Ausmini
It is currently Fri Aug 01, 2025 11:33 pm

Board index » Mini Chat » Mini Chat

All times are UTC + 10 hours




Post new topic Reply to topic  Page 1 of 1
  [ 11 posts ] 
  Print view Previous topic | Next topic 
Author Message
adamstuart
 Post subject: Really boring questions
PostPosted: Sat May 08, 2010 8:19 pm 
Offline
1275cc
1275cc
User avatar

Joined: Tue Sep 15, 2009 11:12 am
Posts: 3398
Location: Quakers Hill Sydney
A few questions on bores, their output and stability.

998:
How big a bore can you go?
How stable is this bore?
What is needed to go to this bore?

1275:
How long is 1380 likely to last, under what conditions?

_________________
You're so square
Baby I don't care
Top
 Profile  
 
drmini in aust
PostPosted: Sat May 08, 2010 8:30 pm 
Offline
religious status
religious status
User avatar

Joined: Fri Mar 19, 2004 6:19 pm
Posts: 39762
Location: near Baulkham Hills, NSW
adamstuart wrote:
A few questions on bores, their output and stability.

998:
How big a bore can you go? +.120" is easiest max, but you can get to 68.0mm.
How stable is this bore? No problem, these blocks are pretty thick.
What is needed to go to this bore? For +.100" or +.120", a set of pistons and a bore+hone job. For 68mm you need Imp pistons + 1100 crank, or bike pistons (more $$$)

1275:
How long is 1380 likely to last, under what conditions?
As long as a 1275 rebore would. ie same as original. But I like to go with 1360, it leaves another bore job for later. No power difference.

_________________
DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R. :mrgreen:
Top
 Profile  
 
adamstuart
 Post subject:
PostPosted: Sat May 08, 2010 8:45 pm 
Offline
1275cc
1275cc
User avatar

Joined: Tue Sep 15, 2009 11:12 am
Posts: 3398
Location: Quakers Hill Sydney
Thanks dr mini, if something was to go wrong with a 1380 bore could it be sleeved and the engine still be good? Or if a 1380 dies then it's dead.

Also, what kind of output would the 990 +.120 give?
998+120=1118?

_________________
You're so square
Baby I don't care
Top
 Profile  
 
drmini in aust
 Post subject:
PostPosted: Sat May 08, 2010 9:30 pm 
Offline
religious status
religious status
User avatar

Joined: Fri Mar 19, 2004 6:19 pm
Posts: 39762
Location: near Baulkham Hills, NSW
You can bore a 1380 to 1400 (if it was offset bored to 1380 or sooner).
Graham Russell can sleeve either a 1380 or a 1400 back to whatever size you need, from 1275-1380.

_________________
DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R. :mrgreen:
Top
 Profile  
 
Kennomini
 Post subject:
PostPosted: Sun May 09, 2010 10:22 am 
Offline
1275cc
1275cc
User avatar

Joined: Thu May 24, 2007 7:19 pm
Posts: 5370
Location: Yandina,Sunshine Coast,QLD
So their is no hp or torque difference between the 1360 and 80? or just not enough to notice in a fast daily driver?

_________________
Respect mine and I'll respect yours.
Top
 Profile  
 
drmini in aust
 Post subject:
PostPosted: Sun May 09, 2010 10:40 am 
Offline
religious status
religious status
User avatar

Joined: Fri Mar 19, 2004 6:19 pm
Posts: 39762
Location: near Baulkham Hills, NSW
True.
And once you bore further to 1400 or more, the cylinder walls get thinner and ring sealing gets worse.
This is why turbo 1275 motors are usually kept to +.060" or less.
Want more cubes, stroke it. :wink:

_________________
DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R. :mrgreen:
Top
 Profile  
 
micowen
 Post subject:
PostPosted: Sun May 09, 2010 11:26 am 
Offline
1098cc
1098cc
User avatar

Joined: Mon Mar 30, 2009 5:38 pm
Posts: 1650
Location: macquarie fields NSW
Sorry to jump in with a question, but do you guys reckon that it would be a bit stupid to take a mild stroker 998 and bore it to 100 thou? This is for a daily driver mind you, not for the track.
Would you if you could or is this in the overkill basket?

_________________
Chuck Norris is the only person alive who can kick you in the back of the face!!
mooo, I'm a pig!
Top
 Profile  
 
poeee
 Post subject:
PostPosted: Sun May 09, 2010 11:37 am 
Offline
1360cc
1360cc
User avatar

Joined: Tue Mar 16, 2004 8:55 am
Posts: 11264
Location: Geelong, Victoria
If you want more CC's out of your 998, just simply go to the next usable bore size and put a 1098 crank in it.

_________________
Image
Top
 Profile  
 
drmini in aust
 Post subject:
PostPosted: Sun May 09, 2010 1:19 pm 
Offline
religious status
religious status
User avatar

Joined: Fri Mar 19, 2004 6:19 pm
Posts: 39762
Location: near Baulkham Hills, NSW
poeee wrote:
If you want more CC's out of your 998, just simply go to the next usable bore size and put a 1098 crank in it.

No problem boring a 998 or 1098 block to +.100", block is thick & pistons are cheap.
A 1098 crank and +.100" pistons will give you 1188cc.
No substitute for cubes, if you want good torque for a roady. :P

_________________
DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R. :mrgreen:
Top
 Profile  
 
adamstuart
 Post subject:
PostPosted: Sun May 09, 2010 2:30 pm 
Offline
1275cc
1275cc
User avatar

Joined: Tue Sep 15, 2009 11:12 am
Posts: 3398
Location: Quakers Hill Sydney
drmini in aust wrote:
Want more cubes, stroke it. :wink:


What is involved in "stroking it"

inbeforelamejokes.

_________________
You're so square
Baby I don't care
Top
 Profile  
 
drmini in aust
 Post subject:
PostPosted: Sun May 09, 2010 2:37 pm 
Offline
religious status
religious status
User avatar

Joined: Fri Mar 19, 2004 6:19 pm
Posts: 39762
Location: near Baulkham Hills, NSW
adamstuart wrote:
drmini in aust wrote:
Want more cubes, stroke it. :wink:


What is involved in "stroking it"

inbeforelamejokes.

Stroking an engine means increasing the stroke of the crank.
A few ways-
998 motor- fit a 1098 crank & pistons, stroke is 7.5mm longer, it adds 100cc.
1275 motor-
1. get a big journal (1.750") 1275 crank, have the big ends offset ground down to 1.625", use Cooper S rods, deck the pistons 1.5mm. This gives about a 3mm stroke increase (more possible if you go undersize on the big ends).
Cost: around $240 for crank grinding.
OR
2. Get a longer stroke crank made, say 86mm stroke. Cost $,$$$.

_________________
DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R. :mrgreen:
Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  Page 1 of 1
  [ 11 posts ] 

Board index » Mini Chat » Mini Chat

All times are UTC + 10 hours


Who is online

Users browsing this forum: No registered users and 92 guests

You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Jump to:  

cron

© 2016 Ausmini. All garage work involves equal measures of enthusiasm, ingenuity and a fair degree of irresponsibility.