Long rod motors?
 

I just thought we should talk about this a little more. So what, if any, tested information do we have on this. I have 2 sets of Crower rods for my car, normal and 6mm longer rods. I was going to come up with a way to test the two sets, keeping as much the same as possible. With the longer rod you need to get custom pistons that moves the pin up in the piston, giving a better rod ratio and more dwell time at TDC. What do we think on this?

~John
I am running a 2.0 still also

Re: Long rod motors?
 

Ironically, I was just talking about this with someone last night. I was going to create a post but I didn't know what to say. I don't know much about it but I would like to.

If people could, could we have information added newb style? I want to be able to understand. good call John.

Re: Long rod motors?
 

The longer rods will give the rod a shallower angle. This reduces side load on the pistons, and as John stated, increases the dwell time. Dwell time is good in an NA application, you can make more power. In a FI engine with high boost, it is not desirable since we are fighting detonation and that gives more time for detonation to occur.

The rod ratio of the 2.4 is 1.5 and the long rod version is 1.56. 1.7 is considered ideal for a NA engine. I really don't see a big enough difference with the long rod version to warrant the extra cost. It is less than a 10% difference in rod ratio and there are some bad effects too.

Re: Long rod motors?
 

I am not sure why you would want a longer rod on a 2.0, unless you want to rev it like a motor cycle. It already has a 1.69 rod ratio, which is quite good. With that and the 88mm stroke, you should be able to rev to 9600 with off the shelf parts. Most of the guys reving higher than that are running aluminum rods.

Re: Long rod motors?
 

So what justification does Marco use for his long rod shortblocks?

Re: Long rod motors?
 

Also do you have to change anything on the motor as far as Oil goes? Talked with my brother about this for like 2 seconds and he mentioned that on his built MR2 Motor that he plans to rev the car to I think he said 8K (but anyrated point is) that he also mentioned he had to have something done to his oil pump in order to keep the flow of the oil up enough to handle the higher Revs? Or at least I think that's what he said. (again really quick conversation, didn't go into depth)...

Just thought that might be why guys like brent go with a Dry Sump system.

Re: Long rod motors?
 

He's canadian?? He sells them saying you can rev them higher than a regular rod 2.4.

A dry sump system prevents foaming of the oil and also allows the engine to be mounted lower in the frame to lower the CG.

Re: Long rod motors?
 

it also cuts parasitic drag since the crank doesn't have to plow through all that oil anymore

Re: Long rod motors?
 

All what oil?

Re: Long rod motors?
 

So for a turbo motor you want the rod ratio lower then a NA motor, so the piston is not at TDC as long. I planned on reving my motor as high as possible, a few things like power band, trap speed will help me deside how high I should go. 9600 might be high enough I do not know.

~John

Re: Long rod motors?
 

Brent got rid of his dry sump a long time ago due to crank problems. DSM oil pumps make too much oil pressure to begin with once you remove the balance shafts and they rarely fail, unlike on some cars like Hondas. So we don't have to worry too much about aftermarket oil pump gears and such, unless you want to do a dry sump system.

Re: Long rod motors?
 

No, it's just that the 2.0 rod ratio is good enough already. You never want a bad rod ratio, the question is just if the hype is worth all the extra effort. Especially, when it really doesn't help the piston speed problem on the 2.4l.

Re: Long rod motors?
 

What the hell are you talking about?? The crank doesn't get changed at all, just the rods and pistons.

Re: Long rod motors?
 

Marco "claims" that in theory, based on the geometry, the rod ratio difference is worth about maybe 200-400 rpm more, but in practice it's worth alot more.

My main reason for going with the long rod version is not because it was the most expensive (althought some might think differently ;) ), but because I wanted the "best of both worlds" so to speak. I wanted the longer stroke of the 2.4L for my heavy car, but I also wanted the ability to turn higher rpms with less chance of scuffing the pistons/cylinder walls that can happen on a high rev'ed 2.4L

Re: Long rod motors?
 

I'm not a fan of Marco or what he "claims"! Long rod motors seem overrated and so does dry sump oil pumps. Just my $.02~


Off topic: Welcome back Mike.

Re: Long rod motors?
 

use some 2.6 rods with some really thick bearings.

Re: Long rod motors?
 

I wondered about the oil thing ever since my motor went. One of the things I changed was reving my car to 8200rpms regularily. Thought Oil starvation was one of the reasons my motor went? And didn't even think to wonder about oil until my brother mentioned it in his list of things he did to his motor.

Thanks for the info... What if you still have your balance shafts?

Anyone know how high Brent and Shep rev'd there 2.0's?

Re: Long rod motors?
 

