Different pistons

[Colza]

Had a chat to a guy today who was of the oppinion that forgies would be a waste of money as Honda spent the most most money, had the most skill and generally made bloody awesome pistons anyway! So, if one was to bore out wards as far as possible (how far would that be?) and drop in some cast iron sleeves (how thick should we be thinking?), what other hondas had pistons which would be convieniently stealable to fit this sort of setting? To be upgraded to forgies at some far later date when money flows like water ;D

Any thoughts? Any chance of getting even slightly closer to that much sought after 1:1 bore-stroke (not in a million years in a city )

[city_boy_t1]

I say ..... depends on how serious you are going to be going with your city turbo...... if you are going to be running NOS or some crazy s#@t like that then forgies are certainly not a waste of time.  But if you are just fooling around with a standard turbo i think it is a bit of a waste of time......you are better off doing something to your cam to be honest

[Colza]

With the amount of boost im planning to run eventually, my cylinders are gonna need something in the way of reinforcement (and maybe with NOS too ;D). The extra displacement sure wouldnt hurt and the more square ratio should help getting it to rev above the current 6000's

Yes?

[city_boy_t1]

well if thats the case then they are worth it

I mean if you are going to be NOS ing it then you would need something along the forgies lines otherwise byebye er engine:)

[Bino]

The closer to square ratio will help a bit with the rev's, but what you really need to do is get custom high-pin pistons, and run a longer rod to increase the rod/stroke ratio.  For the displacement of the engine, the 92mm stroke is huge (if you took it out to square bore/stroke, 92mmX92mm you'd have a 2.4L!).  

It'd be a good idea to try and find a crank that would fit in the ER block that has a smaller stroke, perhaps the EB series engines found in the US (76mm stroke for EB1,2,3, and 82mm stroke for the 1300cvcc engine both in US).  You instantly have a higher rod/stroke ratio, even w/o custom rods (pistons wouldn't come up to the top of the block... not really my point).  Then get your square bore/stroke.

Charles may be able to shed some light on the interchangability.

[Charles]

Bino is on the right track, but the best option is to pick up an EJ 1300 which has the same bottom end as the EN but a CVCC head compatible with the CVCC manifolds of the ER turbo.

Like the EK you need to add material around where the injector cutouts are in the intake port of the ER.

EJ has EN size intake and exhaust valves and flows way better than ER.

Honda pistons are not that great (at least the ER type). Current pistons are much better. The main problem is that Honda have cut oil drain slots rather than drilled holes behind the oil ring. The whole top of the piston can come off at high revs (high pistons speed caused by insanely long stroke).

That said I have not seen a factory ER piston fail provided the correct amount of fuel has been kept up to it and detonation kept away(regardless of boost). I think this is largely because of the small bore.

Stock motors will take 20psi if you back off the timing and meet the fuel demand. Stock head gaskets will pop before pistons let go.

[Colza]

Thankyou Charles! That was exactly the sort of help I was looking for!!! (and Bino too )
How much else needs to be modified to get the EJ head on? Are you suggesting boring out to accept the EJ pistons or just fiting the rods up to the ER pistons to shortent the stroke? Also, how far outward can you bore before you start weakening everything too much?

While were at it has anyone considered a DOHC conversion? Im guessing the only way to rig this up would be making a custom billet DOHC head, yes? Unless there happens to be a convenient DOHC 1300ish engine with the same piston spacing...

[Charles]

Colza,

If you want to use the EJ head you need to use an EJ/EN or EB2/3 block. The ER wont take the crank (different size mains) AND the valves will not fit down the 66mm bore of the ER. The small bore is why the ER has such small valves and will never produce much more than 160-200hp even with stacks of boost.

Start looking for a new motor and build that up. see other post!

[Bino]

Charles is saying you should get an EJ 1300 (what I was talking about ealier I just couldn't remember the engine code) block/head assembly.  The turbo manifolds from the ER will bolt on with very minimal modifications (as mapped out by Charles).  The EJ still doesn't have a very good rod/stroke ratio (I'm thinking in the 1.43:1 range, don't hold me to that though), I've read they're limited to about 8K on factory rods.

IMO, you should take the 76mm stroke crank/rods from the EB1,2,3, put those in the EJ block (EJ crank fits in EB engine, should work other way) and overbore the EJ block 2mm (been done on the EB, should work on the EJ).  Now, you have a 74mm bore EJ with a 76mm stroke that has bigger valves than your ER, has a much better rod/stroke ratio, and still has all your turbo goodies on it... oh yeah, basically all of the motor mounts and transmission mounts are the same from the EB, EJ, and ER engines/tranny's, spline count too (verify that for me Charles).

EJ1300CVCC
82mm Stroke
72mm Bore

ER 1200CVCC
92mm Stroke
66mm Bore

EB2,3 1200 non-cvcc
76mm stroke
72mm bore
(EB1, 70mm bore)

[Bino]

Oops, 90mm stroke for the ER....

[Nick]

I dont know if this is taking things a little to far, but is it possible to use the EP1600 with the EB crank. This way you get a squarer bore a little more capacity and bigger valves.  

[crshbndct]

[quote author=Colza link=board=GEN;num=1066122958;start=0#6 date=10/15/03 at 20:01:35]
While were at it has anyone considered a DOHC conversion? Im guessing the only way to rig this up would be making a custom billet DOHC head, yes? Unless there happens to be a convenient DOHC 1300ish engine with the same piston spacing...[/quote]


a custom billet head? it would be cheaper to just go buy a mclaren f1.....

[Colza]

Speaking of which, I've always wanted a Mclaren...

[Bino]

Especially given the small bore, you'd probably have better luck swapping a head from a litre bike or something.  I've read about guys doing this with Mini's (don't recall where).  Check into a 954RR head or something along those lines before you went all the way to custom.

[hoovermatic]

Just thought I'd put in my two cents worth. I noticed further up some one talking about using a 1300 block with a different head. A couple of years ago I rebuilt a Honda shuttle. As I didn't have much money at the time I used what was sitting around. This happened to be a 1300 crx engine. I couldn't be bothered stuffing around with the extra wiring and emission control box from the crx so I just used the existing carb and manifolds off the shuttle engine. The crx head had an exhaust fed sensor which I had to plug up. Other than that the conversion went suprisingly smoothly and produced more power than I expected. I ended up with a 1300 block and head fed with a 1500 or 1600 (not quite sure, was a standard 88 shuttle) carb, inlet manifold and exhaust. I threw away the shuttle motor with a cracked head and the rest of the crx.

Also, another word on the mighty 1300, I've got one in my toyota corolla and have been abusing it now for the past three or four years with no trouble. When I say abuse, I mean 80,000 ks between oil changes, reving it when its cold, and doing 160 up the bombay hill amongst other things which I'm too embarised to mention.