Engine dies when clutch operated.

I live in hope someone has a solution that does not involve removing the gearbox and engine but fear the worst.

As can be seen from the video, gearbox in neutral, push the clutch in, strange noise which seems to come from the gearbox, revs drop and engine will eventually stall unless clutch is released. Dr google pointed me towards the ECU and possible crank thrust washer / crank walk issue.

I eliminated an ECU issue for obvious reasons, and then after a lot of thinking eliminated the thrust washer issue as I remembered the crank installation was the only part of the engine build completed by a professional and not me.

However, I don’t know of anything else it could be and also alarmingly have had a small oil leak for a while which appears to be from the crankshaft oil seal.



Any advice gratefully received.

Thanks

Nick
 
With that sound I’d pull the engine and trans no matter what. I’m not sure how the GTs work, can you pull the trans only and leave the engine in place?
 

Howard Jones

Supporter
Take the belt off and see what happens. Simple troubleshooting step. Could be the alternator, waterpump, AC pump. You'll know in seconds. Do not run longer than necessary. If the crank is being loaded because the pilot bearing, clutch, throwout bearing, clutch arm etc. is mismatched/ misaligned then you can hurt the thrust bearings.

Are you saying that the noise goes away with the car at idle and the gearbox in neutral and the clutch peddle not being depressed, So if this is correct what happens when you depress the clutch peddle still in neutral? still no noise? Put into gear with clutch depressed, now you have noise? Again do these tests quickly. report back
 
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Take the belt off and see what happens. Simple troubleshooting step. Could be the alternator, waterpump, AC pump. You'll know in seconds. Do not run longer than necessary. If the crank is being loaded because the pilot bearing, clutch, throwout bearing, clutch arm etc. is mismatched/ misaligned then you can hurt the thrust bearings.

Are you saying that the noise goes away with the car at idle and the gearbox in neutral and the clutch peddle not being depressed, So if this is correct what happens when you depress the clutch peddle still in neutral? still no noise? Put into gear with clutch depressed, now you have noise? Again do these tests quickly. report back
Hi Howard thanks, the checks and video were done with the car in neutral. Will report back with results for same check with the car in gear.
 

Keith

Lifetime Supporter
I agree, would not go much further without measuring crank end play because something sounds radically wrong here. Almost sounds like there is no thrust bearing…..
With a pry bar and wood block push the crank towards the rear as far as it will go, set up a dial indicator and push in the clutch.
 
Thanks for all the replies and advice. Part of my technical support team ( Pete Thompson, Mike Pass, and Mark Edwards) from the North West area of the GT 40 Enthusiasts Owners Club were straight onto it, and also advised checking the endfloat with a dial while operating the clutch. Whilst doing so I could see the bottom pulley moving, so it does indeed appear at the moment to be a thrust bearing issue.

As I mentioned fitting the crank was the one job I paid to have done by a Ford V8 engine specialist in 2008, so ironically, I am actually hoping he got it wrong some how, as if not something else has caused the problem.
 

Randy V

Moderator-Admin
Staff member
Admin
Lifetime Supporter
The last bad thrust bearing I saw was caused by the pilot bearing not being inserted deeply enough into the crankshaft - that was also aggravated by the input shaft of the transmission having been modified and had insufficient length on the bearing surface to accommodate the “proud” pilot bearing. Sad state of affairs unfortunately as the work had been done by 3 independent shops and then brought to mine to figure it all out...
 

Terry Oxandale

Skinny Man
Randy, always ready to learn something.

"...not being inserted deeply enough..." causes me to ask why. If there is any insertion at all (assuming no chamfer on the shaft end or pilot hole), what is enough insertion? Lastly, I lack understanding that if there wasn't sufficient penetration, how does this translate into a failed thrust bearing (mechanism for causing failure)? My thinking is failure of the journal bearing radially (non-concentric rotating centers when clutch engaged), not longitudinally, but again, would love to learn something here.

Ox
 

Udo

Supporter
Nick, if the pilot bearing doesn’t fit (see my blog, I had a bearing that only fitted 50% into the counterpart), noises happened only while the clutch was released. If no gear in place, this is very likely not the issue
 

Howard Jones

Supporter
If the input shaft from the gearbox does not freely rotate inside the piolet bearing and instead loads it longitudinally and thus the thrust bearings via the crankshaft they will overheat and fail. This is bad. It would require a complete tear down to remove the bearing material from the rest of the oil system at the least, repair the trust faces on the crank, and replacement of the rest of the bearings in the engine if you are lucky. Bearing material in the oil will very quickly hurt crank and cam journals, lifter bores, piston bores, pistons, and on and on.

