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Engine break-in, Left bank header glows

4K views 24 replies 10 participants last post by  levisnteeshirt 
#1 ·
Im trying to breakin my new 355 I built.

9.5:1 CR
World S/R torquers
262 VooDoo cam
750 Holley
Performer RPM intake

Anyway, I got it fired and was maintaining 2500 to 3000 rpm to break in the cam and only the left bank header began to glow so I shut it down after only 3min. The right bank seems fine. Timing was at 35 total, I tried advancing and got up to 38 degrees but header again started to glow after only 2 min. I rebuilt the Holley so I set my mixture screws 2 turns out to start out. I checked for vacuum leaks and found none. I just cant figure out why just the left bank is getting so hot.

Another question:
I know the new cam cant take much cranking so I tried to get everything right for start up but I ended up cranking it for about a total of 20 revolutions before I diagnosed a bad coil. Now it starts well and I have run it twice at 2500-3000 rpm for just a few minutes at a time like I talked about above. Do you think I have damaged my new cam already? or was the moly assembly lube on the lobes enough to protect it for those 20 revolutions?
 
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#2 ·
Give it as much initial as you can without going over the 38 total. I run around 20 initial and 18 mechanical. Retarded timing or a lean condition can cause the header glow. I have never had to put a fan on one, but you can put a shop fan by the radiator also to help it. I always had mine ready and cranked them and either high idled them or drove them.

Only time will tell you about the cam, but I wouldn't sweat it as it's already done either way. Oh the joys of a roller cam.:D

Good luck with it.
 
#4 ·
The squirters are working fine, I just put in a new accelerator pump. I adjusted the valves to zero lash (not mistaken for bottomed out lifer) + 1/2 turn. The floats are set now as the rebuild instructions stated with that little paper ruler. can I set the floats with it at 2000rpm during break in or does it have to be at idle?
 
#8 ·
You can idle it to set initial timing(have everything ready as in tools and light). Also do a quick float set if need be and then go back to the high idle, varying throttle so as to splash more oil on the lobes.

Where did the carb come from?
 
#10 · (Edited)
Well I tried to idle it to set the floats and it wont idle. If i bring the rpm down to around 1500 it dies and makes a little poof through the carb. Crank it back up and it runs for a few seconds and dies. Even for the few seconds that it runs that left bank header starts to smoke. I sprayed the intake on that side to check for leaks and no raise in rpm. I wonder if the intake weren't meeting the heads on the bottom of the port it could have a vac leak, but in the valley where I couldnt detect it. But I checked the plugs and they have a nice color not like they would be if it were too lean. Also I hear a ticking noise, sounds like an exhaust leak but I couldnt find one maybe I should go through my valve adjustment again.

All this cranking, I might as well go ahead and order a new cam. geez.:beer: Im goin to the store.
 
#12 ·
Remove the float bowls and turn them upside down. Float should be approximately centered in the bowl. This should be plenty close enough to get you started. Glowing headers would indicate a lean condition, so as long as the floats are on the high side they won't cause it to be lean. What oil are you using? Does it contain zinc or did you use an additive? If you have zinc in the oil your cam is more than likely fine.
 
#17 ·
If its a dual plane intake and it has a plenum divider cast into it that runs all the way to the top of the carb mounting base, would it be possible that one side of the carb is running lean? Not sure what carb youre using, but assuming its a holley try setting the idle screws at 1 1/2 turns out to start. Also if im correct in my thinking, in a dual plane the right side feeds the left bank and vise versa.

just throwing ideas out there...
 
#18 ·
Dual plane or single plane can run lean on one side. Could be the main jet or passage is partially clogged. By choking it down the header will stop glowing if it indeed is a lean condition which it seems to be.
 
#21 ·
I think what was going on was I used the cork end seals in the intake gasket kit and it didnt allow the intake to seal to the head all the way and it made the left bank lean due to an internal vacuum leak. I took the intake off and it appeared that the intake did not squish the gasket on the bottom of the ports on that side. I will reassemble with just a bead of silicone (like I should have done in the first place) and let you know if it works. I also readjusted the valves.
 
#24 ·
It's lean on that side, I'm not really sure why? It can only be a problem with the carb. or a vacuum issue. I had the same problem with break in on my truck(85 Chevy) with a 355 , but the carb was set up for the original 305 and it was a computer type Quadrajet. Mine ran for about 10 minutes before the molecules in the headers started glowing. I shut it down let it cool off and finished the break in procedure. I went with a non computer carb. and distributor. It runs fine 40K mi. later.
 
#25 ·
might be rich too ,,, might be some dried up gas in the carb clogging something up ,,, i'd put it on a 1 in open spacer ,,, i'd get a very large can of carb cleaner ,, and spray it in any hole you can find in the carb ,,, check the air bleeds , and make sure the power valve cycle smooth ,, they can stick open and cause a rich condition , especially at a high idle
 
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