Dema Elgin straightened and profiled a NOS 3872304 cam yesterday. Out of the GM package, there was .003 in. runout, which he corrected to no more than .001. If you would like the detailed profile data, PM me with your email address. The site will not accept PDF attachments.

3872304 profile

I wonder if these cams were bent from day one..., or got that way from sitting horizontal for a L-O-N-G time? Someone graciously gave me an NOS 80HP cam that to their disappointment had been packaged as a #304 cam. When it arrived I found the cam to be .004 out of straight at the center. It is amazing how much the cam will visually rise and bind even in a half case.

All was not lost. While nerve wracking I put the outer journals into V-blocks, ground a piece of steel to roughly the non-journal/lobe area of the cam, closed my eyes to a squint, held my breath, said a prayer and gave it a whack near the center (several times). You can see the steel deforming on the top of the piece I made from the striking force. The end result was I got the runout to .0005 and it smoothly turned in the saddles.

Anyone know the specs on Camshaft straighness on an OEM Cam?

I bet its lot more than you think!!


Eric P.
DeWitt, IA

isucorvair Wrote:
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> Anyone know the specs on Camshaft straighness on an OEM Cam?
>
> I bet its lot more than you think!!
>
>
> Eric P.
> DeWitt, IA


In the shop manual, it says that the runout spec for the cam journals is .002". My N.O.S. turbo cam had .007" runout, and coupled with others that have have measured the runout on other NOS cams, it sort of confirms the rumors that I've heard that GM did not scrap their out of spec parts... they sent those to parts houses!!!

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Kevin Nash
Friday Harbor Washington
63 Spyder, Daily driver, EFI read about my project here: [corvaircenter.com]
first test start on EFI here:[www.youtube.com]
first official EFI boost test here:[www.youtube.com]
My new fan! [corvaircenter.com]
engine less 62 Spyder
Canadian 64 Monza Parts car
Test Start#2 [www.youtube.com]

When I rebuilt my engine several years ago and asked the group if one was for sale .I was warned about this and bought a clarks 304 repo. It was less than. 001 out and has worked well.

J.O.

65 Corsa Turbo Vert
79 Honda XL 500S
69 Honda CL 160 D
2010 BMW F 650 GS
2003 Bounder 36D
2013 KIA Optima SX turbo-AKA ZIPPY (wife,s car)
69 Newport Holiday Sailboat
Baja 150 dune buggy cart
Coleman HS 500 UTV
2016 KIA Sorento SXL Turbo

Bethlehem,Pa

I have a Dems Elgin custom grind in 362 and it spec'd out just what he said it was

1964 Bill Thomas Monza Replica Racer
1964 Spyder Street Car
1998 Honda Prelude Dirt track car
1967 Crown V8 under construction
Mike Levine
Cumming Georgia
North of Atlanta

wittsend Wrote:
-------------------------------------------------------
> I wonder if these cams were bent from day one..., or got that way from sitting horizontal for a L-O-N-G time? Someone graciously gave me an NOS 80HP cam that to their disappointment had been packaged as a #304 cam. When it arrived I found the cam to be .004 out of straight at the center. It is amazing how much the cam will visually rise and bind even in a half case.
>
> All was not lost. While nerve wracking I put the outer journals into V-blocks, ground a piece of steel to roughly the non-journal/lobe area of the cam, closed my eyes to a squint, held my breath, said a prayer and gave it a whack near the center (several times). You can see the steel deforming on the top of the piece I made from the striking force. The end result was I got the runout to .0005 and it smoothly turned in the saddles.

Over the years I've used this method to straighten several cams that were bent because they had not been properly supported while having the gear pressed on.

Dan Brizendine, Circle City Corvairs
'64 8 door Greenbrier, +.060, stroked 1/4", 188 ci, 140 PG. "In beautiful Wanamaker Indiana...with one stop light and 5 pizza shops"