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Engine Specific Info and Questions => IDI Engine => Topic started by: oldskool rich on April 17, 2008, 08:32:59 pm

Title: will this 1.7 idea work?
Post by: oldskool rich on April 17, 2008, 08:32:59 pm: ive heard of a few people doing 1.7s and i want to hav a go.

my plan is, AAZ block, 1.6 crank (lightend/balenced), PD con rods, AAZ pistons (ceramic coated) obviously the compression ratio will be all wrong because of the shorter crank stroke.

if i cut the top off the AAZ block it would sort thing out, without buying custom rods 8)

will this work????????????????
Title: will this 1.7 idea work?
Post by: Luckypabst on April 17, 2008, 08:52:56 pm: How thick is the block deck vs. half the difference in stroke? Too much shaving and you'll be in the water jacket.

Longer rods?

Chris
Title: will this 1.7 idea work?
Post by: oldskool rich on April 17, 2008, 08:58:08 pm: i dont know if theres enough to cut off, was hoping sumone will know, are there any stock rods that will fit?
Title: will this 1.7 idea work?
Post by: rabbid79 on April 19, 2008, 12:08:00 am: I have considered doing something like this, but with a forged 92.8mm crank out of a '93-'95 ABA. I've done some calculations, and with a 1.9 head, the compression ratio drops to around 20:1 with the stock rods and the thinnest AAZ metal head gasket available. You'd have 1.84 liter engine with a little better revving capability and still have decent torque. The compression ratio is also better suited to super-high boost applications.
Title: will this 1.7 idea work?
Post by: jtanguay on April 19, 2008, 12:24:37 am: low compression ratio would be great for racing applications (more boost :twisted:) as the high compression ratio was designed for great cold starting. an intake air heater would probably help out a lot for those colder starts
Title: will this 1.7 idea work?
Post by: oldskool rich on April 19, 2008, 08:59:31 am: so how much should i take off the block? i would like to run mega boost but at the same time i dont want to be tring to start it up for hours each day, its still a daily driver.

i am collecting the block next week, and im gona get the top skimmed off strait away, so cud do with some advice, also is there another IDI piston that has a wider bore than the 1.9 but will take the same rods so i cud bore it out to get more torque?
Title: will this 1.7 idea work?
Post by: MJF on April 19, 2008, 01:06:25 pm: You´ll have to cut the block 4mm minimum...
Title: will this 1.7 idea work?
Post by: oldskool rich on April 19, 2008, 06:38:41 pm: ok 4mm, will that lower my compression? how much difference to stock 1.9 is that? does anyone know how wide the 5 pot pistons are? will they fit the aaz rods?

there must be somthin that will fit :?:

i was thinking that to help me start up maybe a could use a more powerfull starter motor or a 24volt battery, any sergestions?
Title: will this 1.7 idea work?
Post by: Baxter on April 19, 2008, 07:33:38 pm: http://www.brick-yard.co.uk/VehicleSpecific/T3/info/enginedata/dsl/KYdata.htm
Title: will this 1.7 idea work?
Post by: Vincent Waldon on April 19, 2008, 07:43:52 pm: Thanks for the link... this is the first time I've seen this:

Dynamic Timing AVL-bosch-Souriau-sun-VLT4139 15* +/-1* @ 900 RPM
Title: will this 1.7 idea work?
Post by: Baxter on April 20, 2008, 04:05:19 pm: One level up from last link.
http://www.brick-yard.co.uk/VehicleSpecific/T3/info/enginedata/engine.htm

Check JX
8)
Title: will this 1.7 idea work?
Post by: oldskool rich on April 20, 2008, 08:52:58 pm: wow that is amazingly helpfull, that saves me asking about 100 questions

dont supose theres one of those data lists for every car in the world with a good seach engine? :lol:
Title: will this 1.7 idea work?
Post by: Baxter on April 21, 2008, 04:40:16 pm: There is yes.
I have it at work.
Its called Autodata!
It comes on a CD now, go check e-bay, theres bound to be a cracked copy of it somewhere.
I mailny fix older cars and vans, so upto 2003 is fine for me, thats what I have, infact, no, I recently found 2006, but I have no idea where it is now or I would run you a copy off.
Title: will this 1.7 idea work?
Post by: oldskool rich on April 28, 2008, 12:13:45 pm: ok so ive took everthing off my dona engine now, im ready to get it cut down, just not sure how much by, the differnce in stroke is 9.1mm if i wanted it to have the same CR id hav to cut that much off.
how much difference wud each mm make to the CR?

if i used a thinner gasket cud i cut less off?

i wud like sumone smarter than me to tell me how much i shud cut off and what gasket, i want it to start up fairly easy and be able to run as much boost as possible :D

sorry i dont want much do i :lol:
Title: will this 1.7 idea work?
Post by: jimfoo on April 28, 2008, 12:21:33 pm: From what I remember of my block, I don't think you will be able to cut off enough to have a high enough CR to be able to start it. The passages start to really open up not all that far down.
Title: will this 1.7 idea work?
Post by: oldskool rich on April 28, 2008, 02:07:51 pm: i know they do, i think i can get away with about 5-6mm, if i end up in the water jacket i supose i cud just weld a bit of support across the top, i cant afford custom rods so i dont have much choice :cry:
Title: will this 1.7 idea work?
Post by: oldskool rich on April 30, 2008, 07:56:21 pm: plans hav all been scrapped

it wudnt work :lol:

cant believe no one thort of the timing, if the block is shorter the belt will be too long and the pullys will be different distances apart. :roll:

think im gona just lighten a tdi crank, fly wheel and use pd rods ect

anyone know of a VNT20 for sale? ill swap for a mental supercharger?

does anyone know of a super thick realy strong gasket i cud use to lower my CR?
Title: will this 1.7 idea work?
Post by: andy2 on May 03, 2008, 11:22:24 pm: You could use a 1.6 timing belt as its 2 teeth shorter than the 1.9 AAZ one.I'm using a 1.6 timing belt on my AAZ but its for other reasons.