I'm having trouble getting a 330 motor in a 76 F600 to run right and was wondering if anyone with more experience with this engine might have some suggestions. I can't get it to idle or run well without the chock almost completely closed. Problem is much worse when it's cold out (below 35F) It has 2bb Motorcraft with manual choke which we rebuilt - no change - changed plugs, wires, cap, rotor, etc. no change. Engine also doesn't want to warm up to temp- has 160F stat which was also replaced with a new one. Temp barely comes off of cold mark. We suspected vacuum leak and took all the vacuum hoses off and plugged them - no change also. Engine has 19,000 miles on it. Truck was used very little (less than 100 miles in the year before we bought it.) Timing is right on 6deg as it's supposed to be. Vacuum advance seems to move and holds vacuum. Engine has trouble pulling out empty, let alone loaded, right off idle. Accelerator pump squirts as it should.

I know I should do a compression test, which we'll do next to see if valves are acting up? Make any sense? Carb has the governer under it and it seems to move freely. I don't think it jumped time as the timing is right on 6deg as it should be and nothing has been disassembled.

Thanks for any help - I'm lost without an EECIV port to plug into.

John

 

You can do a compression test but I don't think that is the problem.

If your ignition is working well you might look at a carb rebuild. It sounds like the truck has been sitting around doing nothing for the most part and the carb gaskets may have crumbled. Your acc pump might be working well but that doesn't mean the rest of the fuel is being metered correctly. You say the engine has trouble at low RPMs. Does it pop through the carb or start blowing smoke?

A bad ignition coil is also a good possibility.

Get the 160 T-stat out of there and put a 195 in. You will be a happier driver and your engine will last longer.

 

rust in tank maybe. we have a 72 f500 with a 330 with 30,000 miles and it idles fine but if we try move the truck it shakes rust loose and it dies.

 

Thank you for the responses. Looks like the temp guage was acting up and the temp is coming up to normal. I replaced the coil with a known good one and it may have helped a bit. I already rebuilt the carb with new everything and that didn't change it's behavior much. It does pop and backfire through the carb when you are sitting still and gun the motor, when you let it settle down and try to idle it won't idle and pops, flames, and shuts down. I'm going to put points and condenser in it for good measure, as all other tune up parts have been renewed.

 

Points could definitely be the problem. Be sure to recheck the timing. I would set it to 10BTDC and your off idle throttle response will improve.

 

Again, thanks for the suggestions. I put in new points, condenser, set dwell to 25 per valve cover, reset ignition timing to 7 degrees (six is spec'd on valve cover), installed a new ignition coil, new plugs as the ones that were in there were carbon fouled already and tightend the intake manifold bolts (8/10 needed tightened). Engine is running better than it has so far, but still isn't right. I can now get it to warm up (to the new 195 degree stat) and it will run even with the choke completely open when warm - which it wouldn't do before at all. However it won't idle below about 1200 rpm - just spudders and dies if I don't keep feathering the throttle. It is also only making 11 inches of vacuum at 1200 rpm - shouldn't it be more like 15-17 (at least that's what the 400's in my pickups give me) The vaccum needle moves a little bit but not more than one inch total on either side of 12. Goosing the throttle drops vaccum to zero and then it comes back up to 15 momentarily and drops to 12 again.

I also did a compression test and low was 120 and high 145 so it's within the 75% Ford spec for compression.

Maybe bumping the timing up would pick up some more vacuum? Can I rule out the valve timing if the chain jumped a tooth? Is there a trick to check this without pulling the cover?

Again, thank you.

John

 

Well if you have low vaccume, might want to see if the intake manifold gaskets are good. Are you losing any fluids, particularly coolant?

 

It doesn't seem to be loosing any coolant.

 

My brother had almost the same truck, sliding flatbed F600 w/330...

He went through quite a few of them, tiring them out at around 100K miles before rebuilding them.

If I recall correctly, he had basically the same complaint. It was a pain to warm up in the winter and took a long time before it would start running right.

I wonder if your exhaust crossover is open and flowing properly? The one that goes from the exhaust manifold, through the head and under the carb... is there a butterfly between the exhaust manifold and exhaust pipe and it working correctly?

Is there that weird spacer under the carb that one heater hose goes to, and then from there to the intake water jacket?

Maybe someone blocked the exhaust crossover or just used the wrong gasket?

 

Again, Thanks to everyone who shared their thoughts and experience. After trying everything we could think of with the carb, we finally broke down and pulled the intake. We found the intake gasket blown in on cylinder 2 - causing a vacuum leak. With this engine design, it was under the valve cover, so the carb cleaner spraying didn't locate it. We'll finish putting it back together tomorrow, but we expect the problem to be solved. Thanks again to everyone for your help.

John

 

Just one final follow up. I replaced the intake gasket, got it back together and it runs almost perfectly, now. It idles right at 550, makes 17" of vacuum at idle, pulls out well, comes right off of choke in a normal warm up time, etc. Thanks again for suggestions and help.

John