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Thread: Rebuilding the Engine--a few practice pointers (for me)

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    Luke Skywalker KVH's Avatar
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    Rebuilding the Engine--a few practice pointers (for me)

    I'm concerned I may have forgotten some of the important considerations, techniques, etc. so here are some warm-up questions before I get deep into my TR4 engine rebuild:

    1) Is there a great trick to lifting my freshly "boiled" block out of my truck and getting it back on my engine stand? For example, should I attach the stand's attachment bracket to the engine first and then mate the engine and bracket to the stand?

    2) Since the block is out, would it be silly not to replace the freeze plugs including at the camshaft rear, or is that asking for trouble?

    3) Do I replace cam bearings as a matter of course--which I guess requires that the rear plug come out?

    4) I have a stack of thrust washers and no recollection of what size I ordered. Obviously, I can mic them. I'm forgetting which way they go in, and as I recall I can lightly sand them to achieve spec for the crankshaft end float. Is there any special advise with regard to thrust washers?

    5) My crank bearings (main and rod) are .010 meaning the crank has been worked on in the past. If my shop polishes up the crank journals and main bearing journals must the journals, after the work is done, be exactly .010 under-size or exactly .020 under-size or is there some acceptable variance? Also, could the mains be .010 and the rod journals .020? I hope I'm not showing too much ignorance. I'm trying to get ready for the confusion.

    6) Can I just reuse my oil pump? I can't recall learning of a bad one.

    7) What is the purpose of the gasket between the oil pump and block casting?

    Thank you for any help.

  2. #2
    Great Pumpkin TR3driver's Avatar
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    Re: Rebuilding the Engine--a few practice pointers (for me)

    1) I don't know of any. I just picked it up with the hoist and wheeled the stand up to it then put the bolts in.

    2) If it was "boiled", I don't think you have any choice.

    3) I would, unless you know for a fact that they aren't worn (and not damaged by boiling). Yes, that means the plug comes out.

    4) The face with the oil groove (which is also the soft face) goes against the crank cheek. The crank moves, the inserts do not.

    5) Yes, there are tolerances in the book; but the range is only .0005" (about 1/10 the thickness of a human hair). You'll need a micrometer to check.
    Yes, the mains and rods can be different sizes. It's best to leave as much "meat" as possible, so don't have them "turned" if they don't have to be.

    6) Probably. The book gives the things to measure, and what the limits are. I have seen them both worn out, and broken. (Check the outer rotor for cracks, while trying to spread it apart with your fingers.)

    7) To stop oil from leaking out. Any oil that leaks at that joint is less oil to be fed to the bearings and so on. Possibly not a big deal if it did leak a little, but some engineer felt it should be there.

    One way to help control the confusion is to print out the relevant pages from the shop manual, then mark each step with any notes you want to keep, check when it's completely done and so on. https://drive.google.com/open?id=0B2...YzNmI3OTg2ODM0

    This is a good read, even though some of the things are mostly race engine oriented. Just ignore the bits about Accusumps, GT40 lifters etc.
    http://www.tonydrews.com/uncle_jacks...lding_tips.htm

    PS, your micrometer should come with a gauge block, and often a tool for adjusting it. Let them both sit at the same temperature as the crankshaft will be, then check and if necessary adjust the micrometer before use. Hold it only by the plastic grips, to avoid warming it from your hands.
    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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    Yoda tomshobby's Avatar
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    Re: Rebuilding the Engine--a few practice pointers (for me)

    Quote Originally Posted by TR3driver View Post
    1)
    PS, your micrometer should come with a gauge block, and often a tool for adjusting it. Let them both sit at the same temperature as the crankshaft will be, then check and if necessary adjust the micrometer before use. Hold it only by the plastic grips, to avoid warming it from your hands.
    WTG Randall! Just because your mic or caliper has all those little numbers does not mean either you or the tool you are using has the capability to measure to that dimension. Calipers are especially unreliable.
    Tom
    76 TR6
    74 Midget
    www.madbrits.org/
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    Obi Wan Sarastro's Avatar
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    Re: Rebuilding the Engine--a few practice pointers (for me)

    I agree with Randall's comments, but I might add a little.

    The two tricky things are the valve timing and cylinder protrusion. We've discussed both here quite a bit. We can discuss them more when you get to that point.

