Allowable play in front connecting rod??

[Eric S]

I removed the top end on my 59 today due to a dropped valve seat in the front head.I have no up and down movement in the rods but have some side to side in the front rod and none in the rear. How much play can you safely get away with before doing a total rebuild. Thanks Eric

[Cotten]

Eric!

There is no way to guarantee that a crank is roadworthy except to disassemble it.

Even if you found it within the manuals' spec for sideplay (you do have a Service Manual, right?), it is by no way a sure thing that the crank is serviceable.
Races close up when overheated, so a crank that is ready to seize can seem cherry.

Only a totally trashed crank is easy to spot:
If you wash out the rollers and firmly pull up on a rod, then smack it down with the palm of your other hand, a really shot crank will make a rod knock noise.

Do you know the mileage on the crank?

Note also that when a hardened seat falls out, the piston often dings the valve. This can bend or twist a rod. That should be inspected as well.

Good luck!

....Cotten

[Eric S]

Thanks Cotten and to others who have helped with other questions that I have posted in the past. This motor had been rebuilt and never started from a previous owner. At that time the heads had extensive work. I ran it about 100 miles and the base gaskets started to leak. I replaced them and the seat dropped while I was checking the timing in my garage. The piston is undamaged other than a small mark in the valve relief. The front rod play is aprox 2/32. I am going to need to purchase heads at the bare minimum. I was thinking about one of Teds replica replacement engines and saving the good numbered cases for a rebuild at a later time. There are very few people in my area that specialize in these early bikes. Thanks again. Eric

[steve_wood]

Hmmm. Too bad VT wasn't still around, he'd probably have lots to tell you about those taiwan tedd engines.

Suffice it to say, I don't think you'll hear to many good reviews.

Perhaps a better option would be the mills from Accurate Engineering. I've heard that they are good. Pricey tho.

93 cubic inches (smallest they make) in natural Finish - $8,750.00

POWER !!


steve

[john HD]

eric

i know a shop that -may- be able to fix your heads.

pm me for info...

john

[Sir_Rat]

If they were mine I would send them out to either Bills Custom Cycles or Head Hogs. I'll vouch for Bills personally and others in here have recomended Head Hogs. Bills is in Pensylvania and I send him my stuff all the way from Hawaii...ur a hell of of alot closer than I am.

Aloha,
Mike

[Eric S]

Thanks again everyone for the input. I contacted Head Hog and because the seats were replaced once with steel replacements he felt that they were too far gone. Nice guy to speak with however. Any vendors come to mind for replacement heads that will take stock exhaust and intake? There is a person on ebay advertising STD castings with valves but I am note sure of the fitment or origin?? Thanks Eric

[Bosheff]

Why does previously using steel valve seats render the heads to far gone for further service?....bosheff

[steve_wood]

Cause Don needs the remanants of the original brass seats still in place to do his metal transfer/build up magic.

[NightShift]

Dear Bosheff and everybody,
If you pick all of the original seat out and thats a lot of fun then it can be welded up for another pressed in seat. Its risky with anything before 56 though because the heads crack easy. Seats wont drop back out if they were put in good and the motor never ever gets too hot.

Getting all the old seat out helps heat transfer too.

Respectfull,

[PanPal]

Its risky with anything before 56 though because the heads crack easy.

Nightshift

Is there less meat in these heads or is it the casting material? Every 58 to 62 head I see has the normal cracks from the spark plug hole towards the seat. Most are FLH heads. I wondered if the standard FL heads are just as likely to have cracks.

I have a 59 rear head in my stash that has a crack throught the bronze seat. Would Don be able to repair this? I'm currenly running a 56 casting probably replacement head with an outside oiler boss not drilled, but it has 3 fins around the spark plug and it doesn't look right where it mates to the cylinder.

[NightShift]

Nightshift

Is there less meat in these heads or is it the casting material? Every 58 to 62 head I see has the normal cracks from the spark plug hole towards the seat. Most are FLH heads. I wondered if the standard FL heads are just as likely to have cracks.

