Ironhead Shovster build take2

[billeuze]

Originally Posted by Ferrous Head

I'm very surprised someone hasn't jumped on this on. All of the hard work done. I don't think I could duplicate it for the price just in parts.

https://www.ebay.com/itm/166379970133

Cool find. And yes, surely it would cost more to accumulate all those parts. a good deal for someone who is looking for exactly that.

[billeuze]

Originally Posted by brucstoudt

^^ it's great to have someone here with shovelhead experience.with the top end installed and removing it requires removing the motor a cam swap seems the easier path?

engine removal not required to remove the heads on this bike

[billeuze]

Originally Posted by JB in NC

No free lunch, unfortunately. Going from .445 lift to .490 will require cutting down the valve guides to move the seals lower,

yes, that's what needs doing.

unless the builder foresaw a cam swap and did the work ahead of time. And with two cam sets available, why was this not done?

yeah, thats the obvious question isn't it. here's why. Many years ago when I sent out the bare NOS heads to be ported and have valves installed, I specified setup for .49 lift. I had r5 cams but I wanted it set up to be able to use v9. a few years later I bought some used v9 cams. a few years later I finally got around to measuring and assembling the engine. What I found is that I was actually getting higher lift from my rockers that what is typical. I would have to look back at notes but I got something like .47 measured at the valves. So, my v9 cams would likely lift the valves to over 5". One reason I got higher valve lift is that while reclocking my rockers for the sportster valve geometry I shimmed between the head and rocker covers to optimize the angle of the rockers to be perpendicular at 1/2 lift. So removing those shims will help lower the lift a bit, bit they were already lifting more than 4.45 before shimming.

Anyway, at that time I realized that if I wanted to run the v9 cams I would have to send out the heads to cut down the guides and I just wanted to get it together and start riding so I used the r5 cams. Had I known at that time that I had somehow miscalculated the compression ratio I was shooting for, I would have thought differently. But of course had I been aware of my miscalculation in the first place I would not have taken as much off of my heads in the first place.

The heads may need a little more spring installed height at .490 lift as well. This is all relatively easy work on shovels, and the guides are long enough that even a shortened guide leaves enough for decent life. But the heads will have to come off.

That is good to know too, and really I won't have to take off very much, probably around .02" but maybe .03. The springs are probably OK, They had lots of room left before binding when I checked them for the .47 lift I was getting on the r5 cams. I will have to recheck at the v9 lift levels to determine if the "lots of room left" is actually enough.

The V-9 at .490 lift and 100 LSA will suit the shovel heads better, in my opinion,

yeah. And I have also learned from this forum is that the v9s would also suit the geometry of a stroker better than a stock motor. I don't understand all the the details of it, but it came from reputable sources.

and closing the intake valve in the early 50s will bleed off some cranking compression and lower corrected compression for more fuel-friendly service.

Jim

Yes, according to the above mentioned compression calculator, that would reduce my corrected compression ratio from 9.7 to 9.2. Also according to that calculator, the static compression ratio I have now is actually 10.6 (I was shooting for 9.5 and I really don't know how I got it that wrong)

[Ferrous Head]

While closing the intake later will drop cranking pressure it only increases it as the revs rise. When the engine hits the peak of the torque curve the charge is going to be denser and effective pressures higher.

There are ways to combat detonation. A better combustion chamber (sqish etc), introducing swirl, better cooling, retarding ignition timing but your going to be limited in those directions.

At 210 the engine will live happily on Methanol. But not "supposed" 98 octane pump gas. As a bonus the Meth will add about 14% more torque and help to cool the engine.

Downside is your mileage is cut in half. And a bit more expensive. and not as accessible.

Reducing the static figure is probably the best option for street use. You lose some of the torque you gained by the capacity increase but here are no free lunches.

And I said "supposed" RON number as gas varies greatly. While fresh at the refinery may show 98 the volatiles bleed off over time. The gas doesn't age all that well. You can notice this when you buy your gas at gas stations in the never-never that only get fresh supplies every June. When I used to race on pump gas I always bought as fresh as I could. A day or two before the meeting at known busy stations. Hopefully, right after a delivery.