22 replies to this topic

[Lt-SilverDragon]

Hi guys, I'm going to have to remove my engine because the thread is knackered in one of the dif end casing holes so I'm pretty sure it's got to come out to sort. This also gives me an excuse to inspect the bottom end as it has unknown modifications. Apparently it is a 1293 with lightened internals but I have no clue what's been done to it and I want to know what cam is in it. If I'm going that far I figured I might as well rebuild it, now the engine is a collection of bits and pieces. It's in a 1275gt but not sure if engine is original, it's an A series not A+ but has a rod change gearbox.
 
I'm not looking for uber performance but to increase the longevity of the engine and to make sure it that it can cope with being thrashed, this won't be a daily or out like that but I want decent performance out of it but it's not really my main gain. I want the best parts I can afford for my lil clubby and my credit card has been taking a massive whack.
 
Anyway parts fitted to engine by me so far
 
12G1805 Head (Cooper S Spec) - Bought off "The Matt", apparently modified by Longman craftsmanship
43D4 Electronic distributor DLB105 Coil & Amethyst fully mappable ignition
Rebuilt HIF44 carb with ram air pipe and BAP needle
RC40 twin box system with 3 into y piece manifold
Super water pump - minispares
ROCKER ASSEMBLY 1.5 HI LIFT FORGED ROCKER - minispares
COMPETITION HEAD STUD AND NUT KIT - minispares
 
For the likes of the big ends and thrust washers do I just get standard 1275 items? Because they say except cooper S but I thought the GT engine and S were pretty similar?
 
Washers
Big End
Gaskets
Oil pump
Core plugs
 
 
Upgraded parts, are any of these a good idea to get while rebuilding or not worth it?
 
Central oil pipe
Cam followers
Med Steel pushrods
ARP conrod bolt set
Kent MD276
Swiftune SW8  - I'd like this cam but will this fit an A series

I'd like the swiftune cam with a decent duplex timing chain and sprockets, will new standard pushrods and new conrod bolts be good enough as I think they're only needed for high revving engines and that cam will be out of power by then.
 
 
When I had the head off, the bores look good so I'm not needing a rebore and I want to re-use the conrods and pistons etc but I will be wanting the engine cleaned. Is it best to take it to someone who can chemically clean it or ultrasonically clean it?
 
As far as the gearbox is concerned I don't want to touch it yet as I am on somewhat of a budget but if I need to upgrade parts I will.
 
Any inputs and thoughts would be muchly appreciated, although I'm not very knowledgeable on the mini engine or performance parts I've been working on cars the last 8 or 9 years in my spare time and I've fairly confident in my ability to strip the engine down and rebuild it and have all the tools needed also.

Edited by Lt-SilverDragon, 03 October 2015 - 04:30 PM.

[carbon]

Reason that some 1275 engine parts are marked up 'for Cooper S' is that the size of big-end journal is 1.625 inch as compared to the 1275GT and other Mini 1275 engines which have 1.75 inch big-end journals. Connecting rod bolts are also different size on the Cooper S.

 

If you're planning on a cam swap to MD276 or SW8 and keeping the 1.5 lift rockers expect to gain horses at mid to high rpm but lose a lot of lower end torque. If you use the car in busy town traffic you may find this gets very tiresome. And to get best out of 276/SW8 and 1.5 rockers where road conditions are favourable may need closer ratio gearbox which in turn begs the question about what final drive ration to go for...

 

Central oil pipe essential fitment unless you're just planning to go fast in straight line. New cam followers are also essential if you fit a different cam. Unless your pushrods are bent I would stick with what you have already.

[Lt-SilverDragon]

It's all country roads for me mate, I live in a small village that leads out to 60s in all directions so town driving will be limited as this will be my fun car as I have a couple of dailys. Both turbo diesels and I love the rush you get once you get boost so I don't mind losing the bottom end. I'll consider the milder swiftune cam but according to their website there test car is running 1.5s and the profile is better then the 276 for town driving, if I go for the SW8 I'll buy a set of 1.3s and see how I like both and then sell the other set or see how I like it with 1.5s and if I need the lower end I can alway get 1.3s.

Ok that's great so I'll get regular stuff, I'll not order till it's stripped down so I can see exactly what it needs.

I'll need to see what final drive is in.

[rally1380]

£95 for pushrods.....yikes!!!!  And they don't add any power!!

 

 

Best thing to do is get the engine out, an get the gearbox and block split apart so you can have a good look at the bottom end.  You need to do this to

 

A - establish what crank you have (this will dictate size of journals and therefore which shells you will need and if the crank has been ground so if you need to buy oversize shells)

 

B - See if the crank needs machining (might be fine, and if so it'll just be a straight swap, but if damaged, might need to be ground, so this will change the big ends/mains you buy)

 

C - Lets you have a good look at the gearbox and transfer side of things - adding power will soon pin point any weaknesses (been there, done that!) here so invest in sorting this side of things!!!!

