Choosing a 78mm crank...

MJ Mitchell · Post by **MJ Mitchell** » Tue Aug 21, 2001 10:53 pm

I'm getting ready to build a 2017cc for my '69 Beetle. Being that this is the first larger displacement VW engine I've built, I'm looking for some input on choosing a crank. I want to stick with a 78mm to keep the cost down and I'm trying to decide between welded or forged. Does anyone have experience with RIMCO's welded CW 78mm cranks? I know they do good case work, but I haven't heard anything on the quality of their cranks (as compared to DMS). What about CB Performance's forged 78mm cranks?

Steve Arndt · Post by **Steve Arndt** » Wed Aug 22, 2001 9:05 am

Go with a forged 1 piece CB Peformance crankshaft.
The 82mm costs teh same as the 78.
They both should use good rods.
That means it costs the same to build an 82 stroker as it does a 78. If you order an 82mm clearanced cam from WebCam you won't have problems.

JohnConnolly · Post by **JohnConnolly** » Wed Aug 22, 2001 10:52 am

MJ,

you have a couple options. We have the SCAT cranks on special right now, 82mm or 78mm. Recently the CB cranks have had one minor problem, but it does require machine work to fix (around $40-50), just so you know. We also stock the Web Cam camshafts, so you can get both in one order and save on shipping and convenience.

Also, I'll do a special Shoptalk deal! The next guy that orders a 78mm 4340 crank and mentions they are a Shoptalk participant gets the crank for $400.

John
Aircooled.Net Inc.

[This message has been edited by JohnConnolly (edited 08-22-2001).]

MASSIVE TYPE IV · Post by **MASSIVE TYPE IV** » Wed Aug 22, 2001 12:28 pm

I use the CB cranks, but as John says they have some minor problems...If you go with one make sure all the keyways are the proper size, and also check the dowel areas..

I'm a fan of the 78 stroke, especially for a first time build..The engine is easier to build, which means alot on the first time around..The 78 stroke still drives like a bug engine, instead of a V8 (like most 82 combos) the zippiness of the rev makes up for the losses...our 2165 (78 x 94) type 1 engines propel our Spyder customers zero -60 in about 4 seconds (if it hooks up, and if gears are grabbed quick enough)but it is a 1200 pound, mid engined, rocket..

------------------
Jake Raby
Raby's Aircooled Technology
www.aircooledtechnology.com

FatAlbert · Post by **FatAlbert** » Wed Aug 22, 2001 11:34 pm

Could you tell more about RIMCO's 78mm welded crank? I called them about 2 months ago (after reading some info in Hot VW's...) and they denied offerring a welded stroker. What's the low-down and how much are they selling 'em for?

MASSIVE TYPE IV · Post by **MASSIVE TYPE IV** » Thu Aug 23, 2001 8:58 am

I do not believe that RIMCO sells the welded cranks any longer..

The BEST welded cranks we have found are from DPR machine, we use them to custom grind our type 4 strokers...All our type 1 engines have forged cranks.

stevestromberg · Post by **stevestromberg** » Thu Aug 23, 2001 9:01 am

Rimco does not build welded cranks they use a company call DPR. I have spoken to Jose at DPR and to the guys at DMS I plan on Using DMS for my next crank. FAT uses DMS to build their cranks. Steve

MJ Mitchell · Post by **MJ Mitchell** » Thu Aug 23, 2001 9:23 am

Last time I called, RIMCO offered a 78mm welded CW crank for $375. They do the welding and knife-edging of the CW's and send them out for grinding and polishing (I don't know who they use). Availability seems to be spotty. As mentioned earlier in my post, I don't know about their quality compared to other welded CW's. I'm leaning towards the CB or Scat one-piece forged cranks.

MASSIVE TYPE IV · Post by **MASSIVE TYPE IV** » Thu Aug 23, 2001 1:06 pm

DPR makes the best welded cranks, one look through the oil passages will tell the truth..I use them to build my type 4 cranks..I have tried all the rest, but I use over 100 DPR cranks every year~!!!

jmillheiser · Post by **jmillheiser** » Thu Aug 23, 2001 10:37 pm

so i take it that the 78 revs faster and produces more top end power where the 82 revs slower but has a lot more low end and mid range grunt?

fastfood · Post by **fastfood** » Thu Aug 23, 2001 11:04 pm

I have run both and totallyy agree with massiveT-4. The 78 just seems to be more driveable. If you can, for longevity, get the forged cranks, they seem to do better in the long run. Good luck with your project!

------------------
Rice, it's what's for dinner!!!

MASSIVE TYPE IV · Post by **MASSIVE TYPE IV** » Thu Aug 23, 2001 11:33 pm

You got it...Exactly..

Steve Arndt · Post by **Steve Arndt** » Fri Aug 24, 2001 8:29 am

Its all in the combo.

Steve

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by jmillheiser:
so i take it that the 78 revs faster and produces more top end power where the 82 revs slower but has a lot more low end and mid range grunt?<HR></BLOCKQUOTE>

Searoy · Post by **Searoy** » Fri Aug 24, 2001 12:34 pm

So even a 74mm crank would have it's place if the setup or purpose was right...Eh?

------------------
*** Teach a Man to Fish ***
Searoy

MJ Mitchell · Post by **MJ Mitchell** » Fri Aug 24, 2001 10:26 pm

Well, I've ordered up a CB 4340 78mm from Aircooled.net (thanks John). I'm sure I'll have a bunch more questions as I start my build. Thanks for the info.