Who has fitted superblend bearings to early commando?

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Dmftoy1

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Looking to pick someone's brain on what it takes to replace the bearings on my 68 early motor with superblends? Is it just a matter of removing timing side ball bearings and drive side roller and race or is there machine work to the cases and the journals on the crank? (NJ306e's planned for both sides)

Feel free to tell me I'm stupid, etc. :). (Won't be first time)

Trying to show this ole girl some love as she already needs new Pistonns, rings, maybe a cam, and maybe con rods.

Thanks in advance,
Dave
 
Dmftoy1 said:
Looking to pick someone's brain on what it takes to replace the bearings on my 68 early motor with superblends? Is it just a matter of removing timing side ball bearings and drive side roller and race or is there machine work to the cases and the journals on the crank? (NJ306e's planned for both sides)

Feel free to tell me I'm stupid, etc. :). (Won't be first time)

Trying to show this ole girl some love as she already needs new Pistonns, rings, maybe a cam, and maybe con rods.

Thanks in advance,
Dave
Click to expand...

Dave,
You shouldn't have any problems changing to Superblends. Check your end float.
Cheers,
Tom
CNN
 
I've installed Superbend's on my `64 Atlas. How's that for early? Age makes no difference (heavy twins).
My Atlas still had the original bearings in place. The only extra work I had to do was have the crank machined for new big-end shells, and I had it dynamically balanced. New bearings went in without a hitch. I didn't even need to shim the bearings since the end float was within spec.

But then, if you have a pre-Combat, do you really need to replace the main bearings? Are they noisy?
If you decide to split the cases, be prepared to have to deal with a lot of other issues you may find. It can be a real dilemma putting a motor back together with a bunch of moderately worn parts. Sort of like shipwrights disease.

Who has fitted superblend bearings to early commando?
 
I have a drive side superblend in my race bike which has a 64 Atlas engine. I have a ball bearing in the timing side which has lasted for ages but it had to be pegged in place as the bearing gets loose in the crankcase when it gets hot.
 
mschmitz57 said:
I've installed Superbend's on my `64 Atlas. How's that for early? Age makes no difference (heavy twins).
Click to expand...

Indeed. Superblends will go into all dommie twins too, right back to the 1949 Model 7 twins.
More bearings than they need really, but some like to fit Rolls Royce quality into anything...
 
Cases are already split, and I know I don't absolutely need super blends, but as I'd replace the bearings anyway I figure I'd rather overbuild and not be in there again in my lifetime. I'm still finding all the surprises from prior owners but I'm hoping to get by .020 over and with standard (new) big end bearings.


Do most people replace the bronze bushes for the camshaft every time the split the cases? (I'm guessing yes)

Thanks again,
Dave
 
Dmftoy1 said:
Cases are already split, and I know I don't absolutely need super blends, but as I'd replace the bearings anyway I figure I'd rather overbuild and not be in there again in my lifetime. I'm still finding all the surprises from prior owners but I'm hoping to get by .020 over and with standard (new) big end bearings.


Do most people replace the bronze bushes for the camshaft every time the split the cases? (I'm guessing yes)

Thanks again,
Dave
Click to expand...

Then sure, I'd replace the main bearings as long as you're already in there. Maybe just the drive side. I've never heard of a timing side ball bearing fail, have you? I've never replaced cam shaft bushes. I don't think they wear very quickly, but then you can always check them for spec.

Journal being .8750
Bushing ID .8735
Difference of .0015

Laying your hands on the crankcase innards is all good fun and good for the soul.
How many miles on this beasty?
 
But then, if you have a pre-Combat, do you really need to replace the main bearings? Are they noisy?
If you decide to split the cases, be prepared to have to deal with a lot of other issues you may find. It can be a real dilemma putting a motor back together with a bunch of moderately worn parts. Sort of like shipwrights disease.

Bloody Oath you do. That timing side ball bearing wont last. If I hadn't been wise, and knowledgeable about what I was hearing, I could have written my crank case off.
You will need to make up a puller to removed the timing gear from the crank shaft. Be prepared to pull the new bearings off again unless you are lucky enough to get 10 thou end float the first time you try.
Dereck
 
I would not worry about shimming the crank unless the end play ended up being over .035 in or so. None were shimmed from the factory with Superblends.

If you decide to install shims the install them between the bearing and the case.

