the process of rebuilding 1.7 type 4 engine for a 912 swap. i purchased it assuming it was a 1.7. I'm going to replace the pistons and cylinders because I'm not sure of compression in this engine. I measured the original pistons and they are 92.88 mm dia. witch would make it a 1.8. my question is,

(1) are the 1.7 piston 90 or 93 mm in dia?

(2) if i have a 1.7 can i put larger piston/cylinders in?

(3) if i can go larger how big can i go?

(3)are the blocks, cranks, rods and heads all the same for 2.0

Also the first two letters of my engine code is EA

EA == 1.7 liter engine originally.

The 1.7 has a 90mm bore and 66mm stroke; the 1.8 has a 93mm bore and 66mm stroke.

There are larger pistons you can fit if you get 1.7 cylinders bored out, but the cylinders wind up too thin and don't hold up that well. The area where the 1.7 cylinders seal is smaller than that of the 1.8 or 2.0, and it seems better to machine the heads to accept the larger cylinders. The 93mm (1.8) and 94mm (2.0) cylinders can easily be opened up to 96mm, which gives 1911cc on a 66mm crank.

The cases are the same for the 1.7, 1.8, and 2.0 motors. (Well, not completely, but they are interchangeable among 914 motors.) The 2.0 used a 71mm stroke, so the crank and rods are different on it than on the smaller-displacement motors.

The 1.7 heads are somewhat different than the 1.8 ones, with smaller valves and different ports and the smaller head registers. The 2.0 heads are very different from the others, with larger valves and larger ports and spark plugs moved.

--DD

Thank you very much!

So it would be safe to assume i do in fact have a 1.7 because of the EA stamp. but because my piston are larger than 90mm they must have been bored out already.
I'm guessing the easiest option would be, just buy a set of new 1.7 pistons/cylinders.

Hi,



Measure the cylinder register in the head and confirm the casting number on the head and check here All you want to know about Type IV cylinder heads 105mm means they are already opened up to 1.8/2.0 size. If they are 1.7 heads with the stock register, I would open them up to 2.0/1.8 register and run 96mm KB's.

You can check Tom's site for other Type IV info.




It's all about the Benjamins. 2056 and 2270 are popular choices.

Good Luck,

Carlos

Ok, now i'm really confused. according to the link you gave me "All you want to know about Type IV cylinder heads" my heads are 2.0 heads, but i match up my numbers and the valves do not match the chart.

022 101 327G intake valve measures 39mm exhaust 33mm
the chars says it should be 37.5mm and 33mm

Click to view attachment

my other head is 022 101 371H

it measured 37.5mm intake and 33mm exhaust. its not on the chart!??Click to view attachment

the other issue is my heads are different (not very happy about that). I'g guessing that because of the intake valves being different sizes and combustion chambers shape (my combustion ratio will be different) these heads are a no go!

i suppose i will start looking for new heads, or at least a matching one
Click to view attachment

Hi,

You have 2.0 and a 1.8 bus heads. 021-101-371S is a 1.8 914 head.