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  #46 (permalink)  
Old 07-30-2013, 10:17 PM
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@Gary

1.) I just finished saying that I was convinced by the membership here, and seriously considering the possibility of going to a roller cam.
Quote:
I've been looking at roller cams all morning and have decided that Comp's XR282HR (11-432-8) seems to fit my build to a "T"
2.) There was only ONE "over and over again", by my count.

3.) You gotta stop banging your head Gary. Seriously.



Yeah, I know I said that I was going to a roller after the first one crapped out ... but I KNEW (and freely admitted) that several mistakes had been made. Was that the fault of the camshaft? No. So I tried another one.

This second cam was, I believe, broken in correctly.
Compare these pics. Zoom right in on the first one, taken 06/17.

As near as I can tell, there aren't any signs of the rough edge there.


This one was taken this evening, and seems to indicate that the damage is very recent.
One theory might be that I'm guilty of making another error when setting the lash ... lobe not on base circle (as was suggested previously in this thread).

I'm also "guilty" of following "the easy method" that I read on the internet. I did follow these instructions and checked them off in sequence.

So who knows? My neighbor stopped by and didn't like the way that the lobes lined up with the lifters. We got to pushing and pulling on the cam, which is still in the engine, with the timing set still in place. The distributor is out which I'm sure factors in to this, but there was approx 1/4" of in/out (endplay).

I'm hoping a machine shop can solve this mystery, once and for all, and put an end to a lot of this speculation.

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  #47 (permalink)  
Old 07-30-2013, 11:01 PM
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If you don't change things nothing changes is the msg here.
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  #48 (permalink)  
Old 07-31-2013, 04:40 AM
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Quote:
Originally Posted by 66GMC View Post
My neighbor stopped by and didn't like the way that the lobes lined up with the lifters.
Ahh yes- the "helpful neighbor". *sigh*

The cam is purposely not in alignment to the lifters. In other words, the lifter isn't going to be right in the center of the cam lobe. The way the cam lobes are slanted and the lifter bottoms convex causes the lifters to rotate.

The combined forces of the cam lobes and distributor/cam gears causes the cam to be forced backwards into the block. But there's a possibility the cam may move fore and aft in use, and if there's enough movement to cause the lifter's contact point to ride off the edge of the lifter, damage will occur. But this is not usually the case, obvoiusly. Some here recommend using a cam button like for a roller cam to set the end play even on flat tappet cams. Something to consider.
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  #49 (permalink)  
Old 07-31-2013, 08:47 AM
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All the help in the world doesn't mean a darn thing unless he understands he has already paid for the roller cam with what he has done to date.And now is the time to end all that by purchasing a roller cam..........
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  #50 (permalink)  
Old 07-31-2013, 09:04 AM
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Originally Posted by 1Gary View Post
All the help in the world doesn't mean a darn thing unless he understands he has already paid for the roller cam with what he has done to date.And now is the time to end all that by purchasing a roller cam..........
I really hope you're right Gary ... that purchasing a $1000.00+ worth of cam, lifters, pushrods, springs, timing cover, cam button, etc. DOES end this frustration.

IF it does ... you have my full permission to say "I told you so."
Deal?

(But I still think that cam was broken in properly, and that *something* happened to it very recently.)

Some of this, perhaps? (Just another theory at this point.)


Or maybe this? (which I believe to be caustic soda left over from the hot tank)

Last edited by 66GMC; 07-31-2013 at 09:18 AM.
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  #51 (permalink)  
Old 07-31-2013, 09:39 AM
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Were the lifter bores machined?
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  #52 (permalink)  
Old 07-31-2013, 09:56 AM
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rule #1 The easy internet method is a sure way to do the lash WRONG and fubar a cam.

Use the goof proof IC EO method. ONLY
Do not spin the pushrods to find the 0 lash point. Up/down is better. Then add the preload (hyd cam)

Rule #2 SBC and BBC flat tappet cams are self centering. The lifters convex shape and the cams shape
cause the cam and lifters to self align correcly in the block. No cam button is required with a flat tappet hyd or solid cam
in a SBC or BBC ever. Only a roller cam needs a cam button in these motors.

