tr4 TR4 to TR4A matching

[RobG]

Hi all,

 

This is a TR4 Clutch conundrum

My problem and question is about a mix of TR4 and TR4A parts.

Some history: I purchased FML604B, a TR4 1964 UK 2 owner car in Summer 2014, complete with late 1980's set of heritage body panels.

Most outside panels are still in original patina Conifer Green, wire wheels and overdrive, I have the heritage certificate to confirm the build.
I have spent the last year building up the body tub from basically a front bulkhead and a rear deck.
This has gone smoothly, brilliant panel fits, chassis was rock solid with no bends or welds so used as a good jig.
But, as the car was purchased in a thousand pieces, I have now sorted through the numerous boxes to realise I have two sets of engine parts. The engine block is CT64863E so is a TR4A engine block, I have duplicate most other parts so I guess the original block (CT31915E) is no more, cracked or blew up. The two previous owners sadly cannot help, no need for further details here.

So what can I mix and match ?

I have assembled the best parts for the engine and it turns over with 50lb psi at churning speed.
But do I have a TR4 or TR4a cylinder head, my parts books imply same part number, is this true?
The SU carbs and manifold fit, so far so good.

But the Flywheel seems to be a problem area. it came with 2 flywheels and one clutch, the clutch matches the TR4 gearbox and I was able to get the TR4 flywheel on the TR4A block ok.
As they have different dowel pins on TR4A clutch, I used the TR4 flywheel, thus we come to my main question.

Is it ok to match a TR4 flywheel and gearbox to a TR4A engine block ?

And if I may waffle on a bit longer, are there any other differences which will bite me in the butt later ?

Any help would be most appreciated, it's like a mega meccano kit, great jigsaw with lots of puzzles.
My other TR projects were all complete cars, so this a new area for me.

Rob

 

[MichaelH]

Most 4cylinder engine parts are interchangeable

Some parts are matched as in your 4 flywheel and clutch but with good engineering the 4 flywheel can be drilled to take a 4A clutch

Rest assured it really is a box of meccano and Triumph engineered it really well

The evolution from low port 1993 cc TR2 to the last TR4A is gradual and all the in engine bits will fit

The later engine bits tend to be stronger and the last cam shaft is a very good standard road camshaft

the engine will run on SUs or strombergs and any TR gearbox will fit

Hope this helps

By the way: there lots of forumits who will give their opinions so you can get a general view

Michael

[ctc77965o]

Yes, TR4 clutch cover, flywheel and release mech will fit TR4a engine.

 

As michael said, use the TR4A engine parts for marginally better performance...choose the head that fits your manifold and the carbs for which you have the linkage.

 

Tr4A engine has different crankcase breather arrangement .

[RogerH]

If you are considering fitting a TR4 clutch cover then ensure you are using the TR4 flywheel - the attachment holes will align.

You can fit a 4A cover to a TR4 flywheel but you need to re-position the attachment holes.

 

Roger

[RAHTR4]

Hi Rob,

 

When the TR4 went into production it was fitted with a cylinder head that was stamped 510084.

 

At engine number CT21471 a revised cylinder head was introduced - 511695, stamped on a raised plinth at front offside corner - this was the last development of the cylinder head which was used until the end of TR4A production.

 

Thus the 511695 is the best developed cylinder head and for best results should be used with either of the later types of inlet manifold - 305744 or 307455, these part numbers are always cast into the underside of the connecting balance pipe.

 

To follow on from that I understand it to be best practice to use the later TR4A exhaust manifold, a TR4A twin down pipe, TR4A front "Y" pipe, which then mates into the remainder of a standard TR4 system.

 

However, this is all based upon the assumption that you have rebuilt your engine to standard specification.

 

Regards, Richard

[Fireman049]

I fitted the 511695 lead free cylinder head to my 3A. Highly recommended.

 

Tom.

[RobG]

Thanks all for the replies so far, very useful and reassuring.

Yes I do have 511695 cylinder head so all seems good so far.

This phase is just trial fit to see how complete the engine is and what state it is in.

I will be rebuilding from scratch at a later date, regrinds and liners to look at.

