Thread: Unknown cam?

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Originally Posted by Geezer2

Superdave asked a question, he did not ask for an opinion.

I tried to answer his question in a simple and direct manner.

I didn't express my opinion on the feasability of what he was doing because that's not what he asked!!

I know yjere are a lot of very knowledgeable people on this board, that's why stop by. BUT, sometimes just answering the question asked may be the way to go.

By the way, I'm NOT trying to start trouble or get anybody riled up, just giving my opinion (which nobody asked for).

Thank You! Right or wrong, I'm just trying to learn more.

PLease read the captions and look at the picture as it describes in generic form the differences by looking at the cam. note there is type above and below picture. The type below the picture is most impotant, I hope this helps you out some.

1, After break in, a flat tappet cam is married to its lifters. You cannot move lifters between different bores, and you cannot use those lifters on a different cam. The lifters either stay with that lobe, or get thrown out, period.

2, The following picture shows a flat tappet camshaft in the front, and a roller camshaft in the rear.

You cannot visibly tell if it is a solid lifter cam or a hydraulic lifter cam. The rate of lift (not the lift) is one factor in the solid/hydraulic design. Measuring such and then analyzing the data is not something you can do...plus you have no "specification" for this cam to compare your data with. That's the problem with unknown equipment. For all you know, it's a stock 2bbl cam that someone removed in order to install a high performance cam. The visible difference between cams is so small, it is a game of chance.

Look closely again at the nose of the cam where the timing gear mounts....like several others have said, there should be a couple of digits stamped there. For all you know, you have a 307 2bbl powerglide cam.

For the expense of tearing an engine down to change parts, it appears risky to use an unknown part. If the lift is too high, you risk coil binding the springs. Perhaps some of the guys here know if you can run hydraulic lifters on a solid cam....you cant do the opposite.

Well it seems most everyone has it in for me now, however, how can I tell if I need to use a hyd or solid lifter? Sorry if I came off as a jerk, just kinda hit me the wrong way I guess. F.Y.I. I got the cam and a new set of lifters for 25 bucks, and all I was told was it had .510 lift, that's the only reason I got it. I understand it's risky, but if it don't pan out, i havn't lost much. Sorry again for being rude, I really do appreciate experienced advice.

how about paint colors gm use to paint them by the gear ??i do not know what color is what but someone may know?????

If the lifters were with the cam, and you're sure they are the right ones, you might get away with using it. I would still recommend buying a new cam to go with the new lifters, but it's your nickel.

Originally Posted by SSsuperdave

How do I go about finding the cam specs on a cam I got at a swap meet. It has no markings on it.

I don't think anyone was hatin' on you.

Lacking any ID markings at all this question cannot be answered exactly so opinions will be the general response. Even if you had the markings you do not know the history of use etc so you are taking on risk at the very least in going forward with it. Period. Seems to me that you do not have enough vested in it now to warrant going forward with it anyway given the cost and availability of new ones.

Even if you ain't a millionaire.

Kitz

Cams are like sex partners....if you dont know where it's been, you shouldnt be screwing with it!!

Here are a few old notes that I dug up re; color codes on GM camshafts – not all mine, some from Car Craft and Chevy High Performance. I do know that the original colors turn after use due to heat and exposure to oil. Surprisingly enough a small dab of acetone on a Q-tip brings back the original color.

The late 60’s Chevy cams were identified with painted stripes on the cam gear end of the cam. Chevrolet 3927140 camshaft had a white stripe (usually turns to beige after use). This was the solid lifter cam used in the 302 Z28 motor. They’re rarer than hen’s teeth so I doubt there are a lot of them at swap meets.

I have an L-79 cam in a small block that had green, orange and white stripes (also discolor after use). This is a really good hydraulic lifter cam with 222 degrees intake/exhaust and .447 lift with 114 degrees separation. A bit of lope at idle, but a string performer through 5500RPM and IMHO, a good cam for a mild mannered SB that still chips tires good and loud when shifting.

GM part number 3736097 used in early 60’s had one green stripe (probably brown with age) on the distributer gear end. Mechanical lifter with .381/380 I/E lift that works well with 1.6 roller tip rockers.

The renowned “Duntov 30/30” camshaft from the FI 327 had a pink or white stripe, pink stripe turns red/brown and white turns off-white with age.

I have several cams that have the part number stamped on the backside of one of the bearing surfaces.

Regards All,
Glenn

I agree with most of the comments and if I end up putting the cam in my motor, I will be honest on reporting how long it lives. However, I still don't know how to tell if it's a solid or hyd cam.

It is a flat tappet cam. On the transmission end it is stamped 268. I understand that the lifters wear together and can't be interchanged, however would not new lifters, a "blank slate" if you will, eliminate this problem? Also, I ask because I don't know, it seems that you could run solids on any cam cause ramp rates aren't a factor like hydralics.

So would it be safe to say that solid lifters would be the best to run if I can't find out whether it's a hyd or solid? Seems to me that a solid would follow the profile regardless of what it is whereas a hydrolic could possibly collapse because a solid profile may be too steep for the hydrolic valving action of the lifter.? I did check it with a degree wheel and dial indicator and it comes out to 230/230@480/480 w108 ICL. I know it's an Erson brand and I found a cam with the same specs on their website.! Also, my dad had a brand new, still in the box Comp cam, with card and all, and I put it in and checked the same way I'd been checking the other and it came out to exactaly what the card showed! I feel confident with my measurements, since I have a known cam to compare against now. A larger degree wheel would be nice too, since the 11" one I'm using now is kinda, eh, but it works. Anyone know what a cam like this would be good for? Still curious about the lifters though. Thanks for all the replys!

If you know it is an Erson cam, call them and give them your specs. Chances are they can tell you whether if it is for hydraulic or solid lifters. And make sure your valve springs are matched to the cam. The wrong springs can cause cam failure or valve float. If in doubt, buy new ones from Erson. Good luck.

Just to really get ya'll riled up, the junkyard motor I'm using this cam is a factory roller block! What a waste, huh?

Originally Posted by SSsuperdave

Just to really get ya'll riled up, the junkyard motor I'm using this cam is a factory roller block! What a waste, huh?

That statement might stir up a hornets nest!