Let's talk about cams.

[Royal.Oilfield]

Ace,

this design was used on the '95 diesel demonstrator engine which had 547cc and produced between 16-18 BHP.
I've never been close to one and will never be.
If you're interested to talk to Dr. McGuigan: mcguigan@criterion.freeserve.co.uk

Regards, Johann

[ace.cafe]

Ace,

this design was used on the '95 diesel demonstrator engine which had 547cc and produced between 16-18 BHP.
I've never been close to one and will never be.
If you're interested to talk to Dr. McGuigan: mcguigan@criterion.freeserve.co.uk

Regards, Johann

Very interesting!
Geoff should see this!

However, I must admit that I am at a loss to explain why they decided to put 4 valves into that.
I guess Dr. McGuigan is smarter than I am, which really comes as no surprise to me!

[rural earl]

... I can tell you that the re-phased cams, when used with the hi-compression piston, will give power within 1hp of the "Performance Cam" set from Hitchcocks and the same hi-comp piston, and do it at a lower peak rpm which the stock bottom end can reach fairly safely, and does not lose midrange torque(which is a problem with the Performance Cams).

That's what I'm talking about!  This makes more sense to me.  I would always figure in some bottom-end improvements for almost any high-power mods, but this sounds like a  sensible improvement for the money invested.  All power increases have to be targeted at the end use...my old man used to wrench for a stock car team, and was able to make a slant-six Dodge beat the bigger Chevys just by getting the power band to match the needs of the track, and then training the driver.  Thanks for getting together a real-world package of ideas.

[luoma]

I wish someone would sell phased cams for the RE. I don't have the skills to machine a set for myself.

Whenever my X needs a ring job, I may put in the new 535 piston and shave the head for 9:1 comp. With phased cams, I would probably have the mid-range grunt of a John Deere tractor. Now that would be fun.

[ace.cafe]

I wish someone would sell phased cams for the RE. I don't have the skills to machine a set for myself.

Whenever my X needs a ring job, I may put in the new 535 piston and shave the head for 9:1 comp. With phased cams, I would probably have the mid-range grunt of a John Deere tractor. Now that would be fun.

Luoma,
All this cam talk I've been doing is directed at the old Iron-Barrel Bullet.
I have never even clocked the cams on an AVL engine, and have no idea how they are timed.
Someone told me that they are "milder" cams than the Iron-Barrel Bullet cams, but I have no idea what their timing is.
So, I cannot say if the re-phasing would, or could, be appropriate, or even be done on that engine.

So, all this stuff must be considered as a potential possiblity for Iron-Barrel Bullet owners only. Not the AVL.
No research that I'm aware of has been done for re-phasing AVL cams.

[ScooterBob]

Wow, ACE - WE ought to bind that in leather and put it on motel nightstands!! VERY well put. As an "old school" tuner, I have (as you obviously have as well ...) learned to maximise a minimum design to stun and amaze the "chrome plated noisy bike crowd" I've done the BSA and Triumph thing for a while - as well as the Norton's and what ever ELSE British rolled down the pipe into the garage. I've followed Enfield for a few years (I had an Interceptor as a "child" ...) and have been wanting to explore the "go fast" on one at a serious level. I see that I have to do nothing but read your posts!! Hahaha!! Keep up the gREat work!

[ace.cafe]

Wow, ACE - WE ought to bind that in leather and put it on motel nightstands!! VERY well put. As an "old school" tuner, I have (as you obviously have as well ...) learned to maximise a minimum design to stun and amaze the "chrome plated noisy bike crowd" I've done the BSA and Triumph thing for a while - as well as the Norton's and what ever ELSE British rolled down the pipe into the garage. I've followed Enfield for a few years (I had an Interceptor as a "child" ...) and have been wanting to explore the "go fast" on one at a serious level. I see that I have to do nothing but read your posts!! Hahaha!! Keep up the gREat work!

Thanks Bob!

If you want to get serious with the Bullet, the first thing you should get is the Hitchcock's Steel Billet Crankshaft with the forged steel con-rod, oversize crankpin and Alpha roller bearing. It all comes pre-assmbled and ready to run, and you can get it from CMW.
Also get the highest quality main bearings you can find that are Europe or Japan, or even the US if you can find any.

Then you have your bottom end sturdy enough to handle whatever you plan to throw at it.
The lower-end on the Bullet is the weak point Con-rods snap, cranks are often out of true, or out of spec in dimension, pistons are crap, and piston speeds get very high when doing any revving.
So, bottom end is the first to do, and then work the power production stuff after that.

