15 replies to this topic

[max-o-matic]

Hello all,

I bought a Mk1 rust bucket almost 15 years ago, for which I had grand plans, but I soon found out that enthusiasm wouldn’t be all it takes to move forward and I didn’t have either the skills or funds to make a dent in this project. I parked it in my parent’s barn and forgot about it until I bumped into (not literally) a raucous Mini in Scotland this summer and the grin on the drivers face made me wish I had one too.

The Mk1 is so far gone it would be an excruciating labour of love, and I haven’t completely given up on it yet, but I thought a softer introduction to the mini world in the form of a running project car might be the best course for me.

So I got back home, found my passwords to the various forums back, dug up the yellow Vizard bible and spent too much time online looking for a decent opportunity until last week when I bought what used to be a 1992 green Mini Special, but is now a black Cooper look alike 1380.


Meet Pi :

The odometer reads 30 000 Km but it may have gone around the clock, the engine however was built 15 000 Km ago.

Body work seems decent, there are a few bubbles on the sills, some flaky paint in the gutters, the panel gap above the boot is too big, and I would venture that the front end was pushed in a bit by a reversing car because the lines of the bonnet, grille and bumper don’t look quite right. A previous owner welded in new footwells, gave it the new paint job and modified the engine.

Most of the parts were ordered from Datch which carries the Minispares products here in France, and as far as I can tell, these are the engine specs :

- 1380 block (no number so it must have been bought « new »)
- Weber 40 carb on a swan neck manifold
- Stage 2 1380 cylinder head from Minispares (I need to check which one, this one is painted black but it is unleaded and the seller mentioned something about the possibility of fitting a turbo)
- Reinforced head gasket
- Omega pistons
- Evo 001 camshaft
- Vernier duplex timing chain
- Some form of programmable electronic distributor (don’t know which one)
- An extra oil cooler
- Maniflow exhaust and RC40 box
- 3.44 differential

That’s really all I know, I need to go through the invoices to have a better idea of what’s what and I know it hasn’t been on a rolling road, so I don’t know how it’s been tuned but it needs some looking into. The seller said he’d chosen one of the appropriate curves for the distributor but didn’t know if it was the best one.

The previous owner also changed the rear subframe (he showed me the original one which had a tiny amount of superficial pitting, and I thought would’ve been worth keeping but a new one is nice too).
He upgraded the front disks to grooved disks, replaced the drum brakes and hoses and swapped the cones for coils and fitted hilos (never mentioned the dampers but I assume they’re new too).
He put up a pair of fog lights but never connected them for some odd reason, and moved the windshield washer bottle and pump to the boot (too close to the battery for my comfort).

The (grey) interior is pretty standard apart from two new fabric Cobra bucket seats and black vinyl door cards and rear quarter liners. He has added a rev counter, and a set of speakers which look big enough to cover the noise of the engine, but I haven’t tried them out yet.

So I picked Pi up on Saturday and asked the seller to drive it so I could find out what kind of thrashing he’d given it. From what I saw, quite a bit (he said « you’ll see, the speedo only goes up to 140 Km/h so when you go above that, the needle just stops and then drops back down once you slow down again. » We were on B roads and I have no idea how fast he was going but he wasn’t slowing down for too many corners!
I decided to take it easy myself and avoid the highways, as it’s always much more pleasant waiting for a tow truck on the side of a country road. Bringing it home was supposed to be a three hour drive, which was unfortunately cut short after two hours when power suddenly dropped and I was running on three cylinders. I’ll know more about that this week, I’m just hoping something wriggled loose and I couldn’t find it.


In the meantime this is the game plan :

- Engine :
- Get the engine looked over, timed and tuned, and live with it as is for a little while.
- Change what needs to be changed to make it as reliable as possible (especially the wiring which looks like it’s been tinkered with a few times too many).
- Upgrade components that should be (such as the swan neck intake manifold, filters etc)
- Clean up the engine bay.

- Exterior modifications :
- Start with a new coat of paint (bare shell, exterior only, I’m undecided at the moment, a lot will depend on quotes from the body shop and what actually needs to be done). At the moment I’m thinking a dark charcoal shade of grey. Color matching 12 inch banded steelies (Datch sell a chrome hubcap kit to fit the standard wheels) under color matching Group 2 wide arches with chrome trim.
- Maybe a right hand fuel tank for extra range and also because I do like the symmetrical caps.
- A stainless steel mesh grill with spotlight holes to actually make use of those decorative fog lamps (not sure about that one yet, just a hunch).

