16 replies to this topic

[stevede]

Hi all

 

Many of you will know my project car from these pages, and although I have not been on TMF much recently, I have been enjoying my mini.

 

The time has now come to build the 1275 engine that came as a spare when the car was bought, and has been sat in may garage in kit form ever since.

 

I know many ask about engine spec, and how much power etc (it'll make what it'll make) but what I am asking for is some honest advice from those with experience, to hopefully make a reliable, but fun engine.

 

The mini is not my only car, and although I use it sometimes to commute, I'm not reliant on it. It goes on the motorway from time to time but not for any extended period.

 

My driving style is quite relaxed. I enjoy a bit of speed in the right places and acceleration, but although my days of traffic light wheel spinning are long gone, it would be nice to "surprise" the odd boy racer.

 

So what do I have already?

 

• A series (not A+) full engine & gearbox which we suspect may have come from an Allegro.
• I have done a swap with Guess works for a 3.44 diff and have on order a full rebuild kit including a X pin diff
• I have a modified cylinder head with 29.2 ex and 36.6 inlets. The head started as a Minisport one but has been via the workshops of MED for additional work (chamber size not measured as yet)
• A Kent 286 cam - New and was at the right price
• I am running megajolt on the current engine
• I have a HIF44 carb and will use the standard airbox with K&N (don't want too noisy) Heated inlet manifold.
• Maniflow 1.75 LCB & Twin box

 

The plan

 

• Bore to +40 (1310?) using new P21253 piston set - idea being to retain some life in the block if needed
• Crank reground to next available size
• Std A series rods
• Convert to pre-verto clutch - Swap gear ring to suit pre engaged starter - Good / bad idea?
• Std (quality) oil pump
• Single (quality) cam chain set using offset dowels (as recommended by Carver)
• Source good condition std rocker set

 

 

I haven't a bottomless pit of money, but don't want to "spoil the ship" etc. It will of course visit a rolling road for set up once complete.

 

• Suggested CR?
• Best head gasket to use?
• Clutch recommendation (don't want heavy comp if I can get away without)?
• 286 cam - I have it already but could it be a mistake?
• Std or lightened (special) followers?
• Push rods - I don't have any at the moment?
• Centre main strap - opinions vary wildly?
• Lighten the flywheel a little?
• Full balance of crank etc?

 

I'm typing this thinking I must have missed the obvious, so feel free to point out. Any suggestions, comments observations on the above most welcome.

 

Thanks to all in advance

 

Let the discussion begin.................

 

 

Regards

 

Steve

 

Edit - forgot the exhaust

Edited by stevede, 09 May 2013 - 08:58 PM.

[KernowCooper]

 The Kent 286 will take a bit to keep it in the power band for road use and may be to much for your intended use, and the engine will require more frequient rebuilds than a lesser cam

 

The twinbox maniflow is going to be very quiet, I have the singlebox Maniflow on my 1330 and its none to noisy.

 

Head Gasket I would use the Payen BK450.

 

Balancing and Centre Main Strap- I have a Kent 276 Cam and I have my Crank/Flywheel Balanced and hardned treatment on the crank, I also have the centre main strap, and if you do decide to go with the Kent 286 I would say yes its a good mod to avoid flexing at revs

 

I would ask Kent what followers they use and get those, mine came as a kit

 

Pushrods standard 1275 ones are ok

 

If you lighten the flywheel you could make the engine very lumpy at tick over.

 

I run the Rally spec clutch in mine and its not heavy or jumpy

 

I would try and get the MG Metro/A+ rocker gear

 

I would though run a duplex timing chain.

Edited by KernowCooper, 09 May 2013 - 09:28 PM.

[ACDodd]

How long do you want it to last?

 

AC

[stevede]

How long do you want it to last?

 

AC

 

Thanks for your reply.

 

I'm not looking to rebuild every 6 months, nor expecting 100k plus. The car is coming up to 2 and a half years back on the road now and has done 5000 miles so even what may be considered a relatively short life in miles would probably see me good for a few years.

 

I'm happy to put up with a regular maintenance routine if the engine gives me some grin factor.

 

Regards

 

Steve

[stevede]

 The Kent 286 will take a bit to keep it in the power band for road use and may be to much for your intended use, and the engine will require more frequient rebuilds than a lesser cam

 

The twinbox maniflow is going to be very quiet, I have the singlebox Maniflow on my 1330 and its none to noisy.

