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4A Engine Rebuild - The Sequel.


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During the Summer I experienced a thing called ratchet clutch. The pedal jerks on the way back causing the car to leap around a lot..

 

Roger,

You couldn't have the slave cylinder piston seal the wrong way round could you?

 

Pete

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Hi Pete,

if only. When it started during June I replaced the clutch slave with a new one (I replaced the Master at the same time).

It appeared to do the trick but only for a few days and it all came back.

 

I'm hoping today's efforts will work. The mis-alignment is the only thing I can find wrong.

 

Roger

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The tried and tested solution for ratchet clutch was to fit the dowel bolts (TR5/250/6) as you have dowels in the rear engine to gearbox mounting face that is not the issue (You do have the two dowels fitted - did I ask this before and you have answered?)

Can you slack the snout attachment bolts and tap the snout so it is concentric to the input shaft? or is that not the issue?

What is the up/down (wobble) movement of the input shaft. A shagged bearing will give you more than 0.020" at the tip of the shaft. Remember the tip of the input shaft is supported in the crank spigot bush, which is why it must be in good order.

 

Colloidal graphite on the gearbox snout that the release carrier runs on is also said to improve things. it is also applied lightly to the spline where the clutch plate runs/slides - like this https://www.amazon.co.uk/C-Tools-T6283A-Graphite-Powder/dp/B003KN0AJK/ref=sr_1_6_a_it?ie=UTF8&qid=1475520161&sr=8-6&keywords=graphite+lubricant+spray burnish it into the surface with a cloth.

Graphite is good as it is non sticky and will not attract the clutch friction dust.

 

Cheers

Peter W

Edited by BlueTR3A-5EKT
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Hi Stuart,

I'm now panicking - which gasket, what copper washer???

 

Help!!!

 

Roger

Items 64 and 66 http://www.moss-europe.co.uk/shop-by-model/triumph/tr2-4a/clutch-transmission-drivetrain/gearboxes-components/gearboxes-external-components.html

Stuart.

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Hi Stuart,

thankfully I did not remove that plate. I removed item #60

 

 

Hi Peter,

no up/down wobble on the splined shaft.

In the summer I replaced the bearing carrier extension ~60 http://www.moss-europe.co.uk/shop-by-model/triumph/tr2-4a/clutch-transmission-drivetrain/gearboxes-components/gearboxes-external-components.html

This had witness marks on the sleeve as if something was jamming/sticking.

If the slight mis-alignment was the cause then hopefully all will be well. However we all know how these things can go.

 

 

Hi Pete.

perhaps I didn't make myself clear - I replaced the slave and master after the first bout of ratchet clutch. The symptoms returned soon afterwards. The carrier sleeve was seriously lubricated and worked for 6 - 8 weeks.

 

Roger

Edited by RogerH
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Roger,

I know I am getting boring - what about the two 3/8" diam dowels that are not illustrated in the Moss cat Pt No is DP 612 which is a 3/8" x 3/4" long

http://www.canleyclassics.com/standard-triumph-hardware-catalogue-dowel-plain

 

Cheers

Peter W

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Thus knowing tdc and the dummy pushrod in the 2nd hole (the first is the exhaust and we are not trying to time that are we? don't ask how I know!)

MichaelH

 

You are not alone - easily done. Fortunately the only consequence on a 6 is the car won't start and you spend an age checking everything from ignition to fuel before the penny drops.

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Hi Stuart,

thankfully I did not remove that plate. I removed item #60

 

 

Roger

Thats the one I am on about post #24 the extension has the gasket and uses copper washers.

Stuart.

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Hi Stuart,

thanks for the clarification.

The gasket is new with adequate Hylomar.

I did not fit new copper washers but used the old ones. Again they had Hylomar on them.

 

Can't fit new ones now so will have to keep an eye on whatever happens.

 

 

I re-used these when I had the GB out in the Summer. There were no signs of leaking or loosening from them.

 

Roger

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Thank you for the info Roger.

Surely if you add a shim under the bearing retainer snout thing it will make the release bearing run at an angle to the input shaft, rather than concentric with it.

The snout has a register in it to retain the bearing and that should be flat/square/perpendicular/concentric to the surface that the release bearing carrier runs on. So is it a problem with the bolt circle concentricilty in relation to that bearing rebate? If it was horribly off the front seal would be on the cock/loaded to one side and potentially leaking.

Confused of Pinner.

Peter W

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You can get new nose covers as I have had to replace them before due to butchery/ wear etc. Not hugely expensive so I would have been tempted to replace rather than risk misaligning everything.

Stuart.

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Thank you for the info Roger.

