engine Build Ideas

[Aston]

Hey guys ive had a quick search but basically i jsut cant find any information about what im looking for, basically im runnign a few ideas through my head regarding an engine build, i would really like to know what parts that are interchangable between the 8v engines, im aware of the 1.2 having a short stroke which is something be looking for but is there anything to stop me putting a 1.2 crank in a 1.6 block for a short stroke motor ? i spent a while searchin last night but i jsut cant find any information about the interchangable parts of the 8v engines, ideally im looking for a short stroke high reving engine, with the shortest stroke and and the big displacment possible any one got any input? and before everyone calls me a noob i know its jsut not a case of putting everythingether and hoping for the best I.e engine management, compression ratio im jsut looking for options but custom cranks arnt really an option because of the £££'s any input would be great

[craig green]

There was a video posted of a european Nova & driver a month or two ago.

The thread sparked a conversation about the car & engine which was a destroked GTE at approx 1300cc IIRC. It revved very high & sounded awesome in the vid.

It can't be that far back. I'll look.

[Aston]

ive seen the video which actually sparked the idea even more but i read that is was a custom crank jobbie is there anythin i can use with standard bits, odviously the crank will need a lot of work for the revs but surley something is interchangable ?

[craig green]

http://www.pngclub.com/forum/showthread.php?t=106396

No idea chap. Maybe a 1.2 16v crank will do the job. Theres only one way to find out............

[Aston]

oh is the 16v version the small stroke as i presumed it was the 8v crank as i was hoping the 8v cranks would be the same bar stroke do you have any information on this ?

[burgo]

i think the problem you will come across is bearing journal diameters. im 90% sure the 1.6 has bigger than the rest. this can be got around with work obviously but it adds to the cost of doing it

[Aston]

thts not 2 much of an issue the journal size as i can get machine work done reasonably priced by a friend and i would need to increase the size anyway to make it a bit more reliable at high rpm, basically im wanting to to a 1.2 8v crank and mix and match 1.6 gte bits any ideas ??

[Stuart]

you will need to work out the right rods, otherwise the short stroke crank will put the pistons some distance from the top of the block, meaning a heavily reduced CR..

[Aston]

i thought all the 8v rods where the same length jsut the trow of the crank differed ?

[Stuart]

assuming the gudgeon pin - piston crown height is all the same, then a shorter throw in the "taller" block will see the piston TDC'ing too low

[Aston]

well what if i used the original 1.2 with a GTE head and fueling, then il still have the short stroke and displament which isnt really an issue but ideally id want to be 100 bhp+ and around 8-9k rpm so maybe there is a better way of doing it, basically im not to fussed about displament and power and aslong as its fun to drive and really high revs so it will be a lairy cam and maybe a little hard around town but thats not important, maybe you can reccomend a build

[Stuart]

have a look through the 1.2 features for a white/blue/red car that I semi built. Thats go an engine spec that should have seen well over 100bhp from a 1200

[Aston]

ok il have a lookbut am i still going to be able to get the revs that im looking for and i presume thats from following the 1.2 tuning guide with a 1.4 head etc

[Aston]

Just another quick question, odviously the the 1.2 stroke will be to short for the 1600 block but does any one have any ideas how much as in would the differance be able to be taken from the top of the block (skimmed) ??

[burgo]

why are you so bothered about how high it revs? if you are only after 100bhp just fit a 1.6

[Aston]

the bhp figure was jsut because of using the 1.2, but i dunno really thts what the original plan was just to fit a 1.6 as the headgasket has gone on the 1.2 so for a bit more work and money i could have a 1.6, i dunno really i just fancy a screamer of an engine and the idea of having a small displacment high power motor really appeals i know it wont be the most drivable, but maybe the 1.6 is a better motor to start with but i started to read about the short throw of the 1.2 and started to throw a few things about in me head, and the fact that it would be summot differant basically im not to sure of compatibility and short of buying all the ohc 8v efi engines and measuring everything im not sure whats going to work, and i dont know why i like/want high revs but they jsut appeal to me and sound fantasic in my opinion so maybe im looking at the wrong engines to start with, so im jsut after information about what will bolt together and develop revs im after and is part of the fun building summot unique