    I've always found it easier to attach the mounting bracket first, then put the engine on the stand. But there are no rules; do whatever seems easiest.

    If you don't have a good set of micrometers, you probably should get the crank reground. Although I haven't dealt with a lot of them, all I've seen have been out of spec by time the engine needs a rebuild, even when they looked pretty good.

    Some time ago, I got a set of medium-quality micrometers on eBay for about $150. One of the best purchases I ever made. If you work on cars a lot, you'll eventually buy a set, so this might be a good time. Avoid the cheapo ones from Harbor Fright and similar places.

    Replacing cam bearings is a royal pain, but I think it has to be done. It's hard to measure them, as a bore gauge can scratch the surface. The big installation problem is that they are not keyed in any way; you have to line them up by eyeball and press/pull them into place. Also, it is extraordinarily easy to get them installed wrong, and then the oil passages to the cam bearings are blocked. Finally, you'll need some kind of tool to hold the bearing square to the opening as it's pressed or pulled into place.

    That camshaft plug fits tightly and, properly installed, is not likely to leak. Installing the bearings and dealing with the camshaft is much easier if you remove it. I don't know how you'd get the rearmost cam bearing installed with it in place.

    Even if the block has been boiled out, make sure that all the oil passages are clean and open. Running a pipe cleaner wet with solvent is one way to do that. For larger passages, you can just fold the pipe cleaner over. Same story for the crank; when it's reground, crud can be left in the oil passages.

    You can get new internals for the oil pump for less than $30, so if there is any question, it's good to replace them. You can make the shop-manual measurements with a feeler gauge, so it's not hard to check. I too wondered about that gasket, but since it was provided, I installed it. Seems unlikely, though, that you'd get any serious leakage through that wide, close-fitting joint.

    Here is a summary of my experience with two TR engines. I don't claim that it's the absolute best way to go, but still there might be helpful info:

    http://www.nonlintec.com/tr4a/engine/

    http://www.nonlintec.com/tr4a/engine2/
    Steve Maas
    1966 Triumph TR4A, undergoing restoration: http://www.nonlintec.com/tr4a
    1952 MG TD, restoration completed 2014, sold 2016: http://www.nonlintec.com/mgtd
    1960 Austin-Healey "Bugeye" Sprite, sold 2010: http://www.nonlintec.com/sprite
    1967 Porsche 912: http://www.nonlintec.com/porsche

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    Great Pumpkin TR3driver's Avatar
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    Re: Rebuilding the Engine--a few practice pointers (for me)

    Skimming Steve's article reminded me of something that might help. This trick helps keep the oil pump screen from breaking at the solder blob.
    https://drive.google.com/open?id=0B2...G9HMFlrYXV0ZjQ
    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: Rebuilding the Engine--a few practice pointers (for me)

    Make sure you, CLEAN OUT ALL THE OIL GALLEYS. My block came back from the machine shop "cleaned". Well there was metal material in the oil galley back by the flywheel. The suction pulled it out and thru the motor. I had to do a tear down with a new crank and cam. I learned to remove all plugs and never trust when they say it is clean. All in all it was my fault and a good learning experience.
    Dan
    TS37148L Restored and running! Again!
    TS23575L gone, but found in a wharehouse
    TS23351L Donor parts for TS37148L
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    Obi Wan M_Pied_Lourd's Avatar
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    Re: Rebuilding the Engine--a few practice pointers (for me)

    You might want to consider side mounting your engine block to the stand for easier access to the rear of the block.

    Cheers
    Tush
    81 Alfa Romeo Spider Veloce, 81 Triumph TR8
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    Darth Vader
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    Re: Rebuilding the Engine--a few practice pointers (for me)

    I believe one of the difficult areas is the rear main seal. On this last engine, I purchased a Mad Max seal, but some of guys have had good luck/skill putting them in stock.

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    Great Pumpkin TR3driver's Avatar
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    Re: Rebuilding the Engine--a few practice pointers (for me)

    Quote Originally Posted by sp53 View Post
    I believe one of the difficult areas is the rear main seal. On this last engine, I purchased a Mad Max seal, but some of guys have had good luck/skill putting them in stock.
    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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    Luke Skywalker KVH's Avatar
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    Re: Rebuilding the Engine--a few practice pointers (for me)

    Very helpful guys. I did spend some time reading and thinking all this through, though some of those rebuild notes require more time.

