Chevy 235 Running like a Tractor

I have a 58 chevy 235 and it runs horrible, black smoke, shacking, misfires(pops from exhaust). Removed #1 spark plug wire and it killed the motor. All other wires didint make a difference. Checked point gap at .018,I checked for current with an inline spark tester and it checks out. Replaced the #1 spark plug with another and the engine would not start. Am i running on 1 cylinder? Any ideas? In process of getting a compression tester and a vacuum gauge.

 

You check the timing?

 

No, not yet, timing was set a while back with a light. I'l recheck it though. Are you supposed to line up the pointer in the bell with the bb on the flywheel?

 

Black smoke sounds like it's flooding. I would be checking the carb.

 

At this point i think this motor has multiple problems. I have replaced the carb with another Rochester and it still smokes. Its been like that since day one. I can almost taste the fuel in the air.

 

You're definitely flooding. Solve that issue first, then go from there.

 

Was it a good carb or just a different carb?

 

Pull all of the plugs to see if they're fouled. If they aren't firing, it will run rich. The plugs should be wet.

 

Engine man, Its a different/good carb that got overhauled. Where should i start looking to make sure the carb i have right now is where it needs to be. I also rebuilt this carburetor not too long ago. I also adjusted the float/tabs just like the instructions say.

 

A few things to check are the carb of course,make sure the plug wires are in the right firing order, check for good strong spark at the plugs,make sure the plugs arent fouled from excess fuel and also you may want to check the oil level and oil for contamination with gas as in overfull of oil. It sounds like you have more then 1 problem to deal with but I would first off make sure you have good fire and close to the right amount of fuel supply.You also may want to check fuel pressure to carb excess fuel pressure will overload the float in the carb. Just a few thoughts that I hope helps.

 

Ever since i got the truck the engine has been smoking like that. I compression test is the first on the list. True, no use in investing time in a tired motor. I will check the oil for fuel contamination. If the plugs are fouled(no good) they should be wet?

 

Could there also be such as thing as a "mismatch" with the 1958 235 and Rochester Carb/Fuel pump.

 

The plugs should not normally be wet what is being said is if they are wet its another confirmation of too much fuel or not enough fire to fire the plugs. If they are wet they are fouled and will probably need replaced or at the very least cleaned and dried. Another thing to think about when you test the compression is if the cylinder walls are washed down from the excess gas it will give you a false low reading.

 

There is a advance scale at the base of the distributor. If the bellhousing pointer lines up with the BB in the flywheel, #1 cylinder is at T.D.C. Therefore, if they line up with the timing light the advance is set at 0 degrees. To set the timing follow these steps....

To initialize the advance scale at the base of the dist., line up the 0 mark with the line that is stamped in the engine block at the base of the dist. Loosen the bolt that clamps the advance scale to the dist. and use your timimg light to line the BB with the pointer, (by turning the dist.). Now tighten the advance scale to the dist. and double check that the advance scale is set to 0 and that the pointer and BB line up with using the timing light.

Now you can use the advance scale to set the timing to whatever amout of advance that you want. After initializing the advance scale a timing light is NOT needed to set the timing.

By the way....One of the best things that you can get for your truck is a FACTORY shop manual. Not a Chiltons, Haynes, or a Motor Manual, but a FACTORY Chevrolet pickup shop manual. These are available in reprints and are very easy to read. It's amazing to compare a 1950's era Chevy shop manual to one for a new Chevy. The 1950's manuals are nice and simple, with good illustrations. It will pay for itself with the cost you will save in unneeded parts and labor.

 

Heck, I don't even use a timing light. Set the timing plate at 0 and lock down. Mark the dist. housing even with the terminal for #1, then remove the cap.

Next, bump the starter (or use a remote starter switch) until the BB and pointer line up. Loosen the pinch bolt behind the dist. housing. Ya, its a PITA to get to, grab a long screwdriver and watch your knuckles! Pull the coil wire from the cap and secure the end 1/4" from ground in a shady spot you can see a spark well. Rotor should be on or near your mark on the top of the housing.

