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    Default Triumph pre-unit engine build

    I picked up a complete 650 engine and trans several years ago and had found it to have a stock bore Wellworthy 8 bolt alloy cylinder and the best looking no cracks any where 59 cylinder head and the kind of hard to find tach drive timing cover. Well the vin number was crudely re-stamped in some giant font so I removed that and smoothed it down and then vapor blasted the cases . My thoughts are that no numbers are better than some hokey numbers . Fast forward to now and last weekend I decided to go ahead and build it with some parts I had been saving and use the other top end on a good numbered case. I am waiting on my crank bearings and other assorted sundries to arrive and then I will get on with it . I have replaced the cam bushings and just got done doing the upper rod bushings, the head is another one I had that was rebuilt and I have a barrel already done .040 over ready to go.
    Attached Thumbnails Attached Thumbnails DSCN7048.jpg   DSCN7049.jpg   DSCN7052.jpg   DSCN7050.jpg   DSCN7051.jpg  


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    Nice.
    Found this bit of info:
    Click image for larger version. 

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    "...Wellworthy Alfin Cylinder Barrel. These were a finely made peice that was based on a steel center that included the head bolt mounting area and cylinders as one peice with the alloy fins and base flange being cast directly to the steel center part.
    All the other later alloy cylinders had pressed in steel sleeves that could come loose and also making for weak head bolt threads.
    The ALFIN cylinders have slightly larger fins than a stock cylinder and the cylinders...had a larger outside diameter cylinder spigots making these useable to a .080" or .100" overbore making them something of a big bore kit as well..."
    http://showandgo.blogspot.com/2009/0...r-triumph.html
    Might wanna check out Show and Go Cycle Shop...
    Last edited by TriNortchopz; 01-27-2019 at 2:21 PM. Reason: link +

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    Thanks for the additional info on the cylinder. I had seen that ad before but did not see the other info you provided . I got the cam bushings sized, this might as well be a tractor engine , pound the ball through the first bushing and then ream the inner bushing . I have a set of unit cams I am going to use and will trial fit those in the case with the new bushings sized and check the fit .
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    That head will crack, they all do. Might as well address it while its apart. They crack typically from the exhaust seats outwards, and usually but not always to the outer large bolt holes leaking into the bolt channel. Seen a few happen on the intake side too.

    Used to freak out at this and do all kinds of milling, new seats, cut and V the heads and repair the cracks. They just do it again. It is what it is, defective stock heads. Thats why they upgraded the heads later and then added the 9th bolt, eventually 10 bolt. Added a lot more alloy meat in the castings to address this.

    ** Fun trivia. When the Triumphs went 750 they also went 10 bolt, However factory heads in later years were cast with 10 bolt bosses but if it was for a 650, they only machined and drilled to the 9 bolt pattern and left the 10th hole blank. I have some of these heads.

    To prevent the problem or address an already cracked preunit head, Machine the bolt holes out carefully and then install steel sleeves with Green Loctite on the sleeves. Machine/hone the sleeves after install to a sliding or slightly loose sliding fit for the factory bolts and use antiseize on the bolt shanks. The cracks cant go anywhere and wont. The seats wont fall out and the head will run just fine.

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    Used to freak out at this and do all kinds of milling, new seats, cut and V the heads and repair the cracks.
    At The Cylinder Head Shop in England, that is what they do; cut out seats, which are a tapered inverted cone shape, fill it and any cracks with weld, machine for and install new non-tapered seats. Options for different valves include using stock, using original inlet and 650/750 unit exhaust, or using both 650/750 unit valves.
    See a 2001 Classic Bike article here: http://cylinderheadshop.com/wp-conte...iumph-head.pdf
    and
    their shop here:
    http://cylinderheadshop.com/

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    Quote Originally Posted by TriNortchopz View Post
    At The Cylinder Head Shop in England, that is what they do; cut out seats, which are a tapered inverted cone shape, fill it and any cracks with weld, machine for and install new non-tapered seats. Options for different valves include using stock, using original inlet and 650/750 unit exhaust, or using both 650/750 unit valves.
    See a 2001 Classic Bike article here: http://cylinderheadshop.com/wp-conte...iumph-head.pdf
    and
    their shop here:
    http://cylinderheadshop.com/
    Thanks for the PDF of the article, that has some useful pictures and illustrations. And its exactly what I used to do when I had my shop. However, in my experience it does not work. They will crack again.
    As to cyl head shop, If you ask around, I am sure they have many happy customers as they have been around for a while. However I also heard a lot of complaints about them. Any shop has those, I did. But I heard some specific complaints that seemed credible. Regardless, I never dealt with them as they are in the UK and I had access to some really talented people locally so I cant say for sure anything about them.

