2258cc stroker with 5.70" rods?, 2258cc build, rod suggestions? Options

[lonewolfe]

I'm planning to build a 2258cc stroker motor for my 914. I already have a 78.0mm CW crankshaft with Type 1 journals, 5.70" H-Beam rods, JE Racing Pistons (96.0mm), clearenced case, 1.8 heads w/ 42mmx36mm valves ported and polished and am still undecided about which cam at this point. My question is in regard to the best rod length. As I said, I have a set of Scat H-Beam rods in 5.70" length that came with the parts I purchased. Are these rods too long for this setup? I'd like compression to be around 9.0-9.2 to 1. From what I've read it seems most people prefer a 5.325 to 5.40 length rod. Any suggestions? I could sell the 5.7" rods and get some shorter ones if needed. What's the best rod ratio for a 2258cc?

[ConeDodger]

Do you plan on clearancing the inside of the case? Spacers for the jugs?

[wndsrfr]

Wow...my 2316 with 80mm stroke and 96mm JE pistons uses the 5.325 rods and needed about .040 of shim to get 10:1. BUT, that was with Len's heads with a step cut to give me a deck height of .045.
Depending on the combustion chamber step cut in your heads, I'm thinking you'll need a pretty thick shim/spacer at the base of the cylinders to use the 5.7 rods....(that said, I do have a set of really thick .140" shim/spacers available.)
Frankly, you'll have to mock it up to tell---gotta do that anyway to confirm deck height properly and to verify clearances. I ran into clearance issues with the CB rods not only inside the case, but also with the cap screws contacting the cylinder skirts & had to relieve them over 150thousandths on the centerline of the crank throws....

[bam914]

Get shorter rods. It will take way to much shim to get the deck height right. Plus the tin will not be easy to put on.

[Bills914-4]

IMHO 5.7 is to big for a 78 stroke crank, 5.4 - 5.5 is better suited , I run a 5.7 with
my 84 stroke chevy journal crank, are you aware that you might need a reduced
base circle on your cam ( rod clearance ) . 5.7 rods are better suited for 84 - 88
stroke cranks , you could use them but I would advise against it , it might lose some of its snappiness with to much rod length , personally I would use 5.4 up to
6500rpm , if you plan alittle more rpm then maybe use 5.5 , just my opinion I'm
No expert , I hope this helps , good luck with your build ,remember to check your clearances , mock it up and check each stage of assembly , this is the time consumming part of the build , once again good luck ! Bill D.

[DBCooper]

Bill's right on, unless you intend to be a bleeding edge drag racer. The 5.325 is standard VW T1 length so those rods match your crank, are easy to find and even the H-beam rods are cheap. If you really need to spin the motor that fast then you're going to need really high quality and expensive parts in the valve train to support those RPMs. In theory long rods also improve piston/cylinder longevity because there's less side loading of the piston, but in an A/C motor I think you'll see everything else wear out faster than any added benefit you'll get from the long rods.

[lonewolfe]

Thanks for all the feedback everyone. You all have confirmed what I was already thinking. I bought a bunch of parts from a guy who intended to build a 2258cc motor but had to sell his car before getting anything built. So, I got a great deal. I picked up a case that had already been prepped at the machine shop, stroker clearenced, CW/welded 78mm crank w/ Type 1 journals, Scat 5.7" rods, JE Racing Pistons, H-Grind Cam etc.... Right off the bat I thought the rods were a mismatch for the rest of the parts. I'm thinking 5.325-5.4" rods are ideal. I'll probably not use that H-Grind cam either. I'll either go with a Web Cam or one of Jakes cams made by Web Cam for him. I'm not building a race motor although I do intend to do some AX next year but this car will be 90% street use and am looking for a long lasting reliable motor. Will probably keep compression around 9:0-1.0. Not sure about the compression yet but nothing too crazy so I can run our crappy California 91 Octane gas. Any feedback on compression for California gas will be apprciated as well.

[lonewolfe]

I forgot to add that I'll be selling the 5.7" H-Beams and probably the H-Grind cam both of which are new and never used. The H-beams have no markings on them but have Scat rod bolts which leads me to believe they are probably Scat's. The H-Grind cam come's from European Motor Works if I'm not mistaken. Seems most prefer Jake's or Web Cam's cams over European Motor Works. As for pushrod spacers, I will probably need those and I know Jake has them. I also found some longer pushrod tubes made for strokers that I'm looking into. They are pricey but in theory seem like a better idea than using shims/spacers. I will get the cam clearenced for a stroker with the 1" base circle option. Anyone used the longer pushrod tubes from European Motor Works?