This may not be the problem, but it's a good idea to check it out for yourself.
 
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Randy, always ready to learn something.

"...not being inserted deeply enough..." causes me to ask why. If there is any insertion at all (assuming no chamfer on the shaft end or pilot hole), what is enough insertion? Lastly, I lack understanding that if there wasn't sufficient penetration, how does this translate into a failed thrust bearing (mechanism for causing failure)? My thinking is failure of the journal bearing radially (non-concentric rotating centers when clutch engaged), not longitudinally, but again, would love to learn something here.

Ox
The way I'm reading it is that the pilot bearing was not fully inserted into the crank, leaving it sitting "out of the hole". Thus, when the tranx was mated to engine, it was already hard up against the shoulder of the main shaft, loading the crank thrust bearing, leading to premature wear, which was only exacerbated by dipping the clutch/moving the flywheel back further into the block.
 

Terry Oxandale

Skinny Man
Thanks Tom. That was my understanding. Just wondered if I was missing something, and why I was explicit in my question of even a tiny amount of penetration into the pilot bearing vs no penetration at all, or never aligned when transaxle was attached to the motor (which would be a huge mismatch and thus unlikely especially when most shafts I've seen are chamfered on the end to aid insertion).

On to our regularly scheduled program.
 

Randy V

Moderator-Admin
Staff member
Admin
Lifetime Supporter
The way I'm reading it is that the pilot bearing was not fully inserted into the crank, leaving it sitting "out of the hole". Thus, when the tranx was mated to engine, it was already hard up against the shoulder of the main shaft, loading the crank thrust bearing, leading to premature wear, which was only exacerbated by dipping the clutch/moving the flywheel back further into the block.
Exactly...
 
Well to cut a long story short, the engine went up to Ben the now owner of Engine Data Analysis Castleford. Got a phone call yesterday from Ben and it wasn’t good news.

The crank is basically toast, he confirmed the thrust bearing wear was on the opposite side to that which would have been expected if there had been excessive pressure from the clutch pushing the crank forward. They are at a loss as to what could have caused it even Kenny well know Ford V8 expert who was there at the time was stumped.

Now looking into option costs but it will need a new crank as a minimum, Ben did mention a stroker option, but I am already panicking about what the cost is going to be, I don’t think it is going to be cheap.
 

Simon

Supporter
I’m afraid I’m unable to offer any technical advice or help, but I would certainly identify the root cause of the problem BEFORE rectifying it…"
JMHO
Simon
 
Well to cut a long story short, the engine went up to Ben the now owner of Engine Data Analysis Castleford. Got a phone call yesterday from Ben and it wasn’t good news.

The crank is basically toast, he confirmed the thrust bearing wear was on the opposite side to that which would have been expected if there had been excessive pressure from the clutch pushing the crank forward. They are at a loss as to what could have caused it even Kenny well know Ford V8 expert who was there at the time was stumped.

Now looking into option costs but it will need a new crank as a minimum, Ben did mention a stroker option, but I am already panicking about what the cost is going to be, I don’t think it is going to be cheap.
What trans-axle?
What clutch/pressure plate set up?

Thrust bearing wear can occur if the pressure plate is set up to handle high HP. It can be creating too much forward pressure for a Ford engine.
A lighter pressure pressure plate, race quality thrust bearings and crank should help.
I'd suggest calling Kennedy Engineering and give them the specs on your engine HP, trans-axle info and current clutch/pressure plate set up. They can tell you what clutch/pressure plate you should have.
 
I’m afraid I’m unable to offer any technical advice or help, but I would certainly identify the root cause of the problem BEFORE rectifying it…"
JMHO
Simon
Thanks Simon fully agree, my biggest fear is brains, knowledge, and ability far greater than mine will not be able to identify what caused it, so it could all happen again further down the line.

What trans-axle?
What clutch/pressure plate set up?

Thrust bearing wear can occur if the pressure plate is set up to handle high HP. It can be creating too much forward pressure for a Ford engine.
A lighter pressure pressure plate, race quality thrust bearings and crank should help.
Hi Allen,

Thanks for the advice, Transaxle is a Porsche G50 with standard Porsche clutch / pressure plate set up
 
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