Surely if you add a shim under the bearing retainer snout thing it will make the release bearing run at an angle to the input shaft, rather than concentric with it.

The snout has a register in it to retain the bearing and that should be flat/square/perpendicular/concentric to the surface that the release bearing carrier runs on. So is it a problem with the bolt circle concentricilty in relation to that bearing rebate? If it was horribly off the front seal would be on the cock/loaded to one side and potentially leaking.

Confused of Pinner.

Peter W

My thoughts exactly.

 

Bob.

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Hi Peter /Stuart,

Back in the Summer I had to take the GB out as the clutch was not controllable - ratchet clutch.

Eventually I found wear marks on the 'snout' of the extension. I could reproduce the ratchet effect by cocking the release bearing.

I then noticed that the snout was 0.020" misaligned with the splined shaft. The shaft has no/little play.

 

The splined shaft sits in the rear of the crank and should run concentric with the flywheel and clutch assy.

The release bearing is 0.020" adrift. I am thinking that when the release bearing hits the diaphragm fingers it is re-centralised about the spllned shaft. This will cock the release bearing.

When the fingers push the release bearing back down the snout is begins to jam.

With plenty of grease it works OK. As the grease thins out is gets sticky/jammed.

 

The extension has been replaced with a new one. I have run the extension in the lathe and everything is concentric.

The extension sits flat on the front of the GB and when bolted down it is where it needs to be. However it is out of alignment.

 

Could the splined shaft not be square to the front of the GB where the extension sits !!

 

So, I have fabricated a tapered shim - 0.020" at the bottom tapering to 0" at the top.

 

It is quite puzzling but I now have the snout and splined shaft in alignment - or rather the end of the snout is concentric with the splined shaft - there is a difference !!!!

 

If the extension is concentric and square within itself and sits hard on the front of the GB then suspicion lies with the splined shaft.

The internal end of the shaft must be located in a bearing etc can this bearing or whatever be in the wrong place !!!

 

Roger

 

PS - until I fitted the tapered shim I believe the bearing 'was' at an angle and causing the jamming - how, I don;t know.

Edited by RogerH
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Hi Folks,

a bit of a gap. I have been busy putting the car back together. It's amazing how long it takes to do little things.

Because I was waiting for some seals to arrived for the GB top cover I decided to fit the engine and GB as one lump without the top cover.

This was interesting. It became so much easier without the top cover. It gave precious inches to slide it in place.

 

The new seals arrived for the top cover. These are Q-seals or Quad seals. They are for the selector rods to replace the usual O-rings.

Now, when fitting the top cover insitu you must be sure that you align all the selector forks. This includes the reverse selector :blink::blink::angry:

Take two - top cover fitted.

 

Today I got to the point of firing her up. What could possibly go wrong.

Anyway after spinning her over to get oil pressure I decided to go for it - nothing.

I tried again - still nothing.

Off with the rocker cover and check that the valves were opening and closing when they should - and they were. Hmm.

On with the rocker cover.

 

Spin it over - nothing.

Have you noticed how far a HT spark can jump. 0.025" easy, 0.040" easy, 0.060" do'able.

However 6" is probably a little tooooo much.

I hadn't connected the HT lead from the dizzy to the coil :wub:

So, connect the HT. Press the button and bingo - the engine started followed by a bonk (as the ratchet I had on the front crank bolt eventually fell off.

 

It was running, good oil pressure (new pump), battery being charged and somebody playing chestnuts (or castanets in Spanish) in the engine.

Off with the rocker cover again re-set the rocker gap. Interestingly #3 rocker had a very big gap and getting bigger - the lock nut was loose.

 

Once running again all sounded not too bad at all.

 

Tomorrow I'll take her for a spin to see how the timing is and and what sort of oil fountain I have anywhere.

 

One disconcerting thing I found on strip down was that all but two can followers had quite a bit of wear (pitting) after only 8Kmiles.

Otherwise all OK.

 

Roger

Edited by RogerH
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:):):):):):):)

 

Hi Folks,

I went for a spin in the 4A today and all went very well.

The tappets tapped, the crank cranked and the pistons er er went up and down.

 

Now to see if the oil leak in the GB selector rods has slowed/stopped.

 

I think the previous valve timing was slightly adrift as the exhaust note had a bit of a bark to it on the overrun. Now it is back to how it used to be.

 

Roger

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Hi Bob,

the clutch action is boringly beautiful. Very smooth and quite light.

But then it was the same during the Summer immediately after the july repair.

Give it 6 - 8 weeks before I can breath easy.

 

I think the logic of getting it all aligned as best as possible makes sense. The only nagging issue is why was it out of alignment.

 

Roger

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