HamadUP

I decided to measure my cam's lobes with a micrometer, I found that I have a .302 for int. and 0.308 for exh. , while it should be (as per the cam's card info.) .3117/.3188 int./exh. .. I have about 700 miles since the cam installed. The cam is a Lunati 60202 in a big block LS5.

I believe I did the cam break-in process right, I used a zinc reach oil (SF API grade) and poured a can of cam break-in additive and let it idle 2000-2500 for 20 min. and then I only used a SF grade oils with STP additive since then.

I thought if I would have a wiped lobe, it would be in the 1st 100 miles or so and it would be much more than that.

Is it the time to invest on a roller?? .. I hope not since I dont have any money left after my rebuild

Gordonm

How did you measure it with a micrometer. You should have measured it with a dial indicator.

SH-60B

That's .010 shorter, not .100, still not a good sign. I think the lobes would exhibit some obvious wear, as well as the lifters. Do you think you might have misread the mic? Digital ones are pretty fool proof, but I have seen some guys mis-read the vernier scale.

billla

Were there symptoms that made you pull the cam?

gkull

I would ask where you measured? On the edge of the lifter in the cam valley is typical. Who is to say how close the cam blank was made compared to a cam card. 1/100th of an inch is nothing for what is spec and what gets thrown out during manufacturing.

dstaley

Isn't an LS5 a roller engine?

73, Dark Blue 454

Install one of those the magnetic drain plugs for your oil pan. Drive her a day or two then see if you've collected any shrapnel on the magnet.

427Hotrod

You're .010 short. That's 10 thousandths...not 100 thousandths. Did you measure right off lifter edge or at pushrod?

Did you measure it before it was run?

I think you're probably fine. Why are we checking it?


JIM

HamadUP

I measured it using a dial caliper not a micrometer (I was so tired last night measuring the lobes and was 1 am already when I did the post!), and I put the tip of the caliper on the edge of the pushrod right in the oil hole.

The reason why I checked it (I know it may be from a different cause) was that my engine wont rev. past 4.5K RPM, not sure if its a fuel starvation or valve float, besides that I was always worried about the break-in process.

When I changed the oil after the 20 min. break-in I noticed that the oil was grey-ish in color, but I didn't catch anything at all on the magnetic drain plug.

OK I made a mistake it was .010-.015 in. in difference, but as the cam was advertised as .530/.541 int./exh. , but based on what I have right now, its .510/.523, which is not good at all.

Now if the wear will stop by that, I may consider leaving it as it is, but if it would continue to wear and send tiny metal particles all over my engine, that's another story!

BB72

If you had one or two lobes that were out I would think it was wiped. Check all of them . If they're all out it was made wrong. A wiped lobe has considerably worn look to it. I would guess that it would be easy to spot a wiped lobe next to all the good ones and you haven't mentioned that so ....it sounds ok.

bashcraft

I'm having a hard time imagining how you did this, but there's no way you're going to get an accurate reading with a pair of calipers.

mrvette

Perzactly....methinks your lack of revs are about ignition or induction/carb.....you sure your dizzy is all dialed in and happy?? IF so, I"d be looking at the secondary function on your carb......

427Hotrod

Lots of variables in your measuring method. Pushrod wiggle, pushrods going at an angle, the pushrod hole itself, a caliper etc etc.

The gray in the oil was likely all the break in lube you used..which is good.

It doesn't sound like you have a wiped cam. If it's not revving it's something else. That's a pretty mild cam so the chances of it breaking in well are good.

JIM

bashcraft

Does it just quit pulling? Or start missing or backfiring? What are the symptoms?

73StreetRace

I think you should take pictures of the 16 lobes and show us ( This is possible if you remove the oil pan ) : a wiped lobe has always signs of wear and scratches.
JIM is right : Lots of variables in your measuring method.
You can't get an accurate measurement of the lobes with the camshaft in the engine.

jackson

~0.011" @ ~9" long pushrod (& ain't held square to the lobe) = cosine error ... go back to sleep.

FB007

The odds of all 16 lobes wearing EXACTLY .01 is phenominal.

Also, without a "before" measurement the same way, it means ZERO.

HamadUP

When it reaches around 4.5K it just seems out of breath, no missing or backfiring, just seems out of power.

HamadUP

So I guess I shouldn't panic for what I found and just return my valve covers back

Well, that's a big relief! .. I've spent endless hours doing that engine and it was my 1st time to go deep into engines.

I still have the post-break in oil in my engine and I will drain it today and see if the magnet would catch anything, I'll let you know for sure.

Thanks a million guys!

BB72

Another thing, if you're worried about a wiped cam and keep going in there....you're going to get your wish. Stop worring about it. Your problem is probably ignition or carb related as mentioned. My bet is on ignition.