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914World.com _ 914World Garage _ Bigger cylinder/piston options for us 1.7/1.8 guys besides 96's?

Posted by: Mueller May 14 2015, 04:44 PM

Seems all the bigger piston and cylinder kits on AA or EMW is geared towards the 2.0 based motors with the longer stroke.

Is there a reason for this besides people just wanting to maximize the CC of their motor build money?


Posted by: The Cabinetmaker May 14 2015, 05:45 PM

Very good question. I await the answer.

Posted by: Bob L. May 14 2015, 06:13 PM

The cases are all the same. As long as it is good condition you can start with a 1.7, 1.8 or 2.0.

IIRC Jake said he likes the 1.7 cases because they have had an easier life. I'm not qouteing him, but something like that.

2.0's have a longer crank (71 vs 66mm)but if you want more than 71mm stroke, you're replaceing it anyway. Otherwise it's just P's&C's, head work, exhaust, wideband... beer.gif

Posted by: Mueller May 14 2015, 09:41 PM

QUOTE(Bob L. @ May 14 2015, 05:13 PM) *

The cases are all the same. As long as it is good condition you can start with a 1.7, 1.8 or 2.0.

IIRC Jake said he likes the 1.7 cases because they have had an easier life. I'm not qouteing him, but something like that.

2.0's have a longer crank (71 vs 66mm)but if you want more than 71mm stroke, you're replaceing it anyway. Otherwise it's just P's&C's, head work, exhaust, wideband... beer.gif



It seems the pistons that are in the kits are for the longer stroke...sure new pistons can be made for the shorter stroke crankshaft, but I would think the price would be higher...or perhaps not?

Posted by: McMark May 14 2015, 10:03 PM

Bigger cylinders have sealing issues.

Posted by: Jake Raby May 15 2015, 07:26 AM

LN will make a piston with any pin height that you desire.

I have a 69X106.3 combo that works great using the 17/1800 rod length ands I have also done this with a factory 66 stroke crank, using the 105.07mm bore size.

Head sealing is an issue when using cylinders and hardware outside the Nickies line up.

In general I prefer stroke over bore hen increasing displacement.

Posted by: r_towle May 15 2015, 07:30 AM

QUOTE(Mueller @ May 14 2015, 11:41 PM) *

QUOTE(Bob L. @ May 14 2015, 05:13 PM) *

The cases are all the same. As long as it is good condition you can start with a 1.7, 1.8 or 2.0.

IIRC Jake said he likes the 1.7 cases because they have had an easier life. I'm not qouteing him, but something like that.

2.0's have a longer crank (71 vs 66mm)but if you want more than 71mm stroke, you're replaceing it anyway. Otherwise it's just P's&C's, head work, exhaust, wideband... beer.gif



It seems the pistons that are in the kits are for the longer stroke...sure new pistons can be made for the shorter stroke crankshaft, but I would think the price would be higher...or perhaps not?

you can get any pin height forged piston you want from the typical piston manufacturers....
I have JE pistons, and you call them to give them all the details you want, they are made to order if you want, but they do stock some normal sizes
Get you head into Chevy and measure up those....the stuff is available cheaper and some of the sizes are close to what we want. (pistons)


BUT, you should still stuff the motor in there and get it running so you can drive it....its fast enough to get you in plenty of trouble.

rich

Posted by: toon1 May 15 2015, 11:04 PM

Not much of interest in short stroke for these engines would be my guess.

the one engine build that still really intrigues me is the 78mm stroke with the 90.5mm bore. a torquey gas mizer

this was the basis for Jakes super two liter,

Posted by: euro911 May 16 2015, 02:00 AM

Dilemma - I'm in the process of tearing my wife's 1.7L D-jet motor apart for a rebuild. At first, I was going to rebuild what was in there - bone stock.

Recently, I've thought about going a little bigger, but want to keep the existing FI system pretty much as is and keep the car fairly reliable (whatever that means, being a 914) laugh.gif

If the 66mm crank and rods check out OK, maybe just a little increase with 94mm P&Cs and a little more aggressive cam. Is this a wise choice? … and an experienced FI guru can list any pitfalls I may encounter?

popcorn[1].gif

Posted by: r_towle May 16 2015, 07:17 AM

You will need to do head work on those heads, or do yourself a favor and get new AMC castings for the 1.8 heads and port design.

Then get a set of 96mm pistons and cylinders from EMW...

Simple build

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