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Discussion Starter #1
I'm making plans to strip down my 1979 T140E engine for gasket replacement to cure the annoying oil leaks I am experiencing. The bike runs sweet with no lack of power and no smoke. I want to replace rocker cover gaskets, timing cover seals, cover gasket and ignition module grommet. Head gasket, push rod seals and O-rings, Cylinder block base gasket, Drive sprocket seal and all associated seals and gaskets on the primary side. In short, pretty much every seal and gasket short of crankshaft and gearbox removal. So I have a question for those experienced in OIF bikes, and a general question;
1) Can I do these repairs with the engine still in the frame? 2) Would you take the engine down this far without doing any machine work? Valve job, new rings, etc?? Am I asking for trouble if I do not ?
Thanks in advance for your input!
 

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Yes you can do all of the work listed with the engine still in the frame

leave the rear drive chain fitted until you have loosened the big nut that holds the drive sprocket - a standard sprocket will pass through the "inspection plate " hole into the primary - in addition to replacing the seal use sealant on the splines of the output shaft

if you are sure that all is OK with the engine then you can just rebuild as it stands - however i would recomend a cylinder head strip to check for loose guides - and for wear in the guides or valve stems - and if all OK a light lapping in the valve to seat faces

if it looks good leave it as it is - dont do unnecessary work just because its stripped down
 

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I agree with wol. I would probably put new rings in, but that’s me. If it’s not smoking or using oil I wouldn’t disagree with leaving the rings alone.
 

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My T120 started leaking oil last year from various gaskets. It burned very little oil but when replacing gaskets, i checked ring gap and they were very worn. replaced them and the gaskets and no leaks. I suspect you might have worn rings causing crankcase pressure to rise and pushing the oil out. For £30 spent on rings, i would change them.
 

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My T120 started leaking oil last year from various gaskets. It burned very little oil but when replacing gaskets, i checked ring gap and they were very worn. replaced them and the gaskets and no leaks. I suspect you might have worn rings causing crankcase pressure to rise and pushing the oil out. For £30 spent on rings, i would change them.
That's a good point.
 

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leave the rear drive chain fitted until you have loosened the big nut that holds the drive sprocket - a standard sprocket will pass through the "inspection plate " hole into the primary - in addition to replacing the seal use sealant on the splines of the output shaft
in some forty-odd years of messing with these, i never ever take this nut off until after the chain is tossed and usually the engine is out and on the stand. and the gearbox is disassembled on the right side.

i curse myself every time, but then forget and do it again.
 

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Personally, if it was me [that's personally :)] I would strip the crank out and clean out the sludge trap and check the big end journals etc....then you're set for the next 50,000. I mean you have gone so far, its not much more to do the lot.
 

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Hi Happyfeet
If you have fallen in love and are looking for a long and fruitful relationship with your T140, then listen carefully to Tridentt150’s good advice.

The T140 has an inbuilt weakness that the T120 never had, the timing side main ball bearing is inadequate for the torque put out by the engine, Triumph tried to mask this by detuning the engine, but the weakness still shows up when you get enthusiastic in your riding, the bearing breaks up filling your crankcase with bits of metal. In 82 Just before they went bust Triumph solved the problem with a special roller bearing.

If it was my bike and I had it stripped down so far, I would take the opportunity to replace that bearing, in the great scheme of things it is not much more work to remove the engine and split the crankcases. Although there are some special pullers needed. As you are not the original owner and do not know the oil change history, once the crankshaft is out cleaning out the sludge trap will serve you well.

Be warned though mission creep can soon set in. Perhaps changing the drive side bearing$$, a crank regrind$$ or polish might seem good$$, and while it’s apart get the crank balanced $$restore some performance by changing the cam timing-or new cams$$$ etc.>:)

Good Luck in what you decide
Regards
Peg.
 