- Interior modifications :
- Figure out a way to match the back seat (and door cards?) to the fabric Cobra bucket seats (I quite like that fabric, I may have to ask Cobra where I can get some).
- Change the various plastic fittings for chrome or stainless ones.
- Take the boxy grey vinyl dash out, and make a custom offset instrument cluster with new dials.
- Find out how clean I can get the carpets and headlining.

I’ll try my best to make this a proper build thread, because I enjoy reading yours so much. Any comments or criticism welcome of course, I look forward to your imput!

All the best, -Max

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[johnR]

Not going to 10" wheels? Looks like a good project.

[max-o-matic]

Well I haven’t done extensive research on prod and cons of 10 versus 12 inch wheels, it just so happens that this one is fitted with 12s and even though rim options are limited in that size, I figured it would be something a little different. I do have a set of Cooper S brakes I’d sourced for the Mk1 project, so I can always convert if handling isn’t up to snuff later on.. seems a shame not to make use of brand new brakes if I have them

[max-o-matic]

First update :

The project has hit a snag (yes, already!)
Pi was towed back to my local garage last week and my trusted mechanic gave it a quick checkup. The news is not good : one of the spark plugs is caked with oil and cylinders 1 and 4 show very low compression. We looked down the bores and they all have varying amounts of vertical score marks. Not sure who put this engine together, but they certainly didn’t do a great job with it. My mechanic says it looked as though it was about to seize. 15 000 Kms really isn’t that much.
The next step is to take the cylinder head off and fully assess the damage. It looks like he’s going to have to pull the engine and put it through a complete rebuild. Various options at this stage : if the score marks are as bad as he thinks, we can either bore it out some more and reach 1410, sleeve it back down to 1275 or go for a new 1275 block altogether. All options imply a new balanced set of pistons and crankshaft, but each have their pros and cons :

- 1410 means I get to keep the same block, but reliability becomes even more of an issue. New pistons etc. Also it’s running a Weber 40 which may be limited at this point for the displacement. The cylinder head should cope fine.
- Sleeves obviously mean new pistons and I’m concerned that the metro valves on the cylinder head (provided that one is still operable) may hit the sleeves as this would result in an offset standard bore. Also compression ratio becomes an issue because the chambers are quoted around 25cc. I am concerned about the reliability of sleeves as well and their price, as these are not exactly standard.
- A new 1275 block leads to various choices : it would seem logical to start out with the stock 1275 and bore it out step by step as the engine wears down, or in the quest for more power as many of you recommend. However, my concerns about the valves remains valid until bored out to 1380, correct? In this case, should I be thinking of a completely new set up, specifically suited to a 1275 and start with a blank slate?

What I want out of this is a reliable engine, with plenty of low end and mid range torque, capable of running on the highway for a few hours at a time so that I can take this car on vacation without worrying about being stranded by the side of the road two days into an adventure. I’d appreciate any advice I can get on this, what would you do?

[Steve220]

You'll only truly know the depth of damage until the head is removed. A lot of scoring looks bad under a torchlight, but tends to be just markings once daylight is on them. Personally i'd see what valves are in there and, if able, get a 1275 block and bore to 1293 (+20 thou).

[GraemeC]

I think your 1410 idea is a non-starter. That was an old school approach back in the day using (I think) Triumph 2.5Pi pistons which will be difficult to get now. Even if pistons are available it will leave very little meat between the bores and is unlikely to be reliable.

[mini13]

yeah, the old triumph pistons were 74.7mm giving 1425 iirc,  I also seem to remember there was a fair chance of finding an oil way during boring, and that the older blocks (preA+) were preferable as less likely to find the oil way.

 

even 74mm 1400 pistons are hard to get now, I think I'd be looking at sleeveing the block down to 1293 (better choice of pistons than 1275??) as you'll get a harder wearing bore.

 

that is of course the bore is bad once you get the head off

[max-o-matic]

News from the front : the head has been taken off and the head gasket was split between cylinders 2 and 3. The cylinder head is the C-AHT133 unit from Minispares, though it has been fitted with upgraded springs. Chamber 4 was caked with oil but the (metro) valves are fine.
The mechanic (named Hervé) found filings in some conduits, and thinks the compression issues do come from the badly scored bores.. He took the engine out so we’re unfortunately headed for a full rebuild. It looks as though this was an amateur job to begin with so it’ll be nice to have an engine built correctly and not have a nagging suspicion something will go terribly wrong every time I want to take it out for a spin (managed to cross that one off my list early!)

At this stage, lining the cylinders seems like the best option, and I’ve contacted Westwood earlier this week but have had no answer yet. Does anyone else carry their products or are there other manufacturers I can reach out to?

