Hello to all
I am in need of some advice- I have a 74 Bronco I picked up a few years ago. It had 59k original miles and was a barn find. They must had been in a hurry and tried starting it without making sure the rings were not stuck. The owner said it had several broken rings when I bought it. I rebuilt the motor- I used standard rings as a big assumption. I did see several broken rings, but the piston ring grooves were not damaged. The cylinders did not require boring. The motor now has 300-400 miles on it and is smoking again. Now I am not a mechanic, but have rebuilt 20 or so Fords over the years- I am thinking maybe I busted a ring on the way back in? Will a compression check verify this? I did just replace the plugs- all were oil covered.

 

Broken rings and no big grooves in the cylinder walls? Did you mic the pistons and the bore and see what the clearances are? Did you hone the cylinders at all? Check the end gaps on the rings? Install 120 degrees apart? Replace the valve seals?

Burning and oil and fouling plugs, I don't see what the point of a compression test would be. It will have to come apart for correction regardless of compression methinks.

 

Check, check check on the questions. I was hoping you were not going to say that, but it was not unexpected.

Thanks

 

I hate when this happens, although my issue was a tad smaller than yours. (heads had to come off). Good luck with it.

 

No short cuts or U gotta go back anyway. 2X whad 'e said:

"...no big grooves in the cylinder walls? Did you mic the pistons and the bore and see what the clearances are? Did you hone the cylinders at all? Check the end gaps on the rings? Install 120 degrees apart? Replace the valve seals?"

May B, just may B a valve seal replace could do, but as the others "I doubt it".
Good Luck, keep talkin...

 

I have been restoring older fords lately and I had to remember what I actually did to this truck. This is a early production 74, but had points not the dura spark electronic ignition. I hear ford did this sometimes when they had changes in production? Is this correct? Also when I changed the plugs recently I was given the correct plug, but it did not fit. Ahhhh- now I remember what I did. rebuilding this, the machine shop said the heads would need completely rebuilt- seeing how these were the worse steel head ford ever made for the 302- I found the best- GT40P heads and had them rebuilt to strap on.
Anyway- back to the original problem- this truck just started smoking like this recently- it has about 300-400 miles on the rebuild. I am pretty positive I did not do anything like put the rings in upside down- but you never know- so agree this will need to come back apart. I have 5 antiques and they sit for long periods and I have been having problems with the ethonol gas in this state. The carb I am running was a spare that I know is worn out. Can improper fuel mixture ( worn out carb) or wrong plug be adding to this issue?

 

A rich mixture will wash the cylinder walls and contribute to an early death via ring wear, but it would take some time, your plugs would be black and you'd have a black cloud out the back for a long time before it turned blue.

 

"... This is a early production 74, but had points not the dura spark electronic ignition. I hear ford did this sometimes when they had changes in production?…"
Yes they did but DSI / II wuz '77 I believe. Not much of an effect w/ur prob.