 

Regards,

 

Rob

[F1loco]

Just be sure depending on the manifold set up you use (i.e., TR4A) you will need to vent that pressure....be sure the original vent tube block is in place. It is a PITA to get out once the engine is in... I know ... the '64 I bought was a bit mixed up and couldn't figure out why oil was blowing out every nook and cranny... Once I installed the vent tube, all is well.

[RobG]

Just want to check something, if you remember this car was totally dismantled and came with no battery and no cables.

I have a modern battery to fit where the +ve terminal is larger than the -ve, but I want to keep to the original spec.

The car still has a dynamo, so I am assuming, checking my workshop manuals and parts manuals that a TR4 was originally +ve earth.

I will for now be keeping the dynamo, can I assume therefore that it was not converted to -ve earth at any time, eg for a radio, if it still has the dynamo ?

Or if it was, is there anyway I can tell ?

 

I plan to wire it up as a positive earth system, any issues I need to know about please ?

Starter motor turns in the correct direction :-)

 

Thanks,

 

Rob

Edited February 24, 2016 by RobG

[Lebro]

Dynamos' are polarity insensitive, so in the past it could easily have been changed from +ve to -ve earth.

 

To change over:

 

1. Reverse battery terminals

2. Reverse ammeter terminals

3. "Flash" the dynamo (that means momentarily connect the field terminal to battery (non earth side))

 

all other items - starter motor, wiper motor, heater motor will all rotate in the original direction regardless of polarity.

If any electronic items have been fitted, then they will have a problem.

 

Job done.

 

Bob.

Edited February 24, 2016 by Lebro

[RobG]

Lebro,

Ok so maybe easier just to switch over to -ve earth, sounds easy.

But what about the voltage stabiliser, is that ok, Revington say to use a different 128484A for -ve earth, rather than 128484, will my old one be ok in the swop over ?

 

Rob

[RobH]

An original bimetallic type regulator will be fine on either polarity. If you have fitted a modern 'electronic' replacement you will have to swap it for the right one.

[RobG]

RobH,

No problem there, this TR4 came off the road in 1981 and was stripped and carefully stored, in a large number of cardboard boxes, so new modern parts at all.

I am also a 'technofobe' (sp) so I prefer as original as possible.

Most parts I am refurbishing and replaciing so it will still look and feel like it did in 1981.

I am only buying new when parts are missing or broken.

The voltage stabliser is crusty, rusty and tired bit I am hoping it will still work.

I know many of you on here would rather just replace all with new parts, but that is not the way I am doing this restoration, apologies up front.

 

RobG

[stillp]

RobG, that's the way to do it! Can't see the fun in buying new bits when you can spend for more time and nearly as much money refurbing the old.

 

Pete

[RobG]

Hi, a couple of members have asked how my TR4 rebuild is coming along. Good progress, so here is an update.

 

Lots of progress since my last postings. Body tub is now complete and fits really well on chassis.

Engine is in and running and gearbox and clutch and drivetrain all in and works. Can run in and out of garage but with no steering or brakes is a bit scary. Currently working on fitting wiring loom and dashboard so I can put the steering column in.

As you can see I am on an up phase and enthusiastic, better than September last year.

Have all the rest in boxes to refurb and replace, let's hope for a good summer.

 

If you in the Brighton area you are always welcome to come and have a look, some recent pictures attached.

 

Best Regards,

 

Rob Grant

 

[peejay4A]

It looks like you have a 4A rocker cover. Do you have the snorkel crankcase vent next to the fuel pump or is it blanked off as per 4A? If it's blanked then you'll need the PCV from a 4A. You already have the 4A inlet manifold with a vacuum takeoff for the PCV. Either that or you'll need to come up with another means of crankcase venting.

 

I like the gear knob.

Edited March 27, 2017 by peejay4A

[RobG]

Hi Pete, it is 4A block so is blanked off.

Yep, I have a pipe on the inlet manifold, can just be seen with a blanked off bit of hose for now, so I will be fitting a PCV as suggested.

 

True, old chest of drawers knob fitted well, maybe replace one day, maybe not, quite cute, bet not a common option.