Rule #3 Put the frigin Moly paste on the cam lobes. If you wipe it all off by turning the crank over etc etc, take the friggin intake off and brush some more Moly paste on the cam lobes before fireing it.
oil your rockers and pushrod tips.

Fire it up with mufflers, and water in the rad, and the timing set. 3000 rpm + w/32-38deg timing.
reduced spring pressure helps a lot. Remove the inner coil for break in.
verify your spring pressure and installed/open heights. 300 to 320 lbs open is more than enough for this HYD cammed engine.
Its up to you to check this and get it right.

99% of cam failures is improper install and fire up.

I like this stuff and they have Moly paste too.
You can get it locally. www.molyslip.com
Moly slip E

Roller cams and roller lifters are not indestructible either.

Last edited by F-BIRD'88; 07-31-2013 at 10:08 AM.
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  #53 (permalink)  
Old 07-31-2013, 10:00 AM
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Caustic soda, or lye, is water soluble. If there are fats in contact w/it, the sresult is soap, or something resembling it). So if the material seen in the coolant passage is lye reacted w/a fat (or presumably grease), in theory it should also be water soluble.

But either way, I don't see it having anything to do w/a failed cam break in. Sometimes these things just happen for no apparent reason.
  • The same lifter bore wasn't involved in both failed cams, so it could be presumed the bores are OK- or they're tight and you just got "lucky" that only one lifter/lobe failed. Measure them and compare the diameter of the bores to the lifter diameter. You want at least 0.002" clearance. There are tools to groove the lifter bore to add lubrication at the cam/lifter interface. For solid lifter cams there are EDM lifters to add lube to the interface as well.
  • It's unlikely the lifters were from a bad lot, else more than one would have failed. Don't use "white box" no-name lifters!
  • Also unlikely the cam heat treat/surface treatment/metallurgy was faulty or more than one lobe would have been affected. Stick w/known brands w/good reputation for not going flat.
  • Endplay can be eliminated as a cause IMO, else more than just one lifter/lobe would have been effected and it was a different lobe each time. That said, using a cam button is a viable option.

This narrows it down to incorrect valve adjustment, the break in lube and/or the break in procedure used. Couple questions:
  1. Was the cam washed clean of the rust preventive it shipped with?
  2. Was the break in lube physically rubbed into the porous surface of the cam lobes?
  3. Was the lube thin and runny or thick, black grease?
  4. It did contain molybdenum, right? Brand?
  5. Absolutely NO IDLING for the first 15-20 minutes, right?
  6. Did the engine start right away?
  7. Valve train clearances all checked beforehand?
  8. Valve adjustment correct? IIRC there were issues w/this.
  9. Was the oiling system primed before initial start-up? (This is important but as long as the oil pressure came up immediately on starting the engine and there was moly grease on the cam and lifters, this shouldn't have caused an immediate failure.)

Looking at the page on cam break in, do you see anything obvious that could have caused the cam to take a dump?

