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PostPosted: Sat Oct 05, 2019 8:02 pm 
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848cc
848cc

Joined: Mon Oct 25, 2004 8:01 am
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Location: Carrum Downs VIC
Just wondering if putting rockers in a 998 auto carbed engine will improve performance much? My mechanic said it is the easiest and cheapest way to get more out of engine but not 100% sure

Thoughts on this and if anyone has done this before?


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PostPosted: Sun Oct 06, 2019 6:59 am 
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1360cc
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Joined: Sun Apr 11, 2004 11:32 am
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Location: Sthrn HiLoLands, NSW, Australia
I think getting another mechanic might improve the cars performance :roll:

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PostPosted: Sun Oct 06, 2019 9:18 pm 
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Location: Wodonga - Vic/NSW border
you won't get much improvement on their own - you probably wouldn't even notice. However, as part of a "package" of improvements like a bigger carb with a needle to suit, good extractors and exhaust and shave the head for more compression you'll get it going quite well

but a 998 auto is never going to be a rocket...

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PostPosted: Mon Oct 07, 2019 5:21 am 
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Joined: Fri Mar 19, 2004 6:19 pm
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Location: near Baulkham Hills, NSW
I played with my Matic a bit before I gave it a 1275 S transplant.
A 998 auto already has little torque off the mark, 1.5 roller rockers or a cam change will make this worse. 1.3s might give marginal improvement, but not worth it for the $$$ involved.
Shaving the head and a little porting does help, as will a freeflow exhaust manifold.
They already run an HS 4 carb.
BMC should have used the 1098 instead...;)
Edit:
If rebuilding I would throw a 1098 crank & pistons into it for more torque. Block is the same.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank @7000+, 45 Dellorto, RE282 sprint cam, 1.5 rockers, 11.0:1 C/R. Going harder with Peak ignition system fitted. :mrgreen:


Last edited by drmini in aust on Mon Oct 07, 2019 7:57 am, edited 2 times in total.

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PostPosted: Mon Oct 07, 2019 7:06 am 
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848cc
848cc

Joined: Wed Jul 02, 2014 11:38 am
Posts: 472
Just witnessed a mate have to pull a big buck V8 down due to roller rocker failure .Not good
Rocker didnt break Needle roller collapsed


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PostPosted: Mon Oct 07, 2019 2:37 pm 
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848cc
848cc

Joined: Wed Jul 02, 2014 11:38 am
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Was talking to a mate today and he commented on how they are used in radius arms in the same duty .


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PostPosted: Mon Oct 07, 2019 5:52 pm 
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Location: near Baulkham Hills, NSW
Ian_B wrote:
Was talking to a mate today and he commented on how they are used in radius arms in the same duty .

Original MK 1 850 Minis in UK had 13/16" dia bronze bushes both ends of the arm. The inner ones used to seize up with the load.
So, around1960 they fitted a full complement (no cage) needle bearing there to cope with the load. All Oz Minis got this.

Big wheel Moke had these needle bearings fitted at both ends, for the same load reason.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank @7000+, 45 Dellorto, RE282 sprint cam, 1.5 rockers, 11.0:1 C/R. Going harder with Peak ignition system fitted. :mrgreen:


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PostPosted: Tue Oct 08, 2019 7:39 am 
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1360cc
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Joined: Sun Apr 11, 2004 11:32 am
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Location: Sthrn HiLoLands, NSW, Australia
drmini in aust wrote:
I played with my Matic a bit before I gave it a 1275 S transplant.
A 998 auto already has little torque off the mark...


Having once driven a nicely restored Matic...I can assure you that they launch quite well and could win just about any drag race over the first 50 yards! 8)

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PostPosted: Tue Oct 22, 2019 3:12 pm 
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848cc
848cc

Joined: Mon Sep 16, 2013 11:47 pm
Posts: 27
Hi, wondering if auto and manual crankshafts from
approximately the same year are the same ? For
example I have a 67 998 auto, would a 1100 crank
from manual car, early 70's fit ?


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PostPosted: Tue Oct 22, 2019 6:54 pm 
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998cc
998cc

Joined: Mon Mar 10, 2014 11:38 am
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Location: Tassie
Yes, pistons would also need to be changed due to pin heights.

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