[burgo]

have you concidered dropping in a jap motor? theres one already on here with a crx engine

[Aston]

no not really if i was going to do a conversion it would be a 20xe, as i dont want the hassel of making mounts and driveshafts modding the loom etc etc i jsut had the idea of making a mix and match motor really but it doesnt look promising, has any one ever posted regarding how much can be removed from the top of a 1.6 block ??

[burgo]

your in new territory mate

[Aston]

well basically heres how its stands atm, ive got a solid shell with 2.0 brakes coilovers etc etc and at the minutes its a 1.2 spi with a F13cr and 4.18 final drive but the headgasket has gone at 50k (had a hard life), so i was initially thinking of a 1.6 gte engine swap but fancied doin summot a little unique, ive not got any plans to sell the car cause of the money ive spend over the 3 years of owing it and i love the car and its looks but the 1.2 is such a bore that ive lost any enjoyment of driving the car so im just waying up some options of building a decent engine or fittign a decent engine, ive read about the 1200 pistons and 1300 crank and rods build but dont really want a longer stroke as if i build an engine id want a high revving motor dont ask why i just do love the noise etc etc so im jsut looking for an engine i could build from the verious differant 8v engines thts another thing i want to keep for antoher unknow reason is there any more work involved fitting a 8v as apposed to a 16v when the origianl car was an 8v ? any input would be great

[craig green]

1.3's are screamers compared with 1.2's but I've learnt that its half to do with the 1.2 cam barely having any lift.

Have a go in a powerbox'd 1600 16v. I reckon you would like a bit of that & if you find the motor cheap, the powerbox mod costs less than 150 quid.

Cheapest route to a screamer IMO.

[novanova636]

can you not just get the 1.2 bored out to a 1.6 useing standard 1.6 pistons?

[burgo]

can you not just get the 1.2 bored out to a 1.6 useing standard 1.6 pistons?nooooo ubber fail. that would only give you a 1233cc engine lol.

CG what makes you think 1.3's rev harder? as they should do as they have a much longer stroke

i thought the rod ratio made more of a difference with the revs anyway?

[Stuart]

its a combo of the two, but stroke is the BIG hitter in that game.

eg the 2.2 engine dosent like to rev as its got about a mile of stroke, compared to the 2.0 USA engine that will rev to 10K on the std crank!!!

[novanova636]

after market pistons then?

[burgo]

after market pistons then?you would need 90mm pistons with the 1.2 stroke lol so no

[novanova636]

do you no what the largest after market pistons are? and what cc that would make it?

[burgo]

just wait until you can afford to insure a 1.6 and fit one of them

[novanova636]

hahaha. im thinkin along the same idea as the guy who started the thread. i dont want a 2L engine but want to make some dif out of a 1.2.

[novanova636]

so do you no the answer?

[Stuart]

KNOW...... ffs not no.


a +2mm rebore would be all I'd opt for safely... thats approx a 50-70cc increase.

[novanova636]

cheers fella. sorry about the english

[Aston]

that shows how small the 1200 stroke is, well heres another idea i read in another thread sticking the 1600 head on gives a compression of 7:1 how much skimming off the head would i need to return the compression to a usable level and can you skim that much off ???

[Stuart]

work it out :D

*edit*
used my calculator (see siglink)
you need to lose 17CC per pot to get from a 1200 engine with 7:1 to a 1200 with 10:1..... thats a LOT of CC's to get rid of imho.


you can work out ho much to skim with the volume of a cylinder calculation from google

[Aston]

hey sorry im a cheeky git but i dont know any of the numbers needed, is there a big differance in potential with the 1.4 head and 1.6 as i remember the 1.4 been 8:1 is that a more realistic starting point ?

