Steel Crankshaft Metallurgy Questions

[Craig S.]

Re: P.S.

Forgot to mention, the dimple rods now have ARP 2000 Pro wavelock bolts after resizing...they were a NOS set of rods when I started. Craig

[Clem Z.]

Re: P.S.

F/M # is CS 165R for the cam,KC 165R for cam and lifters. dur at .050 242/242,lift .520/.520, 114 L/CL

[Craig S.]

Re: P.S.

Thx Clem!!! I saved that info in my cut/paste file for reference when I go to buy. Would you buy the FM unit, or the Crane unit sold through GM parts? Any difference in grinds? I have seen posts here that the base circle is not always the same as the original GM cams. I tried and tried to find one at Carlisle, but none to be found....thx!...Craig

[Clem Z.]

Re: P.S.

i have had some bad results with crane(exhaust lobe 10 degree out of spec) but the stuff they sell to GM would have better QC i would assume. FM make a lot of OEM stuff so maybe all their stuff has better QC JMHO

[Craig S.]

Re: P.S.... I trust your IMHO Clem! *NM*

[Duke W.]

Re: P.S.

Your machinist sounds like he knows his stuff. Good radii between the cheeks and journals will help insure longevity. I've heard that tuftriding is expensive in the field, but there are some other surface hardening processes, on of which I recal is a cryogenic process.

In any event, for a street L-72, I don't think the undersize and lack of tuftriding is going to be an issue. Chevy steel cranks are overkill. The rods are usually the weak link in the bottom end.

My '95 F-M Performance Parts Catalog doesn't show a clone for the L-72 cam, but they do list one for the L-88 and LS-7. Try www.federalmogul.com or find retailer that has the latest catalog.

The L2268F-30 piston has a compression heigth of 1.765" mass of 701 +/- 4 grams a dome height of .266" and net dome volume (dome - minus valve reliefs) of 35.5 cc. This data might be helpful to you in computing your final compression ratio.

Duke

[Craig S.]

Re: P.S.

Duke - yes, I am pretty happy with this machinist. I work at IBM, and there are a few of us gearheads, and a friend of mine that is a Mopar freak (I know) builds 426 hemis with blowers and drag races sent me too him. My first clue was the shop is spotless, you can eat off any bench. Then I saw all the trick engines in the shop, and, a separate closed off engine assemly room. He is a super nice guy to boot, and very easy to work with. The name of the shop is Criss Engine and Machine, and his name is Mike Criss. He measures every piston before and honing, and hones to fit (deck plate of course), he suggested file fit rings. He also is meticulous in every sense. He is in the process of installing the Darton top step sleeve to repair my 66 942 block. I just got back my NOS GM dimple rods, I had him resize the big ends and I put in ARP Pro 2000 wavelock rod bolts (7/16"). These are the GM white rods. On the crank, he specs the clearance he wants to the grinder, as well as the journal radius at the cheeks. While I will do the final assembly, I am very impressed with the care and time he spends. Things take a while though, he is very busy (a good sign). He also has a Bridgeport milling machine for specialty one off operations, such as cutting the valve clearance eyebrow in the new sleeved cylinder.

Clem gave me the following information (posted in this thread) for the blueprint of the 3143:

F/M # is CS 165R for the cam,KC 165R for cam and lifters. dur at .050 242/242,lift .520/.520, 114 L/CL

Do you show that grind in your FM catalog? I will check out the website too. Thx guys, I sure love the help this site offers!!!...Craig

[Duke W.]

Re: P.S.

My catalog is '95, and the part number prefixes appear to have changed.

It shows:

TP165 LS-7 OE # 3904362 242/242 (.050") 336/316 (advertised) .520/.520 114LSA

Sounds like the same specs, but I don't know about the LS-7 and OE number.

They also show the VL43 as the companion mechanical lifter.

Duke

[Clem Z.]

Re: P.S.

i think that should be LS-6 the 454 450HP chevelle engine,

[Clem Z.]

Re: P.S.

duke go to http://www.teufert.net/bbchevy/bbcams.htm and you will see that 3904362 and 2863143 are the same cam.the 362 is still in the GM perf parts book and it is the crane dup.

[Craig S.]

Re: P.S.

Clem and Duke - I had heard the 4362 was the same duration, but the lift was not .520 but .496 otherwise, the same. I have an original 4362 that was installed in my crate LS6 circa 1989 and I measured the lift at about the value listed above, versus the .520. Do you know if this 165 part from FM is the .520 grind or the .496 grind? Sounds like this could be a base circle diameter difference to me...thx!....Craig

[Clem Z.]

Re: P.S.

the lift can be listed 2 ways,the actual,lobe lift times the rocker ratio minus the lash setting or just lobe lift times the rocker ratio not subtracting the valve lash. the .520 lift on the 143 minus the lash of .024/.028 gives you the .496/.492 listed in the catalog for the 362.

[Craig S.]

Re: P.S.

Ahhh....now that makes sense. So these really are the same. I wonder why GM changed to P/N to 4362 from 3143, something must have changed. FYI, my GM original 4362 in my crate LS6 still has the rear groove for the old blocks. I suspect when I buy this aftermarket FM blueprint, it won't. Normally, this would not be a problem, but, in my case I have a 66 942 block. I expect I will need to set it up in my metal lathe and replace the 3/16" by 3/16" groove in the rear cam bearing surface to work with my block....thx Clem!....Craig

[Clem Z.]

Re: P.S.

i wounder why they put a grooved cam in that late a crate engine because there would be a big oil leak at that cam journal?

[Craig S.]

Re: P.S.

Clem - yes, and I saw the fixes for that in the power book. So, I pulled the rear cam bearing, soldered the large hole shut, and drilled it to 0.060" to control the oil flow into the cams groove. Seems fine, but hey, I only have 2 hours on the clock of that engine! I think they were just using up old parts on the LS6 crate engines back in 1989....Craig