View Full Version : 1.2 8v carb
hi all
need some info please?
i am looking at putting a 1.3 crank and rods in to a 1.2 engine!
has anybody done this before? if so did you have a noticable gain (hp wise)
i have used the search engine on here and cant find any information on this at all?
all info or links to threads appreciated!
thanks
jsut put a 1.3/1.4 engine in. about a billion times less work and it wont be a mish mash of crap.
Although I'm assuming you want to do it to make a lager capacity engine with 1.2 still on it for either cheating in racing or for defrauding your insurance...
HI, I did this back in the early nineties. It made for a fun conversion. 115mph indicated (private road of course) on an otherwise standard 1.2 merit 4speed.
The benefits of doing it are that the f10 gbox still fits whereas a 1.4 needs a f13 box cos of the bigger bellhousing/flywheel (cue loads of posts about how I am wrong but When I stuck a f13 box on it was different), the std carb works ok, but you should swap the exhaust manifold & downpipe for a 1.3 4-2-1 type .
the pistons need machining to lower the compression unless you are planning to use that high octane stuff. You use the 1.2 head gasket. The conversion is actually better if you start with a 1.3 block & get it machined out for the std 1.2 pistons because an old 1.2 block will be worn & need boring oversize. which will cost tons.
It does need a bit of care to get the pistons right. Peter Maiden Components from Tamworth used to market a conversion.
jsut put a 1.3/1.4 engine in. about a billion times less work and it wont be a mish mash of crap.
Although I'm assuming you want to do it to make a lager capacity engine with 1.2 still on it for either cheating in racing or for defrauding your insurance...
well you assume wrong!!!!
why leave comments like this?? Why?
HI, I did this back in the early nineties. It made for a fun conversion. 115mph indicated (private road of course) on an otherwise standard 1.2 merit 4speed.
The benefits of doing it are that the f10 gbox still fits whereas a 1.4 needs a f13 box cos of the bigger bellhousing/flywheel (cue loads of posts about how I am wrong but When I stuck a f13 box on it was different), the std carb works ok, but you should swap the exhaust manifold & downpipe for a 1.3 4-2-1 type .
the pistons need machining to lower the compression unless you are planning to use that high octane stuff. You use the 1.2 head gasket. The conversion is actually better if you start with a 1.3 block & get it machined out for the std 1.2 pistons because an old 1.2 block will be worn & need boring oversize. which will cost tons.
It does need a bit of care to get the pistons right. Peter Maiden Components from Tamworth used to market a conversion.
cheers for the reply!
the 1.2 block i have has not done that many miles so shouldnt be to bad
ware and tare wise ,but i will bear the 1.3 block in mind!
you say the pistons will need machining? any info on that?
when you say hi octane you mean above 97 ron ?
was your 0 - 60 improved?
again thanks for the reply
cheers for the reply!
the 1.2 block i have has not done that many miles so shouldnt be to bad
ware and tare wise ,but i will bear the 1.3 block in mind!
you say the pistons will need machining? any info on that?
when you say hi octane you mean above 97 ron ?
was your 0 - 60 improved?
again thanks for the reply
ok, well having a longer stroke means the pistons move further up & down in the bore, so the original wear grooves in each bore will need reboring. using a 1.3 block as a base means the crank is already matched to the mains so you don't need to linebore the mains.
I will try to sort out some dimensions for the piston pockets, but when I did it, I calculated it out using the david vizard mini tuning book methods using a syringe & perspex plates to measure the cc of the chamber. you need to keep the cr down to about 10:1 for normal unleaded.
The main thing about the performance was that it could pull cleanly from 15mph to 115 mph in top(4speed) the power was about 85-90hp but the major difference is the torque increase, I ran a std head & cam & it had a fantastically flat torque curve. its 0-60 was sub 10sec but its speed from a-b was dramatically improved.
EDIT Just did a google search for the original pmc 1.4 nova that predated the works one by a couple of years & inspired me to try it, & found this http://cgi.ebay.co.uk/Citroen,-Renault,-PMC-Nova,-V8-Metro,-Pinto_W0QQitemZ120206967568QQcmdZViewItem it is a back copy of the original CCC mag where I read about it. buy it & there will be a photo of the pistons with machined out dishes, a good engineer will be able to measure from the photo to get a good idea on the sizes
Mike
mikeoxford
10-01-08, 01:50 AM
dont quote me lol! but i think you can fit a small flywheel to the engine to use the f10 instead of the f13 but then you would have problems getting the starter motor to fit
Mike cheers for the reply again!
some good info their!
do you know of any good engineering workshops around your area as im not that far from hinckley myself?
cheers again:thumb:
craig green
10-01-08, 12:51 PM
Using 1.2 bore/pisons on a 1.3 caonk & rods is a well known method of building a damn quick 1400 IIRC.
I've posted about it before, years ago I'm sure.
With a sporty cam & twin 40's you can get stonking power from this method.
dont quote me lol! but i think you can fit a small flywheel to the engine to use the f10 instead of the f13 but then you would have problems getting the starter motor to fit
So change the flywheel so a factory 1.4 will fit but the starter won't fit so IT WON'T WORK ANYWAY!!!!!!!!!!
This is why I reckon sticking with the 1.2/1.3 f10 is simpler because everything fits.
To be Honest, the base engine will be due for a rebuild after 20 years anyway.
bobbyb whereabouts are you based? there is a pretty good place locally called Clayfield & Hall in the middle of Hinckley
So change the flywheel so a factory 1.4 will fit but the starter won't fit so IT WON'T WORK ANYWAY!!!!!!!!!!
This is why I reckon sticking with the 1.2/1.3 f10 is simpler because everything fits.
To be Honest, the base engine will be due for a rebuild after 20 years anyway.
bobbyb whereabouts are you based? there is a pretty good place locally called Clayfield & Hall in the middle of Hinckley
i used to live in hinckley so i know it quit well,i now live in ashby de la zouch which is not all that far from hinckley?
i will be re-building it from top to bottom ,need to source places that do all the parts, gaskets,pumps,bearings,bolts,etc and if i can source uprated parts even better,for the re build!
i will need to source a 1.3 bottom end from some where? am i right in saying the 1.3 astra mk2 is the same as the novas? i presume they are but dont have an astra haynes to check??
Using 1.2 bore/pisons on a 1.3 caonk & rods is a well known method of building a damn quick 1400 IIRC.
I've posted about it before, years ago I'm sure.
With a sporty cam & twin 40's you can get stonking power from this method.
my plans exactly: twin 40's , 4.2.1 manifold and uprated system, uprated cam,internals changed and maybe exhaust valves increased 1mm.
there is a good place in b o t, G L engineering, if memory is what it was. they do tons of rebore work. they will probably do the bits as well.
there is a good place in b o t, G L engineering, if memory is what it was. they do tons of rebore work. they will probably do the bits as well.
bot??? where is that? do you know where i can get all oe/gm engine rebuild parts from? gaskets , bearings etc?
cheers
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