Stock TII or TU rods in a/my 2.5L TIII?

[turbovanman²]

Frank and I have talked about it but curious at to what others think. My stockers are deburred, balanced with ARP rod bolts and a .912 pin. The TU rods are 94 grams lighter so will this make a difference in revability, to move the 2.5's rev limit a little higher and help the pistons live at the higher rpm. I figure it should be good with stock rods to around 65-6800 rpm?

Thoughts and comments? I am leaning to keeping my stock rods but I guess we shall see. I really want to do it right but also do I really need to spend an extra $500. My hp goal is no more than 400 whp but I doubt I will go that high, maybe 350 whp.

[Speedeuphoria]

well look at wallace, he had a similar turboand stock rods(maybe preped) and may a little over 400whp w/ the turbo maxed. I wouldnt worry about the rods as rpms is harder on rods then anything else

they are nice rods and the weight savings will help, but not needed unless you have money to burn or trying to make 500whp

hey what mm are the wires you sell?I just bought some custom Magnecor, didnt know you were selling the Auroras

[86Shelby]

350 hp? I say stock rods since you already have them ready to go. Have them inspected and run 'em.

I'll lean towards aftermarket once 400 whp is a reality for the engine.

[Austrian Dodge]

I may think differently than others here....

but I'm not into it maxing out a stock part were it's built for stock abusement. Rod bolts will surely make a difference, thats out of question, but the rods itself were built to handle stock power levels!

It's the thing on beeing on the safe side! The rods may hold up your needs, but sooner or later they'll give up for sure...the material is just old, has xxx.xxx miles on it and you beat the crap out of it ;)
Were as the aftermarket ones are made for that beating.

I for myself don't mind spending extra $$ for having safety!

[tryingbe]

94 grams EACH rod.

So, that's almost half of pound saving in rods weight.

[contraption22]

Stock rods should be fine. There should be no reason to rev a 2.5 past 5500-6000rpm... 16v or not.

[Mario]

I agree that the stock rods should be fine, however a failed rod can cost you a lot of things. Plus down the road, you may wish to push it a little harder, perhaps in a different car or set-up and you'll already have those rods. :)

[turbovanman²]

hey what mm are the wires you sell?I just bought some custom Magnecor, didnt know you were selling the Auroras


8.5mm, :nod:

Thanks guys, all excellent info.

[Speedeuphoria]

Stock rods should be fine. There should be no reason to rev a 2.5 past 5500-6000rpm... 16v or not.

I dont know about that, if everything is mostly stock then yes. I'll be reving my 2.4 to 7500rpm

[turbovanman²]

^^Isn't the 2.5 harder on piston loads, IE against the bore than a 2.4L?

An 8v 2.5 is good to 6-6500 rpm, add a wicked 16valve head and 6500 it will just come alive, muhahaahaha, :evil: :partywoot:

[Speedeuphoria]

^^Isn't the 2.5 harder on piston loads, IE against the bore than a 2.4L?


just a little more stroke, but its not a daily thing. The 2.4's have been reved close to 9000rpms. If you keep the stock cams and rods then 6500 should be great, TU rods and LW cams and ported head then 7000+ should be fun

[8valves]

I'm just not big on the geometry of 2.5's spinning that high. It works, but I'd imagine after a season or two of some really hard rpm usage (6500+) you would see some significant markings in the bores.

2.3 stroked DSM's have the same issue. We spin ours to over 8000 rpms, but know that in a couple of seasons a fe-fresh will be in order.

AM

[turbovanman²]

I'm just not big on the geometry of 2.5's spinning that high. It works, but I'd imagine after a season or two of some really hard rpm usage (6500+) you would see some significant markings in the bores.

2.3 stroked DSM's have the same issue. We spin ours to over 8000 rpms, but know that in a couple of seasons a fe-fresh will be in order.

AM

Thats what I have heard, was wondering if the lighter rods would help. Also, its a DD so it will only see those kind of revs at the track or dusting off some import or Cobra, :amen:

[Directconnection]

I dont know about that, if everything is mostly stock then yes. I'll be reving my 2.4 to 7500rpm

Your 2.4 is an entirely different animal than the pig of a 2.5.

From the dyno plots I have seen, Mike is correct.

As for rods... if you had the $ to do so, get them. If not, the 350whp should be fine but i am leary of the "deburring" comment. Shotpeening and polishing/deburrung doesn't really do too much for a rod of the stock T-II forging quality.