Turn the key-switch ON. Rotate the housing back-n-forth, watch for spark. See spark - tighten the pinch bolt. NOW, loosen the bolt on the timing plate and advance 6 - 8 degrees, tighten bolt. DONE DEAL!

Call around to the chain stores with a tool loaner program for a compression gauge and a remote starter switch. Write the numbers down for both dry and wet tests, then get back to us. Could be more than one bad valve causing a dead hole, or the rings shot. A wet test with 3-4 pumps of oil from a pump oiler will reveal bad rings if the readings come up. NO improvement means a poor valve seal, time to pull the head.

Good Luck, Tim

 

check your fuel pump and make sure your don't have a pinhole in diaphram sucking oil into fuel system, that will cause smoking

 

Or the diaphragm can leak gasoline into the oil which will also cause smoking.

My question on the carb is did it work on a different engine? If it isn't drizzling fuel at idle, it shouldn't be terribly rich.

Wet, or extremely black plugs won't fire. The electricity will follow the fuel or carbon to ground instead of jumping the gap. You need new plugs or clean the old plugs. The only way I've found to clean fuel fouled plugs is to burn the fuel out of the electrode with a small torch. I suggest using the proper AC brand plugs. One or two plugs not firing will allow unburned fuel into the exhaust.

 

never had a tractor that ran like that.

 

Alright so i went to auto zone and i got new spark plugs and borrowed a compression tester. I also set the timing just like the directions indicate above and the engine sure enough idles/runs much better. The black smoke now is more like a blue/white color. Performed a compression test;#1-130 #2-120 #3-90 #4-30 #5-35 #6-28. I'm going to get another compression tester to compare readings to be sure.

 

30, 35 and 28? Now you know the problem

 

I think the gauge is faulty. I tried to do another test with the same gauge and now i can barely get the gauge to move(on all cylinders). I poured some oil down cyl 1 to see if it would seal and make compression but i got nothing. surprisingly the blue/white smoke got reduced by half and engine sound much better!!!?

 

Blue is oil smoke and the compression might be low because the cylinder walls got washed down and the rings weren't sealing yet.

How did the engine oil look? Was the level high?

 

You might have gotten a piece of carbon caught in the check valve on the compression tester. Does it jump up at all.

 

Thanks for the help Engine man. When putting everything together from the thread you must be right. I also think the smoke is from the gas in the oil from when the spark plugs were bad. Will a heavier oil create more compression/lubricate the rings therefore creating more compression as well as reduced white/blue smoke? Oil is black and liquified. Oil pressure at idle is around 10 when warmed up, on acceleration it increases to about 20. What oil should i use? Thanks.

 

I checked the compression hose to see if anything was in there clogging the hose, nothing. The compression did move slightly maybe 2-5 psi. What if i hook it up to a compressor?

 

A straight 30 weight was what was normally run in those engines in the summer. A #40 probably wouldn't hurt in the summer.

Compression testers usually use shroeder valves like a tire uses. You could try blowing air in it.

 

I tried hooking the compression tester to a compressor and there seems to be a problem with it. Hooked up the gauge directly and couldnt get the gauge to move. Il buy a new one today and retest the engine. Il will also buy new oil and filter and see what type of results i get. Thanks again

 

Got a new compression tester and i got these readings- 1-125, 2-110, 3-108, 4-120, 5-125, 6-110. Next i plan on getting some new valve stem seals to see if i can reduce the the heavy smoking on acceleration. Any recommendation? where to buy them?

 

Smoke from stem seals usually happens on de-acceleration or on a cold start up in the morning. Your compression figures are borderline for bad rings (11.75% from worst to best). Inject a few squirts of oil in each cylinder and run it again to see if the figures improve.

If the numbers get better, I'd say that the rings are bad. Stays the same, you might have a bad valve. Or something else in the valve train gone bad.

Do you have appreciable oil from the breather or is it collecting on the valve cover and firewall?

Bob