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Thread: Tr3A Oil Priming

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    Tr3A Oil Priming

    Hello all, I have just finished rebuilding my Tr3 engine and am attempting to prime the oil system. I made a spade tip rod and chucked it up into a drill. spinning it counterclockwise ate about 750rpm i get oil to the block galleys and through the pressure tube. but no oil is appearing at the top of the head! none at all through the rocker pedestal hole and none at the back aux oil in hole. the block has been cooked during the rebuild. could i have put the head gasket on upside down? It is the steel shim type. what could be causing the lack of oil? Also is there any way to probe the pedestal hole?

    thank You

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    Yoda Geo Hahn's Avatar
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    Re: Tr3A Oil Priming

    The original style gaskets could be installed either way -- they were drilled for the oil passage in both corners. Don't know about the steel shim version.

    But a more likely issue may be the position of the rear cam bearing which, as I recall, has a hole that must line up with the oil passage. Do you recall attending to that during assembly?

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    Re: Tr3A Oil Priming

    To use you spinner without the distributor mounted, it is likely opening the oil gallery below the distributor, so you will get flow, but never get any pressure or altitude.
    John

    1955 TR2

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    Re: Tr3A Oil Priming

    The oil flow to the head is "metered" by the camshaft. Most likely it will start flowing once you are spinning the engine.

    It is possible that the rear cam bearing is installed wrong; it is the only one of the 3 that has a front and back even though all the inserts are identical. But I don't see any way to check, short of pulling the camshaft out.

    You can remove the pedestal from the rocker shaft and look through the passage. But the shaft has to be oriented correctly or the screw wouldn't go in. Be sure to clean thoroughly and use a drop of Loctite on the screw, they have been known to back out.

    To check the passage through the head, remove the plug at the LR corner. Put a piece of wire down through the hole under the pedestal, then another through the hole under the plug. If they touch, that part of the passage is open. To check the third leg, you'll have to pull the head and poke a wire from the head gasket side, then look down the hole to see it.
    Randall
    56 TR3 TS13571L once and future daily driver
    71 Stag LE1473L waiting engine rebuild
    71-72-73 Stag LE2013LBW waiting OD gearbox rebuild

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    Re: Tr3A Oil Priming

    Quote Originally Posted by TR3driver View Post
    The oil flow to the head is "metered" by the camshaft. Most likely it will start flowing once you are spinning the engine.

    It is possible that the rear cam bearing is installed wrong; it is the only one of the 3 that has a front and back even though all the inserts are identical. But I don't see any way to check, short of pulling the camshaft out.
    Yes, that's why I'd vote to crank the engine now that the main bearings have been primed up - with the cam moving you should see some oil come up. If not, it would mean some tricky checking to see if that bearing is in properly - especially if the engine is in the car.
    Randy
    70 TR6 - running
    59 TR3A - slumbering
    64 TR4 - got another one!

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    Re: Tr3A Oil Priming

    Quote Originally Posted by Geo Hahn View Post
    The original style gaskets could be installed either way -- they were drilled for the oil passage in both corners. Don't know about the steel shim version.
    Actually, I believe the TR2 workshop manual shows a gasket with only one oil hole, and talks about how it has to be installed the right way. But I agree, I've never seen one that lacks the duplicate hole (so it can be installed either way), including the "shim steel" gaskets I got from BFE.
    Randall
    56 TR3 TS13571L once and future daily driver
    71 Stag LE1473L waiting engine rebuild
    71-72-73 Stag LE2013LBW waiting OD gearbox rebuild

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    Re: Tr3A Oil Priming

    ok so very very valuable input! Thank you all! My first step was to determine if the head passage was open, it is. next i was forced to pull the head and wired check the hole down the block and into the cam bearing, that was also clear. while turning the oil pump and removing the rear most galley oil plug I saw that there was in fact oil to the back of the galley. now i had to pull the cam out. so its out and i do believe that my cam bearings is either installed wrong by my machinist, or possibly manf. wrong. in the rear most bearing there is a hole to the head, a hole for the set screw, a hole to the main bearings, but there is NO hole from the oil galley to the cam bearing!! is it possible to instal the bearings out of sequence? I saw that Randall noted the rear bearing is the only dirrectional one of the 3 inserts.

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    Re: Tr3A Oil Priming

    Not sure this helps, but a while back I took some pictures of the bearing install operation - the bearing shells I don't think would be out of sequence but I think it is possible to install them and potentially block a hole.
    https://www.britishcarforum.com/bcf/...earing+install
    Randy
    70 TR6 - running
    59 TR3A - slumbering
    64 TR4 - got another one!

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    Re: Tr3A Oil Priming

    ok just to clarify. can someone tell me route the oil takes through the engine. Does oil travel from the pump into the galley, then into the center cam bearing. then down to the crank. it then travels up to the other cam bearings from the mains. then to the head via the rear most bearing and finally back down to the pan by gravity? If that is the proper sequence then i have had that backwards in my head!

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    Re: Tr3A Oil Priming

    I believe there is a direct passage from the gallery to the main bearing, plus another passage from the gallery to the camshaft. Don't recall the exact configuration offhand, whether the two passages tee together or each connects to the gallery directly; but the oil to the main does not go through the cam bearing at all.

    Otherwise, your description is correct. The oil to the rocker shaft flows "through" the rear cam bearing, carried from the inlet hole to the outlet hole by the action of the cam turning and the grooves in the cam journal. Thus the flow to the head is very limited and has almost no pressure at all. I believe this was a deliberate design feature, to limit the amount of oil on top of the head.

    Some folks like to install a bypass line that supplies full gallery pressure to the head, but IMO it results in way too much oil up there. I make it a habit to start the engine with the cover off after adjusting the valves, to double-check that the rockers are getting oiled. When I tried that with the bypass line installed, it literally painted the hood with oil! (I only tried the bypass line on that engine because someone apparently installed the rear bearing wrong and there was no oil flow to the head. The cure proved to be worse than the disease )
    Randall
    56 TR3 TS13571L once and future daily driver
    71 Stag LE1473L waiting engine rebuild
    71-72-73 Stag LE2013LBW waiting OD gearbox rebuild

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    Re: Tr3A Oil Priming

    Thank You! I believe that I now understand It. So the oil to the front two and the rear cam bearings is supplied from the mains not the gallery! Now i have to try to prime it with the cam out whilst turning the crank. seeing if oil surfaces at the front 2 and rear bearings!

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    Re: Tr3A Oil Priming

    Tried priming and oil is now to all of the bearings! I suppose the lesson learned is to rotate the engine whilst priming. Also to prime, if at all possible, before installation of the cam!

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