Cliff ramsdell made around 370whp in his T-III 2.5 If I were you, Simon... I'd be asking HIM all your questions. 370whp... you should be fine at the low 2.5rpms that they put out even the piston acceleration/deceleration is a bunch worse than on the 2.2.

Got the $...get them. Not really, then you're ok as long as they are prepped right.

[turbovanman²]

Your 2.4 is an entirely different animal than the pig of a 2.5.

From the dyno plots I have seen, Mike is correct.

As for rods... if you had the $ to do so, get them. If not, the 350whp should be fine but i am leary of the "deburring" comment. Shotpeening and polishing/deburrung doesn't really do too much for a rod of the stock T-II forging quality.

Cliff ramsdell made around 370whp in his T-III 2.5 If I were you, Simon... I'd be asking HIM all your questions. 370whp... you should be fine at the low 2.5rpms that they put out even the piston acceleration/deceleration is a bunch worse than on the 2.2.

Got the $...get them. Not really, then you're ok as long as they are prepped right.


True on Cliff but he didn't keep his very long and he was using the 2.2 TIII SBEC.

Just throwing out ideas as I am not the only one doing this swap so this is a good discussion point. I agree though, if I happen to have the extra money come engine build time, I will do it just to be on the safe side but if no extra cash, the stockers stay.

Yes, my rods are prepped correctly, thanks, :nod:

No one has really mentioned the weight difference? what will this do?

[Frank]

Well best case senario is the equivelent of loosing 25lbs off the car in 1st gear. A good rule of thumb is that for every 8lbs of rotating mass you loose before the gear set, you gain enough whp to make the car feel 200lbs lighter.


Frank

[Directconnection]

True on Cliff but he didn't keep his very long and he was using the 2.2 TIII SBEC.


What does the SBEC have to do with your rods? :evil:




Just throwing out ideas as I am not the only one doing this swap so this is a good discussion point. I agree though, if I happen to have the extra money come engine build time, I will do it just to be on the safe side but if no extra cash, the stockers stay.

Yes, my rods are prepped correctly, thanks, :nod:

No one has really mentioned the weight difference? what will this do?


I'd still ask Ramsdell with any and all info I could. He may not have answers for you on the rod weight advantages as Cliff isn't a bench racer, but more of a git 'er done type of guy. You want it to work correctly the 1st time around, ask Cliff. Technical hoopla... ask Frank, Menegon, etc..or...

[Directconnection]

Well best case senario is the equivelent of loosing 25lbs off the car in 1st gear. A good rule of thumb is that for every 8lbs of rotating mass you loose before the gear set, you gain enough whp to make the car feel 200lbs lighter.


Frank


That would have to be a huge rule of thumb as reciprocating and rotating are 2 different actions happening.

I know when we calculate the bobweight for a V-8 engine we must add all of the weights such as rod big end, small end, rings, piston and pin, rod bearing, oil, pin clips, etc... the rotating weight must be doubled into the equation for the bobweight. So...rod big end and rod bearings are doubled.

[Directconnection]

^^Isn't the 2.5 harder on piston loads, IE against the bore than a 2.4L?

An 8v 2.5 is good to 6-6500 rpm, add a wicked 16valve head and 6500 it will just come alive, muhahaahaha, :evil: :partywoot:

It didn't with ramsdell's 2.5 T-III and it was built in the same fashion that i am sure you want to follow.

BTW...350whp goal..why not stay with the 8v then?

[turbovanman²]

What does the SBEC have to do with your rods? :evil:






I'd still ask Ramsdell with any and all info I could. He may not have answers for you on the rod weight advantages as Cliff isn't a bench racer, but more of a git 'er done type of guy. You want it to work correctly the 1st time around, ask Cliff. Technical hoopla... ask Frank, Menegon, etc..or...

Well the cal is totally different and apparently, he kept popping the head gasket. I know he made over 400 ft/lbs of torque.

I will drop him aline.


It didn't with ramsdell's 2.5 T-III and it was built in the same fashion that i am sure you want to follow.

BTW...350whp goal..why not stay with the 8v then?

Well, like I said, just aiming low, don't want to get ahead of myself and start breaking things. If you look at what I said, that will probably go out the window really fast, :evil:
Also, again, you guys don't believe me but looking for more effieciency, IE fuel economy. 8 valves and a heavy Minivan don't cut it but add a 16 valve head and hope to pick up 5 mpg, :partywoot:

[ShelGame]

^^Isn't the 2.5 harder on piston loads, IE against the bore than a 2.4L?