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Discussion Starter #9
Thanks to all who have chimed in and to anyone else, feel free to add. Peg, you are spot on with what CAN happen once a person gets started down the spending rabbit hole, and indeed, I don't know the real history of this bike's care. I bought it with 7300 showing on the speedo from a reputable shop, and the shop owner and I agreed that with a 40 YO bike, ticks on the speedo can't really be relied on. But overall condition and inspection gave me confidence in buying this rig.
I really enjoy hearing from vintage Triumph enthusiasts from around the world. There are good people willing to impart their knowledge and experiences. I'm just an old corn-fed farm boy who has seen internal combustion engines abused to beyond the seeming limit not blow up, and pampered projects that go totally wrong. As far as my oil leak repair project goes, I've decided to stop at pulling the head and leave the cylinder block in place. Everything from head gasket up is getting refreshed seal/gasket wise, and I'm going to leave the valves in the head. I'm rolling the dice that my leak in the front push rod tube base area is just that, a push rod tube leak. The timing cover is going to get refreshed as well with new seals on the crank and cam. I may even let the gear box seal go for another day.
I will keep you all posted.

Thanks again! Best Regards, Robert.
 

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Hi Happyfeet, I did what you are thinking about to very good results. I only had 12k original miles from new though. I've done this to a few motors all turned out good.

After you do tear down you can change your mind at any point.

Mark all tappets, push rods, valves. Do not remove pistons. Pad the rods to prevent nicks, damage. Tape up crank case mouth & pack with lint free rags to prevent dirt from falling in.

But for resealing of oil leaks. You must carefully evaluate motor before tear down, but if it really doesn't use oil now, it won't upon assembly unless you mess up rings.

A few thoughts. Very important do not remove rings!!! If you remove rings they will never seat again on used bore you have now. Do not worry about ring gap if it doesn't use oil. Just blow rings clean with compressed air & some carb cleaner. Only carb cleaner if you don't have compressor. Oil well wrist pin & rings, bore on assembly. I recommend using a ring compressor tool. They make it easy & prevent damaged rings. squirt lots of oil down into big end bearings. Remove carbon from piston tops & above top ring. No need to remove baked on oil from piston sides.

The valves always wear out of round. If you don't remove them, they will be exactly as before. If you remove them, they MUST be lapped using fine compound & suction cup. Don't start with course & go to fine. Just use fine only. The seats will be wide & conical. Don't worry. It won't cause a problem. You can measure stem clearance to guide. They can be very worn & still not use oil & seal fine. However they will tick/rattle like the valve adjustment is too loose. If tip of valve is worn from adjuster screw have them refinished at auto machine shop. Under no circumstances should the face be reground. Do NOT let the machine shop talk you into grinding face. Again only lap the face. Lap the valve until all pits are gone from valve face & seat. Assemble with lots of oil on stem. Make sure perfectly clean. Turn head up & fill the valve recess with solvent or gas. Look inside port with flash light & make sure no liquid is seeping through. NONE! If it seeps you either have dirt left behind or you need to lap more. Don't use drill or lapping machine. Do it by hand with suction cup tool. Keep head held such valve is vertical to prevent side loading while lapping. If valve stem is burred at keeper grooves or stem end, stone or file the burr off so valve doesn't scratch guide on removal.

If you determine guide clearance is too large, then you'll need guides, valves & seats cut with cutter or stone. Every Triumph valve I've tried to regrind face left margin too thin for best operation, so I just get new.

Worn/pitted adjuster screw tips can be refaced to a degree if not too bad. I use a lathe & emery cloth wrapped around a file. But you can put them in electric drill to spin them. Make sure to replicate the radius on end.

You will need torque wrenches & special tools to do this work. The sprocket socket must be deep socket or correct tool. I recommend 1/2 drive or 3/4 drive with 1/2 adapter. I have exact tool # if needed. I always torque the sprocket nut with torque wrench.

Purchase tappet block driver that replicates factory tool. I no longer heat cly or chill tappet block. Place the cyl on 4x6 on concrete floor. Use hammer about the weight of a large claw hammer. Using claw hammer is fine. Look at tool & tappet block. Notice block is not straight but angled slightly. Drive it at the angle that's correct. All O-rings should be viton. Make sure. Except the silicon one at bottom of push rod tube. If... your bike uses the silicon one. Later do not.

Deburr head bore & tappet block bore to prevent tearing O-rings. Even micro tears will leak. Deburr/smooth exterior of tappet block where push rod tube seal will slide over. Very important!

The set screw hole it tappet block is not close enough. Get a 3/4 square bar 12" long from hardware store. Take your square & find the straightest you can. Use it as straight edge. Of course a real straight edge is best, but this will work.

So installing tappet block is not hard. It will want to turn as you drive it. A firm wrist pressure is needed to keep it where you want. Never attempt to turn tappet block while it is stationary. It must be moving while driving to rotate.

