Engine and Transmission Tech

Nick,

Pin size of 4/0/4.6 piston is .966" so no good for chevy rods @ .927" I'm afraid.

The 4.2 crank Curtis is talking about is the smaller bearing size also.

kevin.

Opening up the SBC small end by over 30 thou is probably a bad idea...

OK I got another idea from looking up piston availability for Tamas. Wisco sells a VW flat-4 piston that's 94mm bore, pin dia.: .866", with a compression height of 22mm (1.378") that might work. Hmmmm.

Wait, here's another possibility. Forged Mahle VW flat 4 piston: 94mm bore, .866 pin, comp height: 34mm (1.56"). Could use that with your 5.85" rod that puts the slug 35 thou down the hole. That's a little closer. Here's some linx:

[www.geneberg.com]
[www.importperformanceparts.net]

Lastly a link to the 6" small journal chevy rods:

[www.flatlanderracing.com]



Edited 3 time(s). Last edit at 11/27/2009 12:34PM by NixVegaGT.

Another option with the 6.0" rods is either the KB-186 or KB-834 Chevy 305 bore piston. My engine spec is very similar to Kevin's, but I'm using the KB-834 (10cc dish) pistons with the 6.0" SBC small journal rods, a 3.9 block and 4.2 crank, and the 3.9 heads for a static compression ration of about 10.9:1 (8.2 DCR with Isky 282 cam). That's with the block decked about .020 and the composite head gasket. Quench distance of around 0.048". According to Kevin (if I remember correctly), the 4.2L stroke can vary from 3.000 to 3.020, so I've assumed middle ground of 3.010 for the above.

Nic and clan, We should be cautios about using "air cooled" pistons in out motors. Many mfg's use different "cam" profile on skirts, specifically for air cooled motors,(ie. pistons run hotter) and different running clearances. I'm not saying, no, but ask mfg'r?roverman.

Art, I got a similar response from a well known UK specialist. He felt that pistons from air cooled engines run different clearances / are designed with different expansion characteristics compared to wet engines. Having said that, big forged Mahle pistons are used locally in e.g Ford 4-banger race engines and seem to cope well. Again, Fords are iron blocks so who knows. But the Mahle pistons look tempting being forged and having coating on the skirts.

Could be. I was thinking the same thing at first but I got the info from some guys using them in the BMW M10 engines. THanks guys.

Just curious. I know the argument about "it came with one" but if you are changing the engine to that extent, why not consider an LS2? 368lbs dry (without the stock manifolds), 400hp, 400ft/lbs, under $6k delivered with a 2 year warranty. It's about the same size as a 215, so size isn't an issue...

Totally. When I started my project the LS engines were really expensive so I stuck with my initial plan. The main reason to modify the Rover engines is because it's fun.

I think the LS block is actually an inch shorter in length. If I remember right, the LS block is 22", and I think the Rover is 23" or so. Very light and tons of potential. Good engine.

On the weight, not that I'm arguing against the LS here but just saying: My engine ended up just under 300 lbs. dry. So that's a bit of a perk. If I went with the LS I would need to modify the firewall to get better chassis balance for the track. As it is with my 300 lbs engine I'm at 53/47. Another 70 lbs would put me in bad shape. That's just me in my Chevy Vega though. GM built them to be a little front heavy by putting the engine right over the front "axle". I was able to move the engine back 2.5" to put the center of the engine just behind the center line of the front suspension. This isn't as big an issue with the MG cars since the engine is place a little farther back.

I thought the dry weight of the LS was like 345lbs. ?

[cgi.ebay.co.uk]

Thought this might be the best place to drop this teaser in.
Be sure to show the spousal units and drop a big hint about Christmas.
; )
B

Bernard, I'm hopin Mike Perkins,(wedgewoks), wound-up with that set-up for his 4.02" bore, Rover monster.Mike? roverman.

And Nic, is it "totally" too late for you to mentally congugate....mid-engine, Vega ? U-no ,"Hatch a Rover"? You know I got "them" t-axles. Even further weight savings, you would'nt need those canvas rear seats anymore? LOL and more, roverman.

I was at Hot August Nights in Reno a few years back and spotted a 67 Corvair with its transaxle turned around and an aluminum V8 mounted to that. The quality of work on that car was outstanding. To my mind, the 67 Corvair is better looking than the 69 Camaro.

I'm completely impressed with what Nic is doing; an aluminum V8 in a Vega. The only thing I might do differently is to start with a Vega or Monza wagon.

Paul and all. If it was, mid engine, it was possibly a "Crown Manufacturing" type swap, using Corvair T-axle- with reverse thrust on ring gear. With Nic, I was aludeing to Toyota MR 2 Turbo t-axle(tranverse), I consider a better way to go. Dan LaGrou started the ball rolling with "brand new" 215" Buicks in Vegas, 30+ years ago? roverman.

Robert,
On your question "Are there other shops besides D&D that can install 96mm bore tophat liners for less than $2000? ". If you want to go that way, you might give Russell at Allied Machine Shop 703-533-8355 in Fairfax to see if they can do it. I dont know if he would do it but they work on a lot of Rover engines and he did my 215. They are located on route 7 near the 66 access. Richard

Robert,
On your question "Are there other shops besides D&D that can install 96mm bore tophat liners for less than $2000?" If you decide you want to go that way you might call Russell at Allied Machine Shop in Fairfax on 703-533-8355. They do a lot of work on Rover engines and likely can handle that. Richard

I actually did look into rear mounting my spare Olds in our Rabbit grassroots car. That would have be awesome! I was actually looking at using a reverse bug transaxle. That put the engine right behind the driver though. I think the MR2 idea would have worked well though.

Paul, are you on the H-body.org site?

Nic, no, I've not been to the h-body.org site. I'll check that out tonight when I get home.