Okay, I have tried searching and I dont find anything relevant. If anyone has a good link, please post it up and solve my problems :)

Anyways, Im rebuilding the motor right now. I need to know whether to go with the long rod or regular rod. I have heard all sorts of different opinions. I know it will create more torque, but my question really pertains to redline. Can you increase redline with a long rod motor, or does it have to be decreased? Is there a difference in reliability? Can someone point me in the right direction on getting reliable information about long rod motors? Any help is really appreciated. Thanks!

mopre torque, higher redline. no differance in reliability..... anything else?

Did you say Long rod? :P :P

LOL i'm tired.

Some people actually like shorter rod motors. A short rod engine will exert torque on the crank earlier after TDC than will a long rod engine. What is interesting about this is that the power stroke contributes the most torque in the first 100 degrees or so, which is why I like the idea of biasing the crank force towards TDC (shorter rod). Botttom end torque is vital, especially to a turbocharged engine.

There are advantages to a long-rod motor, too. At higher RPMs, it can potentially make more power. Because they dwell longer at TDC, less attention can be paid to the ports, and still have power made. The volume in the intake runners can be reduced, as well. On top of this, there is the obvious advantage of reduced piston wall side loading, and an increased rod to crank angle, which should transmit power more effeciently.

For the same reasons that knock is more likely at lower RPMs, the short rod engine is less prone to detonation. The piston has a better chance of outrunning errant outcroppings in the flame front.

Personally, I like a shorter rod design. In this way, I am very much in the school of thought of Grumpy Jenkins. I just think that any losses because of decreased TDC dwell time can be overcome by a well designed intake manifold, and a properly ported (for the application) head. The increased propensity for a short-rod engine to suffer reversion can be overcome with a properly designed exhaust manifold (and head).

Everybody has a different opinion on this subject, though, and most of them are wrong. There are merits to both. Read up, learn, and make up your own mind.

Also: your bottom end will not be your limiting factor in selecting a redline. Maybe with an underengineered 2.4, but not with a 2.0. Your limitation is in the valvetrain.

So uhhhh.....yea.


Listen to what he /\/\/\ said imo.

Originally posted by Ducking_Fumbass
Some people actually like shorter rod motors. A short rod engine will exert torque on the crank earlier after TDC than will a long rod engine. What is interesting about this is that the power stroke contributes the most torque in the first 100 degrees or so, which is why I like the idea of biasing the crank force towards TDC (shorter rod). Botttom end torque is vital, especially to a turbocharged engine. There are advantages to a long-rod motor, too. At higher RPMs, it can potentially make more power. Because they dwell longer at TDC, less attention can be paid to the ports, and still have power made. The volume in the intake runners can be reduced, as well. On top of this, there is the obvious advantage of reduced piston wall side loading, and an increased rod to crank angle, which should transmit power more effeciently. For the same reasons that knock is more likely at lower RPMs, the short rod engine is less prone to detonation. The piston has a better chance of outrunning errant outcroppings in the flame front. Personally, I like a shorter rod design. In this way, I am very much in the school of thought of Grumpy Jenkins. I just think that any losses because of decreased TDC dwell time can be overcome by a well designed intake manifold, and a properly ported (for the application) head. The increased propensity for a short-rod engine to suffer reversion can be overcome with a properly designed exhaust manifold (and head). Everybody has a different opinion on this subject, though, and most of them are wrong. There are merits to both. Read up, learn, and make up your own mind. Also: your bottom end will not be your limiting factor in selecting a redline. Maybe with an underengineered 2.4, but not with a 2.0. Your limitation is in the valvetrain.

The short version of this is essentially, unless you can design your own cylinder head and intake manifold, you'll want the long rod.

Cool. Ive also heard that the design helps spool the turbo faster, any truth to that? As for cams, what would you guys recommend? I would assume youd need something slightly different than regular turbo cams. Anyone have any experience with the Howell Long Rod kit? For some reason its 100$ cheaper than the regular kit, too. Are there any special parts or anything else I have to consider with the long rod kit - or it there no difference from a regular rebuild? Assuming a well built top end, forged long-rod bottom end, stock crank, and all the proper supporting mods what would you estimate max redline at?

Sorry for sounding like a BANME!, dont know too much on this topic.

Thanks, Dino. :P

Combustion chamber design is fun, though. There is a lot of information out there for somebody motivated enough to poke around. For most people, though, the long rod kit is adequite.

ACTUALLY, for most of the brainsucking zombies around here, the long rod kit is overkill, and the stock rod length (and stroke) is fine.

NOTE: I'm not talking about anybody involved in this thread, thus far.

i have the long rod (snicker snicker), and the ass-o-meter says WOO HOO!!! :thumbsup (No HEF!!!)

We're not talking about a night and day difference between the standard bottom end kit and the long rod bottom end kit. I'm willing to bet that you couldn't tell the difference in performance between them (on the butt dyno). I think that the main reason they offer the long rod kit is because it shares pistons with the 2.2l kit. The 2.2l kit has a low sales volume. If they can increase that volume, they will get a better price on the custom pistons and increase their margins. So, they come up with a long rod kit and offer it a prices below the standard kit. Given the price and expectation of power gains, people opt for the long rod kit and purchase it in even greater numbers than the standard kit. So, they get better margins on the custom pistons and add a model to their product line. It's a win-win. Anyway, it's a good kit at a good price. The only thing I recommend is that you make sure the pistons come with spacer rings for the lowest ring groove. The longer rod requires the pin to be moved further up into the piston. This cuts into the lowest ring land. You need the spacer to cover up the cut-outs in the lowest ring land. The spacer is installed below the oil control rails and expander. If you don't install it, you will eat oil like crazy.

Corbin

'95 ESI-T
Now with more power and fewer leaks



Gimme fuel...Gimme fire...Gimme that which I desire

Awesome, thanks for that info. Id hate to built the motor and not get everything right the first time around :) Anything else?