Cam Problem

[tripowerguy]

I was working today: , well I was, and I went by Dan Collins place of business. I wanted to see if he had put his new engine in his 66 Chevelle, it is a 496 cu. in. big block. He said he did and he was pulling it back out. I said why and he said he flattened number 8 intake lobe. I asked him what cam it was? Surprise, surprise, why it was a Comp Cam. If you remember, Fatride and I both lost number 8 on a Comp Cam, HMMMMMMM Roy

 

[MRHP]

HEY!! Don't curse me! I've just done the cam break-in on my new Comp cam. I have about 25 miles on it now and so far so good. One thing I did for my cam break in was pour in two extra quarts of oil in the motor while it was running. This lubricates the cam and lifters more and helps keep everything cool. I have done this before in performance rebuilds and I have never flattened a cam. It may only be a coinsidence but it works for me. Sorry to hear about the bad luck.

 

[CDNpontiac409guy]

AAAAH!... and MrHP... you get some 2" tube headers W/ 3 1/2" collectors on that beast... THEN you'll find out what it's all about


Trick of the day:

On my Stocker engine. Most of you guys probably remember the picture of my camshaft... remember ? the one with the square lobes ?
Well, besides the rather high RPM that I expect the engine to spin, there is the problem of trying to get a lifter to follow those ridiculous lobes. This necessatates some pretty serious valve spring pressure ( about 175# on the seat ). I will be using a set of ULTRA SMOOTH / hardened Schubeck light weight mechanical lifters. These are known to be MUCH easier on cam material.
The trick ?
Adding an oil groove ( or slot ) in the lifter bore.
This simply is a light ( maybe .025" ) cut done vertically in the lifter bore from the height of the oil hole in the bore, through down to the bottom of it. This is done on the "leading" side ( in cam rotation, the side that sees the pushing up of the lifter ).
This slot creates an oil passage which allows oil to spray directly onto the lobe as it contacts the lifter.

This has been done before... and is fairly common in extreme performance flat tappet engines .

 

[Neil W]

Thankfully, I have not yet had a cam break-in problem, but just the other day, a buddy of mine told me about a lifter that has an oiling hole drilled through to the bottom. I'm guessing it would be solid flat-tappet only but I thought it sounded interesting.

Neil

 

[CDNpontiac409guy]

You bet, Neil... that's another way to do it.
I'm just scared to drill holes into the contact surface:eek: !

 

[Neil W]

Me too! Don't think I would do it myself, but I would hope that if they come with the holes in them already, it must be okay. Don't know anybody that has tried them though, not sure if I want to be the first.

 

[JokersBel]

Should be a Comp Cams hate list by the sounds of it. What a coincidence...

 

[oil4kids]

extra oil

I would not add 2 extra quarts of oil to any motor over factory fill. That extra oil can bend up parts very easily since a fluid cannot be compressed and large volumes of a fluid can get in the way of fast moving parts. As you can guess by my web page i have been using synthetic racing oil since 1986 and very pleased with the low wear and overall performance however all synthetics are not equal. HPS, Royal Purple, Redline and Amsoil are the best ones.

 

[Neil W]

More Comp cams trouble

Was at dinner with a buddy of mine tonight and told him about these Comp. cams failures. He said that he put a Comp. extreme energy in the last motor him and his brother built. Shortly after break-in, they lost the intake and exaust lobe on number 8. After teardown he replaced it with a Schnieder and now it's running great.

The motor was nothing nasty, just a Ford 400 with RV cam and low spring pressure. Might be nothing to it, but I thought it was interesting.

 

[Fathead Racing]

Comp cams.

Wow! I wonder why it always seems to be # 8 that takes the fall? I repaced the failed XE Comp cam with the same Comp cam grind. I wonder if it has anything to do with the engine now breaking up at 5500 rpm??:

 

[saboo]

cam kit

purchased a cam kit many years ago from crowler for a 09 and he suggested a slot on the side of the lifter, more like a very narrow flat on the side, stated then, that he had been doing this for years and the pressure lost is only a couple pounds. no cam trouble

 

[MRHP]

I only added the 2 quarts of oil while I was doing the cam break-in. After that the oil was drained and refilled to the proper level. Should I not add the extra oil while doing a cam break-in? I do not wind up the motor with the extra oil in it. Probably 2500 max. If I did bad, please tell me! thanks guys

 

[dq409]

PDR,,,What are you running for a distributor?,
After I changed to a Dave set-up that did the trick.
I did run into a tight valve guide problem later that caused a miss at about that RPM due to a valve hanging open.
Good luck,,,,dq

 

[oil4kids]

distributor oil slot trick

Adding an oil groove ( or slot ) also at the botton of the distributor (ie .025" ) also cut vertically above the distributor gear helps splash oil on the cam-distributor gear. It should be cut after you time the car and mark exactly where the front of the distributor is facing. Cutting a slot in the wrong place wont help that much.

 

[JokersBel]

cam break in

The extra oil, to me, is uncalled for. I've always been taught never to overfill the crankcase. Perhaps it works for you and makes you more comfortable when performing a break-in. Dunno, but try Royal Purple assembly lube mixed 50-50 with engine oil (to help thin that stuff out, cuz its thicker than molasses- and turning the engine over with straight RP is virtually impossible by hand) I've had no problem with cams this way....Jim

 

[Donovan]

I don't know that it is the cams that are failing but I think that it is the lifters. At the being of this year a couple of the lifter manufactures went out of business and the rest is made in Mexico, so I am told. When my brother got his cam for Elgin Cams he wanted us to send the lifters to him so he could check the spherical lift on the lifter base. It was a .650" lift solid cam and we have had no problem with them. BTW they have the small oil hole in them.