Ok, my 390 has now started to smoke. It didn't do it when I was having the valve noise (bad oil pump). Now that it is running, it smokes as idle only and runs a little rough. I have been looking on here, and started to think. Could longer push rods cause my motor to smoke at idle? I change the P/S push rods out when i was having the valve noise. Could I be floating the valves causing it to smoke and run rough? Thanks

 

What color smoke? Could be a leaky intake.

 

Now that you have abundant oil pressure you could be flooding the heads and if your valve stem seals are bad/gone then you'll get blue smoke at idle.

 

I was thinking that the longer rods i put in might not let the valves seat properly. I was going to change them back, but now it is back firing out of the carb. Could the valves cause that along with the smoke? It looks bluish, but it smells like gas. How do i check the seals. Are they hard to replace?

 

So the oil pump was changed out ? We left off at the "valve noise" thread:

"Put everything back together and it works wonderfully."


This smoke and backfiring may be related to the knock near number 5 that you wrote about earlier. Unless that was the fuel pump.

What I like to check is the timing chain slack. Just put a socket on the balancer/damper and crank it back and forth while watching the rotor in the distributor. A tight chain will move the rotor right away as you change directions with the socket. There's more than likely gonna be some play there...but how much ? May cause or contribute to backfiring but blue smoke...

If you've got the time I'd agree with changing the valve seals and putting the original pushrods back in if you have them indexed for the cylinder they came out of.

What are the compression numbers ? Could be number 5.



the above post reflects some of what I've be taught here at FTE...never too old to learn

 

the knocking went away when i adjusted the timing. The push rods are not indexed anymore. does that make a difference? I guess i will just buy some new ones.

The timing chain has about 3/4" play at the end of a 2 foot breaker bar. Is this enough to cause the timing to change?

eventually i will have the time to change the valve seals and new push rods. How hard is this. I have never done it.

 

What are the compression numbers ?

 

I'm trying to find someone who can do it, but first I have to get it running well enough to get it there. I can get it done for free, but the base it 10 miles away, and i don't want to drive it that far right now. How much will it cost me to take it down town to get it done?

Is that to much play in the timing chain?

 

Wow....this is really turning into a project and a half.

With all the issues you've run into I'm having a hard time keeping all the quirks straight.

We got he oil problem solved...
we got rid of the "knock" when you moved the timing....though do we know where the actual timing is set?

I'm kinda hesitant about putting new pushrods in it, as I don't think they are an issue(right now). Not being there, it's hard to determine all the problems.

Right now it smokes when idling. Since it has oil that it didn't before I'd be looking at valve stem seals, though it could be rings too, but since it didn't smoke before(even though it did run sorta) I'd say that is not my first choice. Valve stem seals are sorta complicated, but can be done by a novice with the proper tools. I'd probably pull off the valve covers and inspect the valve springs to see if there are any seals left(likely gone as typical after all these years).

You sound very hesitant about driving this far, does it not run very well still? What else does it do that concerns you?

 

No I don't know what the timing is. I'm working on getting a timing light. Have to wait for payday.

The backfiring out the carb says the timing is 180 off. The dizzy was pulled, but installed the exact same way. I was running one night, and the next it backfired out the carb when I gave it about half throttle. By the time i got it home, around the block, it was backfire at startup.

I know a little bit, and here is how I am understanding the motor. The longer push rods (swaped from standard to longer ones) could float the valves. If the valves are floating, it could act as thought the seals on the valves are bad (not sealing). Now, here is what I am thinking. If the intake valve is open on the exhaust stroke it could cause the motor to back fire out the carb, and likewise, cause poor compression with the exhause valve open on the compression stroke. Am i seeing this the right way, or am i dumber than i look!

I want to start at the push rods. Is my thinking above correct. You guys are the experts, but everytime i have an issue with this truck it is something simple causing major problems.

The major issues right now is the running rough, smoking, and backfiring out the carb. It ran like a top when it didn't have oil in the top half of the motor.

