Cam condition/performance

Pulled my old cam out this weekend. Suspected something was going on. I have attached a couple pics of worn cam lobes. I know it will affect performance, just not sure how much. Any input appreciated. Also, I havent been using zinc additive but I will now. Thanks for any responses.

http://s959.photobucket.com/user/jc588/library/Cam Pics

 

If you have a lobe that is getting wiped off it will make a huge difference.

 

I'd measure it and compare with the other lobes. A cheap dial caliper would be sufficient.

Is the lifter face cupped on the worn lobe?

Note that the lifters must go back on the lobe they were on. That or new lifters.

 

What is a good zinc additive these days? Or oil type/rating?

http://blog.hemmings.com/index.php/2012/10/18/tech-101-zinc-in-oil-and-its-effects-on-older-engines/

 

I picked up some hyperlube zinc. And it's getting a new cam and lifters.

 

One of those lobes looks like it's gone?....................all that metal had to go somewhere in the system, I would look at flushing out what ever you can to preserve whatever life is left in that motor. Zinc additive's for break-in or oil containing same have been around for a long time although the move for years now has been to remove that product due to the other damage it creates like hydrocarbon molecules in the oil which is another subject...........

The cam lobes and lifters are essentially getting a left over spray from the rockers and overhead above and whatever may get kicked up by the Crankshaft is it rotates which really isn't much..........The lack of oil to the OEM hydraulic lifters over a period of time makes them into solid lifters and that's where all the cam / lifter wear problems really originate from.

Stock Buick 225 oiling systems have to be near the bottom of oiling effectiveness. The overhead gets it's oil from a small port that travels through the block into the head and into the base of the rocker stands.......any debris along the way effects the amount of oil the overhead and lifters eventually see..........Milling and others for years have sold HD oil pump kits for this motor...........the gears are a 1/4" taller and will pump more volume & pressure , but that alone without checking the internal clearance's between the gears and the inside of your front cover may offer no better net results.
Synthetic oils seem to have a much better ability to cling to parts...............

 

You are correct. Two lobes were almost completely gone. I don't really understand what I've got going on. Oil pressure runs around 50psi at operating temp and it looked like the rockers and in the valley under the intake had a good film of oil in there. Also, I've had an issue since I got the jeep 5 years ago, having to run the left idle mixture screw out a lot further than the right to keep the left bank from backfiring. So, I don't know of it's been like this the whole time?

 

Your pictures show a classic case of lobe wear from either poor break-in when new, and/or lack of zinc in modern oils. I have seen this same condition several times in the past year, all on flat tappet engines made before 1985. I run zinc additives in all my vintage engines.
-Donny

 

I also found that one of left port in the intake that heats the base of the carburetor was completely carboned up, no passage at all. I guess that's from running the left side so rich.

 

I have used 15w40 Rotella in all my engines for quite a long time. Diesel oil contains zinc levels much higher than conventional gasoline rated engine oils. I had some clattery lifters in my CJ 6 and an extra stock Melling cam and lifters in the cabinet so I just went thru what you're doing. I love how reasonably priced all the parts are for these little engines. Timing chain n gears like 30 bucks, gaskets around 20.

 

Replace the timing chain if you are replacing the cam and lifters. Rotella, Valvoline ZR1 race oil are the only oils I will run with my flat tappet cams, they have very high levels or zink for flat tappet cams. 5w20 or 15w20 is what comp recommended.

 

Brad Penn is good too. Is it possible to check for cam wear by checking the movement of the rockers or do the hydro lifters make it impossible?

 

Yes you can watch the lifters, hydro or not. They should all move the same height.