I am trying to figure out compression ratios and I was hoping you guys could confirm some things : as it is, the cylinders are fitted with 7cc Omega pistons. If I’m doing the math correctly ((1380/4)+7)/(25+7) I get a compression ratio of 11/1 which seems high. If I drop down the bore to 1293 and use 6cc pistons, the compression ratio becomes 10.6/1 correct? Does this mean I wouldn’t have to skim the head?
Does anyone know if the valves on this head will clear the cylinder linings? Intake valves are quoted as 35,7 mm and exhaust valves at 29.5 mm. The Minispares website mentions that they fit this head to engines 1360 and up which doesn’t bode well..

Thanks for your insight!

[KTS]

MED do liners

 

https://www.med-engi...cylinder-liners

 

i'm not aware of any 5-port heads with valves big enough to overlap the piston bores - the only situation i'm aware of where a block needs pocketing to avoid valve strike is if/when a 12G940 head is fitted to a small bore block.

[max-o-matic]

Thank you very much!

[Steve220]

News from the front : the head has been taken off and the head gasket was split between cylinders 2 and 3. The cylinder head is the C-AHT133 unit from Minispares, though it has been fitted with upgraded springs. Chamber 4 was caked with oil but the (metro) valves are fine.
The mechanic (named Hervé) found filings in some conduits, and thinks the compression issues do come from the badly scored bores.. He took the engine out so we’re unfortunately headed for a full rebuild. It looks as though this was an amateur job to begin with so it’ll be nice to have an engine built correctly and not have a nagging suspicion something will go terribly wrong every time I want to take it out for a spin (managed to cross that one off my list early!)

At this stage, lining the cylinders seems like the best option, and I’ve contacted Westwood earlier this week but have had no answer yet. Does anyone else carry their products or are there other manufacturers I can reach out to?

I am trying to figure out compression ratios and I was hoping you guys could confirm some things : as it is, the cylinders are fitted with 7cc Omega pistons. If I’m doing the math correctly ((1380/4)+7)/(25+7) I get a compression ratio of 11/1 which seems high. If I drop down the bore to 1293 and use 6cc pistons, the compression ratio becomes 10.6/1 correct? Does this mean I wouldn’t have to skim the head?
Does anyone know if the valves on this head will clear the cylinder linings? Intake valves are quoted as 35,7 mm and exhaust valves at 29.5 mm. The Minispares website mentions that they fit this head to engines 1360 and up which doesn’t bode well..

Thanks for your insight!

That'd not hoe you get compression ratio. Use a proper formular which includes the stroke length, piston to deck clearance, etc.

[KTS]

Have a look at these

https://www.calverst...considerations/

https://www.calverst...working-it-out/

[max-o-matic]

That helps a lot! Thank you!!

[mini13]

stick the variables in this

 

https://www.classicm...al/compression/

 

[max-o-matic]

Hello all!

It’s been quite a while since my last port, and the reason for that is that there was no progress to report.
My engine bloc was sent away to get measured and the news is about as bad as was expected : the scoring inside the cylinders is deep, and whoever bored the cylinders out never offset the centers, so the wall between 2 and 3 is too thin to fit a gasket effectively. In addition, my mechanic was suspicious about “shavings “ he found in the coolant. The specialists described the bloc as “disintegrating”, so a new bloc it is! (Also the crankshaft was balanced using a grinder? Sounds like a miracle this engine ever ran at all..)

New plan : build a fast road 1275, using as many parts as I can, and as reliable as it can be.. bullet proof would be nice.

As a reminder, this engine had an Evolution 1 cam, electronic ignition, a duplex timing chain, 3.44 diff, and a Weber DCOE 40 carb.


- first step is finding out if the cylinder head I have can be skimmed down for a decent CR on a 1275. It’s this model, though with upgraded springs : https://www.minispar...px|Back to shop

- second step is sourcing a good 1275 block and crankshaft
- Third is pistons : any recommendations? These were omega, maybe a set of those?

I’m already spending silly money, more than intended in any case, so at this point I might as well go all in because I’m not planning on building a new engine anytime soon. So if you can think of anything worthwhile since I’m at it please let me know.. I don’t think the flywheel was lightened, maybe that could be added to the list?

I wanted to start sorting out the body and the interior but my mechanic is sensible and suggested we fit an engine in first and deal with the rest later.. not sure I agree, it seems to me that an empty engine bay is the ideal moment to get stuff like electricals right..

Anyway, I’d love your input, all suggestions are welcome!

Many thanks,

Max