Vc 460

[KRAZYMATT]

Another thing I was wondering, when you mill the head how much are you taking off? Is there valve interference with the piston? Cutting valve reliefs? I think you guys are building Hemi head motors from what I’ve gathered so not sure you be able to answer. Just curious if I could mill my head some without having to modify/cut valve reliefs in the piston.

So far my build will have:
Vrx460 motor - non-hemi
governor removed.
Torque cam / .260” lift
55 lb valve springs (nr racing advised against dual valve springs with torque cam)
chromoly pushrods
Stainless valves - 36mm intake 32mm exhaust
Titanium retainers
Shaft mounted steel 1.3 roller rockers
Billet valve cover
Mikuni vm32-193 round slide carb
1-1/4 free slow stainless exhaust header
8 degree Offset timing key
Oem Honda 4 magnet flywheel & 18a charging coil
Ut1 ignition.

I know that cam not super high lift just wasn’t sure how much clearance there is between valves and piston with the larger cam and the 1.3 rockers...

Also considering polishing the exhaust port

[raydhd]

I agree with NR the torque cam might not have the hardness for the dual springs. A lot of people have had failures with the offset keys. With the wedge head with the torque cam and 1.3's there is no interference issue. P.S. I don't have the hemi head. Mine is a VC head milled .075 with pretty heavy porting and valve unshrouding. My Omega build will have the Racesing billet flywheel that includes an adjustable timing bracket.What you are building will want to roar up to 6000 rpms. I would suggest getting a good tach and limit yourself to no more than 5600 rpms AFTER an easy break in procedure. P.S. You might want to add the Autolite AR3910X spark plug. It adds a noticeable kick to these engines.Also didn't see the NR racing 180,000 psi rod bolts on your list . The VC billet rod just uses stock clone rod bolts.

[raydhd]

Hard to believe, the arbor shims I ordered yesterday arrived this a.m. Bravo to Amazon.

[Shepard]

I'm building a Hemi and Ray is using a standard head. We are bringing anything that is out of spec into spec as far as our abilities will let us. The main difference between us is I want to use my supercharger. With a supercharged engine ignition timing is very important -- as compression goes up timing has to go down. I have a programmable ignition system I'm working on. It's more like a car -- programmable CDI unit that uses a sensor the reads the flywheel magnet. It has a link to plug into your laptop or tablet to set the base perimeters and you can even adjust it on the fly so you can feel if the changes are good or bad at full power. You set the timing for starting so it starts easier. I know it sounds complicated but it's necessary if you don't want to destroy your engine and all of you work. I think that was the problem other builders had trying to supercharge a small engine.

[raydhd]

Just mocked the block with the balance shaft. There is certainly play there also even without a side cover gasket. The bad news is it's shaft measures out @.575". So the arbor shaft shims are too big and 1/2" shims would be too small. 15 mm would work However a quick search doesn't show steel shims assortments in this size.

[Shepard]

The 460's original dyno chart had the max horse power and torque at around 3600 rpm. After 4000 rpm the chart went down as the rpm went up. I will post a copy of the dyno sheet when I get home. I was very impressed at how fast it revved - 6000 rpm for a lawn mower engine. I didn't like how the horsepower dropped off. Just because a engine can turn 7000 rpm doesn't mean it's make more power. I want my engine to make peak power at less then 4000 rpm. According to my Excell program I can get a 8hp bump in power using my supercharger to boost the compression ratio to 12 to 1 which equals about 5lbs of boost at 4000 rpm.

[KRAZYMATT]

Originally Posted by Shepard

I'm building a Hemi and Ray is using a standard head. We are bringing anything that is out of spec into spec as far as our abilities will let us. The main difference between us is I want to use my supercharger. With a supercharged engine ignition timing is very important -- as compression goes up timing has to go down. I have a programmable ignition system I'm working on. It's more like a car -- programmable CDI unit that uses a sensor the reads the flywheel magnet. It has a link to plug into your laptop or tablet to set the base perimeters and you can even adjust it on the fly so you can feel if the changes are good or bad at full power. You set the timing for starting so it starts easier. I know it sounds complicated but it's necessary if you don't want to destroy your engine and all of you work. I think that was the problem other builders had trying to supercharge a small engine.

I full understand. A lot of the airboats that run aircraft engines are ditching the magneto systems and going to electronic ignition. All set points can be programmed like you mentioned with laptop and the pickup is a sensor mounted on flywheel. Pacemaker is the company that making them.

[KRAZYMATT]

Originally Posted by raydhd

Just mocked the block with the balance shaft. There is certainly play there also even without a side cover gasket. The bad news is it's shaft measures out @.575". So the arbor shaft shims are too big and 1/2" shims would be too small. 15 mm would work However a quick search doesn't show steel shims assortments in this size.

McMaster car has arbor shims with id of 15.19mm but only 1 thickness, .031”...

[raydhd]

I just tried to place an order with a supplier that has 15 mm with 0.10 thickness but the order didn't go thru and there seems it has mass confusion on what is wrong. I worry about it some other time.

[KRAZYMATT]

Surface grinder? That’s how we used to do our motor shims till the were perfect size.