How can I turn the crankshaft after the head is removed?

RobRoy · 19th April 2010, 18:14

Referring to my recent post https://www.the75andztclub.co.uk/forum/showthread.php?t=58164 There was no further miracle. After much head scratching I removed the head by following advice from Haynes and positioning the crankshaft 90 degs BTDC. Examination of the pistons revealed a small piece missing from number 1 that had melted right on its edge causing complete loss of combustion. I have now ordered a replacement piston from Xpart and have clamped the liners, but, as you may have guessed I can't budge the crankshaft to a position where I can access the big end bolts on number 1 conrod. Anyone any ideas?

Rov5 · 19th April 2010, 18:18

Why cant you put a socket on the crankshft pulley bolt and turn it .

RobRoy · 19th April 2010, 18:22

Rov75, thats what I'm doing but the crankshaft won't budge. Haynes state this in the book but I'm hoping there is a workaround

T-Cut · 19th April 2010, 18:34

How have you clamped the liners? Is it this device that's preventing the crank from turning?

TC

RobRoy · 19th April 2010, 19:11

T-Cut, no the liner clamps are home-made and do not come into contact with any moving parts and do not obstruct anything other than lock the liners in place

rrobson · 19th April 2010, 19:20

is there plenty of oil in the bores? if you have wiped any out, it will be hard to turn, i would also suggest applying force in alternate directions ie forwards and back, to get them moving, aswell as putting a decent helping of oil into the cylinders. could you use a longer bar?

Fraser Mitchell · 20th April 2010, 07:46

I think if you read on in the Haynes manual you will find that the piston/conrod assembly cannot be removed from the top as the big-end eye is too big for the liner. It has to come out the bottom, so it is a crankshaft removal job. Funny old engines, these K4s

sworks · 20th April 2010, 08:33

The cranks usually are difficult to start moving initially but ones this is overcome it should turn easier (providing the damaged piston isn't jammind on the liner), are you using a ratchet or big bar? The piston definately comes 'up' without removing the crank.

Gary · 20th April 2010, 08:39

I replaced all four of mine a few weeks ago and the piston will push out through the top of the engine. If you haven’t already done so you will need to think about replacing the liner because you will probably find, if you look closely, that has been damaged as well.

T-Cut · 20th April 2010, 09:49

As mentioned by RobRoy, Haynes says:

'Due to the design of the engine, it will become very difficult, almost impossible, to turn the crankshaft after the head bolts have been slackened.'

There's no explanation of why this is, but it's clearly a fact as demonstrated here. I suspect there must be some form of relaxation in the structure when bolt tension is released and this causes flexure, which effectively locks the crank/pistons in position. There may be a completely different reason, but I couldn't guess what.

The next question is how can you remove the crank for example, if you can't turn it? Very wierd.

TC

19th April 2010, 18:14	#1
RobRoy Regular poster Rover 75 Join Date: Apr 2007 Location: Liverpool Posts: 66 Thanks: 4 Thanked 4 Times in 4 Posts	How can I turn the crankshaft after the head is removed? Referring to my recent post https://www.the75andztclub.co.uk/forum/showthread.php?t=58164 There was no further miracle. After much head scratching I removed the head by following advice from Haynes and positioning the crankshaft 90 degs BTDC. Examination of the pistons revealed a small piece missing from number 1 that had melted right on its edge causing complete loss of combustion. I have now ordered a replacement piston from Xpart and have clamped the liners, but, as you may have guessed I can't budge the crankshaft to a position where I can access the big end bolts on number 1 conrod. Anyone any ideas?

19th April 2010, 18:18	#2
Rov5 Loves to post Rover 75 Join Date: Aug 2007 Location: Glasgow Posts: 290 Thanks: 0 Thanked 1 Time in 1 Post	Crankshaft Turning Why cant you put a socket on the crankshft pulley bolt and turn it .

