13 replies to this topic

[Roboxyz]

I have build a tribute style Mk1 look cooper, this has been built from an abandoned project so the bulk of the parts were in cardboard boxes.

my issue is the 1275 engine was complete, it is based on an A+block possibly an spi as it has a timing sensor bracket on the timing cover. The head is an early flat top 12g940 with 33/29 valves with single collet valves and single spring.
when I removed the head to check the condition I found that the last owner had started to profile the head by taking out the small ridge machined around the valve seat and smooth out the rough casting.

no work had been done on the inlets or exhaust port.

I completed the head to match the work already done but a close inspection the previous work was not to very good standard.

 

Before I spend money on this head getting the head skimmed and the valve guides done, is there a better head that will fit. I would like to have the head modified for unleaded fuel 

 

info on the engine, it has twin 1 1/2 SU , flowmaster big bore , accuspark 59d electronic ignition, the engine had no engine number?
I am looking for reliability before performance.

 

 

 

 

 

[Turbo Phil]

What’s the issue with the work already done ? Can it not be tidied up if it’s not very neat ?

Phil.

[Johnmar]

If it is an SPI head, it will have the inserts for unleaded.

(If I remember correctly, al factory unleaded heads had a rivet at the back side of the head where the thermostat housing is.).
(The above statement on the rivet was wrong (as Turbo Scott pointed out)

So if the prevous owner only cleanend up the ports and addressed the ridge at the valve seat, but the did not touch the valve seats themself, you are ok.

I would then lap in valves, install valve springs and spark plugs. Then place the head upside down horizontal on a bench (by using some wooden blocks) and fill the "combustion chamber" of the head with thin oil. And then wait and see if the oil stays there.

Edited by Johnmar, 16 October 2020 - 02:20 PM.

[Turbo Phil]

If it is an SPI head, it will have the inserts for unleaded. (If I remember correctly, al factory unleaded heads had a rivet at the back side of the hed where the thermostat housing is.). So if the prevous owner only cleanend up the ports and addressed the ridge at the valve seat, but the did not touch the valveseats themself, you are ok.

I would then lap in valves, install valve springs and spark plugs. Then place the head upside down horizontal on a bench (by using some wooden blocks) and fill the "combustion chamber" of the head with thin oil. And then wait and see if the oil stays there.

Unless it’s been converted the head will not be unleaded as he mentioned it’s an early casting. The rivet on the end of the head does not mean it’s unleaded.

Phil.

[Dusky]

What exactly do you think needs repairing?
You mention better heads, better for what?
A bunch of pictures would say a million words.

[KTS]

sensor bracket on the timing chain cover was i think fairly standard for most A+ units whether normally aspirated or injected

 

something else to consider is that any rework of the combustion chambers will alter the volumes, which will in turn affect the compression ratios

 

if you could post some photos of the cylinder head it would help gauge whether it's likely to be problematic or not

[cal844]

sensor bracket on the timing chain cover was i think fairly standard for most A+ units whether normally aspirated or injected

something else to consider is that any rework of the combustion chambers will alter the volumes, which will in turn affect the compression ratios

if you could post some photos of the cylinder head it would help gauge whether it's likely to be problematic or not

Sensor bracket was only fitted to 1990 onwards cars, whether or not its injection or N/A.

[Spider]

Maybe at this juncture, some photos would be in order so we can all see what it is and advise from there.

[Roboxyz]

 A51C08F6-C6AB-4FFA-9517-3034173BC1C3.jpeg   45.43K   35 downloads

 

 FF2CAA63-D11E-4B37-86B7-BEAAB7B79C9C.jpeg   37.63K   25 downloads

 

My opinion is that the head is not from an A plus engine the previous owner has picked this head for the engine but I do not understand why. 
I fitted the head to run the engine. The engine pulls well but the compression test is only about 155-160psi on all cylinders, there were signs of recent honing on the bores and everything seem to run OK,

 I will need to do the calcs for the head skim and spend £££’s getting the valve guides and valve seats fitted for unleaded.

is there another choice of head that would of been fitted to this engine.

[Turbo Phil]

I think pictures of the head work in question might be more useful than pictures of the car. Ha ha
On another note, If you’re hoping to make some decent power the first thing you should do is scrap those air filters. They neither filter or flow well at all.

Phil.

[nicklouse]

I spy with my little eye.....

 

the fan is fitted incorrectly.

[Spider]

I think pictures of the head work in question might be more useful than pictures of the car. Ha ha

 

Well,,,,, I did ask and yes, photos were posted,,,,,

My fault, 40 lashings,,,,
 

[DomCr250]

 

I think pictures of the head work in question might be more useful than pictures of the car. Ha ha

 

Well,,,,, I did ask and yes, photos were posted,,,,,

My fault, 40 lashings,,,,
 

 

Thats like the old tekki joke - 'you got copies and back-ups of your discs'?  Yes replies the customer, going to the filling cabinet and producing photocopies of the floppy discs.... 

[Roboxyz]

The pics were to show that the head is on a running mini, I wanted to get the mini off the SORN and back on the road as quick as possible to check out the mini after an extensive nut and bolt rebuild. I have a few snagging points that will need to be sorted. Getting the latter type shell to look like an earlier mini was not a simple rebuild.

 

I do not know who started this project, someone had bailed out of finishing this car, it had changed hands a few times before I took over, the shell had some parts fitted to get it on 4 wheels the rest of the parts were in several cardboard boxes.

 

So before I take the the head off I need to have a clear idea of choices, unless the older style flat top head gives me some benefits then I would prefer to fit a standard head back on, my best guess is that the earlier head gives the choice of fitting the twin SU’s and LBC exhaust???