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M.J.
 
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Default Morris 803 info needed please

Hi

I'm trying to find ignition timing settings for a marinised BMC 803
engine (as fitted to the early minis/minors and Austin A35s). The
engine has been recently overhauled and I believe it has been fitted
with an unleaded cylinder head so would it be necesssary to retard the
ignition to run on u/l fuel?

I also need contact breaker and plug gap settings. Could anybody
please assist?

Many thanks in advance

MJ
  #2   Report Post  
Graham W
 
Posts: n/a
Default

M.J. wrote:
I'm trying to find ignition timing settings for a marinised BMC 803
engine (as fitted to the early minis/minors and Austin A35s).


The 803cc APHM is an even smaller version of the A series than the 848cc
motor fitted to the early Minis. It was fitted to Minors from about 1953
to 1957 when it was replaced with the 948cc version which has a larger
bore. The smallest Mini motor is the 848cc which is a 948cc with a
shorter stroke.

The
engine has been recently overhauled and I believe it has been fitted
with an unleaded cylinder head so would it be necesssary to retard the
ignition to run on u/l fuel?


Unlikely.

The unleaded cylinder head would basically have hardened valve seats to
prevent valve recession. I would think modern unleaded has at least the
same octane as 1953 British petrol! In practice I would treat the
recommended ignition timing as no more than a starting point. With
modern fuels and after a rebuild you may get away with considerably
advanced timing. Listen for pinging.

I also need contact breaker and plug gap settings. Could anybody
please assist?


Ignition timing: 2 deg before top dead centre, 3/32" or 2.4mm at the
perephery of the crankshaft pully.

Contact breaker gap: 0.010 to 0.012 in. (0.25 to 0.30mm)
Contact breaker gap (high lift cam): 0.014 to 0.016 in. (0.36 to 0.40mm)
(it's probably the latter)

Spark plugs: Champion N5 (was code NA8), 14mm, 3/4" reach,
Plug gap: 0.025 in., 0.64mm.

Condenser capacity: 0.2mf
Vacuum advance 7 to 9 deg
Centrifugal advance 17 to 19 deg, starts 400 to 650RPM.

The distributor is probably a Lucas 25D4 also used in many early Minis,
Minors, Hillmans, etc. Later (up to at least 1980ish) Mini distributors
are probably interchangeable for fit. There are many many different
advance curves, and with modern fuels it's anyone's guess what would be
optimum. Since you probably use the motor to idle or to go at hull
speed, I'd set up the timing for best performance at hull speed.

As you have probably worked out, I've got a Minor workshop manual here,
so if there's anything else you'd like to know from it, just ask, or
contact your local Minor specialist.

Graham.

Remember to adjust my email address slightly...
  #3   Report Post  
Tim Christian
 
Posts: n/a
Default


Graham W wrote in message
...
M.J. wrote:
I'm trying to find ignition timing settings for a marinised BMC 803
engine (as fitted to the early minis/minors and Austin A35s).


The 803cc APHM is an even smaller version of the A series than the 848cc
motor fitted to the early Minis. It was fitted to Minors from about 1953
to 1957 when it was replaced with the 948cc version which has a larger
bore. The smallest Mini motor is the 848cc which is a 948cc with a
shorter stroke.

The
engine has been recently overhauled and I believe it has been fitted
with an unleaded cylinder head so would it be necesssary to retard the
ignition to run on u/l fuel?


Unlikely.

The unleaded cylinder head would basically have hardened valve seats to
prevent valve recession. I would think modern unleaded has at least the
same octane as 1953 British petrol! In practice I would treat the
recommended ignition timing as no more than a starting point. With
modern fuels and after a rebuild you may get away with considerably
advanced timing. Listen for pinging.

I also need contact breaker and plug gap settings. Could anybody
please assist?


Ignition timing: 2 deg before top dead centre, 3/32" or 2.4mm at the
perephery of the crankshaft pully.