 

Head Gasket I would use the Payen BK450.

 

Balancing and Centre Main Strap- I have a Kent 276 Cam and I have my Crank/Flywheel Balanced and hardned treatment on the crank, I also have the centre main strap, and if you do decide to go with the Kent 286 I would say yes its a good mod to avoid flexing at revs

 

I would ask Kent what followers they use and get those, mine came as a kit

 

Pushrods standard 1275 ones are ok

 

If you lighten the flywheel you could make the engine very lumpy at tick over.

 

I run the Rally spec clutch in mine and its not heavy or jumpy

 

I would try and get the MG Metro/A+ rocker gear

 

I would though run a duplex timing chain.

 

Thanks for your reply.

 

I take on board your comments about the cam. I bought it because it was new and a bargain, but if it was going to cause me grief, then a swap to a milder option isn't out of the question.

 

Happy with the Maniflow twin box as it gives a nice note without being too intrusive (I'm at that age )

 

Which exact clutch do you have? - Minispares list a "rally" one, but also state their GCP204AF is suitable for "all but the most powerful engines".

 

Will check with Kent on the followers

 

Thanks again

 

Regards

 

Steve

[stevede]

Great choice of cam you won't be disappointed, especially if it's a weekend fun vehicle. The only thing i'd change would be the carb.........

 

Thanks for your reply. What would your carb suggestion be?

 

Regards

 

Steve

[mike.]

There seems to be much debate about just how lairy a 286 cam is for road use. I'd love to drive a 286 cammed mini before passing final judgement. 

 

I have a morspeed phase 3 cam in my 1275, its similar to a 276 with the power band listed as 2000-7000rpm. Its a really nice road cam in my opinion, it'll idle ok   at 1000rpm, it has good torque for normal road driving, and at around 3000rpm, the exhaust note changes and a big boost of power comes in. Ideal for a fun road engine in my experience so far. 

 

The centre main strap is a good idea i'd say, especially with a 286 where 7000rpm is achievable.  Its cheap and simple to do - Just ensure you buy from a respected supplier and ensure the bolts are of correct length and grade. I was supplied with poor quality bolts that were too short and damaged the threads in my block. 

 

Flywheel wise, a lightened one has a nice effect on the engine, fast revving, responsive and quicker off the line. However, I fitted the lightest ultralight flywheel minisport off and it has resulted in an inconsistent idle (engine makes it own mind up, sometimes idles at 1000, others at 1500) and also a lumpy and jolty low speed ride, when driving in traffic or decelerating in gear. Its fantastic when out for a spirited drive though. 

 

I'd stick with a HIF44 carb, especially if you want it to be quiet. A weber may gain a few BHP at top revs and flat out will be quicker, but it'll use more fuel and require a bulkhead box fitting, worth the gain? I doubt it. Mine with the HIF44 is getting around 30mpg and with a 286 and a weber I would expect that to drop further. 

[elanbaby]

Hi Steve,

 

mine´s a 1275 A+ engine with the HIF44 carb. and I am VERY happy with the MG Metro cam. K&N filter in Metro filter box, LCB, twin box RC40, duplex timing chain correctly timed with offset dowels.

 

You are obviousyl not at this stage yet, but don´t forget to get the timing right! My standard DM65 dizzy proved to be far too lazy. Could have get it modified but decided to install a 123 instead, because the spindle was starting to show wear. I adjusted the timing to around 20deg adv. at 2000rpm and max adv. 32deg at 5000rpm. That made all the difference! The standard clutch, although fairly new, started slipping. Now I have a MG Metro Turbo clutch installed which I bought as a kit from Minispares at a very reasonable price. It works really well!

 

You wrote you are planning to convert to a pre verto clutch? Why would you do that? Isnt´t the A-Series (not A+) equipped with a pre verto clutch as standard? If it´s not a misprint and you have a verto clutch, then I´d really recommend the MG Metro Turbo clutch. 

 

Juergen

Edited by elanbaby, 11 May 2013 - 06:12 AM.

[stevede]

45 Weber or if you don't want to cut the bulkhead, a 28/36DCD Weber works. Ran mine with a HIF44, then a 28/36 and finally a 45, both webers out performed the SU........

Thanks DILLIGAF. I will probably stick with the HIF44 for now as I already have it. I don't want to put a box in for a 45 (centre clocks so guess it wouldn't fit) but I will keep in mind the 28/36 maybe as a future option.

