solid or hydraulic cam I.D.
Thread Starter
Racer
Joined: Aug 2005
Posts: 431
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From: Oita, Japan
solid or hydraulic cam I.D.
I recently bought a '72 number's matching car with the base engine (identified by the "K" in the vin). The engine has been recently rebuilt. It has an aluminum GM intake with casting number 3959594 which I have discovered to be an LT-1 intake. 
Today I pulled off a valve cover and saw that the casting number on the head was 3973487X which seems to be an LT-1 head. 
While I was in there, I noticed that some of the rocker arms were loose so now I am wondering how far "LT-1" they have gone with this engine and if it is a solid lifter cam. Without taking the engine apart, is there any way to tell if it is solid lifter or not? If it is not, I want to tighten up those rocker arms....
Today I pulled off a valve cover and saw that the casting number on the head was 3973487X which seems to be an LT-1 head. While I was in there, I noticed that some of the rocker arms were loose so now I am wondering how far "LT-1" they have gone with this engine and if it is a solid lifter cam. Without taking the engine apart, is there any way to tell if it is solid lifter or not? If it is not, I want to tighten up those rocker arms....
Le Mans Master
Joined: Jul 2005
Posts: 5,752
Likes: 4
From: Austin Texas
I would try this: Pull a valve cover, find a valve that is open all the way. If the engine has not run for 8 hours or so, rotate the engine to close that valve completely. If the lifter is hydraulic, it may bleed down. You may be able to push the plunger down a little. If solid, it won't budge. I hope this works! 
Melting Slicks
Joined: Dec 2001
Posts: 2,025
Likes: 1
From: Billings MT
You can also check the lash with #1 at TDC. While this is not necessarily the base circle, if you can fit a .010-.020" feeler gauge in there I would say it is safe to assume it is a solid. Remember to check and adjust the lash periodically. When the valve is closed, they rocker arm should be loose, not just a little, but floppy like.
Thread Starter
Racer
Joined: Aug 2005
Posts: 431
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From: Oita, Japan
Thanks for your replies. Next time I get a chance I'll try to see if the lifters feel mushy or not as BIG_G suggested. The more I think about it, the more I think it's got to have solid lifters. The rockers do flop around when the valve is closed and the engine is cold. Also, when the engine is running and cold, they make a little bit of noise but quiet down after it warms up. If they were hydraulic, I think they would be a lot quieter when the engine is cold. And besides, if they were hydraulic lifters, I don't think anyone would be stupid enough to adjust all of the rockers to be loose, would they?
Race Director
Joined: Mar 2001
Posts: 11,322
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From: Living in the Hartland
Originally Posted by yukon988
And besides, if they were hydraulic lifters, I don't think anyone would be stupid enough to adjust all of the rockers to be loose, would they?
