Interesting retro hydrauilic lifter & cam regrind info

[396 Signet]

Here's some interesting info on on the retrofit hydrailic roller lifter setups. They are currently sold by Crane & Comp Cams. They have a very large (about 1/2") oiling groove and are a good bit taller than flat tapppets. Bought a Crane set for my 340 & after putting on the heads & front end of the motor I find the pushrods are hitting the heads. The heads had to come off for grinding & I'm out $90 for new head gaskets. Then I notice when rotating the cam that several lifters are actually have the oil grooves raisng above the holes in block at max lift. This is potentially a big deal as it could cause a very hard to find oil pressure problem. After some good advice here I decided the best (cheapest) route would be to have the cam reground . Sent the cam to Crane, they say they could regrind for $202.

Crane finally called yesterday to discuss. They say there is a lot of variance between mopar small blocks regarding the machined height of the lifter holes in the block. Regarding individual cams in a product line, the cams are actually designed such that the position in the block at max lift remains constant. In other words, the base circle diameter is changed between a .500 & .600 lift cam. More importantly, the problem regarding the lifter oil ring exposure would be no better or worse with a higher lift cam. I always thought they kept the base circle constant & used taller lobes. If you had a really high lift cam, there could be a problem with the lifter oil ring being exposed on the bottom side of the lifter bore.

According to Crane, when you get a cam reground, if you use an identical profile with a smaller base circle then the duration is reduced. It's more than you might think- it amounted to 4 degrees for my cam with a .060 base circle reduction. In order for the duration to be maintained, then the profile must be re-engineered (i.e. more $$). Fortunately someone already went through this at Crane & I used their profile so it didn't cost anything extra. I took pics of the various problems & can post if anyone wants to see.

 

[moper]

There's been a few threads on those issues. There are also issues with solid roller tappets uncovering the oil galley while at max lift because of the notch for the roller. If the block in question has the tops of the lifter bores spot faced, there is a decent chance there will be some issues running a conversion hydraulic roller setup.

 

[ramcharger]

I have seen this covered here as Moper says but it never hurts to post photos and give some before and after regrind lift/duration specs. The more info the better.

I have not heard of this issue yet with the Comp retrofit hydraulic lifters but someone please chime in if they have.

 

[340sFastback]

The comp retrofit hydraulic lifters are the same dimensions as the Cranes. I ended up with a smaller base circle cam ground by Comp Cams and the oil grooves were still exposed so I sent it back and they ground one again. Same cam profile, just a smaller base circle, and that did the trick. Engine is running now and oil pressure is nice and high.

 

[ramcharger]

Thanks 340s. I wouldn't doubt if the true manufacturer is the same both companies.

 

[396 Signet]

Here's a pic of an exposed lifter. Will post a pic of the necessary head grinding later.

 

[340sFastback]

Yep, that is exactly how mine were. But only two or three were like that. I had Brian at Indio Motor Machines spec out a custom ground small base circle roller cam for me. The first one he shipped was much better but when running the oil pump oil would squirt out at max lift. So he had me send it back and had another ground which he only charged me $25 total for. The second cam would hold the oil in under pressure both on the bottom and top of the lifter bore. Now that the engine is together the oil pressure is great and there is no valve train noise.

Here is where I had to grind my heads:

 

[396 Signet]

Here is where I had to grind my heads:

Exactly same deal for me except mine are J-heads. Pity the poor slob that thinks they can just throw these parts in an engine without disassembly.

 

[340sFastback]

Just make sure you grind enough because when the lifter pumps up it will move the push rod closer to the side of the hole. You can end up with the push rod binding in the head. Best to verify with check springs. Its a pretty time consuming task. I didn't get mine right the first time and ended up pulling the engine, taking the heads off, and doing it all over again. All is well now but it was a hard way to learn.

 

[camgrinder]

It's too bad Crane Cams has closed and been liquidated.

Clay at Kams, Inc. - Cam & Follower Regrinding, Design, and Manufacturing for industrial engines