[ringoism]

Well, on account of the "database error" can't write everything here I wanted to - maybe that's a good thing!

In short, I had put about 2,000km's on the bike since building it last spring, and with the new carb/filter was enjoying what seemed a bit enhanced mid/upper range power... and a hard uphill, somewhat higher rpm run one day left me with nasty noises coming from the crankcase... not a knock, sounds more like a bad/rough main bearing.  I outlined above concerns I had about how they'd built the crankshaft, but other thing is I put standard-clearance NRB main bearings in it; recently another Brit up in these hills who's hoarded something like twenty Bullets is telling me the NBC's/NRB's used by RE and typically used for rebuilds in India are the cheapest options with corresponding reliability.  So I'll have to open it again, we'll see what's gone wrong. 

1.  ACE/Adrian/BW/other engine guys: How important do you think the C3 spec would be on the main bearings?  A lot of bikes (incl. my Kawasaki) do specify them for the crank - did RE ever?  Seems wise considering our heavy-load hill conditions / short runs / RE's poor machining tolerances (thinking of case misalignments, and I can see uneven wear on the old main bearing races, though it didn't cause any failure in six years).  I can get the Japanese NTN's here (NU205/305) but thus far haven't found them in C3.  Stated otherwise, if it came down to Indian C3's or Japan/Euro standard fit, what would be the better option?  Are Hitchcock's UK-bearings standard or C3? 

Also (ACE), finally found your old breather thread  https://forum.classicmotorworks.com/index.php/topic,4802.45.html wherein you stated it wouldn't work on AVL's due to the lack of the crank seal on the timing side, which in the new low-pressure environment would lead to wet-sumping. 

Now here's the thing: A new senior mechanic showed up here a few days back who apparently used to work at the Chennai RE factory (and independently later), who seems familiar with all the typical AVL weaknesses / mods (incl. CI tappets/spindles/cam conversion, etc).  He says he adds a seal there by re-purposing the (felt?) one from the old point-ignition distributor - presumably kind of squishes it in between the case and the oil-pump drive gear.  Sounds like a classical case of Indian "juggad" but sometimes these things do actually work.  Also says that if I let him build the engine he'll give me a 5-year, unlimited mileage guarantee (why does this sound familiar???!!!). 

Anyway, if the felt(?) were sufficiently saturated with oil and snug in there, and moreover held against the crankcase side by whatever light vacuum is in there, could it be enough to keep excessive oil from moving past into the crankcase... and is the benefit of the relocated breather worth any associated risk of this NOT working?  Machining for the old-model crank seal won't be feasible in this context (don't know anyone with a milling machine), whereas drilling for the engine-side breather and doing the crescent in the case with my die-grinder would probably be pretty do-able.  And on the AVL I still do have to block off the 3mm hold between the crankcase and oil tank, right?  In my case I'd want to retain the catch-can (don't want the rear-exit, it's just too dusty here and it's all going to stick to any oil-spatter/mist), so if the crank/oil tank are again separated, I guess I could drain it back into the latter via the original nipple there, correct?  Or else the timing-case, which does have a duckbill inside already. 

2. Hitchcock's $50 crankpin is the Indian one, no specs available, so no advantage.  Their U.K. made one comes only in the complete, fitted rod kit, which is well beyond my budget... So I'll just get the RE pin over here, a friend up here has 50,000km's on his crank (on a stock C5), and that's a combination of daily short hill runs (7km's commute), and a fair amount of mountain touring with pillion and luggage. 

-Eric

[ace.cafe]

C3 is very I.important.

You could try the felt seal.

Keeping the catch can is okay.

[Adrian II]

You could go down the Rube Goldberg/Heath Robinson route with your breather set-up.



A.

[ringoism]

Well, the supplier found the NTN NU305 in C3, but not the NU205 (timing side).  Unless I want an SKF C3 with a nylon cage... which I'm assuming is not acceptable in this application.  Right? 

Ace, does the C3 spec hold for the outboard 6305 ball bearing too, the one nearest the primary chain?  So far only available in India-made if I want C3, probably FAG.

Secondly, if this felt-seal idea didn't work and I've already blocked the orifice between tank & crankcase and converted to the old setup, what's the worst that could happen?  I'm assuming wet-sumping is not good, but will it blow up my engine, or??? 

Trying to work out a risk/benefit analysis here...

Adrian, a good chuckle before bed is just what I needed.  That setup is just... beautiful...


Thanks to you both,
Eric

[ace.cafe]

I usually use a C4 for the 6305, but a C3 will work.

If you can get GENUINE FAG X-Life brass caged NU205-C3 and NU305-C3 made in India, that is okay. All the FAG X-Life bearings are made in India. The critical factor is that they cannot be fakes. They must be the real thing.

[Adrian II]

I have a set of 500 Iron Barrel cases with the breather stub drilled out by the factory, and it's not that big a hole, so if you do go down this route and plug the small hole through the crankcase wall, I doubt it will make much difference. Using your own threaded pipe union as I described might allow the crankcase to breathe slightly more easily depending on its internal bore.

