It's a long way to 920 type(rary)

Hi there,
Important day to day:
First the squish clearence, I put the cylinder over the pistons w/o the rings, tappets and pushrods, I have different tickness of head and cylinder gasquets to play with, after several try I find a setting: no cylinder gasquet and a head gasket of 1mm, this give me a squish of 1.5mm, you must know that after the work on the valves I mill 0.12mm from the head and when I broke my stock crank I have to weld the cases, not my self of course, but by Yoshan, a Japanees that was working for the Yamaha factory team, He did a fantastic job, but after the welding there was one of the cases that was a little higher as the other case, so we have to mill the cases to make it perfect flat, this milling was also 0.12mm so the total is 0.24mm, this to explain why I put a head gasket of 1mm and not a 0.8mm.
To do the mesurments of the squish I use a 3mm solder lead wire, better as platicine for the squish, when you turn the crankshaft the pistons push on the solder lead wire and give you the exact clearence.
According to Jim Schmidt 1.5mm squish clerance will give 10.2 to 10.3 CR and this si good to me.
This afternoonI tchek the clearence between the valves and the valve pockets in the pistons, to do that I use plasticine, of course I must take the cylinder of to put the tappets, I find aroud 3mm clearence between valves and pistons, more as enough to be safe...
speak you tomorrow
Yves

Hi there,
To day I did a lot of work: I put the rings on the pistons and the cylinder on the cases, after I put lash caps over the valve tips, not a good idee! after I put the head on the cylinder following Jim Schmidt instructions, torque the head bolts and see my stupidity with the lash caps, no clearence and the adjustement screw full out, the only way to take the lash caps off w/o taking the head off is to take the shaft of the rockers out, the rocker out and then remove the lash caps, w/o lash caps the rocker geometry looks good, the adjustement screw is halfway is travel at TDC
The next step will be to take a close look at the lateral position of the rockers and adjust if needed, after I need to look for the valve clash and tchek the timing of the camshaft.
I don't think I will work tomorrow
Keep you posted
Yves

Hi there
To day I work only a few hours:
After removing the lash caps, I did the laterral clearence on the rockers, only one need adjustement, I did it with special shims, the original shim is 0.4mm, I put a 0.5mm in and job done, after I did the tappets clearence 0.15 on the inlet and 0.20 on the exhaust.
On monday I will put the engine in the frame
Keep you posted
Yves

Hi there,
Not mutch work to day, must take care of my wife, she is hill
The only thing I did was to put the oil pump and the hydrolic chain tensioner made by Jim Comstock
Tomorrow I will find the time to do the camshaft timing and take some pics
Keep you posted
Yves

Hi There,
I spend almost the whole day to try to time the camshaft, the way to do explained by Jim Schmidt is easy to understand, but the application is very difficult, at least for me, the most difficult is to fix a gage in line with the valve with the engine on the workbench, so I decide to put the engine in the frame to have more stability, I left the distribution cover off to have access on the timing gear if needed. But I don,'t know so far if it is needed.
J.S. says "never trust the key location on a aftermarket camshaft" Of course the valves are crossing each other at TDC but you must tchek the clearence between the valves and the inlet must be more advanced as the exhaust valve, not easy to do with the D shape port on a FA head, so I will try to do it with a endoscope.
The other point is that I must put the whole transmission in place including the E start, because on my Seeley the gearbox is higher and more to the back as on a normal Codo frame, what will say that you can not trust the graduation scale on the outer cover.
Tomorrow I will do another try for the cam timing, but if someone have any idee to help me to do the job I will be gratfull for the eternity and one day.
The engine look beautyfull at the moment, thats the only thing I can say at the moment
My friend the fotographer will come tomorrow to take some pics.
Keep you posted
Yves

I like this method- adjust for equal lift or crossover at 4 Degrees Before Top Dead Center on the exhaust stroke for all engines, lawn mowers, Lamborghinis etc.

You have to set up dial indicators on the valve stem tops. Is this the method you are using?

