Clutch/ engine / ? Problem

[Bakergt40]

Hi, my previous post on thrust bearings has took another turn.
The engine came out again , the thrust was replaced for an AP thrust.
The gearbox was rebuilt by Klassic transmissions to eliminate the box and the whole thing put back together.
80 miles later the same problem of a loud rattle.
Now depress the clutch and the rattle stops but the Revs drop to 300 then the engine stalls
Work that one out
Any thoughts appreciated !

Going back into E type U.K.
probably an engine out again

Regards all
Keith

[Mich7920]

Hi Keith
If in neutral the small idle is about 700 rpm steady, I will look at the clutch release bearing.
It looks like with the gear engaged, the clutch depressed, you still have a drive that stalls the engine.
The rattle could come from the bearing also.
When the clutch isn't depress and with the gear on neutral, it's quite normal to have noise from the gearbox but it's not "rattle" it's a bearing noise.
Is the fork in a good state and balance with the AP thrust bearing ?
A way to think, but an engine/gearbox out of the car, again...
Mich

[christopher storey]

The symptom you describe is very close indeed to what happens if the thrust washers wear or worse still drop out of the centre main bearing housing . You can diagnose this fairly easily with an assistant : start the engine and let it idle, then get your assistant to press the clutch pedal fully down while you watch the front pulley of the crankshaft. If it moves forwards visibly, then I am afraid you have a thrust washer failure. It is sometimes possible to rectify this with the engine in the car by removing the sump and centre main cap and replacing the thrust washer, although it is a bit chancy because if it has happened once it is liable to happen again unless you pin the washer to the main bearing cap, and of course if it has been happening for a while you may have caused out of limits wear to crankshaft and/or the block

Sorry to give you gloomy news

PS I should just add that in my experience this is a very uncommon failure on XK engines, in contrast to the Triumph 2000/2500 units where it was very common indeed

[Bakergt40]

Thanks for info so
When I say thrust bearing I do mean clutch thrust
The car is going back in today and who knows ?
Thanks all

[mgcjag]

Hi Keith...Christopher is describing what can cause an engine to drop revs and stall when the clutch is pressed...missing thrust washer on the crankshaft allows the crank to move slightly and engine stalls...just something to be aware of.....Steve

[1954Etype]

The engine stalls due to the components connected to the crankshaft being under stress.

[rfs1957]

Keith, it’s a pity you didn’t continue this saga on the topic that you started here

viewtopic.php?f=4&t=16052&p=131966#p131652

as it makes fascinating reading in the light of the smoke and mirrors nonsense you appear to be being sold by the people in charge of repairing your car.

Could Steve reconnect the two threads into one topic maybe ? Breaking up stories like these clutters up the Forum with incomplete snippets, and yours is a good one.

First clutch release, with concomitant speculation about the condition of the gearbox bearings, totally unrelated of course, and now that the gearbox has been (probably unnecessarily) been rebuilt, a whole new can of worms opens up.

Dropped revs and stall equals friction, my vote goes to the crank thrust washers.

Bear in mind that if they have flown the nest, the crank might conceivably have already adopted a fully-forward position.

So if the car has since been partially dismantled, and can’t be run to watch the crank movement, finding a way of forcing the pulley on the crank-nose backwards, before jemmying it forwards, is the only reliable way of establishing what the crank float is.

Please keep us up to speed, so far you couldn’t make it up.

[Tom W]

So if the car has since been partially dismantled, and can’t be run to watch the crank movement, finding a way of forcing the pulley on the crank-nose backwards, before jemmying it forwards, is the only reliable way of establishing what the crank float is.

I wonder if a pry bar, used gently, between the flywheel and the back of the sump/rear face of the block could achieve this?

[steve3.8]

Dropped revs and stall equals friction, my vote goes to the crank thrust washers.

My thoughts too , failures are rare but-- putting the thrust washers in back to front on a rebuild gives a bad result ---- maximum friction.
Lets hope we are wrong as the crank could be -------?

[Bakergt40]

Interesting info
I did discuss the crank issue and it was dismissed by the repairers.
The car has been in with them two days and should get a verdict shortly. I’ll keep updated as soon as I know.
I have an XK140 as well and that too only very slightly drops revs when the clutch is depressed.
That XK 140 engine was built by CKL in 2014 to race spec.
I’ll keep updated and stick to one thread
Keith

[malcolm]

I have an XK140 as well and that too only very slightly drops revs when the clutch is depressed.

Keith

That's normal isn't it? My tickover drops very slightly when clutch is depressed; the engine is driving more mechanically. That's why advice was always to start the car in neutral with foot off clutch, less load than if clutch is in. Or am i wrong?

[abowie]

Keith can you clarify some things for me?

Your initial thread seems to be about the failure of a carbon clutch thrust bearing.

I can't quite work out whether this thread relates to a subsequent failure of the same thing or whether you are now concerned about the half moon metal thrust bearings in the engine that limit crank fore and aft movement.

I've read all the posts and follow what everyone's conjecture is but I wanted to confirm with you that you consider the second failure is a different problem from the first.

[Bakergt40]

Let me clarify the situation.
I had a full engine rebuild to fast road spec.
The clutch was completely replaced for 9.5 “ and aluminium flywheel , new high torque stater and carbs rebuilt and new 2”exhaust system.
On return after 300 miles there was a bad noise / rattle from the clutch area.
The engine was removed again and the thrust bearing has broken, I was in formed the issue was the g box bearings were at fault and I they had the box rebuilt , new lay shaft bearings etc . It was put back in the car. After 80 miles the noise was back a bit worse than before. So it wasn’t the bearings obviously but the rattle is bad and sounds like something is going to break.
They said the gear set is worn but not according to the g box builder who has built hundreds and currently had 19 moss boxes in works
CMC bridgenorth suggests it’s the clutch problem
The saga continues but not as fast as I’d like
So there we are

Keith

[Bakergt40]

Sorry this is the same problem, never been resolved
Never did the g box rattle or have shift issues only since the work was done
Keith

[Bakergt40]

And finally, when idle on 750 rpm in neutral if you depress the clutch the revs drop and the engine stalls.
Lift of the clutch before it stalls and the revs pick up
Work that out

[steve3.8]

Aluminium flywheel ? Why? , sorry but that’s inviting problems .

[Mich7920]

Keith
What I can advise you to do is to go to an EType racing specialist because that's what your transformation looks like.
Someone who knows the gearbox/clutch/racing engine chain well and above all knows the parts and the settings that are specific and vital for this kind of transformation.
A racing EType mechanic is not the same as the one around the corner who will perfectly tune an original EType.
If you want to drive one day and have fun in your car, I think you will have to make the right decisions and get the right people working on it.
" Bon courage !"
Mich

[Bakergt40]

Thanks for the info to date
Situation still ongoing but told it’s a rattle from the gear set and as the revs were too low it sounded worse.
Well I’m testing it Monday so we’ll see.
Aluminium flywheel is part of the package recommended by
e type U.K.
They use the same set up for all there restorations I believe.
Not familiar with these upgrades you have to take the advise of people in the know ... supposedly

Keith

[mgcjag]

Hi Keith...and what was the explanation for it stalling when you press the clutch?.....Steve

[Bakergt40]

No explanation as of yet
It was driven today with no issues I’m told, Monday there doing another test run
Tuesday I’m testing it
I’ll let you know but to me the only thing stalling the car is the clutch but who knows
Tuesday I’ll know

Keith