New Cam Break-in Troubles

The cam in my 1994 TBI engine recently went flat on two exhaust lobes and started popping out the intake.

I went in for my first cam swap and was hoping to get a comp #12-304-4 cam. It was out of stock everywhere, so I went with a #12-388-4.

Lubed everything real good with clevite stuff, the engine had to sit for nearly a week as I pieced it back together in the evenings as I had time.

Finally started it, turned over a little while then ran rough with slow throttle response. I gave it a little more gas and a big old flame silently shot out through the intake and it died.

I advanced the timing a little and tried starting again - this time it wouldn't even turn over, but it turned out to be just a ground issue.
Got the engine started, gave the dizzy a good crank until it sounded pretty decent by ear, then got back in the cab ASAP and brought it up to 2k.
Kind of went between that and 25 for about fifteen minutes before I foolishly forgot to keep an eye on the temp gauge - until I smelled antifreeze and looked at the radiator (had the cap off) and saw it fizzing a little out the top.

Saw the gauge was reading about 210 degrees so I shut the engine off. Immediately coolant geysered everywhere and went a good 12 feet in the air, blew out three or more gallons of coolant.
I checked the gauge again with the key on and it was maxed out. I don't know if that's normal if the system is almost empty or what, but figure I'll make a note of it.

After I'd cleaned the mess I very thoroughly made sure I got all the air out of the system that I could, and this time just poured water in. I assumed either I would have to pull the t-stat out or I had just left too much air in the system.

Started the truck a final time, fired right up - but in about five minutes or less it started making a ticking sound, and then seemed like it progressively got worse to a certain point. At that point I was almost certain the sound was it backfiring again out the intake, but this time a lot more clearly.
I shut it off and restarted it, and then it made the noise even while idling - gave it more gas and it popped a lot louder. I took a video of it but unfortunately seems as though I can't send it on here.

The question of the day: how screwed am I?
Could I have cooked the engine even though the temperature read within the limits?

Could it have been coincidental that it happened after the coolant issue and is a separate problem?
If so, what could it be that would randomly start to occur halfway through break-in?

EDIT: The lifters I used were "Chevrolet Performance Hydraulic Flat Tappet Lifters 12371044". I read good stuff about them, but could this issue be a collapsed lifter? I have no idea

You can post YouTube videos on here, so if you post there, link here.

There are some really smart people on here, hopefully they will come along shortly and give you some advice.
Good luck.

CrashDriver said:

Lubed everything real good with clevite stuff, the engine had to sit for nearly a week as I pieced it back together in the evenings as I had time.

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Thick-liquid "Clevite stuff"? Kinda guessing that most of it dripped-off while it sat for a week.

CrashDriver said:

Finally started it, turned over a little while then ran rough with slow throttle response. I gave it a little more gas and a big old flame silently shot out through the intake and it died.

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Did you degree the cam, or just stuff it in "dot-to-dot"?

CrashDriver said:

I advanced the timing a little and tried starting again - this time it wouldn't even turn over, but it turned out to be just a ground issue.

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Excess cranking is hard on new cam 'n' lifters.

CrashDriver said:

Got the engine started, gave the dizzy a good crank until it sounded pretty decent by ear, then got back in the cab ASAP and brought it up to 2k.

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Timing should be close before the engine is even started. Static-timing is 90% science, 10% art. With practice, you'd likely be within one or two degrees of your target.

But ideally, you'd practice on an engine that isn't breaking-in a new cam and lifters.

CrashDriver said:

Kind of went between that and 25 for about fifteen minutes before I foolishly forgot to keep an eye on the temp gauge - until I smelled antifreeze and looked at the radiator (had the cap off) and saw it fizzing a little out the top.

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Next time, make sure the rad is full, and the rad cap is in place before starting engine.

CrashDriver said:

Saw the gauge was reading about 210 degrees so I shut the engine off.

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210 degrees is NOTHING TO BE CONCERNED ABOUT.

CrashDriver said:

Immediately coolant geysered everywhere and went a good 12 feet in the air, blew out three or more gallons of coolant.

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Which is why you should have the rad cap in place.

CrashDriver said:

The question of the day: how screwed am I?
Could I have cooked the engine even though the temperature read within the limits?

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MAYBE you cooked the engine. More likely you just flattened another cam lobe or three.

The downside is that now you have even more iron debris circulating with the oil. This is why I put a bypass filter on every "rebuilt" engine I do. The bypass filter will catch stuff that gets past the full-flow filter.

I may or may not leave the bypass filter in place permanently, but it'll be there during the entire engine break-in.

CrashDriver said:

Could it have been coincidental that it happened after the coolant issue and is a separate problem?

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Yes.

CrashDriver said:

If so, what could it be that would randomly start to occur halfway through break-in?

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Lack of initial lube, too much cranking, too much slow running 'cause the timing wasn't set properly.

Or just a crappy-soft cam core.

CrashDriver said:

EDIT: The lifters I used were "Chevrolet Performance Hydraulic Flat Tappet Lifters 12371044". I read good stuff about them, but could this issue be a collapsed lifter? I have no idea

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I would not expect a "collapsed" lifter, but I'd not be surprised if you wrecked the bottom of the lifter, or the cam lobe, probably both.

Pop the intake manifold back off, examine the lifters and lobes.