Glen

I haven't looked at what Jim Schmidt recommends, but I assume it is by measuring lobe centers. That's what most race engine builders use. I usually do it before fitting the head. With standard lifters, I use a dial indicator with a long tip that fits into the top of the lifter. With the BSA style lifters, I install a pushrod on the lifter, and fit the dial indicator tip into the cup on the top of the pushrod. I thought I had some pictures of the process, but haven't found them yet. You can also do it on the finished engine with the dial indicator tip on the top of the valve spring retainer. I set it up like that for checking valve-to-piston clearance, but I've also used the same setup to check cam timing. Good picture of the setup here, partway down the page

https://www.accessnorton.com/NortonCommando/return-of-the-nitrous-norton.21511/page-2#post-360215

Ken

Here are the instruction given by Jim Schmidt:

You must have at least .185" gap between the valves when they are on the seats for adequate valve clash clearance with a JS 2 cam.


Set valves at .006 gtappet checking clearance on compression stroke. Rotare crank forward one turn. At TDC the intake lift should be approx. .175" and the exhaust valve lift should be approx. .150". Adjust your cam timing accordingly. (YOUR SPECS MAY VARY BUT IN LIFT SHOULD BE APPROX. .025 GREATER THAN EX). This will give the correct intake lobe center of 103 degrees.

Always visualy check the valves at TDC. Looking in through the port; with a tiny flashlight (magnification helps) - you should see that the intake has a little more lift than the exhaust.
This is assuming that the valves seat are level as with new stock heads.
Yves

Yves - sorry about the difficulty. I made up some brackets to mount a dial indicator on the head so I can measure the valve lift. Once you have the dial indicator mounting hardware its not too much trouble. I can understand the problem with trying to measure valve clash clearance with a D port. And visually checking the valve lift at TDC by viewing through the ports may be difficult with a Full Auto head and the raised port floors. I'll be making a video of the cam timing process in a few weeks and I'll try to find a better solution.

Its a pain in the ass but its important to get the cam timing right - just as important as ignition timing and you can feel the difference when its wrong or when its correct.

Interesting. I haven't seen that method before, but it should give the same result, as long as it's done carefully. Besides, Jim wouldn't be recommending it unless he had thoroughly checked it out. I'm still more comfortable at measuring the lobe center position directly, and I do think it is a little more accurate than indirect methods like this one. But the difference is probably not very significant. It does, however, seem to require you to set up two dial indicators for the measurement, one on the intake valve and one on the exhaust. Another thing I like about the direct lobe center measurement method is that you don't have to know anything about the lift profile to use it (but you do need to know what lobe center setting you want to use). It works for any cam with a symmetrical lift profile, which covers pretty much all the available Commando cams, unless you somehow manage to get one of the few Axtell "Allegro" cams that were made. Other cam grinders may have also experimented with asymmetrical lobe shapes for Commandos, but I've so far not run across any. But that's a whole different discussion.

Caveat: This is not intended as a criticism of the method you are using.

Ken

Tomorrow I will do another try for the cam timing, but if someone have any idee to help me to do the job I will be gratfull for the eternity and one day.

Perhaps you can use this method. I use it when I adjust the valve clearance. Set valve clearenc to zero.
The same attachment is used for both exhaust and intake.

Notice the hole in the center of the bolt to release the compression pressure

Kvinnhering said:

View attachment 3799 View attachment 3800 View attachment 3801 View attachment 3802
Tomorrow I will do another try for the cam timing, but if someone have any idee to help me to do the job I will be gratfull for the eternity and one day.

Perhaps you can use this method. I use it when I adjust the valve clearance. Set valve clearenc to zero.

Click to expand...

Thanks Jim and Kvinnhering,
To day I make a steel plate that come on the top of the head where I can fit my magnetic dial gage, so tomorrow I will do the timing.
So far I did everithing fine, like anneling the gasket, put assembly lube an every moving part and so on
I hope that the timing will be spot on w/o messing with the gears or with the woodruff key
The question is: If I have to advance the camshaft, then the valves will come closer to the pistons no??
My friend make some pics, they will be here tomorrow
Keep you posted

could be of some help
http://www.webcamshafts.com/mobile/degreeing.html

When I was using Jims S's instructions with a JS2 cam , the initial engine builder and I had to make a stepped key for the cam shaft sprocket to get everything just perfect.
I dont run any ignition hardware on the end of the cam, that space is empty, I am using a self generating ignition system on the end of the crank shaft.
The step in the key faces forward , ie half the key in the cam, step in key 1/2 the width of the key to the right as you look at the cam end in the bike.
Ill try and find a pic.
This is for a RH10 head race motor.

marinatlas said:

could be of some help
http://www.webcamshafts.com/mobile/degreeing.html

Click to expand...

