74" head cracking

[T. Cotten]

...I run Cotton type floats lower than the old recommendation for the heavy copper variety as they control fuel more accurately...

Why lower, Peter?

Brass must be set much lower for their mass, but mine are to be set to book spec.

I went to a lot of trouble to calculate their proper volume for proper buoyancy to achieve the same fuel level in the bowl as OEM; Any arbitrary adjustments are at your own risk.

....Cotten
PS: Buzzed Kanker published in his hard-copy rag that my floats should be set higher!

I needed an attorney.

[pisten-bully]

It's been improved recently apparently. If you do try it I, and I'm sure others, would be interested to hear what you find.

https://www.shell.com/business-custo...-30071535.html

Opened up my motor after a 7500 mile season on Aeroshell 100 (50wt), carboned up, so it's no magic bullet!

8CD34036-0117-4BC7-843F-8AA86B64B1F5.jpeg

[T. Cotten]

...Opened up my motor after a 7500 mile season on Aeroshell 100 (50wt), carboned up, so it's no magic bullet!

Any other oil, Harry,..

And it would have 'coked' up much worse, especially after seventyfivehundred miles.

Somewhere in the literature it speaks of "de-coking" at something like three thousand!

Carbon results from high heat, and it looks like that involved the exhaust valve, naturally.

....Cotten

[PRG]

Howdy Harry,

Mercy! You didn’t mention whether the starting point for that 7500 miles was a fresh decoke or merely an oil brand change in a motor with many miles. Either way, there are other factors here for which this oil has been overcome trying to cope. I completed my high compression 80inch hotrod Chief in 12/96. In 2019 now no longer a young whippersnapper with aging knees decided to knock some of that compression off by fitting thicker copper gaskets. Below are the picks of what I found after pulling the heads and lightly running a wire wheel over the deck to remove some tan deposits from the exhaust valve heads. The head pictured was merely cleaned with the brass brush in upper left and some carb cleaner. (Numbers on head are from ccc’g it bare, with fiber and then copper gasket).

The point here is that after thousands of miles over 2 decades the tell tale indication of bore wear, the cylinder ridge above the top ring land was not only absent but my cross hatch from a careful final home with low RA still visible. Operating parameters: case baffles removed, 2050W VR1 and religious use of the ignition advance while underway (like your modern car and bikes does for you) so as to prevent destructive high cylinder pressures, lean carb setting and extended tip plugs to help complete burn. There are any number of factors that can contribute to deposits, worn valve guides being another. Good luck.

[T. Cotten]

I've always wondered, Folks,..

Did the Wigwam actually make copper headgaskets for Chiefs with aluminum heads?

Thanks in advance as always,..

....Cotten

[pisten-bully]

Did the Wigwam actually make copper headgaskets for Chiefs with aluminum heads?

Good question Cotten! The parts book isn't much help (maybe if it was printed in color )

23C546D5-8E89-4288-A5EB-4B2FEB509414.jpeg

[pisten-bully]

So Peter, nice looking motor innards there! Who knows, the carbon pictured above was one season after new heads and a cleaning. Could be my riding style, or it could be your motor is exceptional, too? When I ride I seldom exceed 55mph, it takes me almost 3 hours to ride 100 miles. The motor pulls so well I find myself using mostly 3rd gear and going as slow as 20 mph at times. On the other hand I average over 42mpg, my plugs are brown, and it still requires a good oomph to kick it over. I just figure it's part of the experience!

[PRG]

Howdy Harry,

20 mph in third (on a 28 tooth final or less) is fine.....as long as your ignition is fully retarded. I’m currently navigating post COVID resurgent Bike Week traffic and that same 48 Chief is a far more flexible low speed cruiser than my 41 FL. At any rate, at the end of the day, depending on rod angularity as dictated by bore/stroke ratio most all internal combustion engines reach full flame engagement at 15 - 20 degrees ATDC. Any full engagement before that does not result in energy transfer to piston and downward movement efficiently thus forcing semi burnt combustion past the rings contaminating your oil as well as carboning (sic) up your rings/lands compromising sealing.

