Engine Won't Turn Over

dmcsweeney

dmcsweeney

Active Member
Hi all,

I got a call from a fellow club member during the week to say the engine in one of his cars wouldn't turn over. He's been poorly lately so asked me to take a look. I assumed it was an electrical issue but when I got there this evening I found the engine wouldn't physically turn a full revolution. It's a '72 3500S with a SD1 engine (7000 miles since a rebuild) and box. When I arrived he turned the key, it rotated about half a turn and there was a dull thud and it stopped. I rolled it back by hand and it locked up again. I then turned it the other way with the same result. I checked the oil, all fine, and the coolant (down about 3"). I turned the engine by hand with the oil cap off and could see the rocker on no. 4 operate. Similarly the dizzy is turning. She locked up with no.1 just off DTC so I whipped the plug and stuck in the endoscope, all well. I then tried no. 8 (next in the firing line) and all ok. When rotated the other way it stopped with the rotor facing no.6 lead and the pointer on the crank about 20deg before the DTC mark. I took out no.6 but the batteries failed in the scope before I got a look. The starter, when it briefly turned the engine engaged smoothly, and she was in neutral. Any ideas? She was stood 6 weeks and was ok bar a slight miss fire when parked.

Regards,
Dave
 
Given the fact that the engine has recently been rebuilt, I'd assume initially that the engine is ok in order to rule out other things.
The coolant loss is a worry, check that there isn't any coolant in any of the cylinders and the engine isn't hydraulic locking.
Then I'd remove the starter motor and try again to turn the engine by hand, but don't force it. Then I'd get someone to operate the clutch whilst trying again assuming its a manual car.

Failing that I'd wait for someone more knowledgeable on the V8's to advise.
 
I recently overhauled my Sd1 V8 for my P5B and exchanged the flywheel (from manual to automatic gearbox). When I started the engine for the first time, it only moved half a turn. This was caused by the flywheel rubbing the engineblock. I had to grind some alu from the engine to give the flywheel room and then the problem was solved
Your engine seems to have run after the overhaul so it is unlikely that the cause is the same as with my engine but the problem description was more or less identical
Regards

Peter
 
If it turned over before it was left standing then it could be a valve seized in the guide in the open position, if it has had the problem since the engine was fitted then I'd check the slave cylinder bolts.
 
harveyp6 wrote,...
it could be a valve seized in the guide in the open position
Click to expand...

Hi Harvey,

I had heard that the use of valve stem oil seals can cause this to happen. The seal prevents adequate lubrication of the valve within the guide allowing it to seize.

Ron.
 
Gents,
thanks for your replies! Apologies for the delay in getting back to you, our IT department have blocked all forums :evil: .
harveyp6 said:
If it turned over before it was left standing then it could be a valve seized in the guide in the open position
Click to expand...

I guess it's off with the rocker covers next for a look then. I was wondering if one of the lifters was to blame.

Pat/Peter,

the owner, Tony, told me that he once saw a ring gear move out of position and jam an engine, so I think I will drop the starter just in case, although the starter seems to engage it smoothly. When I said the coolant was down, it was probably only an inch below the level I fill my rad to, so I think it's probably the level he normally keeps it at. I was wondering if it was a failed head gasket causing hydro locking at first as well, but there were no symptoms (steam from the exhaust etc when he last ran it, although it was down a cylinder (but then I found a broken plug lead). It's definitely metal to metal, and there's no spring back.

Thanks lads.

Dave
 
dmcsweeney said:
Tony, told me that he once saw a ring gear move out of position and jam an engine, so I think I will drop the starter just in case,
Click to expand...

Unusual to have ring gear/flexplate problems on a V8. Remove the cover plate rather than the starter, it's a lot easier and quicker.
 
harveyp6 said:
dmcsweeney said:
Tony, told me that he once saw a ring gear move out of position and jam an engine, so I think I will drop the starter just in case,
Click to expand...

Unusual to have ring gear/flexplate problems on a V8. Remove the cover plate rather than the starter, it's a lot easier and quicker.
Click to expand...

Thanks Harvey. I was considering dropping the clutch slave last night and putting in the scope, before the batteries failed. I guess it's an easy one to start with. I just wish I had it in my own workshop under cover!

Regards,
Dave
 
devilsplaymate said:
Hi.

Will it turn over with all of the spark plugs out?
Glen.
Click to expand...

Glen,

didn't try it with all the plugs out. I still haven't got back to the car as it's outside and the weather has been exceptionally poo the last few days. Hopefully this weekend.

Regards,
Dave
 
Hi all,

as you can see progress has been a bit slow on this post! The problem has finally been found. I haven't seen it yet but something made it's way into a cylinder and holed a piston :( . Now for the next question. The engine is an SD1, which was rebuilt at some point with +20 thou pistons. I have a set of pistons lying around from a stripped SD1 engine, but the only markings I can find are a D stamped on the crown. Are these standard pistons? Anyone know of a supplier that could supply a single +20 thou replacement piston?

Regards,
Dave
 
dmcsweeney said:
I have a set of pistons lying around from a stripped SD1 engine, but the only markings I can find are a D stamped on the crown. Are these standard pistons?
Click to expand...

I'd guess they are, as AFAIK SD1 engines had the standard pistons graded in the same way the P6B ones did.
 
Thanks Harvey. I'm not familiar with the grading on P6 engines though. Is it done using letter for different tolerances?
Regards,
Dave
 
Question answered! :D . Thanks for that! Would love to know how to get a 10mm bolt into a V8 without removing a head :shock: .

Thanks,
Dave
 
I believe later RV8 like in the Range Rover had A,B,C and D markings on the engine which as you stated are tolerance classes and D is the biggest but it will not be in the + 0,20 area

Regards
Peter
 
dmcsweeney said:
Would love to know how to get a 10mm bolt into a V8 without removing a head :shock: .

Thanks,
Dave
Click to expand...
Small children are amazing with putting things into small holes and spaces. I have a rattle in Madame's Hyundai
stemming from my son slotting a few coins into the slot that the heater controls run in.... :roll: All it would take
is Muggins being in the garage with the engine on a stand and plugs out or being lifted onto a fender and Bob's
yer Mother's brother, before you could blink it would be done.
 
dmcsweeney said:
Question answered! :D . Thanks for that! Would love to know how to get a 10mm bolt into a V8 without removing a head :shock: .

Thanks,
Dave
Click to expand...


Yes it would be good to know where the bolt came from, and the path it travelled to get there.
The story was " was just sat ticking over, engine just stopped dead, and would not turn over "
( range rover classic ) no recent work carried out.

image_zps5c49285f.jpg





Offending bolt.

image_zpsdac996f5.jpg
 
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