Cam identification, conditioning, re using.

[Princess Valiant]

Ok, so I can say that with all the engines i have ever built, I have never reused a camshaft, that was the reason I had to rebuild a few.

So i have a very stock 75 318 with what I believe us the original cam.

I also have on the other corner a 74 318 that i have reason to believe the cam is aftermarket and probably a more desirable performance unit but the block is trashed.

1. How do I identify a camshaft to find out the technical specs

2. If the one out of the 74 is something good, how do I recondition it for further use, the lobes look strong but there is a little discoloration and Mark's from the lifters but not bad.

3. How do I identify which are the proper new lifters to order

4. How do I know if the stock spring's are right to use.

These are my "acting brand new here" questions for the day.

Thanks

 

[Dartnut]

I have reused cams and lifters before with no issues.
When you pull the cam out of the donor engine (carefully) make sure you mark and keep the lifters for the lobe that it is already on.
Inspect the bottom of the lifter for wear and cupping, this will give you some insight to what the lobes of the cam are like condition wise.
If you find that one or more lifters are badly cupped, scuffed, or worn in an unusual way, make note of the lobe that it came from must be looked at and measured carefully.
If the lifter is worn out, it is junk and the cam may be junk too if the lobe looked unusual that it came from.
As for identifying the cam, the end might have some numbers on it that can be traced or cross referenced.
You can measure the lobes and determine if there are any variances in the wear (overall).
As for the springs, you can measure the strength of them with a spring checker, and compare that to the specs of the cam that you already measured.
Finally, if you have any doubts, just replace everything with new quality parts and be done with it.
I hope this helps, Rani.
Tom.

 

[Demonic]

So ..

1. - a quick measurement with a dial caliper across the base, then across the peak of the lobe. Subtract one from the other, and multiply that by 1.5 gives you the valve lift. There likely might be a few thousandths wear, but it's a start to match up.

2. - cam lobes are tapered as viewed from the side, which allows the lifter to spin in the bore, as it should. It is a very slight taper, might be hard to see. Coloring is normal. A good cam grinder can regrind stock cams to slightly larger.

3. - no big changes, then stock should be ok.

4. - a spring tester. Summitt has them, but only worth it if you're building a few motors in my silly opinion.

 

[Krooser]

You can send the cam in to most cam companies to be " cam doctored" and that will give you every spec.