Thank's Pierre, very intresting!
Merci Yves

Brooking 850 said:

When I was using Jims S's instructions with a JS2 cam , the initial engine builder and I had to make a stepped key for the cam shaft sprocket to get everything just perfect.
I dont run any ignition hardware on the end of the cam, that space is empty, I am using a self generating ignition system on the end of the crank shaft.
The step in the key faces forward , ie half the key in the cam, step in key 1/2 the width of the key to the right as you look at the cam end in the bike.
Ill try and find a pic.
This is for a RH10 head race motor.

Click to expand...

Becouse I use my Seeley on the road I use a Tri spark ignition, but this is not a reason not to make a
stepped key if needed
Thanks
Yves

Just for fun and confusion, this is the Equal Lift timing method as explained to me by Bonneville racer Terry Prince.
I grabbed this cam graph from Google, I'm not sure what engine it's for. The Equal lift method doesn't care, it's the same timing for all engines.
The crossover point in the valve overlap (point of equal lift) is about 4 Degrees btdc on exhaust stroke. You'll see this same crossover point again and again on almost every cam graph for all types of engines.
It seems that if it is a four stroke engine, it likes that crossover point. I'm sure there is some Science behind that common point, but I do not know what it is.

So you play with the timing until the degree wheel shows 4 btdc when the dial indicators show equal lift on exhaust( closing) and intake( opening)
I've timed a couple of Vincent engines this way and a friend has also done two. We've noticed that these engines all seem to have that extra grunt one is always looking for.

These are asymmetrical cams normally timed by Phil Irving's opening and closing numbers.
We are convinced that the equal lift method gives more power than the other method.

I would love to give this a try with the Commando. First would be to measure things as is.
Might find out that it already is equal lift , 4 Degrees btdc. If not, it would be an interesting experiment to make the change.

Hi There,
With the help from you great replys, I was abel to check the timing of the cam and it was spot on w/o any work on the gears or woodruff key. I can not imagine that a Co. like Webcam should put the key way on the wrong place, but you never know...
I put the primary case and trplex chain on the engine with the Alton starter. I hope the starter will be strong enough for the compression, I will try tomorrow.
Still a lot of work to do, but I am used to do this kind of work so I hope to have the engine runing on saturday.
Here be some pics from the work in progress from yesterday
Keep you posted
Yves

jseng1 said:

Yves - sorry about the difficulty. I made up some brackets to mount a dial indicator on the head so I can measure the valve lift. Once you have the dial indicator mounting hardware its not too much trouble. I can understand the problem with trying to measure valve clash clearance with a D port. And visually checking the valve lift at TDC by viewing through the ports may be difficult with a Full Auto head and the raised port floors. I'll be making a video of the cam timing process in a few weeks and I'll try to find a better solution.

Its a pain in the ass but its important to get the cam timing right - just as important as ignition timing and you can feel the difference when its wrong or when its correct.

Click to expand...

Checking valve clash clearance with a D port didn't seem to be an issue to me! I did mine with the engine on the bench, and more than a few times now. Having set the valves to matching lift (i.e. when inlet to exhaust valve clash could occur) I come in from the spark plug hole with a suitable thickness piece of wire. Which is usually double over and shaped with pliers then checked to required minumum clearance size. I am just checking that I have at least the minimum safe clearance, I am not trying to 'measure' the actual clearance, just making sure that the motor is safe.

Or am I talking something else?

Cam timing itself, well, yes it is a pain in the arse process, helped by the bolted on plate and magnetic guage stand, and a lot of patience, retry and record several times until you are comfortable it is repeatable to the same recorded numbers, stick with it!

SteveA said:

Checking valve clash clearance with a D port didn't seem to be an issue to me! I did mine with the engine on the bench, and more than a few times now. Having set the valves to matching lift (i.e. when inlet to exhaust valve clash could occur) I come in from the spark plug hole with a suitable thickness piece of wire. Which is usually double over and shaped with pliers then checked to required minumum clearance size. I am just checking that I have at least the minimum safe clearance, I am not trying to 'measure' the actual clearance, just making sure that the motor is safe.

Or am I talking something else?

Cam timing itself, well, yes it is a pain in the arse process, helped by the bolted on plate and magnetic guage stand, and a lot of patience, retry and record several times until you are comfortable it is repeatable to the same recorded numbers, stick with it!

Click to expand...

Hi Steve,
Do you need to make some changes on the timing gears or woodruff key?
Yves