[TAQuest]

Originally Posted by NeighborsComplaint

If you can rule out rocker/retainer interference, that is one variable out.

As others have said, that backwards rotation after cutting the ignition would normally indicate excessive cranking compression or too much initial advance. How did the engine crank on hot restart? If it "groaned" slowly before spinning, initial timing is too far advanced.

Retainer to rocker clearance needs to be ruled out as a cause. You should have daylight between the rocker bottom rail and retainer. Short Dport pushrods with a 1.7-1.8" installed height can be the cause. This will cause an intake valve to hold open and cause an intake backfire also. Longer pushrods and/or offset locks/keepers can correct this.

No witness marks on the spring retainers from the rockers. Good clearance. It started real nice and idled smooth. Slight run on after shut down. The timing was close but not exactly where I wanted it yet. Close enough not to backfire out the carb. Even though I was sure it wasn't timing, I tried it a little more advanced and retarded. Nothing helped the pop when revved.

["QUICK-SILVER"]

Originally Posted by TAQuest

No witness marks on the spring retainers from the rockers.

Look in the curved area between trunion and valve end of the rocker arm.

That's where you'll see a witness mark if there's a clearance problem. The retainer is a bit harder than the aluminum rocker.

Clay

[400 Lemans]

Move your pump rod to the middle hole on carb and make sure you are feeding full 12volts to your hei and not using the original resistor wire.

["QUICK-SILVER"]

I wouldn't be surprised if the engine runs fine when it's all back together.

If the backfire was from a lean condition...it could easily be from a piece of trash that got lodged in a jet.
Now that the carbs been off and shook around a little...That possible piece of trash could be laying in the bottom of the bowl.
Backfire would be gone UNTILL that piece of trash finds its way back in a jet.

Just thinking out loud
Clay

PS, most common trash found is a sliver out of the inside of a rubber hose

[NeighborsComplaint]

Originally Posted by TAQuest

I will check for clearance between the rocker and retainer. Makes sense. Thanks.

Rocker to retainer clearance gets a lot of things jacked up. One guy on this forum dropped a valve as his retainer was being compressed by a rocker.

The prior owner of my car had a similar issue. He was running the 1.7" installed height springs on RA IV heads and had a paper trail of receipts for changed lifters, springs, retainers. etc. chasing valve train noise. His solution was to grind notches in the underside of the roller rocker rails for clearance! lol

Turned out he was running Dport (short) pushrods causing his problems. I wound up installing Dports with RAIV valves and 1.7" installed height springs and RAIV (long) pushrods and -.050" keepers as a final to get the necessary clearance.

Re: springs, I thought yours was a fresh engine but you say you have run it this way for 10 years?

[TAQuest]

Originally Posted by "QUICK-SILVER"

Look in the curved area between trunion and valve end of the rocker arm.

That's where you'll see a witness mark if there's a clearance problem. The retainer is a bit harder than the aluminum rocker.

Clay

These rockers have a relief cut into them in that area. Plenty of clearance.

[TAQuest]

Originally Posted by "QUICK-SILVER"

I wouldn't be surprised if the engine runs fine when it's all back together.

If the backfire was from a lean condition...it could easily be from a piece of trash that got lodged in a jet.
Now that the carbs been off and shook around a little...That possible piece of trash could be laying in the bottom of the bowl.
Backfire would be gone UNTILL that piece of trash finds its way back in a jet.

Just thinking out loud
Clay

PS, most common trash found is a sliver out of the inside of a rubber hose

I have a really nice carb filter set up where there's only metal line after it. No rubber.

[TAQuest]

Originally Posted by NeighborsComplaint

Rocker to retainer clearance gets a lot of things jacked up. One guy on this forum dropped a valve as his retainer was being compressed by a rocker.

The prior owner of my car had a similar issue. He was running the 1.7" installed height springs on RA IV heads and had a paper trail of receipts for changed lifters, springs, retainers. etc. chasing valve train noise. His solution was to grind notches in the underside of the roller rocker rails for clearance! lol

Turned out he was running Dport (short) pushrods causing his problems. I wound up installing Dports with RAIV valves and 1.7" installed height springs and RAIV (long) pushrods and -.050" keepers as a final to get the necessary clearance.

Re: springs, I thought yours was a fresh engine but you say you have run it this way for 10 years?

Seems like I heard about this with 1.65 rockers, not the 1.5 I'm using.

[TAQuest]

After the cam break in I had a weird tick and then some backfiring out the carb. I took the intake and valley pan off to see if anything went wrong with the lifters on break in. Everything looked great. This morning I'm putting the distributor back in and I found something funny. There's a small cover next to the module that hides the wire connection. That small cover cam loose and wrecked havok inside the distributor. See pic below.

https://share.icloud.com/photos/0KKH...r_Township,_MI

[STEELCITYFIREBIRD]

It sure did! Does the mechanical advance still work?

