Author Topic: Smoking Ironhead  (Read 179 times)

92fxrt and 1 Guest are viewing this topic.

Offline JW113

  • Full Member
  • Posts: 1832
  • Country: 00
  • San Jose, California
Smoking Ironhead
« on: November 08, 2019, 04:12:23 PM »
Starting a new thread, as the dyno days are on hold for a while.

Well, I indeed found some trouble, but not so sure it's the "smoking gun". LOL

Pulled the heads for a look-see. It was smoking, so naturally no surprises here.

  [ You are not allowed to view attachments ]  

Cylinder walls a little more scuffed/worn that I would have hoped for on a bike with not so many miles. Not great, not terrible.

  [ You are not allowed to view attachments ]  

Head chambers of course all caked up with Petroleum Al Carbon.

  [ You are not allowed to view attachments ]  

And then we get to the piston crowns. In particular, the rear. And what have we here?

  [ You are not allowed to view attachments ]  

Hmm. That can't be good. I'll squirt some carb cleaner into the intake port to see if the head is bent, can't imagine it not. Not exactly sure this translates to high oil consumption, though. Maybe damage to the guide? Will need to pop the valve out and have a better look.

Speaking of valves, and that nice little scar on the piston... I don't recall the guy that did these heads mentioning to me that he used 1-15/16" intakes. But that's what they are, look to be Kibblewhites. That would kind of explain the valve/piston clearance problem, since the cams are bone stock P cams. The exhaust valves are stock HD, has the part number cast right into the valve head. Also, the pistons appear to be stock bore.

So the fun begins...

-JW
2004 FLHRS   1977 FLH Shovelhead  1992 FLSTC
1945 Indian Chief   1978 XL Bobber

Online Burnout

  • Full Member
  • Posts: 1275
  • Country: us
Re: Smoking Ironhead
« Reply #1 on: November 08, 2019, 06:05:55 PM »
The pistons should be notched for the intake valve?
And that is how you orient them, notch to the intake side.
There is no front or back you just rotate the piston.
That looks like the rear cylinder intake that hit (no notch).



These are 3 of the many possibilities

« Last Edit: November 08, 2019, 06:15:26 PM by Burnout »
They don't call me Ironhead Rick just because I'm "hard headed"

Offline JW113

  • Full Member
  • Posts: 1832
  • Country: 00
  • San Jose, California
Re: Smoking Ironhead
« Reply #2 on: November 10, 2019, 08:42:49 AM »
And you would be correct, sir. The rear piston is installed backwards, valve pocket is on the exhaust side.

I sprayed a bunch of brake cleaner in the intake port down around the valve seat. Not a speck leaked through to the other side, so apparently no damage to the valve, just has been "rubbing" on the piston forever. No clue yet as to why the oil consumption. Time to pull the heads apart and pistons out of the jugs.

-JW
2004 FLHRS   1977 FLH Shovelhead  1992 FLSTC
1945 Indian Chief   1978 XL Bobber

Online Burnout

  • Full Member
  • Posts: 1275
  • Country: us
Re: Smoking Ironhead
« Reply #3 on: November 10, 2019, 12:20:50 PM »
It's good to know that no valves were harmed during this episode of "As the Ironhead Smokes"!  :oops:

I will offer to weld the tool box shut that belongs to the installer of that piston!   :potstir:
They don't call me Ironhead Rick just because I'm "hard headed"

Offline JW113

  • Full Member
  • Posts: 1832
  • Country: 00
  • San Jose, California
Re: Smoking Ironhead
« Reply #4 on: November 10, 2019, 05:05:23 PM »
I don't know the history of this bike. I bought it from a good friend, who had bought it as a basket case and put it back together. Although I don't know if it was he or someone else that reassembled the bottom end. Matters not, it's apart now and I'll deal with what needs dealt with.

It was a real (prostitute's offspring) getting the pistons out. They had been assembled with Spirolox, which I have no problem with, used them many times in the past. However, on these pistons, there was not access notch, and the tangs on the Spirolox were below the edge of the keeper groove. As in, no way to get a tool on the tang to get them out. I ended up having to carve the piston around the end of the Spirolox to get access to the tang. Did my best to keep the chips out of the motor, but man I hate having to do operations like. The piston skirts look a bit words for wear. They are .030" over, so not the originals. Need to mic them out to see how much clearance. That might be the problem, but hard to explain how it had been doing OK, then suddenly started blowing white smoke. I hadn't wound it up higher than 6K. More investigation needed.

-JW
2004 FLHRS   1977 FLH Shovelhead  1992 FLSTC
1945 Indian Chief   1978 XL Bobber

Offline rageglide

  • Full Member
  • Posts: 3538
  • Country: us
Re: Smoking Ironhead
« Reply #5 on: November 10, 2019, 05:12:58 PM »
I wanted to swing by earlier to see what was up, didn't make it.  :-/ 

Did you look at the rings?  Maybe a busted ring?  With unknown history of that engine ya never know.  Piston in backwards, rings installed improperly who knows.

Offline JW113

  • Full Member
  • Posts: 1832
  • Country: 00
  • San Jose, California
Re: Smoking Ironhead
« Reply #6 on: November 10, 2019, 06:32:46 PM »
Well you didn't miss much, except for a lot of foul language. Ha!