You may be able to get by with a shim between the timing side bearing and the crank but if you install a shim between the drive side bearing and the crank it will usually come out sooner or later and cause much damage. There is nothing to keep it pinched tightly between the bearing and crank like there is on the timing side. Jim
 
Past Peel's moderately beefed Combat cases survived crank jump roping with a DS superblend & 11 ball TS. Still good to go so Wes's '71 has em now. i keep hearing about the fast weak of 'mere' ball bearings but no reports on has fast that is. I'm still confusted [sush] on best philosphy for maxing out rpm toleratnce, resisting the crank flex or allowing for it? Do note just because the superdupers have a bit of end taper don't mean that where the crank bowing actually bears on so resist crank flex similar to all flat rollers corrected Combats got away with in spades. Next Peel is built along resist flex as all costs so higher load rated superdupers on both ends, after cryo tempered fudge.
 
If you don't want the crank to flex then don't start the engine. Neither bearing style is going to help prevent crank flex. The Superblend bearing is less likely to be damaged by crank flex. Jim
 
kerinorton said:
Be prepared to pull the new bearings off again unless you are lucky enough to get 10 thou end float the first time you try.
Dereck
Click to expand...

Not when you use a dummy bearing.
My 71 still had the stock mains, replaced with high quality Made in Delhi SupaBends.
 
Jim, I know at some point the crank will bow to take up slack then a bit more to load bores in cases like crazy, so academically wonder what/how to determine that limit or if its bearings that are the limiting factor. Still balls eliminate the shim issue if wear life still pretty good.
 
comnoz said:
Neither bearing style is going to help prevent crank flex.
Click to expand...

Its a little disappointing to see that someone still hasn't picked this up,
after ALL the discussions on these... ??
 
CanukNortonNut said:
I like what you did there
Click to expand...

For motors with superblends being replaced, it is suggested that the old bearing inners be used to set the endfloat, if needed,
since fitting and removing new bearings has the possibility that the bearings may sustain damage.
 
Hi Dave

Happy coincidence .... I am just doing my 68 now. S/n 128372. I went thru the same thoughts and decided that if I am going to the trouble of overhauling the motor may as well put in the best upgrades that I can. What I am going for is a street bike that is reliable. I am not into riding everywhere flat out but I want to know if I want to " open her up " I can. There is nothing worse than riding and worrying if some part is going to fail because it wasn't up to the task.

This morning I fitted the new superblend bearings and measured end float. Got 0.017" (no shims) so am happy with that, going on what Jim has said and considering that 850 motor end float is 0.010 - 0.024" and it is basically the same bottom end set up. ( I'm sure someone will correct me here if I'm wrong...)

So happy days. Progre$$ :D

What is the S/N of your bike. Just wondering how close it is to mine.

Cheers Dean
 
Dmftoy1 said:
Do most people replace the bronze bushes for the camshaft every time the split the cases? (I'm guessing yes)

Thanks again,
Dave
Click to expand...



Not me, and they need to be reamed in situ. You could check the wear, but I only had to replace mine when I had a load of aluminium paste running around in the oil :)
 
CanukNortonNut said:
I like what you did there
Click to expand...


comnoz said:
If you decide to install shims the install them between the bearing and the case.

You may be able to get by with a shim between the timing side bearing and the crank but if you install a shim between the drive side bearing and the crank it will usually come out sooner or later and cause much damage. There is nothing to keep it pinched tightly between the bearing and crank like there is on the timing side. Jim
Click to expand...

CNN
I had asked Mr Comstock about this via PM and the two shims sets available with the preferred being the bearing OD version.
I did not want to put a new bearing in to check end float as it could be (besides a pita) detrimental to the interference fit of the engine case.
The idea with the aluminum dummy bearing was the timing side new bearing could be installed (unless there was some problem with con rod to bore centres) and the sliding fit dummy bearing in the drive side would enable easy checking of the end float.
A suitable shim if needed could then be machined and fitted to the engine case along with the new bearing.
No undue stress to the interference fit of both the engine case and crankshaft journal.
I know folk had ground old bearings to do the same but this seemed easier and did not have the heart to maim an original SuperBlend bearing (from the 850)

I will do the same (dummy bearing) on my Sunbeam as it also has a ball front bearing as standard and the upgrade is a roller which I have now along with a new rear white metaled bush.
The end float on that needs to be set also at around 0.004"
 
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