The 3" drip-feed oiler as catch-can was a good laugh - it got some good WTF? reactions, and I had a Hellman's label taped to it for a while. However, I found it leaked badly after a while and the acrylic "glass" went opaque with a chemical reaction to the oil/crankcase gases, so it's off the bike at the moment. I now have a proper glass for it and some decent gaskets, so it might go back on.

A.

[ringoism]

On my AVL hybrid I used the longer exhaust pushrod in place of the inlet pushrod, and screwed in a late iron barrel tappet adjuster which used the same 6mm thread as the AVL version. For the exhaust I used the exhaust push rod and tappet adjuster from a 500 iron barrel engine, I made a bronze bush and fitted it to the top of the alloy section of the rod and pressed the top of the old inlet AVL pushrod into that. This means I have one metric and one imperial tappet adjuster, but nothing I can't live with!

The point of replacing the AVL cams with the "S" is that the originals have been found to cause valve bounce at 5,800 RPM, they can be used with the original tappets/followers, though, if you slacken off the tappet adjusters enough.

I'm thinking to stick with the original AVL cams since they seem fine for low/midrange which is mainly where I'm at.  Probably good for fuel economy, as well, and I've been happy with the performance.

But for reliability would like to do the CI tappet conversion.

So if I've got the original AVL cams, is it likely that the original pushrods would basically work if the late-model CI adjusters are screwed into the bottom to mate with the CI tappets?  Keeping in mind that my cylinder is 2.5mm shorter than stock. 

Trying to not get too heavily into custom machining too many items, since here locally nobody's even got a full set of drills, never mind thread taps; and being that the bike could eventually end up in someone else's hands, preferring not to make it too hard for anyone to figure out later. 

-Eric

[Adrian II]

From memory I think the length of the AVL and C.I. tappets themselves is about the same, I will see what I can find in the garage and check. "S" cams and C.I. Indian Bullet cams have a smaller diameter base circle than the AVL, so the AVL tappets will sit higher.

A.

[ace.cafe]

If it is close, you can grind the pushrod adjuster locknut thinner. I have done that a time or two when it was close to fitting.

[ringoism]

Okay, so my supplier finally found both NTN C3 mains and imported big-end needle... 6305 primary side will be C3 in Indian FAG, which is probably fine.  Ordering them up and probably dig into it next week. 

On the tappets (again):

Had a photo posted here earlier of the CI/AVL's tappets/guides side-by-side.  So here's the concern: The weight of the CI tappet itself is a LOT more in view of its increased stem diameter.  If using stock AVL cams, is that going to get me into even more trouble than stock as it concerns valve-float?  I'm going to venture a guess that AVL's engineers reduced the stem diameter specifically for this reason, to reduce weight, knowing they had cams with sharp ramps / profiles that would tend towards float... ()

I don't plan on doing a lot of high revs and if I lost power to float there it wouldn't really matter -

BUT: Could this extra weight /float increase my chances of valve/piston contact (and thereby get me back in a realm of unreliability I was trying to correct)? 

If my brain's working right, I guess the risk would be more on the exhaust side: As the piston moves up to vent gases, the exhaust cam is on its downramp and valve correspondingly closing... piston "chasing" the valve then, and if the valve closing were delayed on account of float, then what...  Intake wouldn't matter since IIUC piston is moving down as valve opening approaches its maximum. 

-Eric

[Adrian II]

Not sure. When I tried a set of cast iron (indian) Bullet cams in my Electra-X it was the inlet valve head that made contact (just) with the piston crown. That was with the timing on the dots. Using the trick of retarding the cam gear one tooth mightr have prevented that.

According to Bullet Whisperer valve bounce with the AVL cam sets in around 5800 rpm, would you normally want to rev it that far? I suppose the alternative would be to have a set of tappets made to the AVL dimensions but with some tougher grade of steel, carefully heat treated and possibly with the flat faces stellite faced?

A.

[ace.cafe]

CI Bullet cams lift about .030" more at the lobe than AVL cams. So, if you then multiply by whatever rocker ratio happens to be in your AVL, which might likely be around 2.2, then you can see that it may get into contact with the piston after doing the squish mod.

I am more optimistic that stock AVL cams would be less likely to make contact with the piston, but it should be checked.

While I am generally in favor of retarding the inlet cam, my old measurements indicated that the AVL stock cams were already retarded pretty well, and would not need much more retarding. I would take a look at possibly using an offset Woodruff key to get just a few degrees more retarding if you need it. A whole tooth retarding is a lot for an AVL, in my opinion.

Maybe a little retarding by a few degrees along with a little valve relief in the piston crown might be the ticket If you get contact or insufficient clearance.

ALWAYS do a check of your valve timing and clearances when fiddling around in this area.

[ringoism]

According to Bullet Whisperer valve bounce with the AVL cam sets in around 5800 rpm, would you normally want to rev it that far? I suppose the alternative would be to have a set of tappets made to the AVL dimensions but with some tougher grade of steel, carefully heat treated and possibly with the flat faces stellite faced?

