Nodge68
Well-Known Member
The automatic tensioner is anchored by a bolt threaded into the head. The manual tensioner head doesn't so the threaded hole isn't there to start with.
I can't see why you can't retrofit a manual tensioner to an auto tensioner engine provided you use the correct belt.
I can't see why you can't retrofit a manual tensioner to an auto tensioner engine provided you use the correct belt.
Last edited:
htr
Well-Known Member
Just to clarify: I'm thinking of modifying a manual tensioner to be an auto tensioner.
What does the manual tensioning head lack that an auto tensioning head has?
Both will have the tensioner bolted to the head. Both will have a second bolt which the spring arm rests against in an auto tensioner and the clamps the base plate of a manual tensioner. Is that bolt in a different position?
HTR
What does the manual tensioning head lack that an auto tensioning head has?
Both will have the tensioner bolted to the head. Both will have a second bolt which the spring arm rests against in an auto tensioner and the clamps the base plate of a manual tensioner. Is that bolt in a different position?
HTR
htr
Well-Known Member
Why bother? well I was working on a train of thought which could be incorrect. I'm fishing for information from the collective experience, wisdom [ often won at great expense $$$$ 
I'm wanting to avoid that awful expense! ] and humour.
My thinking is this: manually adjusted cam belts must need to be adjusted periodically to compensate for any stretch the belt develops over its service life - hence their name. Where-as the auto tensioning takes care of this for you. I like the idea of not having to remove the belt covers and adjust every 20 or 30,000km. As I'm probably going to have to swap a head over in the near future I was wondering if this mod was feasible.
If it involves drilling and tapping holes in a head it may potentially not be worth-while. Swapping drive cogs over isn't a drama - I hope. The cam ones have got to come off anyway.
HTR
I'm wanting to avoid that awful expense! ] and humour.My thinking is this: manually adjusted cam belts must need to be adjusted periodically to compensate for any stretch the belt develops over its service life - hence their name. Where-as the auto tensioning takes care of this for you. I like the idea of not having to remove the belt covers and adjust every 20 or 30,000km. As I'm probably going to have to swap a head over in the near future I was wondering if this mod was feasible.
If it involves drilling and tapping holes in a head it may potentially not be worth-while. Swapping drive cogs over isn't a drama - I hope. The cam ones have got to come off anyway.
HTR
jamesmartin
Well-Known Member
Why bother? well I was working on a train of thought which could be incorrect. I'm fishing for information from the collective experience, wisdom [ often won at great expense $$$$
My thinking is this: manually adjusted cam belts must need to be adjusted periodically to compensate for any stretch the belt develops over its service life - hence their name. Where-as the auto tensioning takes care of this for you. I like the idea of not having to remove the belt covers and adjust every 20 or 30,000km. As I'm probably going to have to swap a head over in the near future I was wondering if this mod was feasible.
If it involves drilling and tapping holes in a head it may potentially not be worth-while. Swapping drive cogs over isn't a drama - I hope. The cam ones have got to come off anyway.
HTR
it doesnt work that way ,your trying to solve a non problem
htr
Well-Known Member
Hmm, you may well be right. But, those are the best kind to have and solve! : D
Was my reasoning accurate? re' reducing a maintenance task. How often is it recommended that a manual cam belt tensioner be adjusted.
Why was there a change to auto adjusting tensioners? After all I think they cost a little more.
I guess the reasoning applies to distributor ignition verses coil pack ignition too. They must have been improvements.
HTR
Was my reasoning accurate? re' reducing a maintenance task. How often is it recommended that a manual cam belt tensioner be adjusted.
Why was there a change to auto adjusting tensioners? After all I think they cost a little more.
I guess the reasoning applies to distributor ignition verses coil pack ignition too. They must have been improvements.
HTR
jamesmartin
Well-Known Member
cam belts arent adjusted as part of a service routine ,they are fitted,adjusted and left till time to change,
Nodge68
Well-Known Member
The only reason that Rover swapped to the auto tensioner was for cost saving. The manual tensioner needs to be pre tensioned by the use of a spring and bolt, both of which are discarded after use.
The auto tensioner is a self contained one piece unit that is pre set on fitting.
I prefer the manual tensioner, it's easier to use with no chance of being incorrect.
Is Jamesmartin said, there's no need to adjust the timing belt in its service life. In fact if it is re tensioned in service, it will likely fail.
Last edited:
Northern Irelander
Well-Known Member
143 teeth manual tensioner with 23mm bolt (except VVC engines which have 26mm bolt)
145 teeth automatic tensioner with 26mm bolt.
Not sure you are right about the sprockets and pulley, last I counted there are 48 teeth on K16 cam sprockets (LHB 101360)..............away to check parts bin!
