supercharged 1275 home brew. anybody fancy a blown minor?

Post by **superchargedfool** » Mon Jan 28, 2008 11:06 pm

hi all.

fairly new to board and minors but I have owned a few over the years (minors not boards).

Current one is the maddest I've had.

1275 marina engine, front uprights, discs, torsion bars, servo, hydraulic clutch. sierra 5 speed. Escort Mk2 atlas rear axle. Telescopic shocks, mk4 cortina front anti roll bar.

New mini supercharger sucking air through a hif44 and blowing into standard engine through homemade manifold at about 5psi.

Engine is currently out for a freshen up but will be back in in a few weeks.

Car is a 1970 2 door in really nice order but a total street sleeper except for 13 inch minilites. ( ford pcd all round).

Photos will go up soon and I hope to share problems and questions with all especially the forced induction guys on here.

I have to say over 100bhp in a minor just doesnt feel right but so what its fun.

Post by **Kevin** » Mon Jan 28, 2008 11:11 pm

Don't forget there is a modified and custom section.

Post by **bigginger** » Mon Jan 28, 2008 11:11 pm

Welcome aboard

a

Post by **dunketh** » Tue Jan 29, 2008 3:29 pm

How did you seal your carb?
I'm sure other folk would be intersted.

Pics would be great too!

Post by **Spag** » Tue Jan 29, 2008 3:40 pm

It's a suck through, so the carb only sees atmospheric pressure.

Hope the blower is a suck through type so is happy with mixed fuel runnign through it ....

Post by **bmcecosse** » Tue Jan 29, 2008 4:42 pm

MINI (Eaton) supercharger is v happy to suck fuel - it IS the way to go! Many very successful Mini installations. Looking forward to these pictures - and some performance figures maybe ??

Post by **superchargedfool** » Tue Jan 29, 2008 10:46 pm

the mini type of install is what i am trying to copy because it works.

I made a manifold that is more of a plenum with smooth tracts rather than the semi circle tube with a small hole in the top of it that you can buy.

The front pulley is a maestro 1275 pulley with threads drilled in it. You bolt it on as normal and then a spacer and a pulley from the alternator off a sierra 2.0 twincam alternator goes on the front of it. These mods did need a lathe though.

The tensioner for the belt is off a 214 16v rover because it is very simple and the pulley on the tensioner is off focus aux belt tensioner.

The needle in the carb is a BBC needle which is what I believe vmax scart supply with there kits. It seems to fuel nicely.

Ignition is 1275 electronic maestro dizzy with the module mounted remotely on the inner wing to allow me to run the dizzy 90 degree clockwise from where intended.

Its all home made on the very cheapo. The car and all mods owe me about £1500.

At the moment the engine is out for a set of rings but will be back in soon and photos will then follow. So far I haven't done more than a handfull of miles in it with the charger but it did feel surprisingly nippy for a worn out engine.

A true 90mph came up quite quickly in 4th before putting it in 5th and easing off. (obviously on a private road!)

I am aiming for 100 to 120bhp. I know you can get that without a charger but at a cost. This car isn't about ultimate figures, it is about being different on a budget.

My personal feel is that if you stray far over 100bhp then an A series is probably not the way to go for value for money.

Photos will come but be patient.

Feel free to offer advice on the forced induction front though, I am a novice in this area.

Post by **bmcecosse** » Wed Jan 30, 2008 12:07 am

Excellent conversion - and very helpful with the pulley details. Did you do anything to drop the Comp Ratio of the engine - such as deep dish pistons, or combustion chamber opened up ? And did you stick with the standard 1275 camshaft ?

Post by **superchargedfool** » Wed Jan 30, 2008 9:39 am

fast road cam but I dont think it needs it. duplex timing chain but not adjustable. engine was from a ital van so already low compression dished pistons, which is why I am ringing it myself rather than buying a recon lump because if I do it myself I know whats in it. Head is slightly ported but thats all.

I believe the vmax scart mini set up uses a decompression plate which lowers the compression ratio to about 8.5:1 and blows at about 5psi and makes about 120bhp with a bbc needle. So that is what I am aiming to copy minor style.

The ital van engines where under 9:1 compression but I dont know the actual figure so I am just going to feel lucky. If I get detonation then I will sort it out.

