Customs Look at these plugs

All fresh rebuilt 390 flat tapper motor for an upcoming project. Brand new plugs….On my test stand I started it up and let it run at about 2000 rpm for about 25 minutes…never ran over 200 degrees …great oil pressure timed it at about 34 degrees total. The next day I started it and turned the idling down and it wanted to keep killing. It would not idle.Took the plugs out and this pic is what I got? No antifreeze in the oil .All looked great there.Maybe just the carb? Ideas?

 

I’d say that’s definitely oil.
PCV stuck or intake leaking in the valley would be my guess.
Compression check will confirm it’s it rings but that I’d say is unlikely with your idle issue.

 

If you have the rocker shafts on backwards on a FE ( which is possible ) it floods the valve guide with oil which could cause what you are seeing. It has been decades since I have worked on one but I have seen it more than once.

 

I very much agree with Oneball, Maybe a problem with PCV plumbing, is it original from Ford or an earlier engine converted from road draft to PCV?

Not that it likely matters, but what make and part # are the plugs?

 

here's what I say. plugs got fouled during break in,... then wouldn't idle with the fouled plugs,,,, I just put a new set of plugs and see what happens.... looks like oil fouled plugs to me... but I don't know nothing about anything so beware

 

i don't see well. but it looks like some one painted them gold!....????? if thats the case,.... they would nt ground good'',,
but like said, I know nothing....

 

....????????? these??? don't look gold enough,,,????

 

Autolite AP45 plugs….oem PVC system

 

Pretty easy to disconnect the pcv and rule that out.

 

I’d change plugs and run if plugs foul again I would remove the pvc and plug vacuum ports , if still fouling then you know you have to dig deeper. I’d bet the plugs fouled on break in or your pvc system isn’t working properly. My 2 cents.
Dan

 

professional rebuild? or at least someone trustworthy?

 

Very trustworthy

 

good, so correct hone for ring material, rings right side up, head gaskets, intake to head gaskets, and a dozen other basic things should all be good.

hopefully it's something as simple as PCV as mentioned

I'd still wonder about proper ring seating,
did you use a "beak in" oil or just regular?
did you vary rpm or just hold it steady?

 

Break-in oil was used ….It smoked pretty good for about 10-15 minutes from first start then no smoke for the remaining break in time m. Sounded great nothing out of the ordinary on break-in. No misses or any other strange issues.

 

I'd change plugs and run it again, I'm guessing break-in oil from the rings seating and I'd say probably some assembly lube if they (like I do) put oil on the cylinder walls and piston skirts and rings when I install all new parts on a new motor.

IF it still fouls them then I'd pull the pvc stuff and try again.

I'm betting it's something simple like that....


...

 

Were positive seals installed on machined valve guides?

My completely overhauled Y block with 9000 miles seemed to have more blowby than expected and ran funny after a factory (62-64) style PVC system installed. I removed the heads and the piston tops had more than expected carbon build up. I cleaned all the piston tops and lapped the valves even though the looked good were sealing fine. Cleaned the stems also.

I bought the Comp Cam seal tool from Summit and positive seals and did the work with a drill. Now with 7000 more miles every thing is perfect. Plugs always clean and engine has never been smoother. Good luck.

 

That is from just running on a test stand ?
You have a problem,,,,and Houston can’t help you .
Check the rocker shafts like some of the smarter guys here recommended.

Something has to be wrong,,,,,I’ve never had an engine smoke on break in run !
If the shafts are wrong ,,,and it’s flooding the top with oil ,,,,,makes perfect sense to me .

At least you had a trustworthy guy to build it ,,,,,hope it’s a simple fix .

Tommy

 

He can just pull the pcv and look in.

 

Oil. If the person is trustworthy, I'd have them look over your shoulder when you swap in new plugs, cut up the oil filter for inspection, change the oil, and restart. Also inspecting the shafts with them there.
They have a lot more riding on it than us. If it clears up, great. If it goes belly up, they will be there to see you did nothing wrong.

EDIT: this can be done over video phone, if it's long distance.

 

Been stalled on this new break in 390 motor and have done everything you guys have mentioned ….except the last test .Today I ran the motor on the test stand with a good amount of the top of a valve cover cut to see if the springs are flooding with oil….,They sure are ….Now a few of you mentioned the the rocker shafts could be ( and according to my flood of oil test ) they are installed upside down….Now working only on 1 side after unbolting the rocker shafts do I just flip the front of the shaft over to the rear and of course realign the rockers and pushrods and bolt it down…Am I right on this technique if not please explain. Here is a pic of the valve cover cut I made. Anybody want to see the oil flooding? I can take s as pic of that also.

 

Yep according to to the above link info both rocker shafts were installed upside down….shaft notch at 11:00 not 5:00 like it should be. Pretty easy fix…Anybody know the torque on those rocker shaft bolts?…..Also do the bolts get into the water( antifreeze ) jackets?

 

Be sure second bolt back from front is installed in correct location also. Drastic things will happen if not in correct location

 

Second from front on one head second from rear on the other bank . Sorry it’s early .

 

if you don't mind me asking,... how the hell did you figure this out??? and wonder how many of these are running that way with a stack of reasons to the moon on how to fix or whats wrong???

 

also... does anyone have a pic of the shaft, and how it needs to go??? like in what to look for???