 

 

Before ordering stuff, just make sure what you have as there is no point duplicating anything or ordering the wrong size of something.

 

Last year i rebuilt my block with new big ends, mains and cam shells too. Also fitted a 276 cam as the SW8 was still not really used by anyone so no one had anything so say about it.  One thing i would say....there is a lot of.....errr....how best to put this......B....S.....written about cams.  Yes cam A might offer more torques at x revs than cam B, but it will be super marginal and your average joe bloggs using the car on the road will not notice the difference.  I am not saying Swiftunes cams are in any way inferior to Kent cams or who evers, but Kent have been doing it a very very long time and these new cams are just slightly tweaked versions of the old boys cams from yesteryear.....so don't ignore them.

 

A badly setup and built engine using the latest 'fashionable' cam will not out perform a well set up and built engine with a deemed olderschool cam (if that makes sense).   Yes you don't want to fit an under cammed cam, but at the sme time you don't want to fit anything daft i assume - hence looking t the midway point between the 266 (SW5) and the 286 (SW10) range of cam......I did the same and happy with what i ended up fitting - but i'm still to fully release the potential from my engine as i had an exhaust valve stick open (not my building mistake i must add) so i've swapped back to a standard and very restrictive head.

 

 

Anyway....back to your questions.....

 

Central oil pickup - YES fit one if you don't already have one

ARP conrod bolts - i'm using standard and my car is a competition car.....unless you are revving the nuts off yours might save you a few quid staying with what you've got?

Cam followers - YES fit new when you change cams - buy a cam kit and it will come with a set of new - should also have new valve springs for your head.

 

Rockers - can't comment as that is an area i've yet to fully explore - but currently i'm using modified pressed steel versions and seem ok but they are starting to wear and do need looking at.

 

Check for wear in your diff, transfer gears and primary gear bush....any weakness here might cost you in the long run.

 

Best of luck with your build.

 

 

Apologies if i've written what you already know, but once the keys start tapping i just go off on one.

[Lt-SilverDragon]

Thanks Rally1380, I'm gonna need to think what I'm going to do. There isn't any issues with the engine that means I need to do a rebuild on it the now and it's been a long time since this mini has been on the road and I'd like to enjoy it before doing major work to it. Can I identify cam without removing it? Once engine is out I will make a decision what I'm going to do, but engine rebuild is on the cards at some point. If I can leave it 6 months then I can keep an eye on the classifieds and collect parts.

[moke123]

You are approaching this the right way - and asking all the right questions.  I agree with what others have said, and will add my thoughts. 

1) Have a look at the extent of chamber and runner porting in the head and the valve sizes.  If it is restrictive, you'll never get the best from the engine nor the best from any cam fitted.  How good the head is will determine 90% of your power potential and will also determine what other mods you consider (spend money on a good head first).  Hopefully, you'll be lucky and the head you have has already been well modified.

2) Measure the chamber volumes and other other bits needed to calculate your CR to determine if its reasonable for pump fuel. 

3) Use good second hand pressed steel rockers and sell on the 1.5's because these can lead to more rapid valve train wear and only make a real difference at high RPM. 

4) Measure the thickness of your head and make sure valve train geometry is correct to avoid rapid valve train wear and/or valve spring binding at full lift. 

5) Spend lots of time planning and measuring before you buy, and have fun with it!

[Spider]

Understatement of the week!

 

  One thing i would say....there is a lot of.....errr....how best to put this......B....S.....written about cams. 

 

My wordy, loads of it.

 

Just on Rod Bolts, I have for many years been using standard Rover Rod Nuts and Bolts in all engines, some with lots of power and never had an issue. However, the last lot I received, all from the same (big Name) Supplier were clearly different out of the bag and in fact one failed when torquing up. This has put me right off these bolts as a Rod Bolt failure is very expensive indeed. I've now gone over to ARP Rod Fasteners.

 

One other point I'll make (and it would be good practice in any case) is to have your new Rod fasteners available when you go to the machine shop, but I'd suggest not fitting them. The Rods will need to be closed and honed as the ARP Rod Bolts are ever so slightly bigger in dia and so will change the shape of the Big End. The reason for not fitting them is to have your machine shop man inspect the spot facings and have him press fit the fasteners. By not press fitting them, there is every risk that when fitted, they won't be seated, even after torquing, or the torque applied won't be stretching the fastener by the right amount (unless you are tightening by bolt stretch rather than torquing). I have always press fitted all Rod Bolts for this reason. Your Rods should be closed and honed as a matter of course.

 

Have a spot facing that is off will lead to a rod bolt failure!

 

I also have to agree with Rally 1380 on the Push Rods.
 

Edited by Moke Spider, 04 October 2015 - 06:38 AM.