I know Shep was shifting over 10k RPM, I saw his AEM log at the 2003 shootout. 8200 RPM wasn't a reason for your engine to die Brian. It may have quickened it, but it isn't the cause. 8200 RPM on a 2.0 is nothing. That is the redline I plan to run on my 2.4.

Re: Long rod motors?
 

I was just running 8500 rpms on the dyno last night, 124 miles on a 2.4, standard rod length. I've yet to see any actual data showing a regular 2.4 can't rev past a certain limit.

Re: Long rod motors?
 

Brian you should be able to rev that motor to 9,000rpm if you want, but 8,500rpm is where I had my rev limit set to all last year.

~John

Re: Long rod motors?
 

Steve, I only reved yours a bit past 8000 on the dyno. We had it set at 8000 most of the runs, then I bumped it up to 8200, to keep from hitting it so often. Fix the fuel and lets turn the boost up to 35psi. :)

Running a 2.4l at 8500 is like running a 2.0l at 9600. The piston speeds are very high at those RPMs. Probably a decent amount past what most V8 engine building books would consider reasonable for even a race motor. :)

Getting a DSM to make good power past 8500 RPMs anyways takes a lot more parts and work than most have. Back on my 2.0l, I think my peak power was around 7500, while on the 2.4l, peak power is around 6600.

Re: Long rod motors?
 

By the book a 60-1 is a bad turbo for a DSM, but it sure seems to work just fine for most people. books and real world they are different, sometimes.

~John

Re: Long rod motors?
 

Yea, Isaacs didn't like over 30psi much.

Re: Long rod motors?
 

6 one way, half a dozen the other. ;) If you are building a "high end" engine with aftermarket rods and pistons, there really isn't that much of a cost difference. So take your pick.

Re: Long rod motors?
 

Thanks, glad to back. :D

Re: Long rod motors?
 

Interesting topic.
My stock 2.2 liter mopar could only rev to about 6,250 before losing power.
Now on my new race motor I went with a long rod setup and 2.5 pistons to see if I can get it to go at least 7,000.
Hopefully someday I can make it to the track and see if it was all worth it!

-Bryan

Re: Long rod motors?
 

I would think your head or intake manifold would be the main reason for a lack of topend power on the 2.2l motor.

Re: Long rod motors?
 

Head I agree,
Intake I do not. I have a hard time believing that the intake tract has anything to do with the power being made.
Show me some plots that show someone making more power due to an intake only change. (no other changes). I will even accept throttle body size.

-Bryan

Re: Long rod motors?
 

DITTO :cool:

Re: Long rod motors?
 

WHAT!?!?!?! :eek:

I guess that's why people do back-to-back dyno runs that show improvements after changing from a stock intake to a SMIM. Put a 2g intake on a 1g and see what happens. :rolleyes:

Re: Long rod motors?
 

Must be something inherant to the damn 2.2
Noone I know has made more power with an intake change.
Then again, it is back-yard style intakes with Old Milwaukee telling the guy where to out the welds.

Re: Long rod motors?
 

I don't actually know anything about the 2.2l intake manifold, just generalizing. Usually on most kinds of cars, top end power fall off can be fixed by cams, or big plenum/short runner intake manifold, or some head work. Sheetmetal intakes often help DSMs in the upper RPMs more than cams do.

Re: Long rod motors?
 

I'll see what the turbo does, if it continues to make more airflow the higher it goes I'll continue to raise the Rev limit.

Re: Long rod motors?
 

I kind of doubt the turbo will be making more power higher than your 8500 redline.

Re: Long rod motors?
 

Ahh, I thought you said we had the limit at 8500. Whew, I feel better. :D Actually, it runs like a champ, I just set it back to AWD, time to go test her out. :eek::eek:

Re: Long rod motors?
 

with regard to a dry sump, once you start using one the crank doesn't have to plow through all the oil in pan since the scavenger pumps keep the oil level in the shallow (custom) pan very low. i would call that less parasitic drag.

i never mentioned anything about changing the crank.

Re: Long rod motors?
 

Next time mention what you are talking about. You didn't mention anything about talking about the dry sump system. You can't expect us to read your mind.

Re: Long rod motors?
 

The crank doesn't plow through oil in a normal wet sump either. The oil level is well below where the crank spins.

Re: Long rod motors?
 

Edit - Probably right Just looked at my dyno charts again right at 8K my power band starts to drop down a little. So that'll probably fallow suit once I rev to 8500rpms. Hopefully won't be that much of a power drop like my 20G used to do.

Re: Long rod motors?
 

That would be one huge turbo if it did that. I am sure the turbo you got will put down good power high up but not higher at 8500 than 8000.