[TAQuest]

Originally Posted by STEELCITYFIREBIRD

It sure did! Does the mechanical advance still work?

You know I'm extremely happy and relieved. Funny sounds and backfiring right after a cam break in can ruin your day, week, month.... Glad it didn't happen during the break in.
There were all kinds of chunks of plastic around the pick up.
Not sure if the advance was damaged.

[johnta1]

In your thread on HEI problem, did you run the distributor?

HEI Problem

Your new rotor:




Your last pic of the rotor that was running:




What's the odds that they both have the rotor tip pointing like that?




Also with a timing light it would have been abundantly clear there was a problem?


I'd look at the cap also, it's probably cracked (or worse)

[TAQuest]

Originally Posted by johnta1

In your thread on HEI problem, did you run the distributor?

HEI Problem

Your new rotor:




Your last pic of the rotor that was running:




What's the odds that they both have the rotor tip pointing like that?




Also with a timing light it would have been abundantly clear there was a problem?


I'd look at the cap also, it's probably cracked (or worse)

Never ran the piece from eBay.
My wife has been paying attention to the details and I asked her the same thing. What are the odds of having a rotor pointing up twice like that?
Life is strange.
Definitely replaced the cap too.

["QUICK-SILVER"]

Was it a black plastic piece like this?



Exactly when did all this happen?
Breakin or after you did all the work and went to fire it up again?
And is it running now?

Too much suspense
Clay

[TAQuest]

Originally Posted by "QUICK-SILVER"

Was it a black plastic piece like this?



Exactly when did all this happen?
Breakin or after you did all the work and went to fire it up again?
And is it running now?

Too much suspense
Clay

That's the piece. It ended up in about 20 pieces.
It was fine until I shut it down after the cam break in. It must have caught on the rotor on the very first start up after that. Started making funny noises and backfiring out the carb. Kind of like a bad lifter. Had to take a look at the lifters. They are fine. I was finishing putting it back together this morning. First chance I had. Took the cap off to put the distributor back on and found it. Haven't started it yet.

["QUICK-SILVER"]

Originally Posted by TAQuest

Never ran the piece from eBay.
My wife has been paying attention to the details and I asked her the same thing. What are the odds of having a rotor pointing up twice like that?
Life is strange.
Definitely replaced the cap too.

That last button you posted got bent up when parts were flying around inside the cap. You can see plastic broke off beside the tip where it was hitting one of the plugwire terminals. Seen this happen when caps weren't seated properly.

Parts flying loose from that may be what did the other damage with that cover.

Clay

[TAQuest]

It runs good. Still has more valve noise than it had with the smaller cam. Ran it for another 20 minutes at 2000 rpm just to make sure the cam was completely broken in. Not sure what more I can do to get rid of the extra valve noise. Might have to live with it.

[TAQuest]

Could the noise be the sound of the valves snapping closed from a more open position with the bigger cam? Does that make sense?

["QUICK-SILVER"]

Originally Posted by TAQuest

This time I had the covers off so I could see the rockers. I bring up the mark and see the rockers are even with each other so I assume they are closed and it's compression stroke. That's where I was wrong. The rockers look almost the same when at TDC on compression or exhaust stroke. So I was confident I was right when I was wrong. Bad place to be. That was the second shoe to fall. I learned that this morning by realizing that I was wrong and confident yet again on start up. At least now I know how and why I was wrong twice. Not going to do that again.

Originally Posted by TAQuest

It runs good. Still has more valve noise than it had with the smaller cam. Ran it for another 20 minutes at 2000 rpm just to make sure the cam was completely broken in. Not sure what more I can do to get rid of the extra valve noise. Might have to live with it.

If you adjusted valves like you was doing the distributor install....You need to go back and adjust valves again.

How much preload did the new lifters call for?

How did you check the preload?

What technique did you use to lock the polylocks down? Need to turn the nut for the final lock instead of just tightening the set screw.

Clay

[TAQuest]

Originally Posted by "QUICK-SILVER"

If you adjusted valves like you was doing the distributor install....You need to go back and adjust valves again.

How much preload did the new lifters call for?

How did you check the preload?

What technique did you use to lock the polylocks down? Need to turn the nut for the final lock instead of just tightening the set screw.

Clay

I followed the instructions with the cam. It said to rotate the crank the way it normally rotates until you see the exhaust valve open then set the intake valve. Then roll it over until you see the intake open and then set the exhaust valve. I did it one cylinder at a time like that.

One half turn lash after the push rod doesn't move up and down anymore.

After I have the half turn lash then I held the nut with a wrench so it didn't turn and tightened the set screw.