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Yep.... I've learned a valuable lesson.... Don't ride my 79' T140E from Phoenix to Tuscon at high noon on one of the hottest days this summer, and pretty much wide open... yep....

Gnarly huh? But I'm looking at it from the perspective that I have time on my hands and am having a great time working on it....

Here's where I'm at....please fell free to advise me on anything i'm doing wrong....

I've got the pistons removed. There is some aluminum on the top of the connecting rod (see picture) that looks a lot like the metal build up that occurs on an abrasive saw. I've checked and I can "chip" it off with my fingernail. I'm going to try and remove it all by hand, but am thinking I might be able to clean it off with a very soft dremel attachment.

I am really hoping to flush metal out of the crankcase instead of opening everything up.....is that even do-able or must I take the dive? I've drained the oil, and removed the oil filter (just planning to put a new one in when it goes back together)....Plan to remove the filter on the bottom of the crankcase and replace it...am having troubles getting it off....can't even get it off with an impact. Will try to remove tomorrow with a breaker bar and hope I don't tip the bike over....

As for the head, I've begun to clean it up with the previously mentioned dremel attachment, being very careful to stay away from any sealing points. really just cleaning out the carbon I'm finding in the cylinder dome. I've figured out how to remove the valves, and am in the process of cleaning the carbon off of them as well with the dremel. I bought a lapping stick and some lapping compound and will lap the valves before I reinstall. Any necessary reason to replace the valves or guides if they have been seemingly mechanically sound?

Now for the cylinders.... In reviewing all the service records for the bike, it has already been bored out .020 over. The cylinder walls have no gouges or grooves or scratches perceptable to my touch. I'm a little wary of boring it out any more if the walls are happy. Should I just bring it to a machine shop and have them hone the cylinders and put a micrometer to it and see if it's still +.020?

My haynes manual should show up on Monday, but I feel I've done everything properly so far.....

Thinking ahead, one point that is unclear to me is how I can torque the nuts for the cylinder base. I had to grind down a 1/2" box wrench just to get it on the 12 point nuts. I'm hoping to read in the Haynes manual that you only have to torque the head to the jugs. Do you recommend the brass head gasket? For all the other gaskets, is there a preferable gasket sealant? Any spray ons?

Would also appreciate techniques for polishing the aluminum on the crankcase. How about polishing the head?

Hope I haven't inundated you with too many questions, but I truly appreciate all your help.

Rick

PS Here's what she looks like (except I have a corbin seat on it now)

 

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Beautiful bike, ugly piston. After a detonation like that I would need to inspect everything from the crank up, just for my own peace of mind. If that engine hasn't been split in the last 30 years it's about time.
 

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Split the cases and clean the sludge trap. Mike the crank & rods, too.

I use "hand pounds" instead of foot pounds on many of the fasteners. You get a "feel" for tightness.

Besides, the torque figures are given for "dry", yet you are supposed to use Loctite on many engine fasteners!

You'd better address your holed piston(s) by carefully strobe timing your engine and getting your carb jetting correct. hot weather doesn't hurt bikes, improper tuning hurts bikes.
 

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Nice looking bike. Sorry about the piston. A word of advice I got from an "old" Triumph guy (well he's a few years older then me) was if I ever holed a piston, to change the rod or it will come apart. I don't know how good the advice is but it makes sense to me. If the piston melted and the metal stuck to the top of the rod, the wrist pin area on the rod must have gotten pretty hot too. Aluminum isn't too tolerant of excessive heat. It tends to soften up (Annealed?). At any rate, the whole engine needs gone through to clean out all the aluminum flakes from the oil passages, pump, bearings and as GrandPaulZ said, the sludge trap. There is a tool that you can get for the cylinder studs. They're not but a few inches long and look like a 1/2" box end on one end with a 3/8" square hole for a torgue wrench or ratchet to plug into at the other end. I think they're called a multiplier. Pretty handy but you have to do some calculations to get the torque right if you use one. Good luck.
 

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Discussion Starter #5
Thanks for the input so far!

Would love more input from others....and answers to some of the other questions in my original post.

Anyone use EMGO pistons? I found a very reasonably priced vendor in Scottland but the site is lacking a catalog. If you tell Grin what you need on the webform, he'll shoot you an invoice with speed and the price so far is very reasonable.

http://www.grintriumph.com

One last thing.... I ordered a complete gasket set off of eBay, NE Brand, and the head gasket appears to be steel on the cylinder side and composite on the outside. Should I just buy a copper one?

Cheers and again, I thank you all sooo much for your help!

Rick
 

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I would split the cases too, and very carefully check the con rods and crank. You can pretty much be assured that a flush of the bottom end will not clean it to the standard you require. I agree with GPZ about tuning. For my money a lean mixture has contributed to the high temp that burned the hole.