20th April 2010, 08:33	#8
sworks Been absent for a while… Rover 75 Tourer, Classic mini Cooper S, Abarth 595 competizione, MG TF and a Hyundai Tucson PHEV Join Date: Feb 2007 Location: Cumbria Posts: 13,065 Thanks: 1,033 Thanked 1,686 Times in 1,040 Posts	The cranks usually are difficult to start moving initially but ones this is overcome it should turn easier (providing the damaged piston isn't jammind on the liner), are you using a ratchet or big bar? The piston definately comes 'up' without removing the crank. __________________ ................................................. 'Marmite' Possibly one of the most famous 75 tourers produced! left the production line as the last of only Three Rover 75 tourers produced in Trophy Yellow. 48 hours later Longbridge closed. The last sold ordered 75 Tourer. Paid for by the Phoenix Four and handed over by John Towers to the Warwickshire Northampton Air ambulance service as a Rapid Response vehicle Last edited by sworks; 20th April 2010 at 08:40..

19th April 2010, 18:22	#3
RobRoy Regular poster Rover 75 Join Date: Apr 2007 Location: Liverpool Posts: 66 Thanks: 4 Thanked 4 Times in 4 Posts	Rov75, thats what I'm doing but the crankshaft won't budge. Haynes state this in the book but I'm hoping there is a workaround

19th April 2010, 18:34	#4
T-Cut This is my second home Rover75 and Mreg Corsa. Join Date: Nov 2006 Location: Sumweer onat mote o'dust (Sagin) Posts: 21,753 Thanks: 341 Thanked 3,660 Times in 2,924 Posts	How have you clamped the liners? Is it this device that's preventing the crank from turning? TC

19th April 2010, 19:11	#5
RobRoy Regular poster Rover 75 Join Date: Apr 2007 Location: Liverpool Posts: 66 Thanks: 4 Thanked 4 Times in 4 Posts	T-Cut, no the liner clamps are home-made and do not come into contact with any moving parts and do not obstruct anything other than lock the liners in place

19th April 2010, 19:20	#6
rrobson I really should get out more....... 75 tourer cdti, MG ZS 180, nissan terrano & 1.8t rover 25 Join Date: Feb 2010 Location: Pontefract Posts: 2,644 Thanks: 17 Thanked 295 Times in 218 Posts	is there plenty of oil in the bores? if you have wiped any out, it will be hard to turn, i would also suggest applying force in alternate directions ie forwards and back, to get them moving, aswell as putting a decent helping of oil into the cylinders. could you use a longer bar?

20th April 2010, 07:46	#7
Fraser Mitchell Gets stuck in Rover 75 2.5 V6 Club Auto Join Date: Feb 2007 Location: Crewe Posts: 898 Thanks: 0 Thanked 0 Times in 0 Posts	I think if you read on in the Haynes manual you will find that the piston/conrod assembly cannot be removed from the top as the big-end eye is too big for the liner. It has to come out the bottom, so it is a crankshaft removal job. Funny old engines, these K4s

20th April 2010, 08:39	#9
Gary Avid contributor Rover 75 1.8T Club - Mitsubishi GTO Join Date: Apr 2009 Location: Weymouth Posts: 107 Thanks: 0 Thanked 0 Times in 0 Posts	I replaced all four of mine a few weeks ago and the piston will push out through the top of the engine. If you haven’t already done so you will need to think about replacing the liner because you will probably find, if you look closely, that has been damaged as well.

20th April 2010, 09:49	#10
T-Cut This is my second home Rover75 and Mreg Corsa. Join Date: Nov 2006 Location: Sumweer onat mote o'dust (Sagin) Posts: 21,753 Thanks: 341 Thanked 3,660 Times in 2,924 Posts	As mentioned by RobRoy, Haynes says: 'Due to the design of the engine, it will become very difficult, almost impossible, to turn the crankshaft after the head bolts have been slackened.' There's no explanation of why this is, but it's clearly a fact as demonstrated here. I suspect there must be some form of relaxation in the structure when bolt tension is released and this causes flexure, which effectively locks the crank/pistons in position. There may be a completely different reason, but I couldn't guess what. The next question is how can you remove the crank for example, if you can't turn it? Very wierd. TC