PRHeads
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Good job!!
What ended up being the cam of choice?
What ended up being the cam of choice?
383 spun main?
- Thread starter RebelRider
- Start date
RebelRider
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The 6401 summit house brand.
RebelRider
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Well that was short lived. I broke the cam in and got it running good. After a while I developed a tick on the passenger side. It eventually started to run rough. I pulled it back down to find 2 ruined lifters and a ruined camshaft. Not sure where to go from here. I verified cam timing multiple times before buttoning it up. I used plenty of assembly lube, as well as a zinc additive. Oil pressure was great, even until the end. All the other lifters look fantastic. I even did a compression check to verify no valve to piston action occurred. Oiling issue? The one with no hole worn in it is locked solid.
Same ones?
RebelRider
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New lifters, same locations. 2 and 8. I would think if it were related, the first two lifters would have visual damage on the bottom. Valves move freely and push rods are all perfect.
PRHeads
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Did you verify proper lifter rotation for every lifter?
I’d check the lobe taper on a few of the other lobes.
You’d like to have .0015”-.0020”
Spring part number and installed height?
Out of curiosity...... how much run time on it?
I won’t get into a big debate here about lubes and oils...... but, what did you use for cam lube and oil for break in?
I’d check the lobe taper on a few of the other lobes.
You’d like to have .0015”-.0020”
Spring part number and installed height?
Out of curiosity...... how much run time on it?
I won’t get into a big debate here about lubes and oils...... but, what did you use for cam lube and oil for break in?
Were the lifters bad in the exact same location as last bad lifters. What I mean exact same lobes.
RebelRider
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I'd be looking at the 2 lifter bores. maybe egg shape so lifters are cocked some how. Mopar blocks are dam good, but those lifter bores? When said 2 & 8 was that what cylinders they worked or what
RebelRider
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Yes, they worked for cylinder 2 and 8. The bores “look” fine.
I'm hoping PRheads or an engine builder would comment. The bores are in main oil gallery. If you put a lifter in if cam is still in engine and a see if you can slip a .002 or a .003 feeler gauge in? Better if you have a way to measure the lifter bore.
RebelRider
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I’m sure he will chime in when he gets a chance. He always does. I don’t have a way to check the bore. If you look at my original picture, the lifters is scarred pretty bad, so there may very well be damage. I’ve already invested quite a bit in this engine, so going further with it is getting very hard. Even if it’s a mistake I’ve made causing it.
If your cam in engine put a lifter wiggle around and compare it to others. PRH gave some good advice.
Demonic
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Block needs to be fully disassembled, covered with detergent and washed, 2 or 3 times, with all the oil plugs out. The issues the the mice in the heads makes me thing sticking valves. Polish the crank, wash the pistons after checking the skirts for scoring.
Did you recheck those 2 valves that you found stuck from mice? Maybe stuck again?
RebelRider
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That’s the first thing I checked. All is well.
RebelRider
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It may come to this, but the block is already 60 over, so if any scoring is present, she’s done.
PRHeads
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I don’t recall the original cam going flat.
Am I remembering that right?
No mention of the installed height on the springs.
The Comp 911 is a fairly stiff single spring.
(If installed at the factory height of 1.860, the load would be 137 closed/[email protected] lift. While many people have broken cams in successfully like that, I think you’d find if you called around to some cam grinders that they preferred the open load for break in to be like 275 or less.)
If you used a zinc additive in regular oil, that’s not even close to the same thing as actual break in oil.
I always use a paste/or grease style of cam lube...... I have no idea about what comes with a Summit cam.
No mention of whether or not you verified lifter rotation.
One of the pics you posted of the old lifters had one that was clearly not turning.
That would have been the first thing I checked with the new cam & lifters.
If you used Summit lifters, they are usually imported. Should show country of origin on the box.
Might not matter...... then again, it might.
And, we don’t know what the lobe taper situation is.
I’m not hating on the OP, but it sounds like there might be at least a couple items that could be “improved” on for a higher success rate of cam break in.
Sometimes **** still happens.
Recently I was talking with a customer who was interested in getting a cam to replace one that didn’t make it thru break in.
We discussed all the things he had done in preparation for the break in, and it really sounded like he had all the bases covered...... and it still didn’t survive.
