hiphop

I have a built 355 roller motor in my 91 rs. Holley 650 carb and lo3 heads (saving up for better heads) I have an hei with an msd 6al box. Timing is set to 32 degrees base timing. I have a dead miss on three of my cylinders and have checked every possible thing I could. The only thing I havent checked was the valve springs in the heads. The heads are stock lo3 heads with about 160000 miles on them. The motor has an lt1 cam in it and Im wondering if it could be the valve springs? Any help would be appreciated. HIPHOP

BMmonteSS

I broke a spring once, and it sounded just like an ignition miss. I'd yank the valve covers right now, before you bend a valve.

hiphop

I already pulled the valve cover. no springs are broke and I have never driven this car. I have been trying to break in this new motor and cant get this stupid thing to wanna act right? Anyone?

vernw

iTrader: (2)

Have you checked compression in the 3 dead cylinders?

hiphop

this motor has less than 30 minutes run time on it. cylinder leakage is none, compression is 200 psi on all cylinders.

vernw

iTrader: (2)

OK, let's try the simple KISS method.... (no ofense!)

You need 3 things for combustion: Air, Fuel, Spark.

AIR/FUEL:
Since it's a carb, the only thing keeping fuel and air out would be valves. You've verified compression, have you verified fuel into the dead holes? Wet plugs? Do the intake valves move like the exhaust valves?

SPARK:
Verify a good spark at all cylinders. BTW - 32 degrees sounds like way to much base timing. Should be more like 6-10 I believe (but won't swear to it).

Just for grins, eliminate the MSD box while troubleshooting.

It's usually something simple that was overlooked

hiphop

the dead holes have fuel on the plugs. I am getting spark I found in two ways. I have a spark checker and also the bastard shocked the hell out of me. Im ketting fuel, Im getting air, and I have compression.

vernw

iTrader: (2)

Then they aren't all getting there at the same time or you would have ignition.

Try the timing at 6BTDC (instead of 32) and see what happens...

hiphop

I will try that. I just know that it is getting good ignition and running fine on the other cylinders except idle is real high and I cant figure that one out yet.

nsimmons

idle is really high because you have way to much initial timing

you want 34-38 total including your mechanical advance, with 32 initial and another 15-20 mechanical you have way to much timing.

Drops it down 12-16 for a mild cam (my car likes 18)

Jproz1167

iTrader: (3)

maybe a bad magnetic pickup coil in the distributor