Not a fan of tossing in a new cam behind a failed one without an engine teardown and cleaning, ground cam metal paste stuck to every surface inside gets slung all over the new stuff can quickly lead into a second cam not making it through break in. Not that I'm a fan of Comp Cams but if I chose one of their cams I would have run their lifters. How the valve lash was set and that you were confident you did it properly is important. Flat tappet cams need to fire up immediately. Cranking for 10 minutes while you play around with stuff is no good. Cool water in a steaming hot block isn't a good plan either, but 210 isn't cooking.

Get into some detail. Could be valve lash or something more sinister depending on how you did things

Here's the link to the video:

Hipster said:

Not a fan of tossing in a new cam behind a failed one without an engine teardown and cleaning, ground cam metal paste stuck to every surface inside gets slung all over the new stuff can quickly lead into a second cam not making it through break in. Not that I'm a fan of Comp Cams but if I chose one of their cams I would have run their lifters. How the valve lash was set and that you were confident you did it properly is important. Flat tappet cams need to fire up immediately. Cranking for 10 minutes while you play around with stuff is no good. Cool water in a steaming hot block isn't a good plan either, but 210 isn't cooking.

Get into some detail. Could be valve lash or something more sinister depending on how you did things

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I know, it was foolish but I was hoping against hope that I could get away with it because I don't have the wherewithal right now to be able to pull the engine and spend the money on it; guess I'm spending more money now in the long term...

The one thing I'm nearly entirely confident of is the valve lash, I already did it twice before when I thought maybe the original cam popping was just bad valve springs.
What I did was I took a little shop camera I could stick in the spark plug hole, brought each cylinder in the firing order to TDC, and adjusted both of the valves until I just couldn't wiggle them up and down anymore and then added another half turn.

I know, I wasn't happy about turning it over either but the ground wasn't letting it turn fast and there wasn't much else I could do until I figured out what the problem was - I was testing it before and after taking the plugs out, was worrying at that point if the cam timing was off or goodness knows what. turned out the starter wasn't getting the power it needed.

Only good news about adding the water was the block sat for a good half hour while I cleaned up the mess.

from what you guys are telling me it sounds like I may have screwed myself in any number of ways...

Schurkey said:

Thick-liquid "Clevite stuff"? Kinda guessing that most of it dripped-off while it sat for a week.

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It was Clevite #2800B2 "bearing guard". Red dyed.

Schurkey said:

Did you degree the cam, or just stuff it in "dot-to-dot"?

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the latter... because I have a low braincell count

Schurkey said:

Timing should be close before the engine is even started. Static-timing is 90% science, 10% art. With practice, you'd likely be within one or two degrees of your target.

But ideally, you'd practice on an engine that isn't breaking-in a new cam and lifters.

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I know... what I did was I brought the engine to TDC, then pointed the rotor towards cylinder 1. Difficult part for me was rotating the oil pump rod so it would line up in the right place.

Schurkey said:

Next time, make sure the rad is full, and the rad cap is in place before starting engine.

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Yeah, I guess so; I had it in my head that it would burp itself and the only way to release the air was to keep the cap off... apparently forgot that on the cap itself reads "15 lb. System".

Schurkey said:

Pop the intake manifold back off, examine the lifters and lobes.

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Will do..... ug.

CrashDriver said:

The one thing I'm nearly entirely confident of is the valve lash... ...I took a little shop camera I could stick in the spark plug hole, brought each cylinder in the firing order to TDC

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TDC Compression, or TDC Exhaust? Get this wrong, and you won't have enough lifter preload, and it's gonna clatter like mad.

CrashDriver said:

It was Clevite #2800B2 "bearing guard". Red dyed.

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Next time, consider a cam/lifter lube that won't run off over time. Some folks like Lubriplate 105; others use thick, Moly-based paste on the cam lobes and lifter bottoms (but NOT on the sides of the lifters/lifter bores.)

If you use the moly-based paste, the oil filter MUST be changed at ~20 minutes, as the moly paste can plug an oil filter that quickly.

CrashDriver said:

the latter... because I have a low braincell count

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Degreeing the cam eliminates guesswork and simplifies diagnostics if the engine doesn't run right.

I always check the cam timing on #1 and #6. Both banks, one at the front, one near the rear. Comprehensive, without having to reposition the degree wheel or pointer.

CrashDriver said:

I brought the engine to TDC, then pointed the rotor towards cylinder 1.

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Next time, point the rotor to #1 terminal on the distributor cap as a ROUGH guide, then look at the alignment of the pickup coil points as a final guide. When the outer points align with the inner points, the distributor should be within a few degrees of perfect.

CrashDriver said:

I had it in my head that it would burp itself and the only way to release the air was to keep the cap off.

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Use a Robertshaw thermostat, which has a VERY TINY vent stamped into the metal. Allows the air to bleed out while being a considerable restriction to water/antifreeze.

Or fill the water jacket of the engine BEFORE you install the thermostat, then just top-off the system after the 'stat and hoses are in place.

Pull the valve covers and use a sharpie to mark a line on all 16 push rods. Run the engine for 30 seconds or so while watching the push rods. They should rotate. If they don't, you killed the cam/lifters. If they do then you might have got lucky and collapsed a lifter.

skylark said:

Pull the valve covers and use a sharpie to mark a line on all 16 push rods. Run the engine for 30 seconds or so while watching the push rods. They should rotate. If they don't, you killed the cam/lifters. If they do then you might have got lucky and collapsed a lifter.

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will do