Know u know this but bears repeating. Indian VTwins already operate under a high degree of duress. They use the upward/downward movement of the pistons past those restrictive case baffles to break up oil droplets slung off your flywheels to create a mist that exits those ports on your timing side case to lube the valve train. This puts stress on your rings (likely why u have 4 instead of the customary 3 on a 4 stroke) already so not managing ignition advance to rpm and load adds to unnecessary peak cylinder pressures which can result in what u have seen. Throw in some valve guide wear (they start at 4 thou new, unheard of) and basically your motor starts to draw some of its intake charge up the exhaust valve guides on shut throttle decel laden with abrasive oil saturated carbon as the motor wears.

[Greasy rider]

PRG, how much total spark advance are you using in your 80" Chief?
tom

[T. Cotten]

I don't think that crack is all that bad, Harry!

We fixed worse on K models for sure. But why fix something that wasn't an issue for twelve thousand miles? You could only break it.

The whole point is to make the head (and cylinder) flat, and if that's a copper head gasket in your thumbnail attachment, it shows signatures over both ports.

A copper headgasket with an aluminum head doesn't make sense anyway.

....Cotten

[PRG]

Howdy sir,

know this answer could be construed as vague but in empirical terms I have not a clue as it applies to whatever Indian specified in the day when saddled with point/condenser ignition, recessed J6’s and marginal fuel, none of which applies to my application. With electronic ignition switching (Clyde Crouch), NGK BPE6/7ES extended tip plugs, a lean mixture and regular manual ignition advance adjustment underway appropriate to load, any factory recommendations from once upon a time are only a baseline to start from and the answer is “seat of the pants feel” . I’ve not put a timing light on any of my three currently on the road. It is not about total advance nor baseline retard as ignition timing is a dynamic that (should) constantly changes. Unlike even direct injection, ignition is essentially changed at the speed of light and if you have a modern vehicle with coil on plug the ECU can be changing timing in real time for each cylinder independently with instantaneous 30 plus degree swings.

These old motors are a willing old mules ready to pull at your behest and you can take the flawed approach of retard to start and advance set and forget to ride and wear your motor out in relatively short order or learn to “feel” what they want, incorporating the above mild mods, and have them last longer than Indian ever envisioned likely knowing then that in addition to these being essentially throw away consumables in the day that they couldn’t possibly ask their customers to coddle them like we/I do now. Flatheads are far less finicky that OHV’s where finding that suitable advance/retard to load is. Experiment with moving your advance up and down at various rpms under varying load to find where it does not labor from too much retard while being on the verge of too “free” from over advance and resultant lugging. You will soon find where your motor wants to run comfortably and in the case of my 41FL that everyone insisted I replace the chain primary with a belt to reduce snatch I merely learned what it wanted and with a well lubed advance control have it running sweetly,

The old adage, it’s about the journey not the destination has been enhanced by learning to work with my motors rather that vice versa.

[T. Cotten]

It would be nice to know, Harry,..

If that crack actually leaks.

A local Hall o' Famer Irwin "Smitty" Smith once performed a sparkplug insert for an associate, and pinned it with a roll pin; Daylight through it.

When my associate asked about it, the reply was "Oh,.. That will carbon up."

....Cotten
PS: This true hearsay is in no way an endorsement of such practices, nor should demean Smitty's legend.

Just an insight.

[pisten-bully]

It would be nice to know, Harry,..

If that crack actually leaks.

Dunno Cotten, it's been relegated. Had one big leak when the plug blew out with insert attached. I do know the crack through the plug hole made the head have trouble holding the insert for the spark plug! One blow out was enough for me, put a small dent in the bottom of the gas tank (turns out spark plug wires can act somewhat as a leash ) ...and it wasn't the only crack, either.