25 replies to this topic

[Flatrightout]

hi all i plan to do the following

1) change cam
2) uprate head
3) roller rockers
4) lcb and exhaust

In the search for some more power,

The engine is a 1984 with 64k on it. Seemed fine before it was removed but don't have any history on it. Compression test was 120 psi there is slight scoring in the bores.

When installing the new cam, I plan to check and overhaul components if nessescary,

This is my first engine strip, can you mini experts help my out with a list of things I need to be checking / replacing.

Many thanks 😄

[Flatrightout]

Bump

[carbon]

There is a really good book on 'Tuning BL's A-Series Engine' by David Vizard, highly recommended reading for anyone looking to build a modified Mini engine. First published 30 years ago, this is the 'bible' and really has not been bettered.

 

Lots of guidance and example engine builds. Does not cover fuel injection, but this is not likely to be a problem in your case.

[Flatrightout]

Thanks for your reply, I actually have the book, I plan to use it to modify my head.

I was hoping a short list of things that I should defiantly change e.g oil pump, and things that I should inspect / measure that might be usable again e.g main bearings

whilst renewing the cam shaft the engine will be in bits, may as well doing thing properly hey

[Bubblebobble]

This series of videos may be of use for basic background knowledge and procedures , what order to do things etc .

 

[gazza82]

If the bores are scored you may need a re-bore or at least the bores honed. Otherwise you will use more oil and not get the best compression. I'd replace all the bearings, lock-nuts, and obviously gaskets. Water pump and oil pump, timing chain.

But first have bores and crank journals checked incase you need machining. Also the block and head faces for flatness.

[Cooperman]

At 64k it would be wise to consider a re-bore and new pistons the next size up.

[Spider]

There is a really good book on 'Tuning BL's A-Series Engine' by David Vizard, highly recommended reading for anyone looking to build a modified Mini engine. First published 30 years ago, this is the 'bible' and really has not been bettered.

 

Lots of guidance and example engine builds. Does not cover fuel injection, but this is not likely to be a problem in your case.

 

 

David's Book is good, but not complete (is anything ever?) it's also quite dated now, not that I'm at all throwing cold water on it!  As Carbon has, I do recommend it.

 

Another very good book, with a bit of a different way of looking at it all is Des Hammill's book  http://www.bookfinder.com/book/1845840232/   I also highly recommended it. It covers a lot of good stuff and many fundamental bits that is not at all discussed in any of David's books.

[Flatrightout]

Thanks for replys, any suggestions on budget for engine rebuild assuming no machine work ?

Do you know anyone who has a John speed engine ? If so any feed back plz Toying with the idea dear of plug and play !

Also is mini spares as good as anywhere for parts ?

suggestions of a cam ? Lumpy at idle is fine.

[gazza82]

Who is rebuilding? You or sending it away? If you, price it up on minispares site ... but don't be surprised if it mounts up I'd estimate £450-500 for the main short engine parts and that assumes the block and crank are OK ...

 

.. and a 64K engine? You will need some machining .. putting new rings in scratched bores or new shells on scratched journals is a waste of money ... you'll be rebuilding again very soon.

 

I someone is building it for you then add £45-50 per hour labour! You might be better off looking at an exchange engine ..

 

 

You probably mean jonspeed .. run a search on this forum for posts ...

 

I've got 99% of my parts from minispares ..  TMF+ gets you 7.5% discount for £5 ... well worth it. I spent over £400 on one order ... mainly engine parts but I had a fairly bare block so had to get studs, nuts, etc.

 

 

What do you want the engine to do? Low down torque, road, fast road, race? What revs do you want to have to pull to get any power? All need something different.

Edited by gazza82, 02 March 2015 - 09:29 AM.

[Cooperman]

When working on any classic car it is important to decide what you actually want to achieve.

A 1275 A-Series engine can be made to give anything from about 55 bhp to 125 bhp (more if forced induction). But there are advantages and disadvantages to each power level.

The more power you get the less low end torque and mid-range driveability you have. Different gearing is often needed to put the power down.

Many people 'over-cam' an engine and lose bottom-end which makes it more difficult to drive in traffic and not as pleasant overall.

So, first decide on how the vehicle is to be used. For example is it to be a competition car or just for the road?

Once that is decided on, an optimum specification can be evolved and an estimate of cost established. There is no such thing as a 'cheap, powerful & reliable' engine. With luck you can get any two of these, although 'cheap & reliable' is a bit of an oxymoron.