    But if you ask John Healy, Owner of Coventry spares and a Triumph east coast service shop, as well as head poo-bah of the TIOC, he will tell you the same thing as I did. They all crack and sleeving the bolt holes solves the problem and just leave the cracks. (I found that hard to accept, against my nature, but its true). I also heard the same from many others I know and respect. But its not a popularity contest. I can tell you from experience. I also worked in Aerospace castings and am licensed as a FAA technician as well as certified instructor, and multiple certifications in NDT for Aerospace. (Non Destructive testing and inspection). I know castings. We cut up some scrap Triumph heads once and I went over many of these topics with engineers in the casting industry. (Norton too)

    The OP can do what ever he likes here, But my $0.02 here (And worth 1/2 what he paid me) Is either sleeve the holes if its important for status points to run a 8 bolt head, But if serious about perf. & Power, run a 9 bolt head. (The alloy cyl would easily be modified to suit).

    MAP cycle did testing and found 1971 and later heads on average flowed 30% better right out of the box, but any 65 and later head will perform miles ahead better than a 8 bolt.

    Being alloy cyl and head, Might want to modify or make custom waisted bolts, Not new tech, but many vintage MC people seem to think its new. But the same principle is used on modern Evo HD motors and works well. The Norton people are just recently figuring this out, But might also help with the whole expansion thing.

    See: https://www.accessnorton.com/NortonC...s-studs.24646/

    " Regardless of the material used, a waisted design fastener is still superior in terms of consistent clamping force and fatigue life. That's why you see it used so much in high end engine fasteners like con rod bolts and head bolts and studs. "

    (I know Ken pretty well, one of the few people on that forum who knows what he is talking about, He also is a very talented aerospace engineer, and accomplished racer)

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    All good points about the 8 bolt heads but with out starting a shit storm what is the issue with a crack there it can not leak at the valve seat and there is a head gasket covering the crack . I do not want a 9 bolt top end on this engine so that is not an option. The head with no cracks that came off of this crankcase had high compression pistons and performance cams and was run like that and did not crack. The only issue I can think of with running a cracked head would be if oil leaked where the head bolt is and then into the combustion chamber.
    On with the work , I trial fit the cams and the timing side bushings needed a slight hone for the proper fit now that is done and I am ready to install the rods on the crank unfortunately my bearings and other stuff have not showed up yet . I also buffed out the donor timing cover and scrounged up a Webco pressure relief valve to use.
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    Well my bearings and stuff finally arrived with the new piston pin bushings installed and sized I got the rods installed on the crank with new bearings, then the main bearings were installed in the cases and I got it all together and sealed up.
    In a post on another forum Mr. Healy suggests using the dowels that are on the cylinder base studs for repairing cracked heads so I am going to drill the holes for a press fit and loctite the dowels in the head because the head I am using for this engine has those familiar cracks . Doug had suggested the same fix but did not say what to use for the sleeves he mentioned but it makes sense now .
    Wouldn't you know it they are on back order with my supplier right now . Next up I can install the timing gears ,pinion gear oil pump and timing cover.
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    Quote Originally Posted by Dougtheinternetannoyance123 View Post

    ** Fun trivia. When the Triumphs went 750 they also went 10 bolt, However factory heads in later years were cast with 10 bolt bosses but if it was for a 650, they only machined and drilled to the 9 bolt pattern and left the 10th hole blank. I have some of these heads.
    Triumph did something like this when they switched from 8 to 9 bolts as well. Replacement heads for 8 bolt motors were made from 9 bolt castings. The 9th bolt boss went undrilled. The other 8 casting bosses were designed so they could be drilled for either the 8 bolt pattern or the 9 bolt pattern which moved the headbolts a little farther away from the bore, no doubt to address the cracking problem.

    Here's a pic of one of those replacement heads that came to me bolted to a '56 TR6. You can see the undrilled 9th bolt boss, as well as the oval shaped bosses for the 2 visible outer headbolts. Amazingly enough, when I took this head off to replace it with the correct one, I found it to be not (yet) cracked.

    Click image for larger version. 

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    Quote Originally Posted by MOTher View Post
    Triumph did something like this when they switched from 8 to 9 bolts as well. Replacement heads for 8 bolt motors were made from 9 bolt castings. The 9th bolt boss went undrilled. The other 8 casting bosses were designed so they could be drilled for either the 8 bolt pattern or the 9 bolt pattern which moved the headbolts a little farther away from the bore, no doubt to address the cracking problem.

    Here's a pic of one of those replacement heads that came to me bolted to a '56 TR6. You can see the undrilled 9th bolt boss, as well as the oval shaped bosses for the 2 visible outer headbolts. Amazingly enough, when I took this head off to replace it with the correct one, I found it to be not (yet) cracked.

    Click image for larger version. 

