Offset Crank Grinding.

[dickie]

Hi Folks,
Bloody hell I have just gone and paid the deposit for the crank and rods.
I hope it does not become a expensive mistake !!
Its a mad idea but someone has got to try it.
The engine geometry will become very close to some of the Honda units but with 285 cams rather than Vtec.
The only other major purchase for the engine will be a flywheel and clutch assembly.
Current engine is fine at 8000 rpm on the DIY lightened flywheel though.

[dickie]

Hi Folks,
Just an update on this.
I have just had an email to say the Crank and rods have been finished.
I have told them they can scrap the Mk2.5 Crankshaft I sent as a pattern but I want the aftermarket billet stock size rod back to put into a set.
It looks like the credit card is coming out to play £££££.

Once the Crank and rods arrive I will attempt to post some Crank and Rod P.O.R.N

I will have to start the next parts shopping list. flywheel, clutch, gaskets seals etc

I will be putting the ITB RS back on the road in May.

[dickie]

Hi Folks,
The Crankshaft and rods have arrived at work !!!

[Zed.]

time to win the lottery or get onto hmrc for a rebate

Rich.

[atlex]

unleash the metal porn!

[dickie]

I will try and get some pics up over the weekend.

[dickie]

This link will take you to the Crankshaft and some of the other parts

[thruxton]

Holy schmoly.
That’s fantastic.

Regards.
Rich.

[dickie]

Nope its just a pile of expensive parts at the moment !!!!!

Rough details.

Bore 85mm

Stroke 79mm

Rod Length 136mm with standard big end and small end size

Rod Ratio 1.72

Bore stroke ratio 1.076

Mk2.5 VVT block bored to 85mm

Wisco 85mm High compression Pistons.( compression height 31.2mm ) 7cc Dome

ATI Superdamper

Boundary Oil pump

This should make a 1796 cc Oversquare BP engine losing 47cc from stock enabling me to enter the sub 1800cc class for hillclimbs and sprints rather than be in 1800cc to 2300cc

The bore and stroke is the same as some Ferrari engines with a few less cylinders as well as a few other high performance engines

I will lose some compression due to the smaller stroke but 7cc dome and the current 80 Thou head skim will help

I will check clearance and measure volumes to get new compression ratio as I can't find where I noted down the current head volumes

I will do some more calculations once the block has been set up and possibly decked.

I am expecting a CR of around 11.6-1 dependant on which Cometic Headgasket I go with.

I will be fitting Supertech +1mm inlet valves into the current head and get the bowls re worked

Currently using Piper 285 Mechanical spec cams with MSM SUBs and Supertech springs with Titanium caps which seem happy at the current rev limit of 8000 Rpm.
The new block should be capable of sustained 8000 + Rpm
With a cam and valve spring change there is potential for a lot more revs.
Current block has stock Mk2.5 internals with the ATI damper so its a risk to use 8000 Rpm for more than a moment in case the oil pump shatters.

Cheers Dickie

[dickie]

Hi Folks,
Update on the engine build.

I have finally paid off the Crankshaft and Rods !!!!

I bought a set of King Racing Bearings when I was in the USA for work last month, less expensive than UK price.
I can now afford to go ahead and get the block bored for the Wossner Pistons and get the bottom end balanced I have bought a lightweight flywheel but not exteme lightweight as its still a road car first.
Being a brand new billet crank, rods, pistons and flywheel the weights and balance it should be pretty good to start off with.
I will ask the guys doing the machine work to gap the rings for me. ( They do it all the time ! its years since I did a set of rings )
Once the machining is done I can then start to assemble the short Mk2.5 block.
I will add some skid nation baffles to the sump.

Cheers Dickie

[dickie]

Hi Folks.
I have been in contact with the machine shop.
I am taking the block pistons crank rods and flywheel over for him to do his magic.
Hoping he can do the measurement and calcs on deck height so that he can skim the block to suit the crank piston rod combo.

I will also be giving him a billet Austin Seven Crankshaft rods and flywheel to balance as well as a block to machine for oversize valves and a bit of porting.

I use this company

www.srdengines.co.uk/

[warpspeed]

This is going to be an absolute ripper of an engine, it makes me all giddy just thinking about it.

Well done correcting the basic engine geometry, a huge step in the right direction.

Its not all that much different dimensionally  to the original B M W   M3 four cylinder engine.

That had an 85mm bore, 81mm stroke and 140mm rods.  

The factory imposed red line for those was 8,000 rpm, and it was a very successful, very reliable mass produced factory engine that has an epic racing history.

[cardo]

A really interesting engineering project 😀 Looking forward to seeing it come together!
A mate of mine uses SRD for his hillclimb engines and rates him highly.

[dickie]

Hi Folks,
I have now delivered the block for its rebore and I will get SRD to gap the rings for me.
Crankshaft flywheel and rods for balancing.
I am just waiting for a clutch to arrive from Bofi so that it can be balanced with the rotating assembly.
So its now a waiting game.

They had a BMC Mini Engine which was modified to have a Tailgate McNoIndicate motorbike head on it !
The block and head were dry decked and some of the studs even lined up
The flywheel was extremely light.

It will be a while before I get all the bits back and can clean it all up ready to start the Assembly.

[warpspeed]

Dickie,

For some strange reason the Forum software throws a wobbly if you enter B M W without placing spaces between the three letters.
The psychotic Forum software substitutes "Tailgate McNoIndicate" for B M W.
Really odd