I posted this over in the FE forum but didn't get much response so I am trying the locals.

So I had the 352 out of my 65 and performed some engine mods. I had the heads completely rebuilt new valves guides seats springs the works. I also installed a small Comp cam and lifter kit. I installed a used Offi manifold that gave me problems down the road(another story). So I removed the manifold after about 1500 miles to change to an edelbrok and inspected the lifters. I found four lifters with a line worn across the lifter. When I checked my tolerance between the rocker and valve stem they were all right at maximum of .150 with lifter collapsed. I found a set of push rods .010 longer than what I had and the engine sounds a lot better. I had installed four used lifters to replace the worn ones and have since bought a new set that will be going in soon. I also bought a set of push rods .040 longer than the originals. I am getting ready to remove the manifold and install all of these parts, what are some thoughts here?

 

Sorry, can't help you much in this situation, if the clearances are within specs, then I see no reason why 4 would be wearing abnormally. Have you contacted Comp Cams regarding this?

Jim

 

No I have not but that is a good idea...Thanks

 

Glad I could be of service!

Jim

 

Wait wait wait....you installed used lifters? That's a huge no-no. Lifters take a set to the cam lobe and you can't use them on any other cam or lobe after that, unless you have them re-ground (and I don't know if anyone even does that any more.) To do otherwise risks chewing up the lifter or flattening the lobe(s) on the cam, or both.

And you do know about modern motor oils and the lack of ZDDP (zinc) which requires zinc break-in additive when using a flat-tappet cam, right?

 

New oils don't have zinc? Good to know when I replace the cam on th Bronco, I'll have to remember to get the break-in additive.

Jim

 

Where do we get the zinc additive?
I have a new set to install and have only a few miles on the 4 used lifters.
But could the lack of the zinc be what caused the original problem with the new lifters and new cam?

Thanks Dan

 

Dan do you think that running at the large end of the tolerance could have caused the original problem?

 

Since most new cams are roller and aren't quite as needful of the anti-wear properties of zinc, and since zinc is harmful to catalytic converters (at least, in higher mileage engines with some blowby/oil consumption) the oil companies have drastically reduced the amount of zinc in today's oils. Valvoline ZR1 racing oil is still pretty high in zinc, but is low in detergent so it carries a recommended oil change interval of about 3K miles when everyone else is up to 5-7K mile intervals. Diesel oils tend to be pretty high in zinc still, with Chevron Delo 400 leading the way from what I've heard. Many engine builders are using it during break-in, then changing to another oil at the first oil change.

I used to run Shell Rotella T in my Rover but they recently cut the level of zinc way back on it as well, though it's more critical during break-in than on a well-worn engine.

And ZDDP/zinc break-in additives are available at almost any decent parts store. Lucas makes a pretty good one, and there should be several other choices available. At least, there were in my local O'Rielly's.

John, I'd be concerned about damage that may have been done to the cam. You'll need to inspect the cam lobes of the lifters that went bad pretty carefully for any scoring. Though, when I was a kid I rebuilt an Olds engine and didn't break the cam in properly and soon lost a lifter, I replaced just the bad lifter and had no more problems with it so I dodged that bullet...just dumb luck I guess...!


And as to something from your original post...if you found a line worn across the lifter faces, then I'd say that those lifters weren't rotating in the bore, which is crucial to spreading the load and wearing evenly. I'd look for the possible reason for that, which could possibly be premature wear on the cam lobes.

Not sure about the tolerance question, but basically the plunger on the lifter should be at about the center of it's travel or a little less with the valve open. I'd have to look it up to get the exact measurements. Sounds like the shop that did the heads didn't set the stem height on the valves...

 

Well talk about dumb luck I did use Shell Rotella and Lucas during the break in but the lifter were probably closer to fully extended due to rod length so the new rods should put me at about half lifter travel. The last inspection should the cam to be in great shape so I am hoping it all works well when I tear it apart again.

Thanks for all the input.

 

Did you use the Lucas oil additive in the quart bottle, or the Lucas Zinc Plus Engine Break-in additive, which comes in a 16oz. bottle?

 

Awwww I used the quart... Thanks again Dan