What to look for on cam wear inspection?

[Tim Cucci]

I don't see any pitting or scratches or anything that looks abnormal. What should I be looking for on my stock cam. Lifters look good too. I did check the diminsions of the journals and they were right on 1.786". I check the total height of all the lobes and the low end was 1.473" and the high was 1.492. Can someone tell me if these numbers are O.K.? I cant find any info on the lobe diminsions.
Thanks
Tim

 

[Tim Cucci]

ttt

 

[Tim Cucci]

ttt

 

[Tim Cucci]

Anybody got any info on this cam stuff?

 

[Steve Wood]

Sometimes the base of the lifter is the best indicator of impending cam problems in my opinion. The base should be convex. Do a visual inspection for signs of wear and put each one on a piece of plate glass and see if it rocks when you wobble it which would indicate the base is still convex. Be sure to keep each lifter associated with the the lobe it was matched to when you pulled it apart. You cannot swap them around once the cam has broken in.

 

[FJM568]

Measure the lobe at the biggest distance, then measure across the lobe at 90 degrees from there and that will tell you the base circle dimension...subtract the two and that will tell you the lobe lift at the cam...The lobe lift on a stock cam is .384int/.408exh

How many miles on your cam??? As long as all the intake lobes and all the exhaust lobes are fairly equal in lift in respect to each other, I wouldn't worry about it...It is real obvious when you have a worn lobe(usually #3 exhaust), it will be almost round with a slight bump where there should be a lobe...

If you plan on reusing the stock cam, I hope that you kept the lifters and marked which lifter bore they came from...You can't just put them all in a pile and reinstall them anywhere...They are now mated and worn into the lobe that they were originally run on...If you didn't keep track of where they were, then you can run new lifters, but you must do the break-in procedure...

Hope this answers your questions...

 

[Tim Cucci]

All lifters and pushrods were marked and placed so that they go back in like they came out. All lobe wear measured within .019" of each other. Steve thanks for the tip on checking lifters I will do that next. They look fine but the glass will be a good check.
Thanks
Tim

 

[FJM568]

Your intake lobes and exhaust lobes should have different heights...All your intake lobes should be about the same height and all your exhaust lobes should also be about the same height...

According to the lobe lift specs of the stock cam, there is .024 difference between the intake and exhaust lifts...So if your lobes were about .019 from highest to lowest, then that is really not that much wear to worry about and if it were me, I would probably reuse the stock cam...

 

[Tim Cucci]

I think I have bad news on my stock camshaft. I measured the total lobe distance from tip to the bottom and have 1.490 on the exhaust lobes and 1.475 on intake lobes (average). The base circle is 1.228 on all lobes. So if my math is right that means I have .262 lobe lift on exhaust and .247 lift on intake.
This is a long way from the specs you gave me Jim. I guess it is just worn out. I have checked and rechecked.

What is the most durable stock replacement type cam? I have heard some horror stories about the aftermarket cams. Can't afford a roller.
Thanks
Tim

 

[Tim Cucci]

ttt

 

[FJM568]

STOP !!! You don't need a new cam!!! I forgot one thing...


Your cam numbers look fine...I forgot to mention that the dimension you get when subtracting the base circle from the max lob dimension needs to be multiplied by the rocker arm ratio(1.55)...Which would give you about .383/int and .406/exh which is really close to stock specs(.384/int, .408/exh)...Keep the stock cam!!! Geez, I haven't checked the BB in a few days, and I hope I caught you in time before you buy a new cam you might not need!!!

I apologize for not getting back to this sooner...

I sent you an email about this, too...

 

[Tim Cucci]

No problem Jim

My light came on after I posted and thought about. My cam and lifters are almost perfect. I am really amazed at the stock camshaft holding up like it does. I have had no recommendations on changing the stock cam everybody tells me I better keep and reuse that stock cam.