The 'Ultimate Mini Builder' DVD is a very good guide. Although it takes you through building a race engine it does have some very good tips and techniques.
1275 Engine Rebuild
Posted 13 October 2018 - 07:28 AM
There's lots of different ways to get what you want.
First part of building an engine is planning and researching.
Second I would say is work out your budget.
How much you can do yourself or learn to do will make your budget go further.
I would recommend getting mappable ignition, that means you bin your clock work dizzy and move into the modern world of ECUs.
I found it means you can run a 285 cam and drive smoothly through town at 30mph in forth, and floor it when you see the nat. speed limit sign and soon be exceeding it without changing gear! Something a dizzy will never be able to do.
Watch for bulkhead clearance on early cars with a hif44.
Posted 13 October 2018 - 06:33 PM
Hi magneto, it's a 1275 I'm redoing, 998 is currently in my car. Thank you all for the responses, I'm finding that each response I'm understanding a bit more about the different aspects of the build. In terms of the head, obviously cost effectiveness plays a role in this, I haven't got over a grand to throw at one element, my question is would changes to the existing head be more sensible when this is essentially going to be a road car and not a track busting hell beast
Posted 25 October 2018 - 02:33 PM
Following on from this conversation I've had a look into some parts and it's confused me a little bit. From what I'm aware my engine is an A+ 1275 (found out from the crank cam6232 as the engine number has rusted to a point it's unreadable) and I thought it was a verto clutch and flywheel but when I had this in the engine it never fit properly onto he end of the crank and the clutch would continuously slip, which made me doubtful. Then I saw minispares and similar sites don't do flywheels for verto clutches. If anyone could shed some light that would be appreciated. Also I was wondering whether "performance" push rods or lightened cam followers make any noticeable difference to the engine. Thanks
Posted 26 October 2018 - 12:13 AM
Not 100% sure what you are meaning about the flywheel never fitting properly, if that is the case then the crank may be toast
The flywheel is bolted tightly to the taper on the end of the crankshaft ( or it should be) and never move
If it was just clutch slip thats entirely different and will be a lot cheaper to sort out.
Minispares do sell verto flywheels I have just fitted a lightened one, which uprates the clutch pressure at the same time.
As you are not after a flying machine don't waste your money on pushrods or lightened cam followers
Your priority needs to be a good quality build using a combination of good quality parts.
As its just a road engine with some added go, you need a good head which has been mentioned
Along with a decent fast road cam MD266 Or MG metro sort of timing / lift will work well
Compression ratio needs to be considered, capacities measured and maybe the head and or block skimmed as needed
Some other good quality components such as an Iwis timing chain, known followers
Its also important that ALL the bearing surfaces in the engine are perfect, crank reground etc
The end float on the crank, primary gear and idler gears should also be optimised.
There are lots of other things to do and consider, including carb, an HIF 44 will be best
First decision needs to be how many CC's do you want ?
A + .060" overbore to 1330 is plenty and can give you twice the power of a standard 998
2nd decision is down to budget...as pistons can vary from less than 200 to about 450 quid
Its important that the parts work together and that its built well otherwise you can end up in a mess
PM me if you want and I can beat most on price and quality
Posted 26 October 2018 - 06:49 AM
Posted 28 October 2018 - 03:20 PM
If the crank was even slightly chewed to start with it will be worse now.
Both the taper on the crank tail and in the flywheel need to be mint, as it handles all the drive from the engine
I always lap flywheels onto the crank with fine grinding paste, so any high spots are removed and both surfaces fit to each other.
Any high spots mean the whole energy is concentrated there and it ends up friction welding as it frets back and forth
Posted 04 November 2018 - 10:56 PM
Posted 14 November 2018 - 11:15 AM
Posted 14 November 2018 - 11:34 AM
holy sh1 t
Certainly needs the new crank
If its brand spanking new its worth having a machine shop polish the journals, make sure its straight, the fillet radii are all good
make sure all the oil drillings are 'opened out' rather than just a straight sharp edged drill hole
Lap the flywheel on with grinding paste
As the crank tail is so mangled I would be changing the flywheel too, the taper in there can't be good
Posted 14 November 2018 - 01:33 PM
On yet another tangent, in the process of cleaning the engine I'm wanting to strip the existing pain job back to start again with a decent surface. Are there any paint strippers of general chemicals that do a good enough job that could be bought from general UK DIY or automotive shops.
I got most off with an old can of Nitromors .. not the water-based carp they sell now .. but in the end to get back to bare metal needed wire brushes .. most attached to a drill! But I also know my engine had been repainted before .. I know the person I bought it off.
Below is my attempt .. tin of engine paint and several brushes!
1330block_20140504.jpg 77.99K 3 downloads
Posted 16 November 2018 - 11:25 AM
Posted 16 November 2018 - 11:46 AM
Posted 11 January 2019 - 01:28 PM
Well it turns out the engine block I've purchased is actually a 1380, complete with (What I believe are) Omega pistons. Upon inspection of the main bearings and big end bearings that came with everything, they were stamped as standards, which makes me think the crank hasn't been machined, which has impressed me as there are no causes for concern over the journals/bearing seats, and whilst the bearings are in poor condition from being out of the engine and not protected properly, they have no signs of scoring or sufficient damage, so thinking of continuing with standard bearings and not machining the crank where it isn't necessary.
In terms of the parts I'm thinking of using to rebuild this engine, I'm still only after a fast road setup at relatively low cost, and I do plan on making upgrades in time as funds come available for elements which can be swapped out while the engine is in use. In terms of the components I'm thinking of upgrading now, I was considering an uprated oil pump and maybe a fast road cam, then beyond that I currently have a simplex timing assembly and have been researching on the benefits of upgrading to duplex, but I'm a little uncertain on whether to stick with simplex and tensioner, duplex and tensioner, or just duplex. If anyone has any recommendations for additional or alternative components then I'm welcome to suggestions
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