32 replies to this topic

[Fordy]

I am looking to send my 12G940 cylinder head away to be reconditioned, has anyone got any hints/tips on what to ask to be done? I.e is there anything worth getting done while I send it away? Thanks

[Carlos W]

What's the car going to be used for? are you doing any other work?

you need to calculate your compression ratio so they know how much to skim

[Fordy]

I am currently just reconditioning a 1275 engine not purchased the car yet due to lack of space to store. When I do it wouldn't be used daily, just for a bit of fun and something to tinker with.

As it's my first time at a project like this I'm trying to use the experience and knowledge of others to guide me in terms of other work I am looking to do, so leaving it fairly flexible at the moment, but don't want to go to over the top as a first time rebuild.

[MRA]

You cannot get a cylinder head "tuned" without first knowing exactly what you have in the way of the engine, and carb, exhaust etc...

 

Well not and get it to work to it's best.

[Fordy]

So what type of engine, carb and exhaust details do I need to look into first? And then once I have them details how do I use them to decide where I want to go with them in terms of the cylinder head?

[MRA]

So what type of engine, carb and exhaust details do I need to look into first? And then once I have them details how do I use them to decide where I want to go with them in terms of the cylinder head?

 

Well, what are you trying to achieve ? and how much do you want to spend, then cost out what you want and then remove the parts you can do without until it hits your budget, that is of course assuming you have a budget ?

 

But a full engine build if done to a reasonable state is not going be a few quid....  some of the top race Mini engines are in the £20k+ region, so the big question is budget and how much can you do yourself to reduce the costs ?

[Fast Ivan]

I am looking to send my 12G940 cylinder head away to be reconditioned, has anyone got any hints/tips on what to ask to be done? I.e is there anything worth getting done while I send it away? Thanks

things to check and get done would be -

convert to unleaded

check valves for pitting and check stem diameter, replace if needed

check valve to valve guide clearance, new valve guides if needed

guides machined to size if new

valve seats recut

new valve springs

chase out all threads

de-coke and clean

skim if needed

 

Now is a good time, if funds allow, to work the head for more power.

normally that means larger valves and some porting work done, but does have a cost implication.

 

All of this has to be taking in to account with your overall engine build and what you want to achieve

[blacktulip]

Rimflo valves

[Fordy]

Thanks for the responses. I am looking to achieve a just above standard build but leaving myself enough flexibility in the future to build upon. Not looking to achieve anything in the region of top face mini spec.

Budget wise I've not got a solid figure as such, looking to weigh up options, and find a middle ground between cost to benifit.

I'm currently out of action to do any work at the moment so thought it would be ideal for me to get someone more specialised to do the cylinder head.

Looking at the current head I have it looks like most parts would need to be replaced/have work done to them froom reading the list above.

Would work such as larger valves mean that further modification MUST be done? Or would it leave me flexibility for the future?

[carbon]

Fordy,

 

If you are running close to standard engine spec then you could decoke the cylinder head and regrind the valves with very little equipment needed (just a valve spring compressor and a stick to twirl the valves). Total cost about £25, plus yout time.

 

If it's not already converted to unleaded and you are not doing big mileage, then the alternative is to use Castrol Valvemaster when you refill the petrol tank, works out at a few pence per mile.

[Fordy]

 

So what type of engine, carb and exhaust details do I need to look into first? And then once I have them details how do I use them to decide where I want to go with them in terms of the cylinder head?

 

Well, what are you trying to achieve ? and how much do you want to spend, then cost out what you want and then remove the parts you can do without until it hits your budget, that is of course assuming you have a budget ?

 

But a full engine build if done to a reasonable state is not going be a few quid....  some of the top race Mini engines are in the £20k+ region, so the big question is budget and how much can you do yourself to reduce the costs ?

 

I have given this some thought over the past couple of days on what I want to achieve, I am looking for a fast road car, not to take onto track or compete. I have looked at a coupe of cams and been speaking to a few people of experiences they have had with various cams, and have liked the look/sound/characteristics/experiences of the Kent 276 and the Kent 286. Is this something I need to factor into the work I get done on the head? And would other necessary upgrades need to be done with either of these two cams?  

[Fordy]

Fordy,

 

If you are running close to standard engine spec then you could decoke the cylinder head and regrind the valves with very little equipment needed (just a valve spring compressor and a stick to twirl the valves). Total cost about £25, plus yout time.

 

If it's not already converted to unleaded and you are not doing big mileage, then the alternative is to use Castrol Valvemaster when you refill the petrol tank, works out at a few pence per mile.

 

I am looking to get it converted the unleaded. And as quoted in the post above I have given it some more thought the past couple of days after discussing with a few people. And really fancy a Kent 276 or 286 cam, just curious on the other modifications this would be some could budget it up and see if it is a reasonable idea.

[carbon]

Fordy,

 

If you're going down the 286 path then that's a completely different ball game.

 

Others on this forum will have first hand experience, but would suggest that to get best out of 286 you're looking at increasing CR, a well modified head with 35.5 or larger inlets, modified distributor or mapped ignition system, uprated carb(s), better inlet manifold, decent exhaust system and possibly a rebuilt gearbox with new diff ratio and a close ratio gearset to make the most of the peak power band... and better brakes.

[Fordy]

Fordy,

 

If you're going down the 286 path then that's a completely different ball game.

 

Others on this forum will have first hand experience, but would suggest that to get best out of 286 you're looking at increasing CR, a well modified head with 35.5 or larger inlets, modified distributor or mapped ignition system, uprated carb(s), better inlet manifold, decent exhaust system and possibly a rebuilt gearbox with new diff ratio and a close ratio gearset to make the most of the peak power band... and better brakes.

 

Carbon,

 

Thank for that information is helpful to see the amount of work would be involved, do you have any idea of how much we would be talking for these kind of upgrades? I shall have a look around on other forums for peoples experiences with the Kent 286.

 

Have you had any experience with the 276? And would as much work be required with this cam?

 

Would you say that building the engine around the cam would be the best thing to do?

[MRA]

The 276 will work ok with a standard head but a slightly modified head will make it work better, a 286 will not reach it's true potential with a standard head...  Same goes for exhaust system, although a 276 on a standard exhaust will be a fair way down on it's true potential and a 286 will be rubbish to drive and not produce the goods...

 

Both will require a modified distributor or better still an aftermarket ECU

 

It is like cooking, you go to a pizzaria and have topping on bread, you would probably be slightly annoyed at getting a beef steak on pizza bread as it doesn't really go together too well...

 

Organise how much you want to spend, then decide how much you can actually spend, get a quote for 5 hours on a rolling road, as this should get it tuned up pretty close, it won't win prizes for dyno tune but it will get you a much more reliable engine for your money.

 

Then make a list of what engine parts you need, don't forget oil and filter, and then go about costing it up you will then in all probability have to carve stuff off your list to make it fit your budget, once done put you list up here to see if anything is missing

 

But just fitting a new cam is going to end in tears, at this stage you either need to keep your engine running or perform a full strip and rebuild, using ALL new soft parts and possibly quite a few core parts.... reground crank, rebored block etc