Valve seats, cam, etc.

[Frank G.]

I may have to replace some valve train components and possibly the cam shaft on my 1970 LT1. While I've got the engine out, I was wondering if there is anything else I should consider doing to this numbers matching car. One thought was some new valve seats to help with the unleaded fuel. Any suggestions? Also, I've got some ideas of my own, but does anyone have any recommendations on where I should be purchasing significant engine components like these (i.e., cam, valve seats, etc.)? Any advice/guidance would be appreciated. Thanks.

[Duke W.]

Re: Valve seats, cam, etc.

Your heads don't need valve seat inserts for road use.

Every part you need - exact GM spec OE replacement parts - are available in the various Federal Mogul and Dana product lines - like Sealed Power, Speed Pro, and Clevite. Use only these exact OE parts - no "hot rod parts".

The one possible exception is con rods as the cost of equal or better rods like the Eagle SIR line is about the same as the cost of inspecting and rebuilding your existing rods.

Everything, and I mean EVERYTHING, other than the above possible exception should be EXACT OE REPLACEMENT because your engine was superbly engineered and doesn't need to be "improved" with the exception of pocket porting, port matching, and chamber relieving the heads. Shoot for a true 10.5:1 CR with the OE replacement pistons and suitable head gasket thickness.

You will end up with about 350-360 SAE net HP, which is a solid 300+ at the rear wheels with SAE air density correction and useable revs to nearly 7000.

Do some research in the archives beginning with "327 LT-1" under my user name.

Duke

[Joe L.]

Re: Valve seats, cam, etc.

I may have to replace some valve train components and possibly the cam shaft on my 1970 LT1. While I've got the engine out, I was wondering if there is anything else I should consider doing to this numbers matching car. One thought was some new valve seats to help with the unleaded fuel. Any suggestions? Also, I've got some ideas of my own, but does anyone have any recommendations on where I should be purchasing significant engine components like these (i.e., cam, valve seats, etc.)? Any advice/guidance would be appreciated. Thanks.

Frank-----

I would not attempt to install hardened valve seats, especially in your case. Small block heads with 2.02/1.60" valve size don't always "take well" to installation of hardened seats. There's a chance that the heads will be rendered scrap if machining out the old seats gets into the water jacket. If your valve seats are REAL bad and need to be repaired, then you don't have much to lose by going in with hardened seats, but this is rarely the case. If your valve seats are ok (as they usually are), just have a good valve job done and let it go at that.

Believe me, you really do not need hardened valve seats. The only engines that do are those that are run at very high load for extended periods of time---like trucks with gasoline engines climbing long grades or certain industrial engines. You'll never run your engine in a manner that will cause significant valve seat recession. If you wish, use a lead substitute that contains Powershield (Alemite CD-2 is one that does), but even this is not really necessary.

By the way, Chevrolets went to unleaded gasoline in 1971 but hardened exhaust seats were not used until 1973. So, there were lots of Chevrolets designed for use with unleaded gasoline that were not even built with hardened exhaust seats.

IF, in the unlikely event you do need to have seats installed in your heads, I would only entrust the work to a shop with MAJOR experience in installing hardened seats in 2.02/1.60 heads. Valley Head Service in Pacoima, CA is one that does.

As far as engine parts are concerned, I think you'll be able to get just about everything you might need through Summit Racing. Their prices will be just about the best you'll find anywhere. Use only major brand name parts, though. By the way, Summit Racing does not just sell racing parts---they carry a complete line of OEM-type parts manufactured by the major automotive parts manufacturers. Some parts for your engine are still available from GM but not pistons or camshaft.

[Patrick H.]

Re: Valve seats, cam, etc.

I may have to replace some valve train components and possibly the cam shaft on my 1970 LT1.

I'm surprised that Duke didn't mention it, so I will...

What signs or symptoms lead you to believe that some valve train parts require replacement?
Let's start there before you end up doing far more than you need or want.

Patrick

[Frank G.]

Re: Valve seats, cam, etc.

The car was running real bad. So I brought it in to Corinthain Mortors in Ramsey NJ (a reputable local shop). They told me that it looked like some knucklehead who was doing some minor resto work for me had adjusted the valves on the driver's side down way too tight. He suspected possible damage to the cam, maybe the valves, etc. I spoke with him last night, and learned that when he had removed the maifold to take a look, he saw some busted pieces that he believed were the clamps from the lifters (not valve train components as originally suspected). So, he brought to his engine guy, who broke it down and will provide me with his own diagnosis and an estimate. One thing we've discussed is new valve seats. But from the feedback you guys have provided, I don't think I'm gonna do that. Thanks for the input.

[Joel F.]

Re: Valve seats, cam, etc.

The car was running real bad. So I brought it in to Corinthain Mortors in Ramsey NJ (a reputable local shop). They told me that it looked like some knucklehead who was doing some minor resto work for me had adjusted the valves on the driver's side down way too tight. He suspected possible damage to the cam, maybe the valves, etc. I spoke with him last night, and learned that when he had removed the maifold to take a look, he saw some busted pieces that he believed were the clamps from the lifters (not valve train components as originally suspected). So, he brought to his engine guy, who broke it down and will provide me with his own diagnosis and an estimate. One thing we've discussed is new valve seats. But from the feedback you guys have provided, I don't think I'm gonna do that. Thanks for the input.

Frank,

I'd ask for some additional info from your guy. Lifters do not typically have clamps.

[Frank G.]

Re: Valve seats, cam, etc.

Would that also apply if the solid lifters had been replaced with hydraulic lifters?

[Clem Z.]

Re: Valve seats, cam, etc.

some hyd and piddle valve lifters have wire retainers holding them together and the wire retainers can pop out.

[Jim T.]

Re: Valve seats, cam, etc.

Frank in reading what you wrote about taking it to a shop and a man removing the intake then tells you something about pieces of clamps. In looking at the valley area of a smallblock with the intake off a person should only see the pushrods coming out of the cylinder head and seating on a lifter housed in the block. Solid and hydraulic lifters are cylinder shaped for flat tappet cams. Roller cam lifters will use a connecting piece to keep them from rotating in the lifter bore. One would think that the initial inspection would give you the information.

[Frank G.]

Re: Valve seats, cam, etc.

I appreciate all the feedback. While we're on the subject, does anyone have infomration on the proper cam set up/grind for this car? Thanks.

[Joe L.]

Re: Valve seats, cam, etc.

I appreciate all the feedback. While we're on the subject, does anyone have infomration on the proper cam set up/grind for this car? Thanks.

Frank----

The original camshaft for your application was GM #3972178. However, it's discontinued. You can obtain an exact duplicate from Crane, Comp Cams, and Federal-Mogul. You can also obtain a Crane-manufactured cam + Crane lifters under GM #12364054.

For your application, I would always prefer a camshaft with parkerized lobes as were the original factory cams. I don't think that the Crane-manufactured cams have parkerized lobes, but they may by now. You could check with them. For Comp Cams, I think the parkerized lobes are an option. I'm not sure about the Federal-Mogul cams.