Contact breaker gap: 0.010 to 0.012 in. (0.25 to 0.30mm)
Contact breaker gap (high lift cam): 0.014 to 0.016 in. (0.36 to 0.40mm)
(it's probably the latter)

Spark plugs: Champion N5 (was code NA8), 14mm, 3/4" reach,
Plug gap: 0.025 in., 0.64mm.

Condenser capacity: 0.2mf
Vacuum advance 7 to 9 deg
Centrifugal advance 17 to 19 deg, starts 400 to 650RPM.

The distributor is probably a Lucas 25D4 also used in many early Minis,
Minors, Hillmans, etc. Later (up to at least 1980ish) Mini distributors
are probably interchangeable for fit. There are many many different
advance curves, and with modern fuels it's anyone's guess what would be
optimum. Since you probably use the motor to idle or to go at hull
speed, I'd set up the timing for best performance at hull speed.

As you have probably worked out, I've got a Minor workshop manual here,
so if there's anything else you'd like to know from it, just ask, or
contact your local Minor specialist.

Graham.

Remember to adjust my email address slightly...


I have the manual for the Vedette (marinised) version here. In practice, I
have found that timing settings are better finally adjusted by ear!

If you have the version with the Solex carb. make sure that the idler jet
screw is correctly set. In practice, this means adjusting the tickover as
normal, then opening out the idler screw a couple of turns! This is because,
at slow speeds, the carb. runs on the idler so mixture becomes progressively
weaker as the throttle opens until the main jet opens. This results in
engine overheat - which vaporizes the fuel in the carb (which is just under
the hottest part of the manifold).

I had to set up a Vedette (A-series) on which someone had moved the flywheel
so the timing markings no longer applied. I felt for TDC through No. 1 plug
hole with a screw driver and set the distributor up on this. The engine
strated OK. Next, I let it warm up, then increased speed to about 2000 rpm,
slackened of the distributor clamp and rocked the distributor a little until
the engine ran as smoothly as possible. It has run fine for four years on
LRP.



  #4   Report Post  
M.J.
 
Posts: n/a
Default

Hi Graham

Thank you very much for the info - much appreciated.


MJ

Graham W wrote in message ...
M.J. wrote:
I'm trying to find ignition timing settings for a marinised BMC 803
engine (as fitted to the early minis/minors and Austin A35s).


The 803cc APHM is an even smaller version of the A series than the 848cc
motor fitted to the early Minis. It was fitted to Minors from about 1953
to 1957 when it was replaced with the 948cc version which has a larger
bore. The smallest Mini motor is the 848cc which is a 948cc with a
shorter stroke.

The
engine has been recently overhauled and I believe it has been fitted
with an unleaded cylinder head so would it be necesssary to retard the
ignition to run on u/l fuel?


Unlikely.

The unleaded cylinder head would basically have hardened valve seats to
prevent valve recession. I would think modern unleaded has at least the
same octane as 1953 British petrol! In practice I would treat the
recommended ignition timing as no more than a starting point. With
modern fuels and after a rebuild you may get away with considerably
advanced timing. Listen for pinging.

I also need contact breaker and plug gap settings. Could anybody
please assist?


Ignition timing: 2 deg before top dead centre, 3/32" or 2.4mm at the
perephery of the crankshaft pully.

Contact breaker gap: 0.010 to 0.012 in. (0.25 to 0.30mm)
Contact breaker gap (high lift cam): 0.014 to 0.016 in. (0.36 to 0.40mm)
(it's probably the latter)

Spark plugs: Champion N5 (was code NA8), 14mm, 3/4" reach,
Plug gap: 0.025 in., 0.64mm.

Condenser capacity: 0.2mf
Vacuum advance 7 to 9 deg
Centrifugal advance 17 to 19 deg, starts 400 to 650RPM.

