just as the title asks... im concerned with heat issues and thin walls



kenny

thanks for the info, trying to figure this whole thing out

Which 96mm cylinder's are you talking about? The cylinders that came with the pistons?

I had stock 94mm cylinders bored out by Rimco to match the 96mm KB pistons. The old set of cylinders that came with the KB's didn't fare so well after 10k miles, hence the rebuild.

is your avtar the melted piston your refering to? did it happen with the aftermarket cylinders or with bored out94's. this is my biggest concern. are there good AND bad aftermarket 96's?

the avatar piston happened on the first drive of a new rebuild 5yrs ago. throttle pedal got stuck, my dad's first reaction was to give it a quick jolt with his foot but that made it stuck at WOT and snap, crackle, pop the fresh engine was toast. That was not a happy day. Both he and I have kicked ourselves for not just turning the key off rather than listening to it roar at WOT...

Ahh, memories...

fwiw, the cylinder used during that session are the one's that came with the KB p/c sets. Not sure if the same cylinders come with the sets these days. I rebuild it last summer b/c I had it mistuned and overheated the engine (damn operator errors ; oh yeah, that operator is me). Anyway, the cylinder's expanded due to the overheating and are out of tolerance which is why I've gone to the stock 94mm's bored out.

I think cost wise, it's a bit more $ going the 94mm bored route but if you can get a set of stock 94mm's in the classifieds for $50 or so then Rimco will match them to your 94mm pistons for about $150 (then there's shipping). Not terribly expensive but budgets vary.

-pt

If you start with factory 94's (1.8's and 2.0 engines) and make the hole bigger to 96mm, then you will lose a little material and the walls will be thinner. Time and testing has shown that this is OK as far as strength and cooling. If you start with 1.7 cylinders (smaller bore than 94's) and bore them out, you have problems with the thin wall at the top of the cylinder (where it goes into the head) in that it is almost a knife edge (sealing issues) and prone to breakage problems.

The old NPR Japan bigbore cylinders for 1.8's and 2.0's are 96's and are good. As per the China cylinders? Who knows what their fabulous quality control is able to produce in consistant wall thickness, consistant bore diameters, voids, cylindricity, porosities, cylinder lengths, etc....

If you are feeling flush and never want to worry about cooling and quality, buy some fabulous L&N Nickies. They are aluminum cylinders with nickasil plating to control wear. The aluminum cylinders expand at the same rate as the heads and the pistons, unlike iron cylinders, aluminum pistons and aluminum heads. Add an aluminum coefficient of conduction much greater than the iron (2-3 times better), and Charles's fanatacism to proper machining and plating and you can see the advantages.

Ken

Hey Kenny and Mike, You should really listen to Jakes radio show. Especially the one last week. It talks about bigger motors and heat. They are NOT related, in fact it's the opposite. A bigger motor takes less effort to put out the same amount of work. It's easy enough to log on and get acsess to listen.

Also, everyone here has said, if you want to reduce the heat in the motor, CHANGE THE CAM.

It cost's very little to split the bottom end, put in new bearings and a cam, cheap insuranse.

Just my .02c

Keith

i plan on going with 1.8/2.0 heads not boring the 1.7 cylinders. the china cylinders scare me. maybe i'm wrong. what are these L&N nickie? big bucks?

The LN cylinders are amazing. They are also a little more than $2K...

thanks for info on radio show, i quickly checked jakes show and saved it last night. yes i plan to do cam, i need to call jake raby's mon. for direction on what to get. i'm only able to do the case split with outside help. several have offered to help. do you think you could be part of the build effort, i know you've got a brain full of valuable knowlege. we plan on getting all the nice new shiny parts together , tear down and clean parts before. we'll thow something on the bbq

OUCH!

the only advice I'm comfortable giving you re a rebuild is BE PATIENT. You will forget to account for something and have to wait a week or 2 or more for a part/parts. If you have a set time frame you will prob end up cutting corners or becoming very frustrated. Jake's video is a good start - BUT NOTE, he doesn't mention tapping the galley plugs in the video and apparently, it should be done...

-pt

are you talking about the oil galley plug that i've read about popping out? if so where is it located?

Telephone is the least effective way to get in touch with us- if you want a very fast response email my parts division at parts@aircooledtechnology.com

The telephone impedes my schedule and I only use it one day per week by appointment.

There are good and bad 96mm cylinders, the ones we sell are inspected and are the same cast iron cylinders that we use in our engine kits and are good quality.

The 96s will NOT cause heat issues IF the engine is properly configured, mine in the 912E have 130K miles on them and the head temps have never even been as high as they were when the engine was bone stock.

With my assistance you can net a 96mm bored engine that runs COOLER than stock- we do it all the time. It's another result of thorough development.

I'd like to help if time permits . I am in the middle of a rebuild myself. I finally found some high compression pistons that look like they will work. Most everything is powder coated .but the car is not ready yet, it's a long process but I want it right this time so I am taking my time

If things work out I will pitch in.

Keith

yes, but there are 5 of them to drill, tap, & plug. Jake has a very helpful article on the what's & how's here:

http://forums.aircooledtechnology.com/showthread.php?t=72