Pistons mic'd out "OK", front had .004" clearance, the rear .006". :-/ Not great, not terrible. Rear seems to be pretty much worn out though.

The rings were all place correctly. Pips side up, and nice wear pattern on the ring faces. I think the oil was not coming past the rings. Need more investigation into the heads.

-JW
2004 FLHRS   1977 FLH Shovelhead  1992 FLSTC
1945 Indian Chief   1978 XL Bobber

Offline rageglide

  • Full Member
  • Posts: 3538
  • Country: us
Re: Smoking Ironhead
« Reply #7 on: November 10, 2019, 06:40:57 PM »
haha i know foul language.  Spiral locks are always worthy of f-bombs.

Good point, could be valve seals.  A visual should be easy.  But that much oil in the intake seems like ring pump.

Offline JW113

  • Full Member
  • Posts: 1832
  • Country: 00
  • San Jose, California
Re: Smoking Ironhead
« Reply #8 on: November 10, 2019, 06:58:47 PM »
Yes, but...

Ironhead, no valve seals.

Came on all of a sudden.

Rings look OK.

Dunno. Still not at the definitive root cause.

-JW
2004 FLHRS   1977 FLH Shovelhead  1992 FLSTC
1945 Indian Chief   1978 XL Bobber

Offline rageglide

  • Full Member
  • Posts: 3538
  • Country: us
Re: Smoking Ironhead
« Reply #9 on: November 10, 2019, 07:15:37 PM »
Maybe the guide dropped?  If not sounds like a ring problem. 

Online Burnout

  • Full Member
  • Posts: 1275
  • Country: us
Re: Smoking Ironhead
« Reply #10 on: November 10, 2019, 10:04:27 PM »
A stepped guide wont drop unless it is broken.

Some guys have blamed the head gasket, saying it sucked oil from the drain hole, but I cant wrap my head around that.
But...
If the ring seal was bad the outer edge of the piston will be washed clean.
Where ever the oil is coming in will be washed clean.
Where the head bolts tight?

Looking at the picture of the rear head in the fire ring step the intake side is washed clean and the exhaust side has cooked oil....
Is that because that is the hot side or was oil coming in on the intake side and washing it?
Is the head (machined/honed) flat or was it worked on with a powered rotary abrasive tool?
They don't call me Ironhead Rick just because I'm "hard headed"

Offline rigidthumper

  • Administrator
  • Full Member
  • *****
  • Posts: 5219
  • Country: us
  • Mark, 06/02: There's no cryin' in modifyin'
Re: Smoking Ironhead
« Reply #11 on: Yesterday at 05:55:09 AM »
Inadequate crankcase breathing and a handful of 6,000+ RPM back to back pulls can cause a temporary build up of oil in the rocker boxes, and a the long decels on the dyno  will suck that extra oil right past the valves into the intakes.

Offline JW113

  • Full Member
  • Posts: 1832
  • Country: 00
  • San Jose, California
Re: Smoking Ironhead
« Reply #12 on: Yesterday at 08:33:33 AM »
Now that's an interesting thought. After the WFO pulls, I rode it another 4 or 5 miles down the freeway, turned around and came back home which was about 12 miles more. That's when I swung by Bob's and he saw the smoke also. If it did fill the rocker boxes up with oil, wonder how long it would take for it to clear it all out and stop smoking?

All the bolts (head, cylinder, rocker box) were quite tight. I don't have a lot of detail on how the heads were rebuilt, it was quite a long time ago. But the guy that did it specialized in Ironheads, so am assuming he knew what he was doing.

-JW
2004 FLHRS   1977 FLH Shovelhead  1992 FLSTC
1945 Indian Chief   1978 XL Bobber

Online Burnout

  • Full Member
  • Posts: 1275
  • Country: us
Re: Smoking Ironhead
« Reply #13 on: Yesterday at 07:45:57 PM »
I doubt it would fill the rockers the drain holes are 5+ times the size of the feed.
Unless there is a leak somewhere, there is very little difference in pressure between the rocker box and the crank case.

I think if you averaged it out the crank case pressure may actually be slightly negative. (if your check valve is working)
That is how they get rid of the condensate, it vaporizes at a lower temp if the pressure is reduced.
They don't call me Ironhead Rick just because I'm "hard headed"

Offline JW113

  • Full Member
  • Posts: 1832
  • Country: 00
  • San Jose, California
Re: Smoking Ironhead
« Reply #14 on: Today at 07:40:02 AM »
Well I've got some .040" over Wiseco 10:1's on order. Hope that doesn't create yet more problems later. Also have a set of Andrews R5 cams on the shelf that I might install. What the heck.

-JW
2004 FLHRS   1977 FLH Shovelhead  1992 FLSTC
1945 Indian Chief   1978 XL Bobber

Online Burnout

  • Full Member
  • Posts: 1275
  • Country: us
Re: Smoking Ironhead
« Reply #15 on: Today at 07:48:04 AM »
Are you going to dual plug it?
They don't call me Ironhead Rick just because I'm "hard headed"