My bottom line is there's just no good reason a flat tappet cam cannot work in this engine. That's not to say a roller set up wouldn't be killer and all, but sometimes that's just not in the cards. And it's not like there aren't more FT cams running in BB Chevy-powered street machines than roller cams.
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  #54 (permalink)  
Old 07-31-2013, 10:30 AM
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Were the lifter bores machined?
Yes, when the engine was originally overhauled.
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  #55 (permalink)  
Old 07-31-2013, 10:43 AM
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Were the lifter bores bushed? If so, correcting/getting the angles right can be a daunting task for the uninitiated, hope whoever did the work was well versed on the procedure. If the bores were honed, they still should be checked to be sure.
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Old 07-31-2013, 11:12 AM
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This narrows it down to incorrect valve adjustment, the break in lube and/or the break in procedure used. Couple questions:
  1. Was the cam washed clean of the rust preventive it shipped with?
    No. I didn't see that in Comp's instruction sheet.
  2. Was the break in lube physically rubbed into the porous surface of the cam lobes?
    Rubbed? No. "smeared* would be a better description.
  3. Was the lube thin and runny or thick, black grease?
    Runny-ish
  4. It did contain molybdenum, right? Brand?
    Lucas Assembly Lube #10153
  5. Absolutely NO IDLING for the first 15-20 minutes, right?
    Not the second time. I did it all myself.
  6. Did the engine start right away?
    Yes
  7. Valve train clearances all checked beforehand?
    Nothing done here, other than just lash adjustment.
  8. Valve adjustment correct? IIRC there were issues w/this.
    I believe that I did it the "one cylinder at a time way", and that I actually DID have a successful break-in. I truly believe that the latest damage is VERY recent ... after re-sealing the intake.
  9. Was the oiling system primed before initial start-up? (This is important but as long as the oil pressure came up immediately on starting the engine and there was moly grease on the cam and lifters, this shouldn't have caused an immediate failure.)
    Yes, to the point that oil was coming out of every rocker arm, and draining back into the lifter valley.

Looking at the page on cam break in, do you see anything obvious that could have caused the cam to take a dump?

I'll have to read that a bit later. I'm at work right now.

My bottom line is there's just no good reason a flat tappet cam cannot work in this engine. That's not to say a roller set up wouldn't be killer and all, but sometimes that's just not in the cards. And it's not like there aren't more FT cams running in BB Chevy-powered street machines than roller cams.[/QUOTE]

Thanks. I appreciate the fact that you have taken the trouble to do this detective work, and will definitely do everything on this list "the next time". (if there is one)
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  #57 (permalink)  
Old 07-31-2013, 11:15 AM
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You can trust in my next first gen BBC for myself is going to be a roller.BBC's leakiest link is the valve train. You see I do put my money where my mouth is.
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  #58 (permalink)  
Old 07-31-2013, 02:05 PM
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Is that coolant leaking into the valley around #7 intake/exhaust lifters ?
Could be your problem right there...



Duke
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  #59 (permalink)  
Old 07-31-2013, 02:33 PM
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Quote:
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Were the lifter bores bushed? If so, correcting/getting the angles right can be a daunting task for the uninitiated, hope whoever did the work was well versed on the procedure. If the bores were honed, they still should be checked to be sure.
Not bushed. Honed.
This engine came out of a 79 GMC 2500 with around 80,000 miles on it, and the PO said that it had never been touched. It was also LPG fuel, and surprisingly clean inside.

When I took the block in for the original inspection (hot tank, magnaflux, and cylinder bore taper, etc) the machinist said it had about .006 taper which would clean up well with a .010 overbore.

At that point, knowing I had a GOOD core, I instructed him to proceed with a complete overhaul, including align honing and freshening of all critical tolerences. I supplied the Clevite (Probe) forged flat-tops, and advised him that there was a possibility of a supercharger upgrade in the future. I had purchased some reconditioned 781 cylinder heads from a different machine shop and had them shipped to me ... and I instructed my machinist to dismantle and inspect to make sure I wasn't going to have any problems with them. He re-assembled them with those Clevite springs that I also supplied. (Most of the components that I supplied were Clevite items because that is what our store sold at the time.)

The crank was replaced with a Scat 9000, as the threads were stripped on the balancer bolt ... so it wasn't going to cost much more than grinding and repairing the stock one.

I also supplied a new (Dorman) balancer and flex-plate, and the rotating assembly was then balanced.

The engine was then fully assembled to the long-block stage and spun up.
I painted the block and installed all of the tinware. The first start-up occured a couple of months later. (I know ... another , but it couldn't be helped. I just so happened to be changing jobs during this time frame.)
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Old 07-31-2013, 02:37 PM
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Is that coolant leaking into the valley around #7 intake/exhaust lifters ?
Could be your problem right there...



Duke

Yup, but I'm not entirely sure whether the coolant you see there was an old leak or freshly deposited when I took the intake off.
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