Some 3400/3500 hybrid build questions

[minion]

Hello,
I have been reading these forums for a few months now and have a few questions still left unnanswered before I start my build.

1.) Do the bolt patterns on the flywheel ends of the 3500 and 3400 cranks match up? Basically, could I bolt a 3500 flywheel and clutch to a 3400 motor to take advantage of the G6's F40 trans? If either a new flywheel has to be made or the stock one machined, can a 3400's clutch disk fit into the splines of the F40's input shaft? At that, has anybody looks into the C20let's flywheel/clutch combination for other possible solutions to use the F40?

2.) I have seen a lot of talk about narrowing 5.7" small block rods to fit the 3400 crank. I am building an engine for high boost levels and am currious if anybody on the board has actually used this combination and if so, with what pistons? On the same note, should I find a good price on a complete 3500 motor, does the 3500 crank have the same rod journal size as the 3400 to where you could use smallblock rods? What about the rod jounral width? Has anybody found another way around the powder rods?

3.) I have seen that a few members have built their motors. Anybody have sites or threads with build lists?

Thanks for the wonderful site. I have been on here this long without running out of reading or feeling the need to post and that should say a lot. I have been on J-body.org for just shy of 5 years now and a site like this is a relief.

[ForcedFirebird]

Welcome!

I have never heard of anybody breaking a rod. I have pics of some that were bent all to hell, but not even a crack.





There is a site article explaining the rod modifications that need to be made on the 327 small journal rods.

[bszopi]

I have a 3500 rod that is snapped in half...

1. AFAIK, the crank bolt patterns are the same between the 2 engines, so whatever you want to do there should work.

2. The 3500 has larger journals than the 3400, so SBC rods will not fit. And all the rods I found (spend a few night searching awhile back) that had the proper diameter were either too short or too long. So as of right now, for the 3500, its either stock or custom rods.

3. Most people post their build info here...

[minion]

Thank you for the information guys. I have pretty high expectations with this motor and do not wish to use factory rods even if non have broken yet.
If the 3500 has larger journals, that would leave the option of an offset grind to add a little more displacement. How do the rod lengths compare? If the heads and lower intake manifolds can swap over, the blocks must have the same deck height so from there the SBC rods should work coupled with 2mm overbore 3400 pistons with wrist pins riased to compensate for the stroke increase after the offset grind. That would be an easy custom order being that a lot of piston manufacturers already have CADs for 3400 pistons.

Is there a place that I could find rod journal diameters of the two engines?
Asside from dissplacement, are there any other advantages of the 3500 bottom end such as sand cast as opposed to foam or oiling channel differences?

[ForcedFirebird]

The deck heights are the same, but Gen3 pistons protrude out of the block by .020". Yes, the crank can be offset ground, Joseph Upson just had a 3900 crank for sale for $100 (IIRC), but that would also need to be modified to go from a 52x to a 7x reluctor wheel.

[minion]

If my reading has served me right, the 3900 has different deck spacing than a standard 660. It is not based off the 3400 block like the 3500 is. Wouldn't I need a complete 3900 motor to use that crank? I would think that large of a stroke might also not be the best for a boosted application.
I'm not too worried about the crank trigger because I will be using an external one with my EMS. I have used megasquirt on my last three engine builds but this time I have extra funds and would like to try out AEM EMS

I have heard the 3500 comes with a forged crank from the factory. I have heard the same of the 3400 dohc motor. Is there any merit to this?

[ForcedFirebird]

The cranks are steel, not cast , I haven't seen any proof of forgings.

I was on the understanding the 3900 crank could be modified to work in the older 660's.

Props on the MS, it's going on my new engine.

[minion]

Let me know if you need any help/advice on the install. My last install was on the sunbird which I recently parted. It had a built 2.0 turbo motor with the euro dohc conversion and fuel/ford EDIS controlled by MS. I still have the v2.2 MS box around if you'd like to buy one preassembled cheap. I skewed away from the instructions a little to install an auxilary circuit to run a GM IAC circuit. I have a wiring diagram and everything plus extra pins in the harness for running it, can also give you the modified code.