 

Regards

 

Steve

[stevede]

There seems to be much debate about just how lairy a 286 cam is for road use. I'd love to drive a 286 cammed mini before passing final judgement. 

 

I have a morspeed phase 3 cam in my 1275, its similar to a 276 with the power band listed as 2000-7000rpm. Its a really nice road cam in my opinion, it'll idle ok   at 1000rpm, it has good torque for normal road driving, and at around 3000rpm, the exhaust note changes and a big boost of power comes in. Ideal for a fun road engine in my experience so far. 

 

The centre main strap is a good idea i'd say, especially with a 286 where 7000rpm is achievable.  Its cheap and simple to do - Just ensure you buy from a respected supplier and ensure the bolts are of correct length and grade. I was supplied with poor quality bolts that were too short and damaged the threads in my block. 

 

Flywheel wise, a lightened one has a nice effect on the engine, fast revving, responsive and quicker off the line. However, I fitted the lightest ultralight flywheel minisport off and it has resulted in an inconsistent idle (engine makes it own mind up, sometimes idles at 1000, others at 1500) and also a lumpy and jolty low speed ride, when driving in traffic or decelerating in gear. Its fantastic when out for a spirited drive though. 

 

I'd stick with a HIF44 carb, especially if you want it to be quiet. A weber may gain a few BHP at top revs and flat out will be quicker, but it'll use more fuel and require a bulkhead box fitting, worth the gain? I doubt it. Mine with the HIF44 is getting around 30mpg and with a 286 and a weber I would expect that to drop further. 

Thanks for your reply

 

I was expecting comment surrounding the cam and of course opinions will vary. I suppose if I fit it and have nothing to compare, then unless it's a pig to drive, I'l probably be quite happy. As I said in my original post, it was a brand new, blank ground for a fraction of the cost normally.

 

I had also read about the quality of some of the centre straps around. Some also think they are not needed, but maybe for minimal cost and the right quality product it can't harm.

 

Regards

 

Steve

[stevede]

Hi Steve,

 

mine´s a 1275 A+ engine with the HIF44 carb. and I am VERY happy with the MG Metro cam. K&N filter in Metro filter box, LCB, twin box RC40, duplex timing chain correctly timed with offset dowels.

 

You are obviousyl not at this stage yet, but don´t forget to get the timing right! My standard DM65 dizzy proved to be far too lazy. Could have get it modified but decided to install a 123 instead, because the spindle was starting to show wear. I adjusted the timing to around 20deg adv. at 2000rpm and max adv. 32deg at 5000rpm. That made all the difference! The standard clutch, although fairly new, started slipping. Now I have a MG Metro Turbo clutch installed which I bought as a kit from Minispares at a very reasonable price. It works really well!

 

You wrote you are planning to convert to a pre verto clutch? Why would you do that? Isnt´t the A-Series (not A+) equipped with a pre verto clutch as standard? If it´s not a misprint and you have a verto clutch, then I´d really recommend the MG Metro Turbo clutch. 

 

Juergen

Hi Jeurgen, thanks for your reply

 

The timing should be an easy one for me as I am running megajolt currently and will switch this over to the new engine. I will need to obtain a suitable map of course but there are a number readily available.

 

My comment on the clutch was perhaps more of me thinking that the current A+998 has a verto clutch and some opinions think the pre verto to be better. Of course the engine being rebuilt would have been pre verto as standard, sorry if I confused anyone. I'm certain it would have had an inertia starter though so a ring gear change will still be in order unless I go for a new (lighter) flywheel. 

 

Regards

 

Steve

[elanbaby]

Steve,

you probably know this video already...?

 

 

I found this very informative AND entertaining,

 

Juergen

Edited by elanbaby, 11 May 2013 - 07:35 AM.

[stevede]

Will have a watch of that. I have the yellow book which I dip in & out of. - Thanks

[stevede]

I saw a post on another thread about the "A" conrods & the large lump on the base. I understand the "A+" are considered better but are the "A" bad?

 

Can the lump be ground off? If so is it a DIY job. (Will obviously need balancing after) 

 

Thanks in advance

 

Steve

[Cooperman]

The 'lump' can be removed and the rods re-balanced.
With a 286 you'll be using up to around 6700 rpm, so a centre main strap is a MUST.
Make sure you select pistons which will take those sustained high revs.