[ACDodd]

1.5 rockers reduce the service life of the valve train and engine when used for road mileages. They do work very well, but they push the power band a good 500rpm up the Rev range. On my own cams testing has typically shown on the ACD - RS going they are worth 10 to 12hp above 4500rpm on a big bore engine. You loose below 2500! Still with extra wear better to run with 1.4 or 1.3 ratio.

Any hoo any engine shopping list starts with a tear down and inspect/measure up. This is something precious little tmf owners do (how many threads have we seen, I am going to re-ring my engine!) Only from this angle can you set your shopping list to fit to an available budget. It's your requirements that set the budget, not how much money you have to spend. So when you plan you then can see what you can afford to do.
As ever I offer a free measuring up service for tmf users. To date this has only been used once since I have been a member!



AC

Edited by ACDodd, 04 October 2015 - 12:08 PM.

[Lt-SilverDragon]

What's involved with the measuring up service? 1.5s will be staying on the now as I've only just bought them and have already fitted them so can't return but on the advice of everyone I will go to 1.3s or 1.4s in the future. I'll use the 1.5s with the cam that's in the now and when I change cam I will fit 1.3s.

 

I have literally done about 60 miles in this car since I've owned it and that's been about 8 years now so I'd like to avoid a total strip down at the moment but I won't be free until Tuesday to get engine out which is why I've started this thread as a thinking ground. I took it for it's mot last month and the car was set up terribly so the engine was crap but I'd like to get it out as soon as possible and enjoy it before the super cold weather comes in if at all possible. So even if I don't do a strip down the now the engine is maybe going to do 500 miles at the most and that will let me get other jobs sorted also then when the decent weather comes back next year I can get engine stripped. The main reason I'm wanting to strip it to find out what has actually been done to the engine and I'd also like to be able to get it cleaned.

 

Head I have is the one on the left

 

My to do list on Tuesday is remove engine, take the head off so I can figure out the compression ratio, take clutch cover off, helicoil the damaged thread in the block, check the diff and remove the cam chain cover and see what's fitted there. Then I can decide where to go from there.

Edited by Lt-SilverDragon, 04 October 2015 - 02:38 PM.

[ACDodd]

Measuring up is where you bring me your stripped engine components so I can measure the wear/running clarances for your. After this I can then tell you what work needs to be done to meet your spec for a successful build.

AC

Edited by ACDodd, 04 October 2015 - 02:38 PM.

[Lt-SilverDragon]

Where are you based mate? I stay in South Scotland but it's something that I would like to do for my own peace of mind.

 

Does anyone know where to get 1.3 rockers, can you even buy 1.4 rockers in Britain or is it some fancy roller tip rocker set that will cost a bomb? Minispares has cooper s rockers but I don't like the sound that it's just close to 1.3. Is that the closest I'm going to get?

[ACDodd]

See www.calverST for 1.4 rockers. I am in Salisbury, wilts.

Ac

[Lt-SilverDragon]

Holy hell, 26 quid each. I'll spend the money on this kit and put my standard rockers back on lol. Thanks for the offer but a bit far to travel and I think it would be too much to post so will take to a local machine shop to look over if need be.

[rally1380]

Thanks Rally1380, I'm gonna need to think what I'm going to do. There isn't any issues with the engine that means I need to do a rebuild on it the now and it's been a long time since this mini has been on the road and I'd like to enjoy it before doing major work to it. Can I identify cam without removing it? Once engine is out I will make a decision what I'm going to do, but engine rebuild is on the cards at some point. If I can leave it 6 months then I can keep an eye on the classifieds and collect parts.

 

Mmmm....you don't know if there is anything wrong with your engine yet.  Just because there isn't any knocking noises doesn't mean your crank isn't damaged or the bores goosed - of course this is worst case, and fingers crossed for you all is well.

 

Cam's are marked at the Oil pump drive end.....remove oil pump and say hello to some numbers/letters.

[Lt-SilverDragon]

Well the bores are fine because I've had the head off and they look pristine to me. No marks or anything but you've put the fear in me so I am just going to bite the bullet and strip the engine down and will inspect thoroughly once it's stripped so I can make sure bores are fine. If the engine is gonna need serious work I've got a freshly bored 1330 A+ metro engine with everything so I can use that until I get the money to do the work to this engine. Only issue with my 1330 is when I got the work done they bought and fitted low comp (well standard) pistons so the compression might be too low but that's a decision for after the engine is inspected.

Like I say the someone has apparently fitted lightened and balanced internals to this motor so I'm hoping everything is peachy but I'm not holding my breath.

What sort of price is a crank reground? What tools do I need to check the tolerences myself? I've got a dgital and mechanical vernier gauge so far. I've got an engine stand but does anyone do the adaptor plates so the A series can be mounted to them?

I think I'll be able to spend about 1k to get the engine refreshed and I'd like to be able to get a new cam and xpin diff with that if possible but am willing to leave out the cam the now to make sure the engine gets the best parts and rebuilt to a very good standard.