Am I remembering that right?
No mention of the installed height on the springs.
The Comp 911 is a fairly stiff single spring.
(If installed at the factory height of 1.860, the load would be 137 closed/[email protected] lift. While many people have broken cams in successfully like that, I think you’d find if you called around to some cam grinders that they preferred the open load for break in to be like 275 or less.)
If you used a zinc additive in regular oil, that’s not even close to the same thing as actual break in oil.
I always use a paste/or grease style of cam lube...... I have no idea about what comes with a Summit cam.
No mention of whether or not you verified lifter rotation.
One of the pics you posted of the old lifters had one that was clearly not turning.
That would have been the first thing I checked with the new cam & lifters.
If you used Summit lifters, they are usually imported. Should show country of origin on the box.
Might not matter...... then again, it might.
And, we don’t know what the lobe taper situation is.
I’m not hating on the OP, but it sounds like there might be at least a couple items that could be “improved” on for a higher success rate of cam break in.
Sometimes **** still happens.
Recently I was talking with a customer who was interested in getting a cam to replace one that didn’t make it thru break in.
We discussed all the things he had done in preparation for the break in, and it really sounded like he had all the bases covered...... and it still didn’t survive.
Last edited:
RebelRider
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I’ll get the installed height. You are correct, the original cam was not rounded at all. The new cam came with a paste style lube, and I did use it. I would think that if it were break in oil related, all of the other lifters would show the same wear. If you look at the picture, the one with the hole doesn’t even look like the same type of wear as the other.
PRHeads
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This is why I don’t like to go down the oils and lubes discussion path.
It’s very hard to change people’s minds on it.
In the early 2000’s, during the peak of the “cams going flat” period....... I never once saw some have a cam go flat on break in where all the lobes were bad.
Yet, later on..... it was discovered how much the oil formulas had changed, and that it was the primary cause for many of the cams going bad.
Countless cams had failed on break in because of inadequate lubrication...... yet most only had a lobe or a few that didn’t survive.
Personally, I’m a big proponent of break in oil.
It only exists because of all the cams that went bad during the oil formulation changes of the early 2000’s.
At this point we’ll never know if break in oil would have made the difference between success or failure in your motor.
But.......we do know that you didn’t use it, and your cam didn’t survive.
One example:
I had a customer with a fast rate .904 SFT cam in his motor.
Broke it in with break in oil, inner springs removed.
No issues.
Installs inner springs..... runs car the rest of the season.
Pulls the heads at the end of the year for some upgrades.
Sees one lobe is gone....... lifter is wasted too.
We discuss the possibilities of why this happened.
Turns out...... he didn’t understand you needed high zinc oil all the time, not just break in...... and he’d been using regular old SM rated oil.
One lobe gone....... 3 others starting to wear the noses off.
12 still look fine.
New cam...... break in oil, inners removed, break in goes well.
Install inners...... run high zinc oil...... cam survives just fine.
It’s very hard to change people’s minds on it.
In the early 2000’s, during the peak of the “cams going flat” period....... I never once saw some have a cam go flat on break in where all the lobes were bad.
Yet, later on..... it was discovered how much the oil formulas had changed, and that it was the primary cause for many of the cams going bad.
Countless cams had failed on break in because of inadequate lubrication...... yet most only had a lobe or a few that didn’t survive.
Personally, I’m a big proponent of break in oil.
It only exists because of all the cams that went bad during the oil formulation changes of the early 2000’s.
At this point we’ll never know if break in oil would have made the difference between success or failure in your motor.
But.......we do know that you didn’t use it, and your cam didn’t survive.
One example:
I had a customer with a fast rate .904 SFT cam in his motor.
Broke it in with break in oil, inner springs removed.
No issues.
Installs inner springs..... runs car the rest of the season.
Pulls the heads at the end of the year for some upgrades.
Sees one lobe is gone....... lifter is wasted too.
We discuss the possibilities of why this happened.
Turns out...... he didn’t understand you needed high zinc oil all the time, not just break in...... and he’d been using regular old SM rated oil.
One lobe gone....... 3 others starting to wear the noses off.
12 still look fine.
New cam...... break in oil, inners removed, break in goes well.
Install inners...... run high zinc oil...... cam survives just fine.
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