Engine build prep (2014)

worntorn said:

......... I'll leave this MK3 alone, it just works so well now.......Glen

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Sounds like a very wise move mister, besides you now have us looking forward to your hooligan build thread :wink:

I have tried a Maney 2:1 exhaust system twice on the dyno now (thanks Chris).

The first time, the bike was running lean, and the Maney system sorted this, the AF ratio became good, and subsequently, power and torque increased (4+bhp peak and more in the mid range)

The second time, the bike was not lean, so the Maney system made the AF ratio rich, and peak power did not improve much, although mid range still did. As we know, richness kills power, so this was not a conclusive test. I did not have the equipment or time last time to change the needles and jets in order to optimise settings with the Maney system and see what its capable of. But I believe that with the carburation set accordingly, the 4-5bhp gain seen previously would also apply now.

My conclusion therefore is that the Maney design has a significant impact. It has a big impact on carburation, and this then needs correcting before any impact on torque / power can be ascertained (obviously). Maybe ign timing needs tweaking too, I haven't tried this as yet.

The only downside is its loud. But, what price power ?!?

I hope to receive this soon (thanks Mike) and will proceed with testing again ... unless I just hang it on the wall as artwork, its certainly aesthetically pleasing enough ...!

Nigel, what diameter is the pipe in the Maney system?

Glen

1 5/8" Glen.

That looks very nice. You get that off of Mike H aka Brooking 850?

gortnipper said:

That looks very nice. You get that off of Mike H aka Brooking 850?

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Yes.

New AKA = Mike the Pipe...!

Fast Eddie said:

Ok Ladies, here it is...

So, the headline is:

Previous best was 55.83bhp at approx 6200.

New figure, after fitting a Comstock ported RH10 head is...

64.60 at approx 6300.

That is a near 9bhp increase!!

Also:
BTW, thats with 1 3/8 pipes, no balance pipe and peashooters.

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I did not go back through your posts here to verify this, but believe you were going to elucidate the performance difference between complete 1-3/8" and 1-1/2" diameter peashooter exhaust systems. Did you get around to this, did you run out of time or interest to conduct the experiment, did you post it and I missed it, or am I simply remembering this all wrong?

WZ507 said:

Fast Eddie said:

Ok Ladies, here it is...

So, the headline is:

Previous best was 55.83bhp at approx 6200.

New figure, after fitting a Comstock ported RH10 head is...

64.60 at approx 6300.

That is a near 9bhp increase!!

Also:
BTW, thats with 1 3/8 pipes, no balance pipe and peashooters.

Click to expand...

I did not go back through your posts here to verify this, but believe you were going to elucidate the performance difference between complete 1-3/8" and 1-1/2" diameter peashooter exhaust systems. Did you get around to this, did you run out of time or interest to conduct the experiment, did you post it and I missed it, or am I simply remembering this all wrong?

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Yes, I tested them a while ago before the re worked head. They did not fair well. I have not tested them with the re worked head, I might do so, but I can't see how / why they should fair well.

Gents,
No new waffle here, just wanna try and add some of the pictures that photo bucket killed. There’ll be a few such posts, as and when I’m get chance...

Here’s the first few showing th JS pistons, pins, rods, cams and cam followers vs stock. This kit ran extremely well in the finished motor:

Here are the pics related to the cleaned up head prior to ceramic coating (which later flaked away in parts and may have been the cause of piston and bore damage), the crank after dynamic balancing, and the bottom end going together:

Here you can see the timing case having been plugged and had the extra hole drilling according to Comnoz’ instructions for using his reed valve sump plug breather (excellent piece of kit that should be compulsory fittment), the rods in situ, the JS cam follower blocks for use with the BSA lifters, and the rockers after being fettled by Pete Lovell (I subsequently removed more material from the ends before fitting them):

Here you can see a finished rocker in situ with JS beehive spring kit etc, the head after ceramic coating (and before some flaked off into the engine), and some of the engine being assembled inc the Comnoz auto chain tensioner fitted:

Here you can see the cNw head steady and carbs fitted, the belt drive, and the finished (version 1) motor:

Then we had a ‘version 2’ build which was basically a full Comnoz head job, new pistons were also needed, probably due to the flaking ceramic coating:

Here are the CFM and velocity graphs, before and after the Comnoz head job. Quite significant improvements I’d say.
These figures equates into a 9rwbhp improvement. Yes NINE.

Version 3 is a 920 build, continued in this thread:
https://www.accessnorton.com/NortonCommando/920-engine-build-waffle.22080/

Question: what’s a guy do when he’s got his bike running better than ever?
Answer: strip it down again. Obviously!

I confess it didn’t feel right doing so, but in order to make space for the 920 motor, the 850 has to come out.

The idea is the 850 will be checked over and kept as a ‘ready to go’ spare.

Sadly, not all was as expected. Check out the piston pics below. Rear face of DS piston looks BAD. However the front face is fine. Small particles had come away from the piston, adhered to the bore, and cut the piston skirt up!

After some thought, and consultation, I’m of the opinion that the hard anodising is at the root of this. It looks to me as though it’s destabilised the surface of the piston, made it brittle or similar, and caused particles to break away. I guess I’ll never know for sure, but that’s what I’m going with at present.

Some may recall this is the second time that ‘magical’ coatings have caused me issues! I think I’m done with after market additions to pistons now.

Rear face of DS piston, ouch. Interestingly the engine ran great, no smoke, good compression:



Front face of the same piston. Certainly ruling out a seizure of any kind.


On the positive side, the rest of the bottom end looks as new, the JS cam and followers particularly so:

Ouch. How do your barrels look?

gortnipper said:

Ouch. How do your barrels look?

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Actually OK.

The bits of alloy that adhered to the bore is what ‘machined’ the piston so effectively. The barrel only has light marks.

They’d clean up perfectly with a light hone.

Trouble is, I’m going to use low expansion pistons next, which require less clearence, honing would make them oversized for these pistons so I’ll go to the next bore size.

Great photos...appreciate you sharing.

There are three things that can cause that kind of wear on a piston. I have had 3 "soft siezes" on my engine, two of the times it was because the piston was fitted just a bit too tight. The last time though it was because the timing was too far advanced. The third thing would be oil related which I doubt in your case. And, trailing in 4th place would be a coating that doesn't hold up to the pressure and heat of a Norton motor. I also doubt that in this case. If I'm right then that leaves only clearance and timing.