An 8v 2.5 is good to 6-6500 rpm, add a wicked 16valve head and 6500 it will just come alive, muhahaahaha, :evil: :partywoot:

The 2.4 is just slightly shorter stroke than the 2.5. Same bore, same deck, same rod length other than that. So, the piston loads aren't that different.

BTW, getting any sleep yet? :)

[Directconnection]

The 2.4 is just slightly shorter stroke than the 2.5. Same bore, same deck, same rod length other than that. So, the piston loads aren't that different.

BTW, getting any sleep yet? :)


Same exact deck? Same exact rod length? May sound like splitting hairs, but if they are just a tad different, then the stack up of "differences" if you will... will amount to much more in the end.

BTW... I went to bed a 12:30 this morning, only to be woken up by my 6 y/o stepdaughter power puking at 1:30. Then, that went on every hour through the night until about 9:30. My wife had it worse as she went to bed at 10pm, to have to get up at 1:30 am and go to work at 4am. She is still up after all this wrapping presents. I don't want a baby and have to go through that crap every night for a month or so that it takes.

[turbovanman²]

Not really, I haven't slept much in the last week, but its worth it.

Thats also why I haven't been around much and not at all on TD.

[TurboJerry]

If you run a 2.4 to 9000 rpm. It will have *extreme* piston speeds. The one I was working with would last 20 passes at a time, and that was optimistic. And the engines had all the high dollar parts anyone could ever have in it. I woulden't do it for a street engine unless you like taking it apart on a regular basis to maintain it. Stock rods polished/shotpeened with ARP bolts are good to 450 hp on a true street car. (and maybe more) And this HP is *under* 7000 rpm. I hope this helps......

[turbovanman²]

If you run a 2.4 to 9000 rpm. It will have *extreme* piston speeds. The one I was working with would last 20 passes at a time, and that was optimistic. And the engines had all the high dollar parts anyone could ever have in it. I woulden't do it for a street engine unless you like taking it apart on a regular basis to maintain it. Stock rods polished/shotpeened with ARP bolts are good to 450 hp on a true street car. (and maybe more) And this HP is *under* 7000 rpm. I hope this helps......

Even for a 2.5L. Is the weight reduction worth it?

[TurboJerry]

I don't know what the TU rods look like, but it's worth it if you want to spend the money........ The stock rods will be lighter if you polish/shootpeen them though. Stock rods have gone above and beyond the call of duty for me for 10's of thousands of miles. And Steve Menegon would agree with me too. He's turned 7400 rpm with his stockers and drove many miles before and after those rpm's...... I woulden't run 500 miles at 7400 rpm continuously, but for 1/4" mile at a time, they should be totally fine eitherway....... (Either type of rods is what I meant to say)

[turbovanman²]

Thanks, I guess money will dictate my course of action but it really does look like I'll just keep the stockers.

[Andre Parker]

You will also have to factor in the weight of the piston. If it's lighter than stock, It is worth it for any longevity. If it's heavier, then it's manditory as it will stress the stock rod and the bolts. It's all about balance. Use a lighter piston, and rod with a stronger rod bolt and it will last longer and maybe rev a little faster and longer. Steve Mercer is right about piston speed and how it snaps when it is at the top and bottom of the throw of the crank. I 100% agree with what he stated earlier. Our stock rods main problem is the stock rod bolts. The rod itself is very strong, but the TU rods would be the better bet as they are stronger AND lighter.

[turbovanman²]

Thats why I love posting about this stuff, you get told info that you would never find otherwise.

Not sure what my JE's weigh but I guess when I decide which Piston to go with, either JE or Wiseco, I guess that will be a factor also.

[GLHSKEN]

Stock rods I had worked lost 22 grams each through the polishing process. My wiseco's weigh 432 grams each. Hope that helps.