Adrian, so you still have the AVL cams, and the CI tappets?  If you're not having problems with premature float, then probably I won't either.  Unless you've also got stiffer aftermarket valve springs. 

I won't often/ever see 5,800rpm, but I was more concerned that the CI tappets' extra weight (inertia) could create the float at even lower rpm : Suppose it happened at 5,000... and if that float put me at risk of valve/piston contact...

Getting tappets made here would be next to impossible.  I do wonder though whether the weakness was in "all" AVL tappets or only some of them... A mechanic for this fleet said they very seldom have seen them break, but I've seen three such cases locally with my own eyes, and you've seen a couple, so I don't feel very confident about them. 

I am more optimistic that stock AVL cams would be less likely to make contact with the piston, but it should be checked.

While I am generally in favor of retarding the inlet cam, my old measurements indicated that the AVL stock cams were already retarded pretty well... A whole tooth retarding is a lot for an AVL, in my opinion.

Maybe a little retarding by a few degrees along with a little valve relief in the piston crown might be the ticket If you get contact or insufficient clearance.

ALWAYS do a check of your valve timing and clearances when fiddling around in this area.

I experimented with retarding a tooth last year, and while it killed my low-end, it also did nothing at all for the mid/top. 

But I suppose the final question is how much clearance is "sufficient"?  Since we don't really know when float would occur with the heavier CI tappets / stock AVL cams & valvesprings, the clearance spec for other setups may not be appropriate; And I can only measure it statically - Knowing what it's doing at 5,000+rpms is the tricky (and critical) part.  But I suppose a little extra relief on the crown would be the best insurance, it's easy enough to do. 


On another note, I also was able to source the big-end needle bearing with hardened outer race, as per Hitchcock's kit.  Basically it's got the same needles, the race adds 3mm to the OD (making it 45mm), for which the rod would have to be machined.  I'd like to try that, theoretically it could probably be done straight / accurate on a CNC boring machine (which we have here not too far away) - but the trouble is the existing heat-treating of the rod's big-end, which would make it too hard for standard cutting tools to manage, I'd assume.  What I'd gain would be the ability to use the old-style rods w/ small-end bush, while having a 58-62hrc outer race on the big end for the needles to run on, in the process also giving me a fully rebuildable rod.  Just not sure whether it's machinable as is.  Would I have to use an ID grinder (good luck finding that here).  Or maybe have to "anneal" it?  And if messing with heat does that get me into all sorts of other trouble with straightness, etc?  Might be getting in over my head here...

-Eric

[ace.cafe]

Adrian, so you still have the AVL cams, and the CI tappets?  If you're not having problems with premature float, then probably I won't either.  Unless you've also got stiffer aftermarket valve springs. 

I won't often/ever see 5,800rpm, but I was more concerned that the CI tappets' extra weight (inertia) could create the float at even lower rpm : Suppose it happened at 5,000... and if that float put me at risk of valve/piston contact...

Getting tappets made here would be next to impossible.  I do wonder though whether the weakness was in "all" AVL tappets or only some of them... A mechanic for this fleet said they very seldom have seen them break, but I've seen three such cases locally with my own eyes, and you've seen a couple, so I don't feel very confident about them. 

I experimented with retarding a tooth last year, and while it killed my low-end, it also did nothing at all for the mid/top. 

But I suppose the final question is how much clearance is "sufficient"?  Since we don't really know when float would occur with the heavier CI tappets / stock AVL cams & valvesprings, the clearance spec for other setups may not be appropriate; And I can only measure it statically - Knowing what it's doing at 5,000+rpms is the tricky (and critical) part.  But I suppose a little extra relief on the crown would be the best insurance, it's easy enough to do. 


On another note, I also was able to source the big-end needle bearing with hardened outer race, as per Hitchcock's kit.  Basically it's got the same needles, the race adds 3mm to the OD (making it 45mm), for which the rod would have to be machined.  I'd like to try that, theoretically it could probably be done straight / accurate on a CNC boring machine (which we have here not too far away) - but the trouble is the existing heat-treating of the rod's big-end, which would make it too hard for standard cutting tools to manage, I'd assume.  What I'd gain would be the ability to use the old-style rods w/ small-end bush, while having a 58-62hrc outer race on the big end for the needles to run on, in the process also giving me a fully rebuildable rod.  Just not sure whether it's machinable as is.  Would I have to use an ID grinder (good luck finding that here).  Or maybe have to "anneal" it?  And if messing with heat does that get me into all sorts of other trouble with straightness, etc?  Might be getting in over my head here...

-Eric

Safety margin for piston/valve clearance is .060" for inlet valve, and .100" for exhaust valve

Just buy the complete rod and bearing assembled from Hitchcock.

Don't be concerned about tappet weight. It won't matter.

[Adrian II]

Adrian, so you still have the AVL cams, and the CI tappets?

Not in the same engine! I have used C.I. cams with AVL tappets but never the other way round.

A.