The distributor is probably a Lucas 25D4 also used in many early Minis,
Minors, Hillmans, etc. Later (up to at least 1980ish) Mini distributors
are probably interchangeable for fit. There are many many different
advance curves, and with modern fuels it's anyone's guess what would be
optimum. Since you probably use the motor to idle or to go at hull
speed, I'd set up the timing for best performance at hull speed.

As you have probably worked out, I've got a Minor workshop manual here,
so if there's anything else you'd like to know from it, just ask, or
contact your local Minor specialist.

Graham.

Remember to adjust my email address slightly...

  #5   Report Post  
Graham W
 
Posts: n/a
Default

Tim Christian wrote:
I have the manual for the Vedette (marinised) version here.


We live and learn. Was this a factory job or just a big marine supplier
in the UK?

In practice, I
have found that timing settings are better finally adjusted by ear!


Yep. Engines age and fuels have changed enormously over 50 years.


  #6   Report Post  
Tim Christian
 
Posts: n/a
Default


Graham W wrote in message
...
Tim Christian wrote:
I have the manual for the Vedette (marinised) version here.


We live and learn. Was this a factory job or just a big marine supplier
in the UK?

In practice, I
have found that timing settings are better finally adjusted by ear!


Yep. Engines age and fuels have changed enormously over 50 years.


The Vedette series of marinized BMC A series and their own gear box were
made by Newage Lyon Ltd., Stamford, Lincs. I don't think they are still in
existence.

Some spares are held by Sheridan Marine, but DSN Classics of Attleborough,
Norfolk are also a good source. They also rebuild them.

Newage must have made at least a thousand of these units in the late '50s,
'60s. They are found in a lot of Freeman 22s, for example. The Mk VI (1957 -
1964) used a 950 cc engine; the Mk VII (1964 to 1967) used an 1100 cc unit.

Final thought: it is well worth fitting a thermostat. I use the 72 deg C
tropical version for the Minor from DSN.



  #7   Report Post  
M.J.
 
Posts: n/a
Default

Hi Tim

Thanks for that. Now you come to mention it, it's fitted with an SU
carb - any ideas on how to set the mixture on these?


MJ


"Tim Christian" wrote in message ...
Graham W wrote in message
...
M.J. wrote:
I'm trying to find ignition timing settings for a marinised BMC 803
engine (as fitted to the early minis/minors and Austin A35s).


The 803cc APHM is an even smaller version of the A series than the 848cc
motor fitted to the early Minis. It was fitted to Minors from about 1953
to 1957 when it was replaced with the 948cc version which has a larger
bore. The smallest Mini motor is the 848cc which is a 948cc with a
shorter stroke.

The
engine has been recently overhauled and I believe it has been fitted
with an unleaded cylinder head so would it be necesssary to retard the
ignition to run on u/l fuel?


Unlikely.

The unleaded cylinder head would basically have hardened valve seats to
prevent valve recession. I would think modern unleaded has at least the
same octane as 1953 British petrol! In practice I would treat the
recommended ignition timing as no more than a starting point. With
modern fuels and after a rebuild you may get away with considerably
advanced timing. Listen for pinging.

I also need contact breaker and plug gap settings. Could anybody
please assist?


Ignition timing: 2 deg before top dead centre, 3/32" or 2.4mm at the
perephery of the crankshaft pully.

Contact breaker gap: 0.010 to 0.012 in. (0.25 to 0.30mm)
Contact breaker gap (high lift cam): 0.014 to 0.016 in. (0.36 to 0.40mm)
(it's probably the latter)

Spark plugs: Champion N5 (was code NA8), 14mm, 3/4" reach,
Plug gap: 0.025 in., 0.64mm.

Condenser capacity: 0.2mf
Vacuum advance 7 to 9 deg
Centrifugal advance 17 to 19 deg, starts 400 to 650RPM.