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    Yes MOTHer,, You are correct, If you understand how tool & die works in relation to castings its easier to understand that Dies are super expensive to make so they cut corners and mod stuff too.
    You are in danger of starting a discussion though of Delta race heads, preproduction dual carb 500 preunit twin heads, some of the preproduction 650 heads and then they made these heads for preunits well into mid 60s for dealer stock. (I have a bunch of that stuff)
    Later production heads, Even if made for preunits had more casting meat in them so not as likely to crack.

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    Quote Originally Posted by britbikebuilder1 View Post
    Well my bearings and stuff finally arrived with the new piston pin bushings installed and sized I got the rods installed on the crank with new bearings, then the main bearings were installed in the cases and I got it all together and sealed up.
    In a post on another forum Mr. Healy suggests using the dowels that are on the cylinder base studs for repairing cracked heads so I am going to drill the holes for a press fit and loctite the dowels in the head because the head I am using for this engine has those familiar cracks . Doug had suggested the same fix but did not say what to use for the sleeves he mentioned but it makes sense now .
    Wouldn't you know it they are on back order with my supplier right now . Next up I can install the timing gears ,pinion gear oil pump and timing cover.
    Glad its moving fwd! * Just got back into town, many days at the cabin drinking and playing in the snow, But before I left did a swap for some prewar Triumph stuff and other bits for a 53 T100C project bike, So now I need to round up the race kit parts to complete it.

    As to your idea per Healey,, Meh, that might work as they are probably sized for head bolts, but its not what I would use. I didnt specify because its not a off the shelf product, but if theres a market for them maybe I should knock out some kits for that purpose.
    My wife works for a machine shop and they make high volume of a variety of parts for well know manuf. of sporting goods, firearms, automotive, industrial etc. If I named names you guys would know the products. But the point is, there is a ware house full of 12 foot bars of tubing, bars stock, flat stock, copper, brass, steel, aluminum etc . (She manages inventory as part of her job) I thought it was understood to look at dimensional stock and make the sleeves.

    Personally??? Id look at some full length steel tubing and size it so you only do a minimal hone fit for a slight interference fit. **I Can mic some bolts for reference as its been a while so dont recall off the top of my head, ** but we took bench stock that was close. We did full length sleeves and heated the heads to 200 deg F, chilled the steel, a smear of anti seize and slid them in place. Not too tight you have expansion issues, but not too loose. Set the inner ID to a snug but sliding fit to the bolts. Again use Anti seize.

    *Keep in mind the entire point here is, The cracks wont go anywhere, but they DO leak a tad bit up those bolt holes. All you are doing is sealing the leak. You CAN weld them but the castings typically crack again. Its a casting defect with not enough meat, and bores close to the holes. So a full length sleeve with anti seize and a moderate interference fit stabilizes the casting as well as SEALS it, but going with a short length dowell is problematic in that only one end is stabilized coupled with expansion issues. But its possible it would do the trick. Ive done 4 builds myself, and did the machine work/repair for 3 others and no issues. Worked perfectly.

    The problem with using shorter dowells is they are short. IMHO you want the entire hole sleeved. But I suppose it would work using shorter dowells but the idea makes me uncomfortable for a few reasons.
    Healey is great in many respects, that guys forgotten more about Triumphs than most mortals will ever know. Except when he is wrong. Sometimes he is, but no use in pointing it out. Not worth getting yelled at and he yelled at me a lot years back. Im not alone. Everyone gets yelled at by Healy.

    If you like, I can see if my wife can snag you some tubing if you like. If you want it machined,, that might be more complicated, but I might still have some in the shop as well.

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    Cam gears , pinion gear and oil pump all installed time to move on to the pistons and cylinder . I also got the sump filter screen and cover installed .
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    I got the pistons , rings and cylinder installed this morning and I also have this nifty alloy timing gizmo that takes the place of the magneto and will allow me to install an electronic ignition so a fixed gear will be used as no manual advance will be needed. now would be a good time to use a degree wheel on the crank to time the ignition while the head is not installed.
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    Good plan on the Maggie-Neato replacement, While the kids love the nostalgia of the Mags, the reality is they are not that great IMHO. The EI presents way improved ignition assuming you have a decent power supply. Will be interesting how you deal with that. The EI by itself does not generally consume a lot of power (Amps/watts) however some are voltage sensitive. Nice stuff.

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    Nice work so far. Who makes the ignition setup, is that the Tri-spark one?

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    Zeeman I am not sure of the brand of the ignition housing , it was left over from one of our race bikes. The Tri-Spark has a cover and the wire exits in the center where this one has a hole on the side for the wire and accepts a standard points cover.
    I enlisted the help of a friend for the cylinder head so that it would be a nice press fit for the dowels I knew my chinese drill bit collection just would not make a precision hole.
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