I have a 59 rear head in my stash that has a crack throught the bronze seat. Would Don be able to repair this? I'm currenly running a 56 casting probably replacement head with an outside oiler boss not drilled, but it has 3 fins around the spark plug and it doesn't look right where it mates to the cylinder.

Dear PanPal,
Heads with plumbers nipples havent much meat for the intake seat. Cracks around the plug means lots of heat or maybe a cheater bar on the plug who knows. Cracked seats really make a cutter jump. Only Headhog knows if he wants to fix it and I bet he dont have time but you aught to get it in line anyway.

Hs aways ran hotter because compression and heat mean the same thing to the head. But something really wrong made them too hot when they cracked.

Those undrilled overhead oilers came out for replacements like you said. Some of the best heads ever made but resto people like Cotton snivel at them.

Respectful,

[Bosheff]

Would somebody explain to me what exactly Don (HeadHog) does when he replaces/repairs a valve seat. It sounds to me like he spraywelds (for lack of a better term) over the existing seat only he uses some sort of a bronze alloy. Am I thinkin in the right direction, or am I out in left field on the whole process? What exactly do you mean (Steve Woods) when you say he needs the remnents of the old seat? Are ya talkin bout what's left of the used up seat so he has somethin to bond to? Would appreciate someone enlightenin me to the process....bosheff

[steve_wood]

Okay, here it goes....

Don's exact method is a closely guarded secret. I suspect it's some type of spray weld or electroplating.

As I understand it, the original seats were cast in place. The diameter at the bottom of the seat is greater than the diameter at the top of the seat (where the valve contacts it). The aluminum is cast around it making it impossible for the seat to come out ! (unless there is a catastrophic breakdown of the aluminum surrounding the seat).

I believe that Don uses the existing seat as a starting point. He probably cleans it up, then starts his magic process for building up enough metal to bring it back to OEM specs. Once he has enough metal, he machines it to spec.

If the original seat has been pulled out, then the replacement seat (if there is one) is a simple press fit. Even if he could run his magic build up process on the pressed in seat, he would not be able to guarantee that the remachined seat would not come out. Remember, the pressed in seat does NOT have the wider diameter at the bottom so it IS possible for the seat to come out if the head gets hot enough.

Just as an aside, when Don worked on my heads, he found that three of the seats were original and one was a replacement press fit. He was able to do the magic on the three originals, but he had to improvise for the pressed in seat. He ended up sourcing brass stock that had virtually the same coefficient of expansion as the aluminum. He machined a seat from the stock and pressed it in place. This particular seat is not covered by guaranty. He explained all of this to me and we both agreed that it was the best solution. I can see why he might be reluctant to refurbish a set of heads were ALL of the seats were replacements.

[Cotten]

Let me add,
The original seats have tangs on them that project into the casting.
The remains of these can be painstakingly removed with a diegrinder or keyway cutter.
Then, as Mr. Shift pointed out, the casting can be TIG'd up to provide a matrix for a new pressed-in seat.

It is a tedious process, but it has saved many a Pan head.

But the dilemma remains about seat material.
A bronze insert with a decent expansion coefficient will not require the enormously tight press-fit that hardened seats require,
saving many heads from cracking.
They will not shrink as dramatically as hardened seats, so their chance of falling out is minimized.

And although they are not retained by tangs within the casting, the casting can be be rolled over the top of them:
The seat is chamfered on top before installation;
After pressing it into the casting, a piloted burnisher is turned like a cutter upon the aluminum,
to deform it over the chamfer.
This is called "clinching", and was state-of-the-art for generations, until auto shops got lazy.

A properly installed bronze seat,
with a little extra insurance from a conductive gap-filler-adherent ("Fluid-Weld"), would be 'as good as new'.
(Cast-in seats have their own issues, by the way.)

All we need to know is a source for the bronze!

...Cotten