 

Thanks

Edited March 27, 2017 by RobG

[Paul J]

Rob I shared your belief in repairing the original parts rather than replace when rebuilding my 4A, not a good idea when it comes to brake and clutch cylinders though. Having stripped and cleaned my masters and slaves I rebuilt with seal kits, the cylinders all looked in a good condition, I have now had to replace all slaves and the clutch master, the brake master also now needs renewing, the seal kits are not of a good quality and should be avoided.

Your 4 is looking good, I'm now on the road with a big grin but at a loss with what to do. Even contemplating some gardening!

Cheers

Paul

[RobG]

Paul J

 

Thanks for reply, My original Girling cylinders were too far gone so I am replacing all with new ones. Clutch master can be seen in engine picture.

I will keep the old ones just in case next owner wants to refurb them.

 

Must admit I would have a lot of time on my hands if I was not restoring this TR4.

 

RobG

[ianc]

Adding to Lebro's notes on changing polarity, be aware that the coil must be considered, too.

 

According to Tony Tranter in Haynes "Automobile Electrical Manual", ignition systems are designed to have negative polarity at the centre electrode and if reversed can be up to 40% less efficient.

Coils for both Positive and Negative earth vehicles were produced, but who knows if anyone has changed a coil for the wrong type in the history of older vehicles, so it is wise to check polarity of the spark (see below for testing polarity using a lead pencil).

With early coils, swapping the CB and SW leads will switch polarity of the spark. Later coils use + and - but the requirements are the same.

To test the spark direction with a lead pencil, interpose the writing tip of a lead pencil between the spark plug top stud and the HT lead, leaving a small gap either side of the pencil tip. If the polarity is correct, a flare between the pencil and the spark plug will be seen (if the flare is between the pencil tip and the HT lead, then the polarity is reversed).

Since all modern vehicles use a negative earth system, almost all replacement coils will expect the vehicle to be negative earth. Almost all in-car entertainment systems are designed for negative earth, as are almost all in-car electronic devices.

There may be validity in keeping a positive ground in an older vehicle for the sake of authenticity, but if it has any modifications, switching to negative earth is to be recommended highly.

 

Ian Cornish

[BlueTR3A-5EKT]

Back to the clutch/flywheel.

1.

TR4 has a spring type clutch that has 3 fingers for the FLAT faced release bearing to contact.

TR4A has a diaphragm clutch that has multiple fingers for the DOME faced release bearing to contact.

2.

The TR4 uses a release bearing carrier (the brassy thing the bearing is fitted to) that is shorter than the TR4A item.

I will measure and post lengths in required.

 

Peter W

[RobG]

Peter W

 

Wow now you got me worried.

I did not realise the release bearing was different.

It's in and working so I cannot check it, I think it was flat.

I had a box of bits of both a TR4 engine/gearbox and a TR4A block.

So I assumed I could fit my TR4 gearbox and clutch to a 4A block, using the TR4 flywheel, I had both but only TR4 flywheel fitted the clutch locating bolts.

Not ideal I know but that was the cards I was dealt.

 

Is the fact that it all works ok mean I am in the clear ?

 

RobG

[ChrisR-4A]

Hi Rob, do youself a favour and dont fit a pcv valve, they were inefficient at best and unreliable and unnecessary if you fit the tr4 snorkel to the crankcase and a vent tube to the rocker cover.The pcv was introduced to aid emmisions at the detriment of screwing up the mixture as the engine is forced to eat its own crap.

Regards Chris

[RobG]

Potts4A,

 

I can't fit the snorkel as the hole in the block is plugged as it is a TR4A block.

Have you another way to fit the snorkel ?

I recently fitted a small crankcase breather to my sons motorbike, I may do that, looks nice in red.

 

RobG

[stuart]

Potts4A,

 

I can't fit the snorkel as the hole in the block is plugged as it is a TR4A block.

Have you another way to fit the snorkel ?

I recently fitted a small crankcase breather to my sons motorbike, I may do that, looks nice in red.

 

RobG

You can remove the plug and retro fit a breather tube.

Stuart.