|
||
|
17th December 2018, 19:22 | #1 |
Newbie
Rover 75 Tourer Join Date: Aug 2010
Location: Waterlooville
Posts: 15
Thanks: 1
Thanked 0 Times in 0 Posts
|
Crank turned backwards by mobile mechanic
A mobile mechanic to remove the failed auxiliary belt behind the crank pulley put a big spanner on the pulley and wound it backwards. The BMW 320 had been running ok with out the belts before but after would not start. Talking to my garage they say a write off yet only done 120 k and regularly returned nearly 50 mpg. Do you think garage right as so sad to loose. My present motor is a V6 of same vintage returning half the mpg.
|
17th December 2018, 20:22 | #2 |
This is my second home
R75 Saloon. Join Date: Feb 2009
Location: France/or Devon.
Posts: 14,003
Thanks: 3,851
Thanked 2,167 Times in 1,816 Posts
|
If only the auxiliary belt was broken then turning the engine backwards should do no harm to it. All the internal moving parts will simply move as they should do.
|
17th December 2018, 21:36 | #3 |
This is my second home
ZT260 #243 (resting) Join Date: May 2010
Location: Prestonpans
Posts: 22,424
Thanks: 650
Thanked 4,624 Times in 3,358 Posts
|
I can't see how hand turning the engine in the wrong direction is going to do any damage. When you say would not start what do you mean, won't turn over, won't fire, what?
|
17th December 2018, 22:35 | #4 |
This is my second home
Rover 75 CDT Manual Connoisseur SE, Rover 75 CDT Automatic Connoisseur SE & a Freelander Td4. Join Date: Jul 2009
Location: Hampshire
Posts: 11,531
Thanks: 3,470
Thanked 3,119 Times in 2,247 Posts
|
On some chain driven diesel engines it can be a problem - IIRC Mercedes Benz had non ratchet hydraulic tensioners on the cam chains on some engines, and if turned backwards all the slack built up in the wrong place allowing the chain to jam or the valves to hit the pistons.
Haven't heard of any similar problems with the M47R, and I'd be amazed if there were given there are two separate timing chains on our engines, but if the OP has been told similar damage has occurred then worth carrying out a compression test. . Last edited by Mike Noc; 18th December 2018 at 09:23.. |
18th December 2018, 01:52 | #5 |
Been round the block
75 Tourer Join Date: Apr 2009
Location: Cannock
Posts: 4,115
Thanks: 3
Thanked 189 Times in 121 Posts
|
Done this myself, if it started before, and not after, the mechanic has forgot something, or damaged something. How does a garage say it is a write off.
Last edited by Devilish; 18th December 2018 at 01:58.. |
18th December 2018, 10:52 | #6 |
This is my second home
Rover 75 tourer Club CD/Limo Tints Join Date: Nov 2008
Location: Meneac
Posts: 6,759
Thanks: 5,007
Thanked 1,609 Times in 869 Posts
|
If it is something the "Mechanic" has done and damaged the engine then I would be after the "Mechanic" to sort it out at his cost.......
__________________
] "I started out with nothing, and Ive still got most of it left!" |
18th December 2018, 17:35 | #7 |
This is my second home
Rover 75 cdt club + Rover 2.5 KV6 Conni SE Join Date: May 2008
Location: Birmingham
Posts: 11,356
Thanks: 6,587
Thanked 2,262 Times in 1,729 Posts
|
Errr. Why did he turn the crank backwards/ forwards to change the auxiliary belt? Are you correct in your statement, or is it an assumption?
__________________
Great Barr, Birmingham. |
18th December 2018, 18:58 | #8 |
Been round the block
75 Tourer Join Date: Apr 2009
Location: Cannock
Posts: 4,115
Thanks: 3
Thanked 189 Times in 121 Posts
|
I have done it before, many times, last time on a M47, every time I tried to move the tensioner with the spanner, it come loose, so I wound the belt on turning the crank. Don't know why the mech would turn it opposite to its normal rotation. I always believed, the M47 chain tensioner is capable of allowing the crank to be turned in the opposite direction, otherwise the cam would chatter in normal rotation.
|
18th December 2018, 19:07 | #9 |
This is my second home
R75 Saloon. Join Date: Feb 2009
Location: France/or Devon.
Posts: 14,003
Thanks: 3,851
Thanked 2,167 Times in 1,816 Posts
|
If the broken belt was jammed behind the pulley then maybe the only way to release it was to turn the pulley in the opposite direction.---
|
18th December 2018, 19:09 | #10 |
This is my second home
75 Tourer 2.5 Auto, 1.8T, 75V8ZT Join Date: Jun 2007
Location: Johannesburg ZA
Posts: 6,200
Thanks: 1
Thanked 859 Times in 613 Posts
|
I agree. And I cannot see any ill effect from that either.
__________________
Worth his V8 in gold |
Thread Tools | |
Display Modes | |
|
|