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4303 Posts Member #: 1321 Post Whore Wiltshire |
26th Nov, 2006 at 11:43:01am
just a thought.
On 7th Oct, 2010 5haneJ said:
yeah I gave it all a good prodding |
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 1497 Posts Member #: 100 Parisien Turbo Expert Paris\' suburb |
26th Nov, 2006 at 03:52:31pm
the max I know to have bored on these is 68 mm requiring plugging some passages and use "s" rods |
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 11046 Posts Member #: 965 Post Whore Preston On The Brook |
26th Nov, 2006 at 06:43:48pm
69mm at a push but youll need to find the pistons first On 26th Oct, 2004 TurboDave16v said:
Is it A-Series only? I think it should be... So when some joey comes on here about how his 16v turbo vauxhall is great compared to ours, he can be given the 'bird'... On 26th Oct, 2004 Tom Fenton said:
Yep I agree with TD........ |
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4303 Posts Member #: 1321 Post Whore Wiltshire |
27th Nov, 2006 at 06:20:57pm
thats a hell of a lot removing 6-7mm from each cylinder. On 7th Oct, 2010 5haneJ said:
yeah I gave it all a good prodding |
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Forum Mod 10979 Posts Member #: 17 ***16*** SouthPark, Colorado |
27th Nov, 2006 at 06:30:47pm
I thought Peter 1071 took it to something ridiculous against the 'traditional' advice.... On 17th Nov, 2014 Tom Fenton said:
Sorry to say My Herpes are no better Ready to feel Ancient ??? This is 26 years old as of 2022 https://youtu.be/YQQokcoOzeY |
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 2742 Posts Member #: 637 Post Whore Hertfordshire |
27th Nov, 2006 at 07:25:34pm
were is peter?
My build thread..
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 8604 Posts Member #: 573 Formerly Axel Podland |
27th Nov, 2006 at 07:51:54pm
This what Peter had to say:
On 5th of Jun, 2005 at 08:29pm mini1071s said:
Hi, there are advantages to the 850 engine, but in a roundabout way... It is a quick and cheap way to a short stroke free revving A series without having to pay out for billet cranks... You can put an 850 crank in the 998 block, you have to use custom made thrust washers as the 850 centre main is wider than the 998. You then put in a set of 998 +60 thou pistons, preferably on the later rods, arp rod bolts, centre main strap, lightened as per vizards book. Deck the block so the pistons are flush at TDC. A standard chamber volume 12G295 head would give a nice low CR suitable for a turbo. This gives you a 936cc engine that is nearly square. (bore x stroke). You also get nice thick cylinder walls and proper cam bearings. Top this off with a 12G295 cooper 998 head and an SW5 cam. I built one of these for my girlfriends MK1 as she wanted to keep the 850's revvy nature. Was a blast to drive and revved to infinity. Unfortunately I didn't fit new or ARP rod bolts and blew it up when I buzzed it to somwhere over 8000rpm missed a gear chav baiting. I am going to rebuild it with a turbo if my 998 turbo project goes OK. I think this would be a nice project. You can bore the blocks further to take hillman imp bore size if you offset the bores, (p404 vizard I think), but the actual pistons used would need more compression height, (or you need longer rods), as you can't deck the block by the required amount, I am sure that there must be some tasty bike pistons or rods out there but have not managed to find any info on bike pistons/rods as yet. I know KAD use them in their expensive 16V engines I am using a garret GT15 turbo of a HDi which is ideal for my 998 and apparently flows enough air for 220bhp, which is no where near what I will be producing so it's not like you are sacrificing power for the super fast spool up. If short stroke mini engines appeal, then you can get hold of the 850 stroke cranks to fit into 1275 blocks, (check out Jai's - minicranks- posts on the minimania forum - mnicranks@hotmail.com he sells them). This gives a nominal 1071cc, or 1160cc on a 73.5mm bore. I bought one off him a couple of years ago that I want to build an engine with, which I will get round to one day. Take care to have the cranks indexed though as they are not machined too well from the factory, KC reckons so anyway, not that I beleive half of what he writes...have not checked mine out in detail yet. Good luck with the project. I hope to post some pics of my progress soon, as soon as I can figure out how... Personally, i'd start with a 998 A+ block as it is much stronger to start with and has cam bearings. I think he must still be in Africa. Edited by Paul S on 27th Nov, 2006. Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
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4303 Posts Member #: 1321 Post Whore Wiltshire |
27th Nov, 2006 at 10:08:25pm
how strong are 850 cranks, what sort of bhp are they capable of handling, including turboing. its just i am considering and 850 block with a 998 crank and some sort of turbo, as i am interested in hillclimbing.
On 7th Oct, 2010 5haneJ said:
yeah I gave it all a good prodding |
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11046 Posts Member #: 965 Post Whore Preston On The Brook |
27th Nov, 2006 at 10:15:08pm
850 block and 998 crank wont fit without machining the thrust faces of the crank. TBH the 998 block is an overbored 850 block and has the right thrust spacing.
On 26th Oct, 2004 TurboDave16v said:
Is it A-Series only? I think it should be... So when some joey comes on here about how his 16v turbo vauxhall is great compared to ours, he can be given the 'bird'... On 26th Oct, 2004 Tom Fenton said:
Yep I agree with TD........ |
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4303 Posts Member #: 1321 Post Whore Wiltshire |
27th Nov, 2006 at 10:50:21pm
my thinking behind the 998 crank was that has a longer stroke than the 850 so would be better for torque rather than have a short stroke screamer.
On 7th Oct, 2010 5haneJ said:
yeah I gave it all a good prodding |
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11046 Posts Member #: 965 Post Whore Preston On The Brook |
27th Nov, 2006 at 11:08:36pm
I have a set of +60 998 pistons im keeping for an 850 project. I have the cooper S rods and a fresh regrind 850 crank for this as well, just dont have the 850 engine yet, LOL
On 26th Oct, 2004 TurboDave16v said:
Is it A-Series only? I think it should be... So when some joey comes on here about how his 16v turbo vauxhall is great compared to ours, he can be given the 'bird'... On 26th Oct, 2004 Tom Fenton said:
Yep I agree with TD........ |
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 982 Posts Member #: 97 Post Whore Near Daventry, midlands |
28th Nov, 2006 at 07:52:59am
850 cranks are just as good as 998 ones I've seen the future and tbh its Pie
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 7763 Posts Member #: 74 I pick holes in everything.. Chief ancient post excavator |
29th Nov, 2006 at 07:51:29am
A friend of mine in the UK has got a big bore crank that makes 850 with a 1275 bore + 20. That's what you guys need. That thing revved to 13000 but was rather docile under 7000 :) On 13th Jul, 2012 Ben H said:
Mine gets in the way a bit, but only when it is up. If it is down it does not cause a problem. |
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