[Rattlesnake]

Well Simon, I'm with the others too. If this is a DD and your TII rods are preped there's no need for the TU rods. But you are just like me, you like to try new boundaries and set goals for yourself. Maybe higher shift points or cam the head to move the rpm band up especially on your 16v combo. That's were the TU rods come into play. The TII rods have tremendous strenght, I believe they are drop-forged. That fall in the category of hot-working metals, and the advantage of a hot-forged piece is that it permits continuos deformation without any internal structural changes such as strength and elasticity. The addition of ARP bolts and weight-match of the rods, the balancing of the rest of the rotating items will add to the reliability ot the engine, specially at high revs.
That's what I have in my motor too, the almighty TII rods preped just like yours:amen: But because the type of abuse I'll be putting in the motor I don't think they'll last too long. I'm working in a high reving combo and did some road course simulation runs on a dyno shifting at 6800rpm, holding the revs at that level for more than 8 seconds in 2nd, 3rd and 4th gear, down shifting and keeping the revs up and repeating the upshifting as above., the thruth was that I was wating for the KABOOOMMM!, but the engine held together and it felt stronger than ever:amen: . But I will have no piece of mine after puting the high rev combo and take it to the road course, that's why I broke my piggy bank and got TU's new rods.
"Race fee= $300, engine refreshed with TU rods=$600, putting the hammer down and smile while it screams past 7k and get glued to the seat, and bringing the car home in one piece...., priceless. For everything else there's Master Card.":thumb:
:lol:

Reinaldo Moloon

[turbovanman²]

Thats a good one Reinaldo, :eyebrows:

Ken, what do stock pistons weigh?

[Directconnection]

Hey, put them on your Master card and then you cvan afford them. (but paying on them for the next 20 years) :eyebrows:

[Frank]

That would have to be a huge rule of thumb as reciprocating and rotating are 2 different actions happening.

I know when we calculate the bobweight for a V-8 engine we must add all of the weights such as rod big end, small end, rings, piston and pin, rod bearing, oil, pin clips, etc... the rotating weight must be doubled into the equation for the bobweight. So...rod big end and rod bearings are doubled.

I was going off of some turbo firebird v8 guys were telling me a year ago. Can you explain more?

[turbovanman²]

Hey, put them on your Master card and then you cvan afford them. (but paying on them for the next 20 years) :eyebrows:

Hahhhha, yeah, I could have bought a ton of heads, engines etc but I won't let myself get in that trap, if I can't pay for my engine cash, I don't do it, :eyebrows:

[ShelGame]

The nominal dimensions are the same, yeah. There's probably some difference in manufacturing tolerance, but that would be small enough to neglect when looking at piston loading.

Before the SRT came out, many Neon guys were using the T2 rods in 2.4 conversions. Probably still are.


Same exact deck? Same exact rod length? May sound like splitting hairs, but if they are just a tad different, then the stack up of "differences" if you will... will amount to much more in the end.

BTW... I went to bed a 12:30 this morning, only to be woken up by my 6 y/o stepdaughter power puking at 1:30. Then, that went on every hour through the night until about 9:30. My wife had it worse as she went to bed at 10pm, to have to get up at 1:30 am and go to work at 4am. She is still up after all this wrapping presents. I don't want a baby and have to go through that crap every night for a month or so that it takes.

[Whorse]

Hahhhha, yeah, I could have bought a ton of heads, engines etc but I won't let myself get in that trap, if I can't pay for my engine cash, I don't do it, :eyebrows:

Well if you save your pennies and save the money I'm going to pay you for the van, sucka, you can buy the sweetest set of rods you'll ever own.

[turbovanman²]

Well if you save your pennies and save the money I'm going to pay you for the van, sucka, you can buy the sweetest set of rods you'll ever own.

Hahhaaha, we'll see, I have other bills ya know, :p

[Whorse]

Your shop is supposed to cover those bills. Selling vehicles and parts should be paying for your van. Well...ideally. I know that's not how it works for me either.

[8valves]

I was going off of some turbo firebird v8 guys were telling me a year ago. Can you explain more?

To simply rotate something (flywheel, wheels, brakes, etc) only takes initial energy to get it up to that speed. To keep it rotating is less of an ordeal.

A rod has to accelerate, stop, re-accelerate, stop........ To remove weight doing that is a much larger gain. Not to mention the rod isn't trying to pull itself apart on the exhaust stroke as much either.

The same goes for anything involved in the rotating assembly beyond the crank and flywheel and dampner.

AM

[Directconnection]

I was going off of some turbo firebird v8 guys were telling me a year ago. Can you explain more?

8lbs of mass before the gearset.... very broad statement. Not mentioning the rotating assembly of the engine... what about the flywheel? *lbs on the outer edge or 8lbs right at the crank flange? Mkes a HUGE difference right there. 8lbs at the intermediate shaft won't amount to much.

But, anyways, i was initially talking about the rotating assembly as the rod's big end and crank's rod journal is rotating along with the rod bearing and the oil, but the piston and rings are reciprocating. In a balance job, the rotating weights are doubled when coming up with a bobweight for the balancing.