Thought just came to me. Since I only put the longer pushrods in one bank, if I disconect that bank, the smoke should stop if it is the pushrods causing the issue. Right?

 

The longer pushrods, holding the valves open will NOT affect the valve stem seals. The seals are just rubber cups that are under the springs and are there to keep oil from running down the valve stem into the cylinder and thus causing oil burning. These seals get old/hard over time and usually fall apart and will be found laying in the head area(under valve cover), if no one has cleaned them out before. Since you have minimal oil getting into valve train, there would be no oil build up in the heads that could run down the valve stems. Now you have lots of oil and this could be causing the smoke, Maybe.

You are right about loosing compression from valve holding open.

Removing the pushrods from one side will cause the motor to barely run(if at all)....so if you just put the old ones in then maybe you could test it.

The issue with backfiring is interesting. It just "started doing it" and got worse? You have either jumped time(timing chain) or the gear on the distributor has sheared the little roll pin and has allowed the gear to rotate and throw the timing out. I would pull number 1 plug out(pass side front), roll the motor over til piston is up top and then look at damper and make the TDC mark line up with pointer(remember you could be on firing or 180 out, so might have to roll it over again to get mark on damper). Then look at rotor and see if it's pointing right at #1 plug wire on cap. If it's moved anywhere, then you have issues. Maybe you didn't have distributor tightened down enough? Or could be pin sheared. We need to get some things narrowed down so we can eliminate some of the problems.

There are multiple things for any problem and the only way to determine is check multiple things. Hard for us to diagnois over the internet without being there and seeing.

 

Thank you. Now I understand why the pushrods would not affect the oil burning. Do I need to pull the head to fix the valve stem seals?

I ment i would pull the plug wires and run it to see if it still smokes.

could the floating valves cause it to back fire out the carb?

 

Hi Bill,

Having only 3/4 inch movement of the 2 foot long breaker bar before the rotor starts turning sounds good.


The #1 plug wire in the distributor cap can be marked on the distributor housing with a piece of tape or sharpie, that way when you remove the cap to watch the rotor pointing at #1 you will have a reasonable idea of the location.

Found mine by putting a stick/dowel in #1 spark plug hole and watched it move as the piston travelled through the stroke comparing it to the mark for #1 firing at the distributor. At first I was dumbfounded because the piston had topped out however #1 was on the opposite side of the rotor contact point for firing, dumb***, that was the exhaust stroke. lol

Since your waiting for payday it wouldn't hurt to retrace each plug wire comparing to the diagram for the distributor cap. Tagging each one at the cap helps too...then you can run out and pull the plug wires off and tear into the valve seals and have no worry...they're all marked.

Enjoy

 

I retraced the plug wires last night. I'm going to put the dizzy on the number one spot and make sure it lines up with the timing mark. Then i'm going to pull the dizzy and check to make sure it is on the compression stroke.

Also, i have a foul smelling gas coming out the hoses connected to the valve covers. I was told to put Engine Restore in for the first oil because it had sat for a few months. Could that be a factor?

This engine has become quite the hemroid.

 

It can be a hemmoroid. You gotta get some enjoyment or some type of satisfaction out of it all or just forget it, in some cases it's the money.

I've lost count how many nice shape(when I got them) vehicles were towed away to the junk yard because I couldn't grasp how to plan repairs out.

My buddy is trying to convince me to do the valve seals on a '60 352 tbird. One method is an adaptor to the spark plug hole that connects to an air compressor, compress the spring, remove some hardware, keepers I think, remove the old valve seal, probably crumbling, slide on the new valve seal, reassemble the parts, decompress the spring, repeat 15 more times. You don't want those old seals getting into the oil pump. Maybe a wet vac standing by.

Felpro FPSS13401 is a kit the advertises direct replacement without any machining.
??

Now there are many on here that can do this with their eyes closed getting a kick out of all this newbee stuff. lol

Enjoy