the quick story of my 998 engine build

[ljonez]

been sorting out pics so thought I'd post a quick picture story of my 998 engine build.

spec
1030 block (998cc +40')
rebuilt 12g940 cylinder head
sw5-07 cam
lightened duplex gears
stage 1 kit
center main strap
rebuilt box
megajolt
stage 1 kit
hif44

998 block bored +40 and pocketed


painted in colour of choice


no pic of the pistons being fitted on to the con rods sadly

+40 pistons installed


crank reinstalled also a center main strap added


new oil pump


gear box, transfer housing, flywheel and clutch installed


1275 head


head going on


new cam


timing gears installed


pretty much finished


installed in mini ;D


every bush,seal, gasket was replaced during the build and the gearbox also had a full rebuild but i can write a book on that on its own

the old engine and a spare both waiting for the same treatment

[taffy1967]

Excellent work and there's nothing like a freshly painted block.

[exuptoy]

LJ, nice one m8, how did you know the exact placement of the valve pockets and I assume you used a 1275 head gasket. How did you work out the CR?

[ljonez]

Feb 17, 2009 23:06:58 GMT 1 exuptoy said:

LJ, nice one m8, how did you know the exact placement of the valve pockets and I assume you used a 1275 head gasket. How did you work out the CR?

i had a technical drawing which was done by Simon from morspeed and posted on minifinity a while back, took it along to machine shop and they did the pockets ( their exactly 1cc)

yeah using a 1275 gasket

iirc compression ratio = cylinder volume + combustion chamber volume / cylinder volume

[exuptoy]

Feb 17, 2009 23:19:05 GMT 1 ljonez said:

Feb 17, 2009 23:06:58 GMT 1 exuptoy said:

LJ, nice one m8, how did you know the exact placement of the valve pockets and I assume you used a 1275 head gasket. How did you work out the CR?

i had a technical drawing which was done by Simon from morspeed and posted on minifinity a while back, took it along to machine shop and they did the pockets ( their exactly 1cc)

yeah using a 1275 gasket

iirc compression ratio = cylinder volume + combustion chamber volume / cylinder volume

When you state cylinder volume, how do come by that, did you just tdc it and fill the chamber and measure it? Does the standard water pump fit up to the head with a bypass hose. The thing is I got two 998's here and it just seem like a good idea with the relative lack of 1275 lumps about.

[ljonez]

Feb 17, 2009 23:56:50 GMT 1 exuptoy said:

When you state cylinder volume, how do come by that, did you just tdc it and fill the chamber and measure it? Does the standard water pump fit up to the head with a bypass hose. The thing is I got two 998's here and it just seem like a good idea with the relative lack of 1275 lumps about.

if its a standard 998 just divde 998 by 4 which gives you the volume of one cylinder
when i had the rebore the bloke told me the new volume.

yeah the pump fits fine altho you do have to file a small amount of the top edge to allow head clearance and fit the smaller pulley from a pre A+ engine.

its a good route to take if you like fast 998s mine is currently around 65ish BHP which is 1275 cooper teritory and my spec is relativly mild.

[exuptoy]

Thanks for all the advice fella. If I wanted to go for 1.5 or 1.3 ratio roller rockers then obviously that will affect the pockets yeah? also would that only be for a standard cam and would I just be better off sticking with standard ratio rockers and going for a wilder cam maybe with longer duration?
I do have a copy of Vizards book here somewhere but it's easier asking the questions to someone who has carried out the work yeah.

[ljonez]

Feb 18, 2009 12:32:33 GMT 1 exuptoy said:

Thanks for all the advice fella. If I wanted to go for 1.5 or 1.3 ratio roller rockers then obviously that will affect the pockets yeah? also would that only be for a standard cam and would I just be better off sticking with standard ratio rockers and going for a wilder cam maybe with longer duration?
I do have a copy of Vizards book here somewhere but it's easier asking the questions to someone who has carried out the work yeah.

yeah the higher the lift the deeper the pockets will need to be but there is a maximum before the piston rings hit it.

personally i think roller rockers are a waste of money on a road car, keep the standard rockers which are 1.3 anyway and get a better cam (probably works out cheaper as well).

the pockets i got a deep enough for most high lift cams (sw5 etc) bit obviously you have to check clearances as you build the engine, last thing you want is the valve hitting the block.

cam choice really is personal preference, it all depends on how the car is used.

for example, if you want a nice road going mini the sw5-07 or the morspeed ph2 cam ( both similar to the MG metro cam ) are good as they give good torque and a low down power band and wont make look silly come a track day, or if its a track weapon you could go for a 286 or even a 300 which give high power outputs but don't produce the power until some think like 4k rpm which can be a pain in traffic. or any where in between

personally i wish i had gone for a slightly hotter cam due to the way i drive ;D

[dai9fxey]

There was a 2nd hand set of + 40 thou flat tops with brand new rings for sale on Ebay tother day.
I think they sold for about 70 squid.
Would have been ideal for this type of engine build.

[ljonez]

Feb 19, 2009 19:43:17 GMT 1 dai9fxey said:

There was a 2nd hand set of + 40 thou flat tops with brand new rings for sale on Ebay tother day.
I think they sold for about 70 squid.
Would have been ideal for this type of engine build.

wish i had seen them as i might be building another one soon. mine cost me £50 each

[miniandmodels]

Ive got a freshly bored 998 +40' with brand new flat top pistons. The short motor has been built and has new pennies, also has brand new duplex fited and a sports cam. Think shes a 265 or 275. Has also been chemcially dipped afterwards to wash the swarf out properly and even had the pressure release valve housing removed to clean it properly, which most engine builders like moorespeed dont do.

Looking to get rid of that if your interested in cutting the cost and work of building another from scratch.

Jamie......

[gavinhendy]

hey mate what timing gears do you have there ,

[coedy]

Feb 17, 2009 0:13:43 GMT 1 ljonez said:

been sorting out pics so thought I'd post a quick picture story of my 998 engine build.

spec
1030 block (998cc +40')
rebuilt 12g940 cylinder head
sw5-07 cam
lightened duplex gears
stage 1 kit
center main strap
rebuilt box
megajolt
stage 1 kit
hif44

[ljonez]

Lightened vernier duplex

www.minisport.com/mini-spare-parts/info_C-AJJ3327.html

[gavinhendy]

cheers boyos il be using the same in my 998 see

[ljonez]

Jun 19, 2011 11:12:39 GMT 1 gavinhendy said:

cheers boyos il be using the same in my 998 see

To be honest you could save a lot of money and just get normal duplex, I only went for vernier because I had a very good deal at a show

[gavinhendy]

whats the diference ?

[ljonez]

Jun 19, 2011 14:04:42 GMT 1 gavinhendy said:

whats the diference ?

About £60 in price. With normal duplex you buy different woodruff keys to get the cam timing right but with the vernier the gear is in 2 section and you rotate the center to get the timing right then lock them together via Allen bolts.

With duplex you can get the timing very close but with vernier you can get it perfect.

[coedy]

To save £60 though couldn't you just adjust the Dizzy advance to make up for it?
(Have no idea about timing..)

[ljonez]

Jun 19, 2011 19:42:58 GMT 1 @coedy said:

To save £60 though couldn't you just adjust the Dizzy advance to make up for it?
(Have no idea about timing..)

It's cam timing not ignition