Lean mixtures can give you some get up and go, but they also increase the temp.

I hope things go well for the rebuild.
 

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Bummer!!!! Before going any further, I would recommend you buying one of the engine rebuild video's for sale on Ebay...Your also going to have to buy some special tools.

Your complete oil system needs to be cleaned, including the frame..I'd go back with some type of oil filter just to be on the safe side......Good luck with it..
 

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Just picking up on the head gasket enquiry. Whilst I have no experience with warpage on a Triumph alloy cylinder head, your motor has been very hot and it will pay you to ensure the cylinder head is flat. A steel rule can be used to check this. The steel/composite gasket would be quite OK when used on good flat surfaces, ie, steel down, composite up. If there is any doubt about the surfaces, the copper gasket will be more forgiving and accommodate any slight imperfections on the surfaces of either the barrel and cylinder head.

Trust this is useful for you.
 

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Most of the part houses carry the pullers and different tools needed....I really would watch the video, than you can tell if your getting in over your head, and what all you need.. Your going to need a tap & die set so you can clean all the tread holes...

No one has mentioned it yet, but i would s-can the oil pump....The manuals give you the spec's on the length the head & rods bolts should be...your going to need to mike them to be sure they haven't stretched.....I would size both rods and have them shot -pinged...Sure wouldn't hurt to balance everything while your at it....

You might have it dyno tune it after you get done, so you know for sure everything is right....Cheers
 

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Discussion Starter #11
A few more ?'s....

My parts guy is spec'ing out EMGO Pistons that have a 8.6 : 1 compression ratio, but my new friend Haynes says that the ratio should be 7.9:1

Remember that it's +.020 --- does this sound right?

Also, the bearings that I should replace are the crankshaft bearings right? Labeled as main bearing left and main bearing right in Haynes.

And finally (at least for now) any others have thoughts on replacing the oil pump?

Thanks

Rick
 

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I suggest you try to get copies of original Triumph factory manuals, service and parts. Reprints are readily available. All the special tools will be found in those manuals. Failing that, Chilton and Clymer make good aftermarket manuals. Glenn's is excellent, but scarce. I think they are all out of print. I'm lucky that my local public library branch has a good selection of manuals, including Glenn's. Sorry to say, but IMHO while certainly better than flying blind, the Haynes manuals bring up the rear
 

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Struth
Dont be in a hurry to assemble, if your not familiar with this type of work the video will be a must and a real manual also. The conrods will need to checked properly both big end/main and the small end for out of round etc plus straightness bend/twist and crack test hardness new bolts. Acid to remove the molten piston from the rod should be available at your local machine shop. Same with crankshaft valves/seats etc. One thing that often gets overlooked is valve springs especially after being cooked they lose tension. Also be careful with that dremmel. who said porting?
Good luck and nice bike.
Daryl.
 

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Rick,
Your compression ratio does not change when you increase the size of a cyclinder.....

The oil pump is the "heart " of your engine.......Basic engine rebuilding 101 is always replace the oil pump when rebuilding.
That said, you have stock, 4 valve, and performance which will all bolt in like the orginal. Stock would be my last choice...

You also have a local "Triumph Club" in your area that may be able to guild you.
 

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What Speedtwin said. You are talking complete engine overhaul here. Take your time, repair, replace everything back to spec while you have the cases split. Do it right the first time. You might even get it oil tight that way. Then you will have confidence that everything is right. You won't be taking the chance that some errant piece of shrapnel got left behind to blow it up again, and barring another grenade job you won't have to go back in there for a long time.

One of the old guys here had 85,000+ miles on a carefully built up 650, last time he reported in. They can do it, if you do it right.
 

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EMGO pistons should be just fine. I have a set in my Norton.
 

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Split the cases and clean the sludge trap. Mike the crank & rods, too.

I use "hand pounds" instead of foot pounds on many of the fasteners. You get a "feel" for tightness.

Besides, the torque figures are given for "dry", yet you are supposed to use Loctite on many engine fasteners!

You'd better address your holed piston(s) by carefully strobe timing your engine and getting your carb jetting correct. hot weather doesn't hurt bikes, improper tuning hurts bikes.

I second ALL of these comments.. I always assemble certain parts (eg. cylinder head bolts/gasket) using graphite or molyslip grease. It means they will come apart without damage but you do have to 'feel' for tightness. Often it is just a matter of taking up all the slack plus a quarter turn or less to 'tighten'. I have rarely seen a problem caused by under tightening anything but often seen stripped threads from overtightening, especially when the thread is in aluminium. Con rod bolts are tightend to a pre determined stretch
 
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