If adding power by way of some 'add-ons' be aware that increased power will show up any shortcomings elsewhere in the engine (pistons for example) more quickly and can end up in a further re-build in the short term.

You will need some machining, if only to get the compression ratio correct (after doing the measuring & calculating) so re-boring would be a good thing to do at this time with new pistons of the right type.

Best advice is to leave it alone unless you do the whole job properly.

[Flatrightout]

Yes u should have mentioned car is for road use, fun weekend car, that hopefully will have around 85 -95 bhp. Not going to light the streets up but better than the 55bhp of when standard. With this in mind do you have a cam suggestion. I intend to use it on A and B roads mainly.

I have access for some machine work such as head skimming, I am coming around to the fact that I might need a rebore, but intend to check everything before deciding on what needs doing. I am not going to bodge it.

I will be rebuilding engine, although this is my first mini rebuild, I build jet engines so have engineering knowledge and a manual and time. Don't fancy paying £45 per hour.

Can't believe how expensive mini engines are.

[Cooperman]

It's the labour that makes Mini engines, and most other engines, expensive.

You will have no problems building it yourself.

For a nice road engine do not over-cam it or you might not be pleased with the results. The Mini is never going to be a quick car in overall terms.

Best to build a nice driveable car with around 80 bhp and with that you can use a standard gearbox with a fairly high final drive ratio.

Consider the following:

 

Re-bore to the next size up and use 21253 pistons.

Set the compression ratio to 10:1

Gas-flow the cylinder head and fit 35.6 mm inlet and 29.5 mm ex. valves.

Lighten the flywheel slightly.

Use an MG Metro or Kent 266 cam (or equivalent SW or Piper).

Use a standard rocker shaft (not worth a 1.5:1 offset roller shaft as the gain is small for the cost)

LCB ex. manifold.

RC40 twin box 1.75" ex. system.

HIF44 carb on alloy inlet manifold.

Fit an Aldon 'Yellow' distributor

 

Build it all very carefully with help from on here and you will have a very nice Mini with good road performance for a classic car.

[gazza82]

I have access for some machine work such as head skimming, I am coming around to the fact that I might need a rebore, but intend to check everything before deciding on what needs doing. I am not going to bodge it.

 

Where are you based? We might be able to help out with suggestions of A-series friendly machining outfits.

 

My local guys hadn't seen one for a few years but had a few old Ford Pinto blocks (and some much more modern metal!) in the shop when I called in. They didn't need to do much to mine, but had it lightly honed and the crank journals checked and polished, and everything cleaned. They put the head through the wash too for a small donation to the tea/coffee/beer fund. They did fit my pistons to the rods as well as these are push-fit and needed a press (1275cc). They had been building them in the past for race engines .. just race engines have moved on ..

 

The rest, I am doing .. rebuilt a 1098 from a Midget back in the 80s .. and the first engine I took apart and rebuilt was an A-series .. out of a GPO Morry Minor van!

[carbon]

It's the labour that makes Mini engines, and most other engines, expensive.

You will have no problems building it yourself.

For a nice road engine do not over-cam it or you might not be pleased with the results. The Mini is never going to be a quick car in overall terms.

Best to build a nice driveable car with around 80 bhp and with that you can use a standard gearbox with a fairly high final drive ratio.

Consider the following:

 

Re-bore to the next size up and use 21253 pistons.

Set the compression ratio to 10:1

Gas-flow the cylinder head and fit 35.6 mm inlet and 29.5 mm ex. valves.

Lighten the flywheel slightly.

Use an MG Metro or Kent 266 cam (or equivalent SW or Piper).

Use a standard rocker shaft (not worth a 1.5:1 offset roller shaft as the gain is small for the cost)

LCB ex. manifold.

RC40 twin box 1.75" ex. system.

HIF44 carb on alloy inlet manifold.

Fit an Aldon 'Yellow' distributor

 

Build it all very carefully with help from on here and you will have a very nice Mini with good road performance for a classic car.

Cooperman's suggested build is a good blueprint for a good fast road 1275. The only change I would suggest based on experience with MD266 is using rockers which give slightly more lift, as this cam only has 260 thou lift at the lobe. This change really does improve mid-range and top end power at slight expense of smooth tickover. I used the offset bushes in std rockers, but the new Calver 1.4 ratio rockers look like they may be an even better option.

 

For the distributor make sure you use one with vacuum advance unless you are happy shelling out a lot more money on fuel - and would strongly recommend using 99 octane Shell V-Power or similar.