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The 4A Engine Rebuild


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Hi Roger, why are you changing the crank, have I missed something. As its already done many miles it shouldn't be prone to breakage, but how well do you know the one you are proposing to use instead?

Chris

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Hi Chris,

it's madness I know.

The new crank is a prototype that the SDF are putting together with Moss bringing it all together. (Thank you Fergy TRactor)

 

It has been cast in India and machined in Birmingham and now needs testing.

 

In theory it will be equal to what ST did in the 50's, 60's at hopefully 25% to 33%% the cost of a billet steel crank.

 

I'm slightly nervous because if it goes bang it could get expensive.

 

Roger

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Hi Nick,

indeed it is a saw.

I have found in the past that getting the camshaft all the way through into the block can be awkward. So perhaps cutting the block in half may help :P

 

Roger

 

PS - not sure why it was there.

PPS - it's not a saw. It is a saw blade that I have converted into a knife.

Edited by RogerH
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Hi Folks,

good news this morning.

Before going too far with things I needed to make sure the new crank would fit in the block.

I had a problem though - do I buy a cheap (£30) set of main bearings and if all is well then buy an expensive set (£60).

Or do I buy an expensive set and panick if there are problems and the project binned.

 

I slept on the problem but woke up tired. So I had a think over a cuppa - bingo.

 

When I bought the 'other' new crank (Fergy TRactor crank) it came with main/big-end and thrust washers).

So I plopped in the main bearing shells, sorted out the thrust washers and stood back and admired what I had done.

I then attached the DTI and checked the end float. The Tolerance is 0.004" to 0.006" - the end float was 0.004". I couldn't make it any more - happy smile on face :)

 

This afternoon I will pop out and see what I can buy at what price. (I'm not good at haggling)

 

Roger

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Hi Folks,

Christmas budget blown :o

Just had to do it. I've got some nice shiny bits and pieces.

 

Perhaps the nicest is the Christian Marx rear oil seal. This is so gorgeous that I have decided to fit it on the front of the timing chain cover so that all can see.

If I decide to fit is at the back end (always a chance) does anybody have the dimensions of the mandrel.

I'm sure on diameter is the main bearing hole (without the bearing) and the other is the seal holder diameter to centralise it. But!!!!

 

One of the few item that has significant wear is the crank pulley hub ~75 http://www.moss-europe.co.uk/shop-by-model/triumph/tr2-4a/engine/engines-components/internal-engine-components.html To have a speedy sleeve fitted costs about £30; a new hub costs about £34 - crazy.

 

I toyed with the idea of rotating the liners thro' 90' and reusing the pistons etc - nice economic answer but do I need economy.

I investigated buying new 86mm liners and reusing the pistons - but this is almost as expensive as new liners + new pistons.

So I have plumped for new 87mm + 0.010" liners and pistons - I may have to upgrade the brakes :blink:

 

New standard cam. I thought about a road race cam but I considered the extra whatever it gives isn't required.

 

Tomorrow should be fun.

 

Roger

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Roger, I have 87mm liners and pistons in my car, and it runs strong. That's a good upgrade. It did seem to make cooling more challenging, so next you'll likely be wondering how to spend money on water pump and radiator.

 

We also upgraded my cam to something falling into the fast road category. It's proven to be very driveable, and gives strong pull from 2500-4500 rpm. Here's its specification, for the record:

Intake :: opens 20 degrees BTDC; closes 60 degrees ABDC
Exhaust :: opens 60 degrees BBDC; closes 20 degrees ATDC
Duration :: 260 degrees
Cam lift :: 0.290", valve lift 0.440"
Valve settings (hot) intake:: 0.012" - 0.014"; exhaust 0.014" - 0.016" (in practice, 0.014" warm for both, not necessarily hot)
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Hi Don,

Looking forward to giving it a good run.

 

Regarding the Christian Marx rear oil seal - I've read a few old threads and one shows the oil seal having a hole cut in the 6-o-clock position to allow adequate draining.

My new seal does not mention this. I will need to ensure that the drain hole is not obscured.

 

Roger

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Chris's has these instructions on his site as of today, Roger. I seem to recall a continuing evolution in the details. The earlier version required machining to the original metal seal ring, yet now this is supplied as new parts, yes?

 

The centering tool has also evolved, I believe -- at least in the US where Joe Alexander offers Chris's kit.

rear%20main%20seal-500x500.JPG

 

My engine has the older Rover seal on machined crank -- Chris's parts were just coming out when we did mine. One of the key things to get right is the direction the rubber lip seal faces on the crank, at least for that other style and I'd guess similarly for Chris's. There has been at least one shop here with egg on their face after complaining about junk parts when they had the Rover-Revington style seal installed backwards.

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Roger central heating engineers use a very high temp silicon for sticking rope seals into place might be the solution to the pushrod tube issue.

Pool liner ......too small,won't stretching into place,guessing?..........kettle of hot water on the beaded edge,watch your pinkies but it will stretch like you won't believe.repeat as necessary.

Iain

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Hi Iain,

still thinking about the tubes.

Metal to metal is no good.

Solder is probably too prone to problems.

Swagging with some form of seal sounds the way to go but it has to be spot on.

 

Still time to think more about it.

 

Roger

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I have both the original style for original rear seal and the Marx one. They are different Roger.

Stuart.

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Roger

A bit of a jump back to the start of this thread when you mentioned rust in the nearside sill.

Harks back to years ago but I was always told that cars were generally parked nearside to the kerb.

Kerbs had a bigger camber back then and therefore the car sat over at an angle and accumulated water that could not escape through the horizontal drain holes.

Urban myth or true?

Steve

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Hi Folks,

I was cleaning some bits and pieces today and found the source of one oil leak.

The small hub that takes the crank pulley for the water pump etc

 

It never dripped directly below itself but got blown back and made other things wet.

 

I think a bit of JB Weld should sort it.

 

Roger

 

 

Edited by RogerH
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Looked at the photo and thought about the "hub" that takes the pulley for the water pump etc

Are you talking about the front end of the crank or the timing chain case-or the pulley? I am lost

Am interested because my engine looses oil and I can't see where?

Do post a wider photo so I can see what you are talking about

please

Michael

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