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'69 Engine rebuild notes

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  • '69 Engine rebuild notes

    I just completed a rebuild of my '69 TR6 engine, and thought i'd collect some notes in case it's useful for others along the way.

    Backstory: my engine was running fine, but knew that it had previously had thrust washer issues, and it was burning/leaking oil at a quart every 500 miles or so. When i first got the car a thrust washer was in the pan, and while replacing it I found that the #4 bearing cap had been previously repaired by welding on a steel face on the bearing surface. So i primarily wanted to rebuild for a more solid engine that i could trust on longer trips.

    I knew the crank had some damage to fix, but after examining the block, the machine shop recommended finding another block to work with (rather than fix the cap and line bore at a cool grand before any other work). Luckily, i found a short block out of a '72 TR6 from a local guy for $50 that had relatively little wear, but some surface rust from outside storage.

    The machine shop deemed the '72 a good core and bored it out to 0.40 over and ground the crank to .020 under to clean up the pitting,. They also rebuilt the cylinder head with parts i supplied and refaced the flywheel (well 2 of them, because i got the wrong replacement the first time with my long- to short-back crank replacement). I did the rest of the assembly myself.

    The cylinder head had previously been shaved, but the machining was rough, so it got a skim cleanup. I measured it at about 3.43", which is close to 9.5:1 compression with the 0.40 over pistons. The new cam is the BP270, and the whole combo is noticeably more powerful than what i had, even keeping it under 4000 rpms for now.

    I haven't gone through all of my receipts, but i have a spreadsheet with most of the costs. Machine shop charge for block cleanup, boring, cylinder head rebuild, and flywheel recondition was about $1400. Engine parts were about $3200 with just a couple of splurges like ARP rod and head bolts. I ended up with Nural pistons because with supply issues everyone seemed to be out of 0.40 County pistons at the time. I also rebuilt the gearbox over the winter, those parts were about $400. I spent another $1000 or so on a few upgrades like gear reduction starter, new exhaust, adjustable jets for the carbs, striped hoses, and electric fan.

    Click image for larger version  Name:	IMG_3784-1.jpg Views:	0 Size:	3.37 MB ID:	542365

    Initial compression right after initial break-in was 175, 180, 175, 175, 175, 175. I'll measure again after the next oil change.

    Lessons learned:
    • Always take measurements and confirm the right replacement part if swapping something like a flywheel.
    • For cam timing, do a sanity check of running through the combustion cycle to check that the valves are doing the right thing at the right time for the crank. I initially had it wrong, even though the BP270 is very simple to set i somehow set it ATDC instead of BTDC. It definitely won't start that way, and less fun to set timing after the engine is installed.
    • It also helps to check the distributor when walking through the combustion cycle to make sure it's pointing to the #1 plug. My plug wires were 1 position off, though i hadn't touched them since taking them off the engine before, so they must have been shifted in the previous build.
    • If it doesn't start right up take a break, maybe have a beer or sleep on it before proceeding. Rechecking the steps carefully will likely find the problem.

    Finally, thanks to the helpful folks this site and all the great info shared here over the years. I've done countless searches here (along with consulting local club members) to get through this project, and i don't know that i would have even started without such a great resource. I'm happy to answer any questions about the build or process to help anyone else tackling their own rebuild.

    Video from the first startup:

    Last edited by frostr6; 06-22-2021, 10:56 PM.
    Bill Connell
    1969 TR6 CC28790
    TR6 project log
    St. Paul MN

  • #2
    Congratulations, Bill and HAPPY MOTORING !
    Driving a 1973 TR6
    Doing ZS carb repairs
    email kencorsaw"at"aol.com

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    • #3
      Looks great, sounds great, Bill. Will be so nice to go cruising. Cancel all appointments, fill 'er up and get lost in the countryside for hours.
      Walt
      CC80954U '72 TR6 original condition/sold 16.500.
      poolboy rebuilt the Z-S Carbs. Philstr6 rebuilt both rear hubs.

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      • #4
        Well done, bill. Congrats.
        1972 Sapphire TR6 #CC84,something

        1973 Harvest Yellow MGB V8

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        • #5
          Cool! Brings back memories of my rebuid a few years ago, flywheel discovery , timing cunudrms, and more.
          Love that pic of the refreshed motor on the hoist. So much to see there.
          Enjoy.
          CF1634U+O Pimento/Chestnut
          2nd owner, since 1975
          Now in Fair Oaks, CA

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          • #6
            Congrats Bill! Big Milestone.

            Cheers,
            Tush
            81 Alfa Romeo Spider Veloce, 81 Triumph TR8, 1973 Ford Capri
            73 Triumph TR6 CF4874UO, 68 Triumph TR250 CD5228LO
            62 Triumph TR4 CT6716LO, 60 Triumph TR3A TS69891LO
            60 Triumph TR3A TS64870LO, 59 Triumph TR3A TS44836LO
            https://www.youtube.com/user/cheftush

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            • #7
              Love the bookmatched dash.

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              • #8
                Thanks! I saw that it was done on the 250s and decided to try replicating it when I replaced the veneer a couple of years back.
                Bill Connell
                1969 TR6 CC28790
                TR6 project log
                St. Paul MN

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                '69 Engine rebuild notes

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