which is the stronger engine

[hotrodder13]

right it turnes out the midget has had the same reboar as the marina engine,

which engine is better the marina or midget, which is best suited to use for a supercharger rebuild

also if it has been reboard +0.20 is it still 1275cc

thanks tom

[LouiseM]

which engine is better the marina or midget

Only one way to find out.......... FIGHT!!!!!!!!

Sorry, couldn't resist it! (It's a Harry Hill thing for those who are confused)

I'm sure Roy will be along in a minute to advise

[les]

Whilst waiting for Roy, just to say that the capacity will be slightly increased by the rebore but nothing to speak of. The Marina engine block will be more rigid because of the lack of side covers, so if you do decide to use a blower it would probably be the best choice.---confused? everyone watches harry hill, don't they?

[chrisryder]

i'm not sure on the maths. it will be over 1275. it probably gains about 10 or 20cc so.

Capacity = (Bore area X Stroke) X No of bores

Bore area = pi x radius of piston squared

Stroke = distance between centres of oposing big end journals on the crank.

So if you can measure your piston (or if you know the standard size for a 1275 piston then add 20 thou) and times it by the stroke (not sure what it is for a 1275 off the top of my head) then you can work it out.

It definately goes up in capacity though.

As for strength, larger diameter journals are better. I'm not sure what the sizes are between marina and midget... bmcecosse will be along soon enough!

[bmcecosse]

The Spridget 1275 engine doesn't have side covers either............... The capacity is 1310 at 20 thou. The Spridget engine has the smaller diameter big-end bearings - and therefore (rather lighter) connecting rods to match - but these are NOT the real (expensive!!) Cooper S rods (AEG 177) - they are the rather less strong AEG 625 - which however are still 'ok'. However - the crank 'may' be nitrided for hardness - check if it has EN 40B cast into one of the webs. If it is nitrided - well done - if not - forget it. I'm pretty sure later Spridget engines used the larger diameter (ie Marina) crank and rods.

[hotrodder13]

thanks for that
well i think i might put the piston and rings out of the midget engine into the marina engine and then run that one and supercharge the midget one becuase 1275 turbo forged pistions at +0.20 are 400 quid

but i will be able to check if this maria engine has a road race cam like i was told or not

[bmcecosse]

The piston/swap idea is not good -to say the least. The Spridget rods probably won't fit the Marina crank....... Although entirely possible the Spridget engine has been fitted with a Marina crank - I have one on my bench!

[hotrodder13]

so which would you supercharge if u could haha

marina or midget

which ever you would i will use the other one in my blue car to keep it goin and the engine u would will be kept in the garage for a rebuild

thanks tom

[les]

Unless you have one already the supercharger will cost more than those pistons!!
Not sure about the mini one though.

[hotrodder13]

i know a full kit sold on ebay for 800 quid

[bmcecosse]

IF the Spridget engine has the nitrided EN 40B crank - use it. Otherwise use the Marina crank - but it MUST be tuftrided first!

[hotrodder13]

Otherwise use the Marina crank - but it MUST be tuftrided first!

well il see 2moro what it has but what is tuftrided haha

thanks for your help

[les]

You will find no end of useful info in the tuning book from david vizard, it will enable you to choose the right components for your projects, plus give you an insight into the a series engine, and what you can and shouldn't do. It also tells of the strengths and weaknesses of these engines, well worth knowing if you are going to put one under stress! It's one of the handiest references you can have.

[chrisryder]

i concur with les. it's not known as 'the bible' for nothing!

u can get a copy dirt cheap on amazon, got mine for £13!

[bmcecosse]

http://www.crankshaftco.com/steel-crank ... ening.html

What they don't say is that few steels are suitable for 'nitriding' - EN 40 B being the one used for crankshafts to be nitrided.