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TR4/4A TR4 Engine Rebuild Qs from a newb

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cornfed

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My engine (removed from '67 TR4A, going in to '65 Morgan +4) is completely disassembled and in the capable hands of my local machine shop. The machinist will clean, inspect, and measure everything. They will give a shopping list of what I need to buy as their suppliers don't dabble with Triumph parts.

A complete rebuild is in order because the car sat for 30 years. I soaked the cylinders with Kroil for a week which freed two of the piston rings from the cylinders, but the other two stayed put and fell out attached to the slugs.

The emphasis for this build is reliability- not maximum/race performance. I intend to convert to pump gas, electric ignition, and maybe a different camshaft within the limits of stock valve springs.

The question I'm getting to is what advice can the group offer as far as reputable brands to source and general 'things' to avoid? I've checked out a few vendor websites but I won't contact them until I get my complete list (which will probably be everything under the sun).
 
Welcome-

I'm not an experienced rebuilder but I just went through this the past year and have gleaned I think some reasonable information.

For bearings, King tri-metal are very good, considered best option to original Vandervells which aren't around easily anymore.
For pistons/sleeves, I went with Mahle but I've seen many comments that the generic County brand pistons work fine for a decent road engine.
One area to watch out for is lifters - many tales of woe there. I went with the performance ones with the drilled holes, but I had a hardness test performed on all of them before they went in the build.

Thats some initial thoughts anyway

Randy
 
I've heard good things in the recent past about the lifters from BPNW. Greg Solow (The Engine Room) is another good source of both lifters and Morgan +4 wisdom.

IMO replacing the valve springs is a must. They lose tension over time, which can lead to valve float, burned valves, etc. At the very least, have your shop test the installed seat pressure. Check whether the new spring set requires spacers under them. Last time I checked, some did and some did not.
 
Aloha Cornfed,

If you are considering changing the rear main seal, there are a few options available. You can replace or reuse the original scroll seal, buy original aluminum seal halves that have been machined to accept a vitron split lip seal (a relatively new option), or machine the crank shaft scroll and install a split lip seal. If you choose the machine the crank shaft route, make sure you thoroughly research the necessary dimension for this job. Some of the instructions that come with the kit have wrong dimensions listed and may result in too much material being removed from the crank shaft. A search of the site and others for "TR3 rear oil seal" should provide you with a lot of reading.

Good luck. I'm in the process of rebuilding a TR3 engine.
 
MGTF1250Dave said:
or machine the crank shaft scroll and install a split lip seal.
Click to expand...
Given how many crankshafts have been ruined, and how many of those seals leak even worse than the worn-out original, I would not even consider that option!

The factory seal actually works pretty good if you use a road draft tube AND set the seal correctly. The numbers in the factory books are wrong (as are the tools sold by some vendors).

Which reminds me, I need to get off my duff and send my old seal into Joe A to be machined for Chris' trick Viton seal.
 

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Randall,

TRF has a "corrected" mandrel and the parts needed. These are made by ARE so I suspect Joe also offers the the mandrel if you need one. I should be installing mine in the next few weeks, I need a few more engine parts before I start.
 
Thanks for the feedback. Modifying the rear main seal hadn't crossed my mind. I'll just replace what's there and hope for the best. If the car doesn't drip oil, how will I know when the pan is empty?

What's the rule on rocker arms- can they be resurfaced? The lifters weren't dished/grooved out, and the rocker arm tips aren't flat.
 
MGTF1250Dave said:
These are made by ARE so I suspect Joe also offers the the mandrel if you need one.
Click to expand...
Yes, he does. What TRF doesn't offer, AFAIK, is the service to machine your old seal housing to accept the Viton seal. Saves a few bux.
 
cornfed said:
What's the rule on rocker arms- can they be resurfaced?
Click to expand...
Sure. If the tips are in need of attention, chances are that the bushings need it too, and the shaft needs to be replaced. I found it easier and cheaper overall to just send the assembly off to

Rocker Arm Specialist
19841 Hirsch Court
Anderson, CA 96007
Tel (530) 378-1075
fax (530) 378-1177
https://www.rockerarms.com/
mailto:rocker@c-zone.net

Their web site is flat atrocious and doesn't even really mention their rebuilding service. But the work was top-notch, and the cost even with shipping about the same I would have paid for the parts required.
 
cornfed said:
Thanks for the feedback. Modifying the rear main seal hadn't crossed my mind. I'll just replace what's there and hope for the best. If the car doesn't drip oil, how will I know when the pan is empty?
Click to expand...
If you use the original setup, there is nothing to replace. But, if the machine shop removes the aluminum seal halves from the block and bearing cap, then they need to be re aligned with the mandrel tool (see Randall's post above) so it has the proper clearances from the crank. Otherwise it will leak far worse than it should.
 
Welcome, if you are going to replace the pistons and liners you might aw well go with the overbore 87mm (I think there are some bigger sizes as well) Sounds like you want more grunt without sacrificing reliablity/driveability. The bigger pistons will give you more grunt, no real downside.

I would also consider a lightened flywheel *having it lightened is pretty inexpensive), once again, no real downside if moderate weight reduction.
 
I rebuilt my TR3A engine last year. Went with Mahle pistons and liners (very well made, very expensive), Had the head rebuilt with new valve springs, bronze valve guides ( reemed to fit)hardened valve seats and stainless exhaust valves.
Also went with a fast road cam and a header. Eventually everything went together and works very well and I am very happy with my engine. I did find two problem areas in my rebuild. First the cam bearings available today are all made in India. They look poorly made and I have been told by people who rebuild these engines, and sell the parts, that they are terrible. But that's all that's available, and they do work. If you can find better ones go for it. Secondly new oil pumps are available, also made in India. IMO they are garbage. I installed one that looked shoddy, but it was new and the original one was 50 years old. It failed two minutes into my running in the cam (no damage). I replaced it with the original, 50 year old oil pump, which has never missed a beat. Again if you can find a better built, or rebuilt, oil pump go for it. One other tip, find a local machine shop you can trust and use them. Oh, one last thing, it is possible to install the cam on a TR3 engine 180 degrees out of sync, which makes starting the car impossible, but interesting. Good luck.
 
If you decide to re-use the old oil pump you can get usually do a little work on the end float by taking some fine sandpaper and on a
VERY smooth surface and getting the vertical fit a little tighter (a manual will have specs) I and other LBC guys I know have done this and gotten a pump that performs like new (factory new, not india new) work slowly and carefully, you will probably be taking off a few thousands of and inch at most.

I think some of the workshop manuals describe this procedure.

edit: You will of course need to clean everything off well afterwards, because you don't want metal dust in your new motor.
 
glemon said:
The bigger pistons will give you more grunt, no real downside.
Click to expand...
Except possibly a bit more chance of cooling problems. The extra displacement burns more fuel even when cruising, which means more heat to get rid of.
 
Banjo said:
If you use the original setup, there is nothing to replace.
Click to expand...
I think that is one of those "it depends" things. Although the design is intended to be non-contact (meaning no wear), worn main bearings can allow the crank to contact the seal and wear it. That's why ARE also faces off the halves and rebores them to round.
 
Aloha Randall,

TRF doesn't offer the machining, but there is a $25 core charge credit if you return your old aluminum seal halves to them. They even provided me with a self addressed jiffy bag for that purpose.
 
Thanks, Dave, I did not know that.
 
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