I want to try the AEM system only because of the active EGT/wideband input. Unfortunately, their universal EMS is only ideal for the 4 cyl engines as it has 4 EGT inputs. On a birght sight, I have drawn out some schematics to use a sensor at each of the collectors active to the fuel tables and the other two inputs active to gauges, taking inputs from a sensor in each runner and only displaying the output of the hottest cylinder in its bank, marked by three LED lights under each gauge. I have a feeling well be driving hover cars by the time the bugs are worked out.

Back to the crank discussion, its seams like the blocks of the 3900 motors would need to have the cylinders spaced further apart due to the bore increase. I'm sure the spacing is only a couple mm at most. I guess it would be possible to use the 3900 crank with enough machine work but it would probably cost less to simply weld and offset grind a 3500 crank; that is assuming I am right about the deck spacing which I may not be.

[ForcedFirebird]

Let me know if you need any help/advice on the install. My last install was on the sunbird which I recently parted. It had a built 2.0 turbo motor with the euro dohc conversion and fuel/ford EDIS controlled by MS. I still have the v2.2 MS box around if you'd like to buy one preassembled cheap. I skewed away from the instructions a little to install an auxilary circuit to run a GM IAC circuit. I have a wiring diagram and everything plus extra pins in the harness for running it, can also give you the modified code.

PM me with a price. I just saw DIY has MS1 kits on sale for less than $150, but if you have one assembled (and the IAC code that I need to keep a GM TB), I might just go that route.

I want to try the AEM system only because of the active EGT/wideband input. Unfortunately, their universal EMS is only ideal for the 4 cyl engines as it has 4 EGT inputs. On a birght sight, I have drawn out some schematics to use a sensor at each of the collectors active to the fuel tables and the other two inputs active to gauges, taking inputs from a sensor in each runner and only displaying the output of the hottest cylinder in its bank, marked by three LED lights under each gauge. I have a feeling well be driving hover cars by the time the bugs are worked out.

I was under the impression that MS could be used with a WB input, am I wrong? Is it only MS2?

Also why do so many people use EDIS with MS? It will run GM's DIS.

Back to the crank discussion, its seams like the blocks of the 3900 motors would need to have the cylinders spaced further apart due to the bore increase. I'm sure the spacing is only a couple mm at most. I guess it would be possible to use the 3900 crank with enough machine work but it would probably cost less to simply weld and offset grind a 3500 crank; that is assuming I am right about the deck spacing which I may not be.

You are probably right about the cost factor.


So you are startting from scratch, or are youjust wanting to put 3500 heads on a 3400 you already have put together? A full 3500 swap would probably be better in the end. You do realize the 3500 heads have larger chambers and will lower your compression if used on a 3400 (actually more boost friendly @ 8.9:1 or so). Mine will probably be a little less with the chamber mods I'm making. I'm using 3500 heads on a 3.4 Camaro engine.

[minion]

Yes, I am starting from scratch on this one. I have not bought a thing yet besides for the car it is going in, a third generation J-body with a blown 2.2ohv engine.

Yes, MS does have the ability to accept wideband input. The only problem is that you have to calibrate the sensor with a test gas that has a preset amount of oxygen in it. The whole process is a total PITA. Another option for MS is to use an innovative LC-1 controller but they are quite pricey costing more than MS itself.

I think I could match 150 for my MS box.

[sharkey]

ms1 does do wideband inputs. there are also schematics on doing 8 egt input circuits for logging only. edis is used mainly because anywere in the world you can find the coils/modules and the 30-1 crank wheels is very simple to adapt and attatch a crank sensor. building a 7x trigger wheel and mounting the sensor is a little more complex. however, if you have an internal crank trigger and crank sensor, may aswell use it, gm dis works just fine with MS.

[ForcedFirebird]

Minion:
I have an LC-1 already. Sound good on the MS, I'll get back to you as soon as I can afford to get it from you. I have recently purchaced all my gasket, another set of 3400 heads just because they have the yellow spring mod to go on my 3500 heads, a new crank for my old motor that is already sold, and had to get a new fender for the wife's BMW (it's mint and 21 yrs old with 75k miles, she drove it for a month and hit a pole in the parking garage ) That is if you don't mind waiting a week or two.

Sharkey:
Yes, I'm using a 3.4 block that has DIS provisions, thanks again .