stroke a 4AGZE a little bit.

[nick.parker]

DISCLAIMER :: I know if I want power I shouldn't be mucking aorund with a 4AGZE, this is for my interest and please pretend money is no object (it really is, but just pretend!!!).

Hi,
I found a place that sell custom rods - costs a bit more than standard aftermarket rods.
I got to thinking about stroking the 4AGZE for a bit more capacity to an 82mm stroke (and 82mm bore with 40 thou pistons). 5mm would have to be ground off the crank (is this possible?) to get +/-2.5 mm more stroke (5 total). This would give 1732cc (up from 1587cc) and still a reasonable bore/stroke, but I calculated the rod/stroke ratio would be even smaller at Rod/Str = 1.46 (stock = 1.58 I calced). And I read that ratios outside 1.6 - 1.8 were not good design. Would 5mm off the 42 journals on the ZE crank be too much?

Just looking for comments, since HK$ had a 1.8L kit for the 4AG(Z)E once.

Cheers, Nick

[fixeruperer]

5mm shit man thats heaps i wouldnt take 0.5 -1 mm off

[The Witzl]

easier would be to take a 7A block and crank... and get some custom rods for that to match up to either some custom made forgies or the stock smallport 4A-GZE pistons.

saves the effort of fudging up a perfectly good 4a crank - and gives you closer to 1800cc

[nick.parker]

Based on the feeling behind those comments it sounds as if the HKS setup would have been a custom crank then, rather than a machined stock crank?

[kingmick]

DISCLAIMER :: I know if I want power I shouldn't be mucking aorund with a 4AGZE, this is for my interest and please pretend money is no object (it really is, but just pretend!!!).

Hi,
I found a place that sell custom rods - costs a bit more than standard aftermarket rods.
I got to thinking about stroking the 4AGZE for a bit more capacity to an 82mm stroke (and 82mm bore with 40 thou pistons). 5mm would have to be ground off the crank (is this possible?) to get +/-2.5 mm more stroke (5 total). This would give 1732cc (up from 1587cc) and still a reasonable bore/stroke, but I calculated the rod/stroke ratio would be even smaller at Rod/Str = 1.46 (stock = 1.58 I calced). And I read that ratios outside 1.6 - 1.8 were not good design. Would 5mm off the 42 journals on the ZE crank be too much?

Just looking for comments, since HK$ had a 1.8L kit for the 4AG(Z)E once.

Cheers, Nick

you mean either ARGO or PRI, they both do custom rods! and it isnt worth the money to stroke them, better of doing a 7afe with custom rod and piston, you can get right up to 2 litre then.

[nick.parker]

Hi,
Thanks for the opinions. But why is it worth stroking the 7A and not the 4A? Obviously a bigger motor is more power (and more power in the form of more drivability = goood). But then a 4AGZE already bolts straight into my car and a 7A doesn't (I dont think anyway).
Cheers, Nick

[kingmick]

yes it will bolt in and the reason its not a good idea is the cost for the gain!

[mullett]

I think you'll find that the 7A is almost a straight bolt in, I did a fair bit of looking into it. The custom bit is mating a decent head to the 7A block. That being said, the stock 7A crank sucks, as do the stock rods...etc. So it'd be a pretty custom motor to do a good job of it...But the basic bolt patterns and stuff are pretty similar. On the same note, what's a 5A?

RM.

[LeeRoy]

On the same note, what's a 5A?

5A-FE - 1.5 L (1498 cc) I4, 16-valve DOHC, FI, 100 hp (75 kW)
Heres some more A series info

- LeeRoy

[nick.parker]

The custom bit is mating a decent head to the 7A block

I think the 4AGE head bolts on. I know people have done this conversion.
I guess the crank is trouble waiting to happen, doesn't it have 6 bolts instead of the 4AGZE's eight?

[kingmick]

both the 20v and the 16v bolt on.

if the engine is built properly the crank is fine. there is a bit of R&D going on now to take the crank down even more to see if it will take it.

[rolleraction]

both the 20v and the 16v bolt on.

if the engine is built properly the crank is fine. there is a bit of R&D going on now to take the crank down even more to see if it will take it.

regarding the 7A or the 4A crank Mick??

[kingmick]

the 7a crank! the engine will be testing very soon to see if it can handle it, if not it will have to be a custom crank.

[The Witzl]

But, if you didnt want to go to the lengths of offset grinding (or whatever you call it) the crank to provide a longer a stroke, the straight bolt-in of a 7A crank along with some decent H-beam rods and forged slugs would make a decent little 1.8L A-series engine.

The thing what makes a 7A p00 is it's rods. Go past 6000rpm much and watch them cave in faster than Johnny Howard to George W.

[nick.parker]

Damn!
Thats fast alright. Ok I'll think I'll try and find the specs of 7A crank!
Nick.