Drive down to about 1/4 from home aligning by eye best you can. Then stop & measure with Vernier caliper or depth gauge using your square bar against tappet block ear measuring to spigots of each cyl. Use a marking pen & make an arrow on tappet block which way you want to rotate it. Then drive block down further rotating as you go. If you get home before it's square, no problem. Turn cyl over & drive slightly out while giving rotating pressure. Then back down turning as needed. You can zig zag like this several times only moving 1/16" inch or so. You'll very soon get the hang of it. The next tappet block will be much easier with this practice. Try for at least .003" max difference spigot to spigot.

Good alignment reduces tappet wear in my mine.

Resealing rocker shafts can be hard to get the o-ring in without tearing. I have a good special too to guide in ring. Many don't work well. Buy several spare rings. If you see even a trace of rubber peel off ring it will leak. Deburr & smooth bore in box so it doesn't catch, tear ring. A little smear of silicon on ring is not a bad idea in my mind.

When doing the rear sprocket look close at how deep the seal is. If you put seal too deep it can miss sealing surface on sprocket. Not deep enough & sprocket will rub side of seal. Feel how easy the sprocket turns now. When done it should feel the same or only just a slight more drag. If it feels tight at all something is not right! As was said put sealant on splines even with the o-ring. The o-ring & non oring sprockets are different. The o-ring type is chamfered. Don't use o-ring with non o-ring sprocket.

Pull the seal from inside main shaft with a bent wire hook. They usually come out easy. The rear sprocket seal can be really hard to pull out. I have a slide hammer seal puller, but don't damage the thin trans case in this area while pulling seal. After you remove sprocket the high gear will move in/out a lot. That is normal. The inner face of sprocket is the bearing side race so it should only have a trace of side movement once nut is torqued.

Overall your plan is very sound & straight forward. Doing in frame is how I've done it & works good. Don't scrimp on tools. If you need to force it apart because you don't have proper tool you are at great risk.

Remember you are not improving the motor in any way, just stopping leaks. It will be the way it was, but no more leaks. Suppose you had no leaks? We wouldn't even be discussing this. You'd just be riding it. You could cause damage during repairs by just taking it apart & putting together. So as long as you understand that you are good to go. So give every last part a good visual inspection or measure as you go. Make a parts list as you take motor apart. I'd recommend buying a 1" micrometer & 6" Vernier caliper if you don't have one. They are a must.

Don.
 

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I would not count on the push rod tube seal being the only reason your oil leak is in that area. I have seen many tappet blocks leak from the o ring around them and look like oil is leaking from the tube. I have replaced tube seals and still had them leak after doing all of that work .
 

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Hi Lenardoldphart, Thanks for bringing this up.

You are 100% correct. It is not wise to not reseal tappet blocks when you have leaks.

I had some lower PRT seeps on my Tiger 750. No big deal. I stuffed a black rag behind PRT. One day wife & rode to store. I noticed a puddle of oil under bike 3". Certainly couldn't be from me!
Next store another 3". This was when parked returning to bike. This time I payed attention The tappet block leaked a cup of oil per mile! Luckily close to home. Frame was 50% by time we got home though. Yes tire was oily too.

I found the exhaust tappet block o-ring was fractured, hard as glass & the fracture had a gap 1/64" wide pumping oil out. Inlet block ring was cracked also, but didn't really leak much due to no pressure feed.

I now replace the O-rings every time I remove a cyl. With some practice only takes a few minutes.

Don
 

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There are many theories on Trusty Triumph rebuilds, all have some merit and have presumably worked for those who offer them. I have been riding and rebuilding Triumphs of various ages for many years. The most common oil leak is indeed the push rod tubes and i have tried many things to cure this for any reasonable length of time including using double seals. using alternative O rings, applying various sealing compounds and most anything else that has been suggested so will be very interested in what you do and if it is successful

PS Did you know that Triumph invented total loss lubrication and automatic rust prevention
 

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Discussion Starter #14
Here's what I did...