[burgo]

the 1.4sri head has a very small combustion chamber and yet the same size valves as the 1.6. so id recommend going down that route

[Aston]

yeh it doesnt seem il get the 1.6 down compression wise, whats the engine numbers of the SRI ? and is it worth fitting the fueling system from a 1.4 and if so would tht mean i would need the ecu and loom??

[burgo]

aston it depends what you want from it and your budget. theres 101 things you could do and im not going through all of them. the sri engine is c14se. your more likely to find one in a mk3 astra

[Aston]

hey cheers for the reply, im sure there are a million ways, but basically im not to bothered about CC, or low down driveability basically i jsut want to build a short stroke screamer, but basically atm ive got a 1.2 SPI c12nz? not to sure on the number and the head gasket has gone some im looking for a replacement engine either a 1400 or 1600 that i will buy complete and hopefully build an engine from the two any input would be brill cheers

[Stuart]

I think its going to be a case of you need to get both engines in bits (lets face it, a 1.4 or 1.6 engine should be peanuts to buy thesedays) and start measuing/fitting parts and seeing whats what.

you will be doing what no one has really done before so any help here will be vauge at best.

[Aston]

yeh id got the impression really, is there going to be any issues with fitting the differant heads (water and oil ways are my biggest concern) jsut so ive got all the info in one thread wats the engine number for a 1.6 MPI motor the gte one

[Stuart]

the heads are interchangeable on the water/oil way front yes. (Bar the 1.0 8v of course)

C16SE one of the 1.6 mpi engine numbers

[Aston]

cheers guys

[jimbob-mcgrew]

man... 17cm's from each pot for the 1600 head, hah, there wouldnt be any head left after that.

i was gonna suggest boring the crap out of the 1.2 block with larger diameter piston heads, and a skimmed to sh1t 1400 mpi head on it, but after reading the posts.. ive learned it wont happen.

i want to create a fully lightened and balanced 8v myself at some point, but it'll probably cost me a few grand.

how about keeping your 1.2 block, but doing a few bits to it like a cam, a lightened flywheel, 1300 inlet manifold with a pierburg 2e carb on it, decent exhaust too.

course for the money it'll cost to do those bits, it still wont be as powerfull as the 1600 lump

tricky choice.

what would the 1.2 head be like on the 1600 block i wonder ? compression ratio would be high as a kite, if it didnt blow up straight away it would rev well i woulda thought.

[Aston]

the 1.2 spi head is usless basically but ive gopt one last question jsut so im clear in me own head, is the 1.2 SPI or the 1.2 carb the motor with the short stroke as i know there the opposite way round between the engines but just cant find which one is which cheers

[jimbob-mcgrew]

oh spi is it the one u have, i dunno the difference in the head ports between both, all i know is spi is crap lol

i woulda thought the bottom end would be the same, spi head and fuel supply setup is for economy tho, thas why there turd.

[burgo]

ok something i was looking at before realising small blocks are for girls is this.

use a 1.2 block and pistons but with 1.6 crank and rods. this could give you a 1.5. i never got as far as checking piston heights tho but its something else for you to concider

[jimbob-mcgrew]

why not just dump the 1600 in.. 1.2 spi is around 45 bhp, whereas the 1.6 mpi is 99, more than double

[burgo]

cos thats easy and certain naughty people like to lie to the insurance lol so a block that is stamped up as a 1.2 and has the bore of a 1.2 is quite crafty

[Aston]

nah insurance aint the issue been passed three years and had the car that long but does anyone know which engine has the short stroke ?

and there is no way my SPI is even 45bhp with the old headgasket gone but it still chuggin along but fuel economy isnt the best hahahha

[jimbob-mcgrew]

be 45 donkies now lol

[Aston]

your not far off m8 i do compare it to a mule

[Stuart]

the stroke info is in the haynes manual, which every nova owner should have a PAPER copy of!!!!!

oh and its not m8 its mate... ;)

[Aston]

sorry mate for got the text speak, yeh ive got a haynes il take a look later cheers