Triumphrat

PHxS · 02-23-2010, 05:08 PM

I'm tearing down an engine which is said to be a 1963 T120 (frame year as well) and I was a bit confused about the cam gears. The service tools show what seems to be an inner threaded piece and a bolt to press on the shaft. The gears on this engine have no threads, but it has two holes with threads for a different style puller.

Can anyone confirm a year/model/whatever these gears came from or is this one of the quirks of a possible '63 engine? Is there something I can use to tell me, or get me close, to the actual year? There is no serial number on the top of the case.

Thanks,
Ryan B.

jimmy bush · 02-23-2010, 06:51 PM

Someone may have put the later wheels on. They are heavier and dampen some of the valve train vibration. The later cam wheels had the two holes and require a different puller. They should be American threads. I used my sears puller to get mine off. Just make sure you block off the end of the exhaust cam so the snout doesn't get spread and cracked. Why are you pulling them? There is rarely a need to unless you're changing the cams. The bushings wear very little. You can do the rest of the engine work with them left in the right case half.

PHxS · 02-24-2010, 11:49 AM

I figured I could work around them without removal, but my buddy wants to make sure everything is good. As said many times, if you're already there, might as well. I had already tried an SAE bolt and it fit. Kinda funny as I work on mainly all metric stuff and the first bolt I grabbed was a random standard bolt which fit the holes.

Was there a period in which Triumph didn't stamp the engine case with a serial number? My friend and I have found absolutely nothing to indicate it was ever numbered other than part numbers.

Thanks,
Ryan B.

GABMA · 02-24-2010, 02:12 PM

Jimmy told you right. You apparently have the "fat" camwheels off a much later model. You should be able to pull those off with a standard wheel/hub puller and two 1/4-28 UNF bolts.

The cam bushes are replaced from the inside (crankshaft side) of the case. After installation, the DS and TS bush pairing must be line-reamed with a special Triumph reaming tool. So you do NOT want to replace this bush "just for fun" or you'll create MORE problems than you'll ever solve.

On the other-hand, bushing wear should be investigated. TS cam bush wear directly affects the camwheel clearances and fits, which can lead to other problems... such as centering errors with the ignition cam in the points plate.

Due to the pressure of the valve springs, cam bushes always wear oval at the 6 o'clock position.

Hope this helps!

PHxS · 02-25-2010, 02:23 PM

Thanks for the extra info and confirmation, GABMA. I don't feel any unusual play with the camshafts, but the engine has been sitting for twenty some odd years and figured a little extra effort to check things would be better while I have it here. I figured if they needed replacement, some sort of line honing/boring/reaming would have to be done. I'm not surprised to hear about another service/special tool being needed.

The only thing so far which has me worried is the excessive amount of play at the crankshaft end of the left cylinder connecting rod. I'm really hoping the bearing is trash and not the crank. I need to get the service tool so I can get the crankshaft timing gear removed. I've managed to get by with only buying the clutch hub removal tool by cobbling together a makeshift puller for the camshaft gears and used the piece and another which is ready to split the cases.

Say, would GABMA stand for Greater Atlanta British Motorcycle Association? Glad to see the name hanging around here. I've heard of you from a buddy/friend-of-the-shop who has done the British in the Blue Ridge Rally a few times. You know of Ian at Cycle Depot in Mableton?

Thanks,
Ryan B.

GrandPaulZ · 02-25-2010, 02:44 PM

Quote:

Originally Posted by PHxS

...The only thing so far which has me worried is the excessive amount of play at the crankshaft end of the left cylinder connecting rod. I'm really hoping the bearing is trash and not the crank...

Insert a gudgeon pin in the rod end and attempt to "twist" the rod in place on the crank.

ANY AMOUNT "twist" means significant wear that must be addressed.

Side-to-side play along the journal from left to right is normal (within spec). It can fool you into thinking you have too much slop when it could be nothing more than slightly / normally worn bearing shells.

Plewsy · 02-25-2010, 07:50 PM

Twist! will point out severe wear as you say GPZ,
Its the small amounts that count, any play that can be felt on the big end means a replacement bearing.
Saying this I have seen motors run with no copper on the shells.
direct lift and push on the con-rod is the best test, if oil is removed from the journal
with a few squirts of paraffin (kerosene) and a few spins, even better.
Remove crankcase plug when using paraffin in motor.
Wear on the mains can be detected by levering the ends of crank,
Be very careful the oil seal end use the crank pinion to pry against (within reason)
any lift and the mains are suspect.
Quite a few of the Triumph "Special tools" can be made, which can save you a few bob

and they are quite satisfying to make
but a crank pinion and a clutch hub puller are a must.

GABMA · 02-26-2010, 09:26 AM

PHxS -
One way is to simply grab the 2 rods with one hand and pull them towards each other with hand pressure while the crank is at TDC. That will lock-out any play in the rods. Then lift up-down or rock the rods side-to-side. Any play you feel is in the main bearings.

However, if you feel any up-down in the rods caused by the big-ends or the mains, then the bottom end has to come apart. Diagnosis is useless after play-due-to-wear is detected. So the reality is this: When the crank comes out, it all has to come out. When the crank is serviced, then the whole thing is serviced.

Obviously, the issue(s) will be fully detected (and hopefully corrected) at that point.

PHxS · 02-26-2010, 12:20 PM

I'll never say I can't be fooled. It does seem to be mainly side to side play. Is there a 'spec' to the amount of play? The left con-rod moves along the crank journal a hair less than 2mm while the right con-rod moves about 1.25mm (eyeball and tape measurement). Trying to twist or push/pull on the con-rod produces no discernible movement. The crank itself has zero play.

I'm splitting the cases mainly to clean out all the crap which has fallen in due to sitting for such a long time partially disassembled and to get the cases to a presentable shape. But I want to be sure the engine will be solid for my buddy. Being my first old triumph (first old british bike), i'm questioning everything I see in a quest to learn all I can while I have it here.

Thanks again,
Ryan B.

GrandPaulZ · 02-26-2010, 01:01 PM

Since you are splitting the cases, there is no reason NOT to do a plastigage test on the rod bearings. If you have a proper micrometer, you can just measure the crank's rod journals to get your preliminary info. Bearing shells are marked on the underside with "STD" or the undersize spec.

There is ALMOST no reason not to spend a few bucks and use new bearing shells regardless.