If you have read this thread in its entirety, then you know what my original proposal was. Here is the work I did and how things have turned out. I installed new copper head gasket using copper spray as an added sealant, new push rod tube O-rings and seals, new O-rings on the rocker spindles, and new seals in the timing cover for the exhaust cam and crankshaft. In the process I cleaned the combustion chamber, de-carbonizing, as I have seen it called. I also cleaned the piston surfaces, but did not get too aggressive there. I did not remove valves. I did perform the workshop manual test of pouring kerosene into each valve chamber and timed how long it took to see any seepage. With 10 seconds as a passing grade according to the manual, mine hardly seeped at all in over 30 seconds so I considered the valve seats good to go. I did not remove the cylinder block, so no base gasket replacement. No piston ring replacement, the cross hatching on the cylinder walls looked good so I left them alone. I did resurface the rocker box gasket surfaces using 180G sandpaper and a plate of glass. A PO had used a gasket sealer that was very stubborn to remove, I tried several methods and products with little or no success, so patience and elbow grease was the order of the day. I found some plastic razor blades at a hardware store that helped get the cylinder head surface clean on the rocker box surface. So in short, new seals and gaskets everywhere I opened up except the tappet inspection covers, which I had replaced just recently. I used metal core gaskets for the rocker boxes and covers. I used no gasket sealant, as I knew I would be disassembling part of my work to re-torque the head. I did use gasket sealant on the timing cover gasket, but only on the timing cover side, not the crankcase. I also annealed the copper washers for the oil feed line to the rocker boxes, which seemed to work well. Now with the head re-torqued and about 100 miles of various riding conditions, including road speeds at four thousand RPM for several miles in summer riding conditions, I can happily report that the engine oil leaks I set out to stop have thus far stopped, and the bike performs better and runs much smoother and more quiet than before this process. I plan to tackle the gear box seal issue next month after doing a bit of riding! Thanks to everyone who offered input on this thread and project!
 

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Hi Happyfeet, That is great news. Good going! If you still see honing marks you mileage is reasonable. I still had some at 12k miles.

At 30600 miles original pistons/rings from new, still not using oil & no smoke. Original valve guides also. I can't see any honing pattern anymore though.

Your trans sprocket seal replace is not too hard of job. From what you did so far, you'll have no problems. One thing I found replacing 5 speed seals is very carefully measure how deep seal is now. If too deep it can miss the seal surface on sprocket. It too far out it will rub back side of sprocket.

I don't recall for sure, but I think by 1979 you'll have o-ring sealed sprocket. That reduces leaks, but I'd put some sealant on the spines in any case.

The sprocket can be tight on splines so don't force it off. It should be drilled for a puller. I used my vibration damper puller. Drive the sprocket on less you can & then draw it in with nut. After sprocket is seated then go back & fit the lock tab etc.

I bent some music wire to a hook to pull seal from high gear snout. It pulls easily. I also bent a hook from fat music wire to pull sprocket seal. It was a very tight fit & hard pull. A fight really.

New high gear seal went in easy. Sprocket seal was very tight going in. I got some PVC pipe from hardware store. Glued a coupling on it. Then hacksawed the coupling off & smoothed end flat. Put a cap on the end. That made a good driver. PVC can shatter violently so use safety glasses!! Be careful, the case is thin around seal area & it can break if not treated gently. Deburr the case as needed so seal is not cut during install.

Inner snout of sprocket is side race for roller bearing so don't damage it. The high gear snout will be free to move in/out until sprocket is torqued. I don't feel torque is willy nilly. I used 80 ft #. No spec in shop manual I could find. One forum said 80#. It felt about right. If anybody can verify factory spec that would be appreciated.

I held sprocket with a chain whip. You might hold with rear brake after fitting chain. Put chain around sprocket before the clutch door is installed.

The sprocket seal is so hard to install I would recommend buying 2 incase of damage to first one. Same with seal on clutch door.

I got a large deep socket on Ebay. 3/4 drive & 1/2" adaptor. 1-7/8" size. Cheapo Sun brand from ebay. The end of main shaft sticks out a long ways. The end actually went inside of the 3/4" drive of socket so adaptor couldn't go fully home, but far enough for safe grip. Much cheaper than the sockets sold by Triumph parts sellers. I don't like the sheet metal sockets that are really a water heater element socket with tommy bar hole.

Hope this helps you to be more prepared than I was. I lost a month of good riding time.

I messed up the first seal... Had to order 3/4 drive socket as my 1/2 drive wasn't deep enough. If you can weld, you can make deep socket.

I've covered 7k miles so far, no leaks.

I have photos if needed. PM me if you need them.
Don
 
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