Technical 302 + holley 2bbl, just cant run right?

Hi all - I have been dealing with this motor for 2 weeks now.. had it together - 125psi cold on all 8.. had some apparent spark trouble (had 6 in a bag that sat for a few years but still brand new plugs) - has an unknown variant of holley 2 barrel (list-7018-2, doesnt come up anywhere on holleys site).

Cleaned carb out again - new power valve (2.5 0 i know it shd be a 7 probably since its a stock motor with no acc's)..

Blows huge puffs of black smoke out the back - current timing is 1-5-4-2-6-3-7-8, its a 1974 ford 302. Just put in new bearings and rings - everything checked out, it must have been re-machined because all journal clearances are perfect.

Having said that - im starting to get a little superstitious about this darn motor. thoughts?

 

my thoughts are either inadequate spark and/or carb jetting wrong- i have 60 jets on both sides.. fuel psi at3.5, no leaks and choke open.. timing at 8 degrees.. ive been messing with motors for years but this ones really got me

 

Might have the other cam/ firing order. Ford 302s can have two different firing order.







Bones

 

Bones hit on something that I would have missed.

 

You have or have had spark problems. You don’t know what the carburetor is so fuel problems is not a big jump.

Time
Fire
Fuel

Solve each issue systematically rather than the whole. It’s a step by step process.

 

Having screwed up with the firing order on a '90 f150 with a replacement '95 long block with the different firing order, it would not run enough to make it to the point he is at. I finally found out what that problem was when I noticed the valves were open at the wrong crank positions. I learned the value of not ripping all of the plug wires off without looking at their positions that day.

 

I tried all of the newer firing orders before the teardown and the old 302 one worked best. I'm going to try a gap test, I'm strongly suspecting an ignition related issue..

Have a new hei I'll stab in but this is just very odd.. cant figure it out

 

You say 1-5-4-2-6-3-7-8

You might try this. HRP

 

I dont think it would run without back firing using a later 5.0 firing order. I'd put in a 7.5-8.5 p/v to start.

 

Have you considered upgrading to a Chevrolet engine?

 

el scotto tell me about it, no valve lash! really dump oil pump shaft design to boot (when u get the tension washer in the wrong direction / working upside down thinking upside down)!
@HOTRODPRIMER thats exactly how i have it - (different terminal positions of course).. Ive been setting points and timing for 20 yrs lol -

Im making up new wires (maybe 2day if i can scrounge up the motivation).. and will put in my chinese HEI and see what happens but i have 2 other jobs to get thru and this pig has taken up WAY too much time for a toaster style motor..

fyi the block did roll over and a got a small crack on timing cover at top bolt hole on the outside - nothing else seems out of place so i dont see an issue there..

will update later -

 

@RmK57 - i had a power valve in there with 3 numbers, 7 and 5 and 3 i think, all in different locations.. i had one pv that was def bad in the box which i confirmed by rotating the anti-backfire spring, he good ones dont cos the rubber is good, and i sprayed carb cleaner on the top to see if it leaked and the 2 good ones i have dont. one in there now is brand new from a 4150 kit - is it true that all ower valves with the spring on the end has the anti-rupture ball design or is it internal?

not that ive dealt with power valve issues b4 but all my symptoms do suggest an issue- going to vac test the one i had in there and do a open spark gap test to see whats happening..

 

The anti rupture valve is in the base of the carb.





Bones

 

Holley carb itself has power valve protection from the factory since 1992 or somesuch. They don't necessarily leak fuel as such when defective, if they fail to hold vacuum they are still defective.

 

one thing is make sure the gasket on the power valve is set proper. i had one slip just a bit and it gave me a fit till i found it. good luck.

 

I use superglue to secure the gasket on the powervalve itself. Seems to hold up to gas, it won't move.

 

hi yes gasket was good - the holley power valves are in the center wafer, not bottom like webers / etc- either way 90+ outside today so ill give it a miss till next monday and try another 2 barrel..

 

Well my 2 cents , it has to have correct wiring for the cam or it would be backfiring like my old Harley with a blown exhaust gasket . My thoughts are black smoke is really rich . If you are running a 500 CFM. 2 barrel it will never lean out enough not to smoke . Timing as in vacuum advance would give you the effects of late timing and rich mixture . Ford Autolight 2 barrels were at one time a dime a dozen , I would try to locate one with 1.21 cast into the left ( driver side ) of the fuel bowl , rebuild it and start from there . The idle mixture bleeds could be so corroded in the Holley , 2 good mechanics and a priest can not normally get them clean .

 

picked up a rochester 2 barrel from a olds v8 - will check jetting and see if its close to a 302 and try it -

 

Please post the rest of the story when you get it fixed.

 

so found a mercarb 2 barrel (same bore size of 1-1/2 each side) form a 99 mercruiser.. the manual lists the same jetting for the 305 and 350 so i think its safe to assume the same applies to a 302 maybe..

After rebuilding the old holley 2 barrel twice (incl new power valve) the thing ran pig rich.. i might get a wire gauge set and check the jet sizes..

Anyway - popped the mercarb on and fired right up.. little on the rich side but zero black smoke and idles great so now im gonna see if i can find a 2 barrel adapter cos the old ford has a large bolt pattern and the newer carb smaller (i cut a 3/4 piece of plywood and made one for testing) -

funny thing is the holley came on the motor originally- so im not sure what the heck is going on.. the list # doesnt even come up.. closest i could maybe match was a 2300... its vintage for sure, late 60s early 70s only..

 

DeathrowDave, I usually agree with you! But..... the 500 cfm Holley, tuned right will tun perfectly on a 302 Ford. We put a lot of them on 289s back in the day when they were common in Fords little car! Most of the time they were just bolt on and go! Sometimes we had to mess with them a little. But never saw them smoke....unless you had them on the floor! Lol. Just my experiences.





Bones

 

I have also run 4 different 500 cfm Holley's on 5 different engines. Never had one smoke. I usually jetted them slightly smaller than out of the box, but otherwise left things pretty much alone. I have run 2 350 cfm Holley's on 2 different engines. Had problems with them running lean off idle, which I tuned around.
Best trick I found was using an Autolite 350 cfm 2 bbl, off a 390 on a 302. I pulled one from my father's car as he was having problems. The thing made a good seat in the pants difference. He had distributor problems, we soon learned and he wanted his carburetor back!
I can't say that I've heard of the one he's having problems with. Perhaps a smog replacement for an oem application?