Post by **bmcecosse** » Wed Jan 30, 2008 2:06 pm

The fast cam may not be a great idea - it will tend to blow fuel straight through to the exhaust on the overlap! Most charged engines keep to 'soft' timing. Your CR should be fine - although you could perhaps open up the chambers a bit - and of course you will need top quality petrol. Ignition timing may need special attention - too much advance and it will detonate. You can always try some water injection when on full throttle to kill any detonation.
GAS on here has a very similar set up, but he had some hot starting problems - dunno if he has sorted that yet.

Post by **superchargedfool** » Wed Jan 30, 2008 2:48 pm

the engine came with the cam in and the cam would be the first thing to come out if I suffer detonation problems.

From the limited experience of driving it I have hot starting wasn't too bad.

Water injection is also an option as I do have an erl injector controller kicking about from a previous project and have been looking for an excuse to use it such as water injection.

I only started this project within the last month and aim to be properly on road by april at the very latest.

Post by **GAS** » Wed Jan 30, 2008 5:31 pm

I have a mild road cam on my motor,The fuel pump was my problem.
Not to mention the two big cooling fans that i had to fit to stop it cooking in traffic.

Post by **superchargedfool** » Mon Feb 04, 2008 10:29 pm

hi gas. are your fans in front of the rad? If so what are they off?

I am hoping fuel pump won't be a problem, I have a facet 3psi rated at up to 150bhp in the boot.

My new pistons just came back from my local trustable engine builder (KL Engines in Kings Lynn) attached to the rods. Hoping to fit them soon and completely re-gasket and seal the engine. Should be in for weekend ready for some driving and pics.

I thought price was good at £170 for pistons and putting them on the rods.

I did have a respected minor specialist lined up for some of the engine work but when i told him i wanted the low compression pistons for an ital lcv he got back to me and informed me they were very rare and would cost a bit more. Strange that because i already new they are still in the current AE parts catalogue that most engine builders use and available next day at same cost as normal ones.

Couldn't blame him for trying but i won't be ringing him again. I won't name and shame him. i just hope he watches this forum.

Post by **GAS** » Tue Feb 05, 2008 5:52 pm

I've fitted 18cc low compression pistons in my A+ block,The fans are a pair of 10" kenlowes from "Burton"and are fitted just behind the grill.I had to slot the rad bolt holes on the apron and squeese the rad a bit closer to the pump pulley.
My facet pump would work great on short runs,but would run dry on longer outings,even when there was fuel in the tank.
This would cause the plugs to burn out,making it very hard to start the now hot engine.
This could be because i had the pump pulling instead of at the tank pushing.

It would not be any fun if it all works straight out the box would it....

Post by **bmcecosse** » Tue Feb 05, 2008 7:41 pm

Glad to hear you have it sorted out now GAS! It's a fabulous Traveller.

Post by **GAS** » Tue Feb 05, 2008 8:58 pm

Thanks Roy.

I wish i had more time to play with it.

Post by **superchargedfool** » Fri Feb 08, 2008 9:52 am

at last some photos but more to come.

car without engine sat waiting in corner

fairly clean and tidy engine bay minus engine

engine about to go in

homemade plenum/manifold. quite smooth inside.

will post more photos when engine in and all plumbed up.

Post by **bmcecosse** » Fri Feb 08, 2008 10:22 am

Manifold looks fine - it doesn't need to be too smooth inside - some turbulence is ok when it's being force fed!

Post by **superchargedfool** » Fri Feb 08, 2008 10:59 am

i realise some turbulence is good, manifold isnt flowing bends and beatufill inside but I just cant see how having the air flow restricted such that it hits faces that have a hole in them somewhere can be any good.

So the outlet from the supercharger 100% blows into the plenum rather than about 30 to 40% that I have seen on some.

All of my homemade bits are slightly different from the buyable bits, maybe it will work well maybe it will be a pain in the backside to get right.

Post by **Orkney** » Fri Feb 08, 2008 11:58 am

Its an interesting and highly debateable subject the vortice vs smoothness effect.
Had a long term discussion about this years ago with a mate who had a motorsport parts business. He was also a weber main agent.
I'd put a pair of twin 40's on a tweaked project, straight trumpets.
Came to that we started looking at the venturi's I argued that a heck of a lot could be done to slim them down by quite a factor - but also you could in theory make the supporting rods an aerofoil shape to introduce turbulence - suggestion being have them offset like a corkscrew - set up a suction whirlpool and get the mix through faster.
Even speculated further that if you had ram air from the front of the car this might really give some boost at and beyond xyz speed.
Never got anywhere with it not having a wind tunnel and a degree in whatever, but would make a nice winter project one year just to see what if any gains could be made for a very simple and cheap mod.