Smoking Ironhead

[JW113]

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.

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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.

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

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

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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

[Burnout]

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

[JW113]

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

[Burnout]

It's good to know that no valves were harmed during this episode of "As the Ironhead Smokes"! 

I will offer to weld the tool box shut that belongs to the installer of that piston!   

[JW113]

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

[rageglide]

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.

[JW113]

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

[rageglide]

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.

[JW113]

Yes, but...

Ironhead, no valve seals.

Came on all of a sudden.

Rings look OK.

Dunno. Still not at the definitive root cause.

-JW

[rageglide]

Maybe the guide dropped?  If not sounds like a ring problem. 

[Burnout]

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?

[rigidthumper]

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.

[JW113]

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

[Burnout]

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.

[JW113]

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

[Burnout]

Are you going to dual plug it?

[turboprop]

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

No help to offer, but will share some totally unrelated BS like most people do. Reading your posts about your  ironhead may have caused some sort of shift in magnetic flux or something as two old friends came by the house this week (different times) on their ironheads. One was a typical rats nest of issues and general ugliness, but the other one looked and ran like it was maintained by one of the TC lifter fanatics on this page. Out of curiosity, I went for a short ride on it. Amazing. 10:1, CV, DTT ignition w/dual plugs, worked over heads by Baisley, Andrews close ration back cut gears, higher end suspension. Bike weighed almost nothing, had some dirt track bars. Was a whole bunch of fun. Few bikes crackle like a high compression ironhead. Almost makes me want to build one.

[98fxstc]

No help to offer, but will share some totally unrelated BS like most people do. Reading your posts about your  ironhead may have caused some sort of shift in magnetic flux or something as two old friends came by the house this week (different times) on their ironheads. One was a typical rats nest of issues and general ugliness, but the other one looked and ran like it was maintained by one of the TC lifter fanatics on this page. Out of curiosity, I went for a short ride on it. Amazing. 10:1, CV, DTT ignition w/dual plugs, worked over heads by Baisley, Andrews close ration back cut gears, higher end suspension. Bike weighed almost nothing, had some dirt track bars. Was a whole bunch of fun. Few bikes crackle like a high compression ironhead. Almost makes me want to build one.

sometimes totally unrelated BS is appreciated by others   

[JW113]

Interesting, and encouraging. Yes, am planning to dual plug it. And you're pal's recipe for the motor anyway sounds remarkably similar to what this one of mine is going to end up like. Am hoping the weight of the Wiseco pistons are close enough to the ones that came out that I don't have to pull the bottom end apart to re-balance. Mixed opinions about this out there in the interweb...

-JW

[JW113]

Got my Wiseco pistions, and dropped the heads/cyls off at the shop. He (Roger) gave the goods the eyeball, also did not see anything obvious that would explain the smoke, but who cares at this point.

He's going to attempt to fit valve guide seals, although he says it's a real pain-in-the-butt to do on an Ironhead. Also going to try and fit it for M-8 type spark plugs, which are a smaller hex than a standard 12mm plug I hear.

So... guess this thread is dead until, uh, maybe next March?



-JW

[Buglet]

   Are those Wiseco piston made to take hastings rings other wise you might still have oil problems. I know years back they made two different styles. 

[Burnout]

I would not attempt valve seals on a Ironhead, it's a sure fire way to invite sticking valves to the party.

[Buglet]

   With the new valves and guides you should have no problem running valve seals. The material they use in valve and guide is a lot better today. 

[JW113]

I believe they came with Hastings. At any rate, the top ring is of the moly type. So seat in should be short.

When the heads were last rebuilt, the guy used manganese bronze guides, and the intake valves are Kibblewhite stainless steel. I think the problem with using valve stem seals on an Ironhead is the lack of room for them. Although I think there are some guides available that use an internal O-ring. Am going to leave it to the shop guy to figure out, he knows his stuff, and I sure ain't going to second guess him on this.

-JW

[Burnout]

I have not heard of anyone using guide seals on an Ironhead successfully.
I have heard of many that stuck valves trying to use tight clearances.
Doesn't seem that seals would do much good with the loose clearances they seem to like.

[turboprop]

Baisley and others do seals in ironheads. He also does vey nice roller rockers for ironheads.

[Burnout]

I'll have to talk to Ryan next time I'm over there.

[Maddog]

no valve seals!! the little extra oil helps keep the valves cool,,, one can run seals on the intakes but not exhaust,,

[JW113]

So do manganese-bronze valve guides, or so I have been told.


A little puff of blue smoke every now and then never hurt anybody, but in my humble opinion, the main benefit of using valve seals is to reduce the amount of bleeaakh that builds up on the back side of the valve heads.

-JW

[Hybredhog]

   I ran guide seals on both int. & ex., mostly using cast or Ampro45 in the day on everything. You can set them up significantly tighter than stock (like under .002" on ex.), as you don't get the build up on the exhaust stems. You just had to watch your top collar clearance with help from trimmed down guides & relieved lower collars.

[JW113]

Well hell's bells, some progress. Like I said last November, maybe get my parts back by March. Well, I didn't miss it by much!

I picked up the cylinders yesterday, and he's cutting the 2nd plug holes today. With any luck, they will be ready today or tomorrow. I had to take him a "shorty" J12YC plug this morning as he didn't have any in the shop to adjust the plug depth with.

Knocking on the door of 5 months to get a Ironhead top end done. He explained to me that with the volume of TC and now M8 stuff through his shop, all the tooling is optimized to crank that stuff out. Any oddball stuff like Ironheads or other antique stuff he has to reconfigure all his equipment, so he only gets to it when he has the time. I get it, and I know going in that it's going to take a long time, but he does excellent work and he's local. About the only guy in the south bay area anymore that does this stuff. About the only other shop is Duncan Keller, but he ain't any faster.

Hopefully in a couple weeks, back on the road and start tuning it for the dual plugs.

-JW

[nibroc]

.... ....JW. patiently awaiting on an update......