14 replies to this topic

[MinesRed]

Good evening.
So,on my A+1275 stage 1 I need to check the valve clearance's but the Haynes manual says 0.27-0.33 mm.
Just wondering if there is a more concrete clearance figure?
Cheers all..

[MiniMadRacer]

I believe its 12 thou (in old money) or 0.30 mm

[nicklouse]

It depends on the cam shaft.

[MinesRed]

It depends on the cam shaft.

Standard cam with high lift rockers

[Cooperman]

Maybe I'm a bit strange, but I always set the valve clearances to 12 thou.

The clearance is to ensure that as the valves heat up they still fully close and the stretch in valves is the same on all the engines, plus or minus a very small difference and because the coefficient of expansion is the same for all valves, the lengths don't alter much and the temperatures are virtually identical.

There will be some who say that smaller clearances alter the cam timimg slightly, which may be true, but not many will notice and tighter clearances technically increase full valve lift and increase the valve opening times very slightly. 

In 60 years with Minis I have always set 12 thou on all engines from standard 850's to very full-on 1380's and never had any issues.

[croc7]

Do a google search for ‘Calver valve clearance’. Its a great article on Calver’s Special Tuning website that explains why the A series engine uses different valve settings according to the type camshaft and rocker arm ratio in use. Good stuff.

[croc7]

It depends on the cam shaft.

Standard cam with high lift rockers

Basically, it’s .010” multiplied by your rocker arm ratio but varies according to your camshaft and rocker arm ratio. See Calver’s article on his Special Tuning website.

Edited by croc7, 10 March 2021 - 05:46 AM.

[nicklouse]

 

It depends on the cam shaft.

Standard cam with high lift rockers

 

What standard camshaft then? The A+ had a few different standard cams. But from the little info provided I would use 12 thou.

[Vanman20]

I've just set my MG metro engine at 14 thou if that helps

[MinesRed]

It depends on the cam shaft.

Standard cam with high lift rockers

What standard camshaft then? The A+ had a few different standard cams. But from the little info provided I would use 12 thou.

If there were different standard cams on the 1275 A+,I have no idea which one.
Can you determine from the engine number?

[MiniMadRacer]

Yes and No...You cant tell the CAM from the engine number but you can tell which "car" it came from and hence derive which CAM would have been fitted by the factory. Of course someone could have changed it since though

[Cooperman]

The problem is that because BMC/BLMC/ARG/ROVER were so bad at paying their bills, some subcontract manufacturers could refuse to deliver until an earlier bill had been paid. In the case of cams, this led to engines being fitted with whichever cam was in-stock. Thus an MG Metro could end up with a cam from a 998 Mini.

[MinesRed]

The problem is that because BMC/BLMC/ARG/ROVER were so bad at paying their bills, some subcontract manufacturers could refuse to deliver until an earlier bill had been paid. In the case of cams, this led to engines being fitted with whichever cam was in-stock. Thus an MG Metro could end up with a cam from a 998 Mini.

My word,really....every day n all that....
Cheers for the replies folks..

[Cooperman]

 

The problem is that because BMC/BLMC/ARG/ROVER were so bad at paying their bills, some subcontract manufacturers could refuse to deliver until an earlier bill had been paid. In the case of cams, this led to engines being fitted with whichever cam was in-stock. Thus an MG Metro could end up with a cam from a 998 Mini.

My word,really....every day n all that....
Cheers for the replies folks..

 

 

The Longbridge 'Accounts Payable' dep't took 180 days to pay an invoice - if you were lucky! They also wanted a really low price for everything.

The company of which I was the M.D. used to carry our design work for them on facilities and sometimes on product design, but I had to pay my staff at the end of every month and they took 6 months to pay, which meant large & expensive bank borrowings. In the end, they tried to screw me right down on the price for a fairly large job and then I said that the only agreement which we would reach was that I was not registered charity and they were not prepared to pay a fair price for a professional job! I walked away from them.

Later I met the head of Engineering Procurement and he told me about the situation with components such as cams, after I said I was not prepared to do any more work for Austin-Rover Group. he said I was not alone and he changed jobs soon after.

[MinesRed]

The problem is that because BMC/BLMC/ARG/ROVER were so bad at paying their bills, some subcontract manufacturers could refuse to deliver until an earlier bill had been paid. In the case of cams, this led to engines being fitted with whichever cam was in-stock. Thus an MG Metro could end up with a cam from a 998 Mini.

My word,really....every day n all that....
Cheers for the replies folks..

 
The Longbridge 'Accounts Payable' dep't took 180 days to pay an invoice - if you were lucky! They also wanted a really low price for everything.
The company of which I was the M.D. used to carry our design work for them on facilities and sometimes on product design, but I had to pay my staff at the end of every month and they took 6 months to pay, which meant large & expensive bank borrowings. In the end, they tried to screw me right down on the price for a fairly large job and then I said that the only agreement which we would reach was that I was not registered charity and they were not prepared to pay a fair price for a professional job! I walked away from them.
Later I met the head of Engineering Procurement and he told me about the situation with components such as cams, after I said I was not prepared to do any more work for Austin-Rover Group. he said I was not alone and he changed jobs soon after.

Well,there you go,I'd never have thought that of Austin-Rover...thanks for the insight..