[ScooterBob]

ACE - Been there - seen ALL that ....... got the "jay-oh-bee" at Classic Motorworks ... hahaha!!! I just now have HAD a little time to explore the forum after MUCH chiding by the co-workers. I hope to develop a very decent alloy "replacement" rod for the iron barrel fiends (like me) out there as well as a few "voodoo" parts for the regular guy to enjoy. The alloy rod is one of my "god child" projects because the stock one is barely capable of putting up with my old Paw-Paw ass - but the Carillo is a bit spendy for the "regular" guy. My "replacement" one should fill the gap without emptying the wallet.Stay tuned on THAT account ... At least here, I'll have the pick of the broken crap that comes in the door to build a "muley" with .... They'll be happy to get SOME of that stuff out from under the workbenches and "re-stored" somewhere else!! Hahahaha!! I'll keep an eye on your posts!

[ace.cafe]

Hey, that's great, Bob!
Didn't know you were working with CMW.
Congrats!

The alloy rod project sounds interesting. You sure have your work cut out for you with that one.

Let me know if I can help with anything!

[ScooterBob]

ACE - I'll sure keep you on the "up front" with the projects .... I'm betting that talking to someoen who HAS scattered one or two of these will save a man a little time .... and some disappointment!! Hahahaha!!

[jonapplegate]

sorry to be chiming in to such an old series of posts but couldn't help myself. The four valve design probably came out of that time period not so long ago when everyone was thinking of multivalve as a way to increase efficiency and therefore, performance. Two small valves will carry more flow than a similiar sized big valve because of greater vacuum if I recall. Just writing this makes me wonder if that is actually true in practical applications. Even if it is, time showed that in a fairly simple design four valve technology just meant twice the number of things that could go wrong. Also, more parasitic power loss since you have that many more parts siphoning power away from the rear wheels.
 All the very most hipo designs run multi valves but they are designs which every component of the engine is meant to complement the other.
 Okay, I think I think i have gotten that out of my system!

[ace.cafe]

Jon,
There are pros and cons to any design, no matter what it is.
The multi-valve systems do very well, and they have alot going for them.

We can get a very good result from our little hemi.

[ace.cafe]

Some late breaking results just in.

A member here, "longstrokeclassic" is also a member of a forum in the UK, which I also participate in.
And he decided to do the cam rephase on his 350. I worked with him by internet on the proper instructions, and he did it, along with some other mods.

At first, he had too much power for his clutch to handle, but he upgraded it, and rectified that issue. And he did a bit of running-in for the engine, and then reported. Then when he finished the clutch work, he put the cams back to normal alignment, and ran it to see what the difference was between the 2 different cam timings.

Here is his latest report, which I lifted from his post on the UK forum;
"Whilst fitting the uprated clutch I took the opportunity to swap the inlet cam back so all the timing marks correspond, but left the 3 way pinion insitu running in the advanced position. What this revealed was what I mistakenly thought to be a carburation problem was a soft spot in power delivery at low revs. This disappeared when reverting back to normal cam timing but was also accompanied by a noticable loss of power at the same time.

Without the aid of a dyno I can only hazard a guess at what was happening.
But this is what I think.... With the rephased cams there was a noticable drop in power at low revs but I dont think this was so much a loss in power over the standard setup, but the rephasing providing a sudden increase which made everything below it seem flat in comparison.
Nothing like the sudden power delivery of a two stroke twin or triple coming on song but more like the difference between riding the along flat and then going down a steep hill.

I intend to run the bike with the rephased timing (with the inlet running retarded) because although this provides something of a slight jeckyll & hyde power delivery it does mean I can still potter around at 45-50 without really noticing any difference or can open the bike up and take advantage of the extra acceleration and increase in top speed over the standard when the mood takes or the need arises.

Quite a successful outcome -"
--------------------------------------------------------

So, we see that he got exactly what was expected. He kept approximately the same power as a stock Bullet in the lower revs, and got a significant boost in the upper rpms.
Still very roadworthy and manageable, and spirited when he wants to run hard.

So now we know it works fine on 500, 535, and 350.
I'm still awaiting the report from the 612 user, to see how he liked it.

[geoffbaker]

Ace,

this design was used on the '95 diesel demonstrator engine which had 547cc and produced between 16-18 BHP.
I've never been close to one and will never be.
If you're interested to talk to Dr. McGuigan: mcguigan@criterion.freeserve.co.uk

Regards, Johann

An Enfield prototype diesel twin? How very cool!

Too bad they didn't go ahead and make it....

[Blltrdr]

 I suspect all the data collected will be used in the development of your new cams. I would figure the new cam design will eliminate any need for the 3-way pinion or the re-phasing. This thread keeps getting better. Keep it coming Ace, It's almost lunchtime!  

Blltrdr