Okay, just bought this 79 FLH with a 80" dual plug heads, supposed complete rebuild from PO. Test drove it around the block pulled hard no issue no smoke, maybe running rich.

Bought it and didn't get 10 mins down the road when I noticed the front cylinder exhaust was pouring out smoke. Shut it down, trailered it home and tore down the front head.

Here's what I'm looking at? What do y'all think?




Looking at head gasket clearly oily and appears to be a partially blocked oil passage.





The gasket was lined up and seated perfect to all bolt holes, but still the oil passage hole was off by 1/4"





Couldn't pull the one side plug because the rocker was in the way...I don't know how they changed it without removing the rockers





The PO had HD put in NGKs, these are fully seated but appear to still be 1/4 of the threads short even being fulled seated





The wall looks good know marks, scrapes or heat damage, just looks like a ton of oil





Same piston, different angle.

 

Rings lined up at the gap...
Or improperly cleaned after final hone..Makes an oil burner.
That mismatched gasket is sad looking, but, I doubt that caused yer issue.

 

Shovel heads can be turned on the barrels a fair amount so I don't believe the gaskets are a problem.

The first thing I would check is that the crankcase breathing system is working properly. If it is plugged in any way as soon as you started building pressure it has to go somewhere and will find the easiest way out.

 

If it was the rings wouldn't the oil buildup be all around the piston and not on one side?

 

Also, it would only smoke once fully warmed up. Right before I pulled the head drove it around a couple times to check oil pressure. Wouldn't start smoking until engine was warm.

 

Not where compression is escaping, or blowby is entering..the burned part is oil, the not burned is Washed by oil.

Can't smoke till ya burn the oil...that takes Heat!

You have no choice but to pull the jug...then look...Hell! Maybe the ring gap was too tight and a ring Broke...or maybe the second ring is upside down...Won't know till ya Look!!

 

Might be reflections in the picture, but the gap between the piston and the cylinder wall looks huge...wrong size piston? Something else to check.

 

Yep, it end up measuring .005" at the smallest and .006" largest...think it should be .003-.004" max? Buddy of mine said they walls are pretty glazed and the rings prob. never seated.

 

good catch Tom --

to me it has forged pistons and 9.5 or more compression

picture up the ports you may also have guides leaking

 

She's passing way too much oil around the rings for one thing and take a hard look in the intake & exhaust ports to see if they are wet looking on & around the guides also. It's R&R time for that upper end and I'd pull the cam cover and take a hard look at the breather gear, the port and the oil & breather lines, Somethings pushing a lot of oil there.