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TR6 TR6 engine rebuild suggestions

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ichthos

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Hello,
I am currently getting ready for an engine rebuild for my 69 TR6. I burned a valve, and then had the head rebuilt. I also rebuilt the rocker assembly. I also had the carbs rebuilt professionally. None of these items were reinstalled on the engine. I had planned on just do a ring job, but I found there is enough wear between cylinders that a ring job would be a marginal solution at best. I have decided that I want to invest the money to do a proper rebuild. I want my engine to remain stock. I was given a couple of good rebuilders from the forum last summer, but what I need help on is what services should I be asking for when I go to a shop, and what should I be expecting for this service in the way of costs? I always feel uncomfortable going to a shop, because I am not totally sure of what I should be asking for. A list of things I should be asking for would greatly be appreciated.
Kevin
 
The way I've dealt with a machine shop that I trusted was to bring everyhing in to them and ask them what needs to be done. They'll take measurements. do calculations and compare the results to specs and give you their evaluation of the situation.
Yeah you'll have to know what they are talking about, but having them tell you what they recommend along with your input as to how you are going to use the car (ie do you want a race engine ?) makes for a good relationship and mutual understanding of your expectations.
That's about all I can offer, I know it's not the list you requested, but more of an attitude when dealing with a competent professional.
 
To add to Ken's comments...

If you don't know what they are talking about, tell them. A good machine shop will educate you and not degrade you for needing to be educated on the subject. It is well beyond the average home mechanic sometimes. My first trip to a machine shop I asked a lot of questions which were thoroughly answered. You don't know what you don't know so don't be bashful about asking questions. They won't think your stupid, in fact, they might think your smart by wanting to educate yourself.

If you find yourself being told they don't have time to answer your questions, ask if there is a better time to come back when they can answer them. If they say no, find another machine shop.

The list,if you already have a rebuilt head then you are dealing with what is called a "short block" which is just another way of saying everything below the head.

This list would be based on your having had disassembled the short block and you reassembling it as well.

Cleaning (hot tanking all the parts and flushing the block)
Magnafluxing the crank and the block are not bad ideas.
Otherwise.
Bore/hone the cylinders
Align Bore the crankshaft main bearing carriers
Machine the crank (main and rod journals)
Rod truing (checking for twist in the rods and resizing the rods big ends)
Balancing (crank, rods, flywheel, piston heads and clutch are all part of that process)
You'll also want them to check the bore of the camshaft journals and compare it to the main journals on the camshaft. If they are in spec you can get away without camshaft bushings. Otherwise, they would need to line bore the block for camshaft bushings.

There is a small list. But like I said above. Just ask and they should be more than willing to teach/explain the process. If your still confused. either ask again or come back and ask here.
 
poolboy said:
bring everyhing in to them and ask them what needs to be done.
Click to expand...
:iagree:
There is a wide range of what "should" be done, depending on your goals, the condition of each specific machined surface, and of course your pocketbook. There can easily be a 10:1 range in price (or more), depending on whether you want/need a simple rebore or a full blueprinting (with cam bearings, etc.).
 
I forgot to mention that one of the lifter surfaces was pitted. I can't see any damage to the cam on the camshaft, which suprised me, but wouldn't it be likely this would have to be replaced, or is this something that can be machined? Also, how much more do you think it would be to have them put the entire engine together? I have way too many projects rigth now. I am restoring a Bugeye sprite, which will keep me busy for a few months yet. I am hoping to have the TR6 driveable by the end of August.
Kevin
 
The pits are caused when bits of metal actually break away from the lifter. YOu should probably just replace the lifter, but it might be saved by grinding it down and rehardening. I hear RAS does good work on Triumph lifters (send them the whole set), but I've not tried them myself, yet.

The cam may or may not be OK, only way to tell is to measure lift at each lobe. Then of course you have to decide how much wear you can live with, which gets back to the intentions and finance thing.

Not sure what they would charge to assemble for you, but with machine shop charges running $70-100/hour or more, it could easily be a few thousand.

"Blueprinting" means somewhat different things in different contexts. But I believe it comes from stock car racing, where it refers to the practice of taking every single parameter or tolerance, and making sure it is at the most desirable end of the allowed range. For example, if the rules allow for compression ratio of 8 to 1 +/- one point (tenth); you go through every cylinder and make sure it is exactly 8.1. For a street motor there aren't particularly any rules, so you just optimize all the parameters (eg decide you want 9.0 and then make sure each cylinder is 9.0).

Lotta work, and while it certainly does add to engine life and efficiency, it also adds a lot to cost.
 
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