The distributor is probably a Lucas 25D4 also used in many early Minis,
Minors, Hillmans, etc. Later (up to at least 1980ish) Mini distributors
are probably interchangeable for fit. There are many many different
advance curves, and with modern fuels it's anyone's guess what would be
optimum. Since you probably use the motor to idle or to go at hull
speed, I'd set up the timing for best performance at hull speed.

As you have probably worked out, I've got a Minor workshop manual here,
so if there's anything else you'd like to know from it, just ask, or
contact your local Minor specialist.

Graham.

Remember to adjust my email address slightly...


I have the manual for the Vedette (marinised) version here. In practice, I
have found that timing settings are better finally adjusted by ear!

If you have the version with the Solex carb. make sure that the idler jet
screw is correctly set. In practice, this means adjusting the tickover as
normal, then opening out the idler screw a couple of turns! This is because,
at slow speeds, the carb. runs on the idler so mixture becomes progressively
weaker as the throttle opens until the main jet opens. This results in
engine overheat - which vaporizes the fuel in the carb (which is just under
the hottest part of the manifold).

I had to set up a Vedette (A-series) on which someone had moved the flywheel
so the timing markings no longer applied. I felt for TDC through No. 1 plug
hole with a screw driver and set the distributor up on this. The engine
strated OK. Next, I let it warm up, then increased speed to about 2000 rpm,
slackened of the distributor clamp and rocked the distributor a little until
the engine ran as smoothly as possible. It has run fine for four years on
LRP.

  #8   Report Post  
M.J.
 
Posts: n/a
Default

Thanks to all for all our replies and info (sorry about delay in
responding - only just checked this ng)

Thanks again


MJ (M.J.) wrote in message m...
Hi Graham

Thank you very much for the info - much appreciated.


MJ

Graham W wrote in message ...
M.J. wrote:
I'm trying to find ignition timing settings for a marinised BMC 803
engine (as fitted to the early minis/minors and Austin A35s).


The 803cc APHM is an even smaller version of the A series than the 848cc
motor fitted to the early Minis. It was fitted to Minors from about 1953
to 1957 when it was replaced with the 948cc version which has a larger
bore. The smallest Mini motor is the 848cc which is a 948cc with a
shorter stroke.

The
engine has been recently overhauled and I believe it has been fitted
with an unleaded cylinder head so would it be necesssary to retard the
ignition to run on u/l fuel?


Unlikely.

The unleaded cylinder head would basically have hardened valve seats to
prevent valve recession. I would think modern unleaded has at least the
same octane as 1953 British petrol! In practice I would treat the
recommended ignition timing as no more than a starting point. With
modern fuels and after a rebuild you may get away with considerably
advanced timing. Listen for pinging.

I also need contact breaker and plug gap settings. Could anybody
please assist?


Ignition timing: 2 deg before top dead centre, 3/32" or 2.4mm at the
perephery of the crankshaft pully.

Contact breaker gap: 0.010 to 0.012 in. (0.25 to 0.30mm)
Contact breaker gap (high lift cam): 0.014 to 0.016 in. (0.36 to 0.40mm)
(it's probably the latter)

Spark plugs: Champion N5 (was code NA8), 14mm, 3/4" reach,
Plug gap: 0.025 in., 0.64mm.

Condenser capacity: 0.2mf
Vacuum advance 7 to 9 deg
Centrifugal advance 17 to 19 deg, starts 400 to 650RPM.

The distributor is probably a Lucas 25D4 also used in many early Minis,
Minors, Hillmans, etc. Later (up to at least 1980ish) Mini distributors
are probably interchangeable for fit. There are many many different
advance curves, and with modern fuels it's anyone's guess what would be
optimum. Since you probably use the motor to idle or to go at hull
speed, I'd set up the timing for best performance at hull speed.

As you have probably worked out, I've got a Minor workshop manual here,
so if there's anything else you'd like to know from it, just ask, or
contact your local Minor specialist.

Graham.

Remember to adjust my email address slightly...

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