    I'm wondering, can you knock out the old cylinder liners while the engine is on the stand or is that bad given the physics of it all?

    Also, in Steve's pics i can't figure out what I'm looking at in a few pics where I see a dial gauge attached to what appears to be a long rod? What is that? It appears to be in the cam-bearing discussion and associated pics.

    I guess it's wrong to not replace the small end bushings in the connecting rods, right?

    Is it just as wrong to replace the rods without rebalancing them?

    I worry about those rods. Am I correct that if anything happens to those rods, it's hard to find decent replacements, and that even then they can't safely be mated to the crank?

    I'm still trying to understand the grinding and bearing size issues. Let's say, hypothetically, that my crank journals are .002 undersize due to wear, age and use. Sloppy in other words. Does that mean that they must be ground to a minimum of .010 undersize? I can't imagine anything in between, since the oversize .010 bearing wouldn't work.

    Then, I assume the .010 bearing is already of a thickness designed to give the recommended clearance with an undersize .010 grind.

    Am I close here?

    Thanks all.

  11. #11
    Great Pumpkin TR3driver's Avatar
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    Re: Rebuilding the Engine--a few practice pointers (for me)

    Should be no problem knocking out liners on the stand. The block has plenty of mass to absorb the blows.

    Are these the photos you're asking about?



    That is a dial bore gauge, being used to check the main bearing bores in the cylinder block. Not a bad check to make, but I've never bothered.

    Rebushing and balancing the rods kind of falls into the same category. Probably a good idea (and I'm sure there are plenty who will tell you it's foolish not to); but I've never bothered with it. As long as the wrist pins (aka gudgeon pins) are a tight fit (and the engine didn't blow up before), the bushings are almost certainly fine. And they are already balanced as well as the factory bothered to do it (assuming you have all 4 original rods). You probably can do better, which should give a tiny reduction in vibration (but not much) and a tiny improvement in power output (again not much). But it will run fine without.

    Used original rods are easy to find, as they rarely go wrong. I've probably got 4 or 5 sets laying around; I'm sure Marv Gruber has them, and I think my Dad sold several sets to Ted Schumacher in Ohio (along with a ton of other old Triumph parts). They aren't matched to the crankshaft (although the rod caps are matched to the rod). If you mix and match, though, it becomes important to check that they are the same weight. The factory rods apparently varied quite a bit over time. It's also best to keep them numbered 1 through 4 if you can (or at least modify the markings on the duplicate rod/cap).

    I believe you can still get aftermarket forged rods as well, but they tend to be a bit pricey. (ISTR last price I heard was $1200/set.) The racers use these, as they are lighter and stronger than the stock rods, giving more power and less stress on the crankshaft at high rpm.

    I've also got a write-up somewhere on how to use Chevy rods (by modifying the crankshaft and using custom pistons). Probably not cost-effective though, unless you're having forged pistons made anyway.

    Yes, if the journals are worn below spec (or scored or damaged in any way), then you have them ground to the next .010" step. The clearances stay the same, so both crank and bearings are smaller by exactly .010", .020" or .030" (plus or minus the given tolerances).
    Randall
    56 TR3 TS13571L once and future daily driver
    71 Stag LE1473L waiting engine rebuild
    71-72-73 Stag LE2013LBW waiting OD gearbox rebuild

  12. #12
    Obi Wan Sarastro's Avatar
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    Re: Rebuilding the Engine--a few practice pointers (for me)

    Problem is, you don't really know what is necessary unless you can make some measurements. Often, for example, it's enough just to polish the crank journals, as long as the diameters are within spec. But if you can't measure it, your only option is to take the whole mess to the shop and have them deal with it. Then, probably you will be told that everything is necessary.

    I've found a good, inexpensive shop, so I have just let them do everything: grind the crank, restore the connecting rods, install new bushings, and balance the lot. The parts went together beautifully.
    Steve Maas
    1966 Triumph TR4A, undergoing restoration: http://www.nonlintec.com/tr4a
    1952 MG TD, restoration completed 2014, sold 2016: http://www.nonlintec.com/mgtd
    1960 Austin-Healey "Bugeye" Sprite, sold 2010: http://www.nonlintec.com/sprite
    1967 Porsche 912: http://www.nonlintec.com/porsche

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