Bobweight is the weight of piston, pin, rings, small end of the rod, clips, oil, rod big end + rod big end, rod bearing + rod bearing.

[Frank]

I see everyone's point... I never really gave it much thought. I believe they originally talked about lightening the crank and flywheel. I had just assumed that would relate into the "bob" components.


Frank

[turbovanman²]

So, do lighter rods help in revability like a lightened crank or flywheel, or does it just help parts live longer?

[8valves]

So, do lighter rods help in revability like a lightened crank or flywheel, or does it just help parts live longer?

Both! You don't lose a darn thing with them... revability, longevity, power gains, economy gains, strength... not to mention peace of mind!

AM

[Rattlesnake]

Heavier parts require more energy to be moved, they also increase frictional power loss due to the weight. If there's a way to make them lighter, the saved energy can be used more efficiently. Add to that equation the time it takes to produce the energy to move the heavier parts, when lighter parts take their place that time is reduced, which will result in a faster reving engine. The loads as the assembly rotates are equal if you also balance and weight match the items on the rotating assembly, resulting in less stress to the engine.

[turbovanman²]

Does the engine have to be rebalanced?

[Directconnection]

An inline engine...no. A V-8 or V6...yes. Any engine that the rod journal shares with two rod/piston assemblies that are somewhat opposing, then it MUST be rebalanced.

Light rods will aid in quicker revs=more HP and also more high rpm capability. It will also make things easier on the rod as well.

Downside? Cost and you probably could lose some torque. But we are talking miniscule here.

[Rattlesnake]

Re-balance is not necesary if it was done before as long as you mark everything before you take it appart. But if you replace the rods make sure your machinist weight match them as close as possible.

[johnl]

Good thread.

What are the best procedures for "correctly" prepping rods?

I've heard that with a forging there a surface "shell" (like a heat treatment) that is important to the part's strength. This idea says you can go too far, you can deburr and chamfer and polish too deep - and ruin the part!

This theory says deburr lightly, chamfer stress risers lightly, then shot peen, then re-bolt and re-size, and then leave it "well enough" alone.

[Mario]

Face it, down the line you're going to want to push greater power levels. Why not upgrade now? :D Just sell that one head and use that money to buy them. :thumb:

[turbovanman²]

I figured the rebalance wasn't necessary but just wanted to double check, brain is full of sugar and alcohol the last few days, :confused: :eyebrows:



Good thread.

What are the best procedures for "correctly" prepping rods?

I've heard that with a forging there a surface "shell" (like a heat treatment) that is important to the part's strength. This idea says you can go too far, you can deburr and chamfer and polish too deep - and ruin the part!

This theory says deburr lightly, chamfer stress risers lightly, then shot peen, then re-bolt and re-size, and then leave it "well enough" alone.

I ground off the ridge on the side of the rod, then had them resized with ARP's and had them balanced. Didn't get them shot peened but If I reuse them, thats what I will get done.

[Directconnection]

You also want the sanding "grain" to be parrallel with the rod, not going against it.

[Rattlesnake]

Hey Simon, a cheaper alternative is to crio treat them. That will align the molecular structure of the rod simetrically.

[turbovanman²]

By the time I send them to Wallace, pay frieght etc, not worth it. Plus I'll be doing the swap over a 1-2 week period so won't have downtime, or limited.

If I make some money this next year, I might build another engine just for the TIII but my plans are to reuse my old shortblock and just put some new pistons in and bolt the head on, :thumb:

[Rattlesnake]

Wallace? who said Wallace, send them directly to 300below (217)423-3070. That is the phone# and ask to speak with Mr Mayberry, he'll answer you any question you have.

Reinaldo Moloon

[turbovanman²]

Wallace? who said Wallace, send them directly to 300below (217)423-3070. That is the phone# and ask to speak with Mr Mayberry, he'll answer you any question you have.

Reinaldo Moloon

I did, ;) He's the only one I knew that did it, no one in my area does it, :(

[cordes]

Wallace? who said Wallace, send them directly to 300below (217)423-3070. That is the phone# and ask to speak with Mr Mayberry, he'll answer you any question you have.

Reinaldo Moloon

Hey, that is my area code! Do you know exactly where those guys are out of?

ETA: those guys are about 45min. down the raod from me. Sweet. Thanks for the tip.

[Rattlesnake]

You're welcome:thumb: