2G 2.0 Long rod, & +625 worth the $?

[90laserRSfwd]

For pistons i was looking at ross stroker pistons, they are off the shelf. And have the correct pin offset

While the pin height may be correct for using a longer rod, the compression ratio listed will never be achievable. The dish (negative volume) will create a very low static compression ratio. You don't want a -21cc dished piston!

 

[miliman13]

The piston to wall clearance is dependent on the piston alloy (2618, 4032, etc.), the manufacture, how you intend to use the engine. I will agree that loser is better to a point. Ring gaps are the same as PTW clearance, depends on a few factors. Rod and main bearing clearances need to take into effect max RPM, intended use, etc. You can't just "add some" to the stock clearances and "hope" the motor lives. I mean, you can, but that isn't the correct way to do it. Each piston manufacture will have it's only formula for finding PTW and ring gap adjustments, which will have a range (example would be 4 to 5 thousandths of PTW clearance, building a high RPM engine, you'd want things on the "loser" end (aka 5 thousandths) for this example. If you just go off what another person did, and your not using the same parts, you deserve what you get (aka a blown motor). There is a reason companies go through testing to come up with ideal clearances. Following instructions, or live the jack stand life...

FYI. Wiseco recommends .02+ for ptw clearance and .019 for ring gap.
And even then I chose to go losser based on my own research.

What you said is correct, but I said
(for example). I didn't feel detailing alloys and part numbers were necessary.
Smoker will do his own research and decide. This is just Base line. A reference of sort.

 

[90laserRSfwd]

FYI. Wiseco recommends .02+ for ptw clearance and .019 for ring gap.
And even then I chose to go losser based on my own research.

What you said is correct, but I said
(for example). I didn't feel detailing alloys and part numbers were necessary.
Smoker will do his own research and decide. This is just Base line. A reference of sort.

Sorry if I came off as sounding like a dick. I just wanted to clear the air in the fact that every piston setup is going to be different (clearance wise). I didn't mean to attack you personally.

 

[Archer Fabrications]

While the pin height may be correct for using a longer rod, the compression ratio listed will never be achievable. The dish (negative volume) will create a very low static compression ratio. You don't want a -21cc dished piston!

So your saying only a custom piston will work?

 

[bastarddsm]

The change in rod angle is negligible. It's fine that 156 are same price as 150's, 150 stuff is more common, so when you need a replacement part later on.

By the way steel rods are not any harder on bearings than aluminum. Heavy rods are harder, but how hard? I ran TT's and I ran the shit out of it. I spin it 9500 a lot, bearing life was excellent.

 

[Archer Fabrications]

Common is a good point.....

 

[ThunderChild]

Perhaps it comes from the frequency one is at those rpms that rod bearings may suffer? I'm a firm believer that if your bearing clearances are set well, you shouldn't have rod bearing issues, but erring on the safe side is usually my practice.

I just think a heavy rod has a tendency to push the oil wedge down and cause contact more often at high rpm than a lighter rod may. But if the oil pressure is up to snuff, the problems should be negligible.

Anyway, without side-tracking too much, I'll be interested to see what urban chooses for parts and see how they perform.

 

[Archer Fabrications]

Well looking at the choices of off the shelf pistons I'm leaning back to a 150mm rod, here is what I'm thinking.

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Ive noticed a lot of us including myself getting hung up on the little things but how much of a difference does it really make? Is it all negligible? The rod weight thing, the rod angle thing, do they really make a difference when compiring rod bearings of another steel rod that is lighter?i know less rotating mass is better but were talking grams here not ounces or pounds Or do they look the same. Just reqding back on posts from the past even it seems there is a lot of worry but not a kot of proof.

 

[familyMAN]

You can use "stroker" pistons for a 156mm long rod 2.0. Pin height is correct. For what it's worth, my next set of rods will be ffwd aluminum.

 

[90laserRSfwd]

You can use "stroker" pistons for a 156mm long rod 2.0. Pin height is correct. For what it's worth, my next set of rods will be ffwd aluminum.

I've already stated this a few posts back. It's not the pin height that's the problem with off the shelf stroker pistons, it's the dish.

 

[lasthope05]

Weight and rod bearings play a huge role when your reving and staying that high in the rpms for an extended amount of time. On my old pauter/ross combo i was swapping bearings every other season. Never had issues with the h beams and so far so good on the aluminum rods.

 

[90laserRSfwd]

Ive noticed a lot of us including myself getting hung up on the little things but how much of a difference does it really make? Is it all negligible? The rod weight thing, the rod angle thing, do they really make a difference when compiring rod bearings of another steel rod that is lighter?i know less rotating mass is better but were talking grams here not ounces or pounds Or do they look the same. Just reqding back on posts from the past even it seems there is a lot of worry but not a kot of proof.

I'm using the same rods you listed. I plugged the numbers in from the pistons you listed, according to Eagle's online compression calculator, ASSuming you bore the block .020" over, will net you less then 10:1 static compression. Unless the deck height or cylinder head dome volume is changed. Just something I thought I'd share. The thing about rotating mass, (keep in mind the actual rod / piston weight doesn't physically change) is the forces generated by a part, or forces acted upon by a part, multiply as RPM increases. In other words, while a few grams don't seem like much, lighter parts produce less "force" on the rod bearings at higher RPM. Also, lighter parts take less force to accelerate (think of lighter parts as it would relate to an engines ability to rev). Now, I will admit, simply saving 10 grams on a connecting rod is nothing to write home about, but it's the combination of lighter weight parts that equate to the end means.

A perfect example of this, that many of us have experienced personally, would be a light(er) weight flywheel. The engine accelerates (rev's) more quickly. More noticeable to some would probably be the rate at which the engine would decel (return from a higher rpm to idle), remember how some cars with a light flywheel would "almost stall" when pushing the clutch pedal in? Although it's probably a more extreme case in rotating mass weight savings, it still illustrates my point.

 

[90laserRSfwd]

1G rods- 695 grams or 1.53 pounds
(measured rod only with no bearing but WITH rod cap and bolts installed)
Stock piston- 365 grams or 0.80 pounds
(measured the piston only. no piston rings or pin)

Total weight (including 4 pistons and 4 rods)(stock)- 424 grams or 9.32 pounds

Scott

According to Scott, in his post here (http://www.dsmtuners.com/threads/weights-piston-rod-crank.196776/), stock 1g rods weigh 695 grams each (same as my Manley Turbo Tuff I beams), and the pistons weigh 365 grams each without the stock wrist pin (16 grams more then my Wiseco's). After adding in the Wiseco wrist pin, rings, and rod / main bearings, I am hoping to be equal to a stock 1g 6 bolt rotating assembly weight in running forum (crank, pistons, rods, bearings, rings, wrist pins, and rod bolts). This might not seem like any kind of accomplishment to anyone. Keep in mind though, with clearances set correctly, along with other factors, in theory, the rod bearings SHOULD see the same force as stock parts. Though we all know theory doesn't match real life results every time. Still I'm hoping for the best. Point I'm trying to make here, is that by selecting rotating parts with lighter weight, you are not only gaining the ability to contain more force (aka being able to make more hp), but you also (MIGHT) be able to see bearing life resembling that of a stock rotating assembly abused to the same extent.

Basically, if you were to make the same power, and abuse the engine as if it were a stock short block, you'd see the same bearing life. Now we all know a stock short block isn't going to last (if even make it) to 800whp. With that said, we also know no one is (for the most part), going to build a 1000hp capable short block and run an EVO III 16g on pump gas. But IF those cases were true, bearing wear would be the same. Having the same bearing wear, and being able to make 800hp would be great!

 

[lasthope05]

One crucial point you failed to take into consideration is rev limit. The factory rev limit is 7k rpm and as we all know stress/load increases exponentially the higher you rev. With that in mind you should be shooting for a lightweight assembly to help compensate for that increased bearing load.

Stock assembly weights, stock clearances, stock anything goes out the window (to a certain extent) when building a race motor that exceeds the limits of the manufacturers intended purpose.

:Edit:

Just saw the post above and you did touch on rpm/load increase.

 

[dexterholland04]

Why not just build an aluminum rod motor? Much lighter.

 

[bastarddsm]

The tension forces on the rod stuff from rpm is orders of magnitude less than the compression forces from the powerstroke. The rod weight really doesn't matter all that much. They build 4.5" stroke BBC with small rod journals and turn them 10k with steel rods. Why does a 3.5" stroke DSM need to be rocket science to do yhat. If your hurting rod bearings look at your oil system not your rod weight.

 

[90laserRSfwd]

One crucial point you failed to take into consideration is rev limit. The factory rev limit is 7k rpm and as we all know stress/load increases exponentially the higher you rev. With that in mind you should be shooting for a lightweight assembly to help compensate for that increased bearing load.

Stock assembly weights, stock clearances, stock anything goes out the window (to a certain extent) when building a race motor that exceeds the limits of the manufacturers intended purpose.

:Edit:

Just saw the post above and you did touch on rpm/load increase.

I agree. I wasn't trying to project the thought that because my chosen parts weighed close to stock, that the motor would live in an elevated RPM / HP setup. I was, more of less, trying to get my point across that choosing lighter weight parts will help with bearing life. The OP already stated he's not looking to run and aluminum rod, so I was offering my thoughts and personal setup as an opinion / example.

Would an aluminum rod be the easiest. YES
Would another steel rod (like the Pauter X beam) be better then a Turbo Tuff. Possibly

The thing you need to keep in mind is that (even my) opinions are just that, the thoughts or experiences of another person. My success doesn't guarantee yours and visa versa..

 

[Archer Fabrications]

Why not just build an aluminum rod motor? Much lighter.

Cause even the manufacturers claim these as race only parts and there is a decrease in service life (or service intervuls) that I'm not really looking to move on to at this point. I'm fine swapping bearings once a year or every other year, but it's not something i want to do every season. A lot of these rod manufacturers dont list their weights. But boostin is a prime example of the turbo tuffs not being an issue at high rpm. These are almost all the same forging (4340) so i probably can't go wrong with any of the rods raited for the power, but I'm more prone to go with something that has been proven time and time again then to experiment when i dont have an endless budget. I'm looking to do this once more, and hopefully not again for a long long time.

For what it's worth marco from magnus has been reving 2.0 steel rods to 10.5k for years with no problems.

Which brings me to another question, do many people use the magnus rods? Pretty sure they are made in house in canada.

 

[90laserRSfwd]

For what it's worth marco from magnus has been reving 2.0 steel rods to 10.5k for years with no problems.

Which brings me to another question, do many people use the magnus rods? Pretty sure they are made in house in canada.

I've never used Magnus rods, so I have no comment on them. I will however point out, that the use Marco is talking about, is probably 100% (or close to it) of TRACK ONLY use. Driving a car on the street (were coolant and oil temps are almost guaranteed to be less closely monitored), will probably not come close to the life span of that he's currently seeing from the rods / bearings / rings.

I never did ask (my fault entirely), but what do you intend to use the engine (car) for? Street car that you drag race I assume?

 

[Archer Fabrications]

I've never used Magnus rods, so I have no comment on them. I will however point out, that the use Marco is talking about, is probably 100% (or close to it) of TRACK ONLY use. Driving a car on the street (were coolant and oil temps are almost guaranteed to be less closely monitored), will probably not come close to the life span of that he's currently seeing from the rods / bearings / rings.

I never did ask (my fault entirely), but what do you intend to use the engine (car) for? Street car that you drag race I assume?

Honestly, I'll drive it on the street for tuning and maybe to a meet or two, otherwise it's drag car and will be trailered. Car is gutted with one kirkey seat, no dash, no interior and probably still a hefty 2600lbs without me in it (so race weight is probably 2850 cause im a fatty. Still havnt fabed the 8.50 nhra spec cage. I have two other cars me and my wife ise as daily, and were selling the truck for a new 3.5 ecoboost f150. So the dsm is definately mainly a race car, probably with a few 50 mile trips on thr weekends. (Probably not often) i want to go 9's and 150+mph at the track. And i dont want to have to rebuild the motor often. Bearing refresh is fine. And try and go lower ET from there. This will also be my businesses shop car to showcase my turbo manifolds and other dsm fab.

 

[90laserRSfwd]

Realistically speaking, as long as you are religious and consistent with the attention the car requires (oil temp, pressure, and health), coolant temp, plugs, inspection the oil filters or checking bearings, you'll be fine. Don't check up on those things, or let the car get to hot on a street drive, and bearings start fretting, chips in the oil, so on and so forth..

I'm also a fatty (232 lbs). Race weight for me is always an issue.

Another thing to keep in mind (that a few LOW ET guys have reinforced to me), the short block HOLDS the power, the head makes it...

 

[Archer Fabrications]

Realistically speaking, as long as you are religious and consistent with the attention the car requires (oil temp, pressure, and health), coolant temp, plugs, inspection the oil filters or checking bearings, you'll be fine. Don't check up on those things, or let the car get to hot on a street drive, and bearings start fretting, chips in the oil, so on and so forth..

I'm also a fatty (232 lbs). Race weight for me is always an issue.

Another thing to keep in mind (that a few LOW ET guys have reinforced to me), the short block HOLDS the power, the head makes it...

Previously before my magnus billet oil filter backed off and ran the motor dry (I'll never use that filter again) i had changed my oil every 750 miles, had 14,000 on it when the head got destroyed and started knocking the cams and rods.

As for head, ive got one next to me that i just bought as a bare core with caps 99 head. I am going to be using kiggley HP beehives and BC 276/276 stage 3 cams BC adjustable cam gear on stock valves, the domes of the head are polished, I'll clean up the intake castings, throw an HLA ON and call it good, still deciding on intake manifold, but will be using stock 2g til then. Also for the revs I'm getting the kiggley girdle. And realistically I'll prob shift at 9500 max going through the traps

 

[DSMraver]

I think you've got a missing decimal place in the PTW clearance recommendation. I just put a motor together at .0055" PTW and that was fairly loose IMO...

FYI. Wiseco recommends .02+ for ptw clearance and .019 for ring gap.
And even then I chose to go losser based on my own research.

What you said is correct, but I said
(for example). I didn't feel detailing alloys and part numbers were necessary.
Smoker will do his own research and decide. This is just Base line. A reference of sort.

 

[DSMReviver]

I would be very careful chosing these manly I beam rods. The are very hard on the bearing which no amount/kind of oil can protect. Buschur did a tear down on one of their customer who had 16g on their short block. The motor only had 10k miles in it. I don't think he admit it but you can see some wear in cylinder 4 and 3 rod bearings. It probably will be fine with less horsepower and low rpm but if you are going to be shooting for 800hp, I'm not sure if it will be a great choice. Manly does, I believe, makes HD h-beam rods which weight less which can be a great alternative to use. If not there are other lighter I beam rods you can get from other manufacture. Another great thing about lighter rods is that you can rev much faster.

 

[90laserRSfwd]

I would be very careful chosing these manly I beam rods. The are very hard on the bearing which no amount/kind of oil can protect. Buschur did a tear down on one of their customer who had 16g on their short block. The motor only had 10k miles in it. I don't think he admit it but you can see some wear in cylinder 4 and 3 rod bearings. It probably will be fine with less horsepower and low rpm but if you are going to be shooting for 800hp, I'm not sure if it will be a great choice. Manly does, I believe, makes HD h-beam rods which weight less which can be a great alternative to use. If not there are other lighter I beam rods you can get from other manufacture. Another great thing about lighter rods is that you can rev much faster.

Did you bother to read any of the other posts previous to yours? Every thing you stated (except the Buschur comment) has already been said. Again, not being a dick, but your post is a copy paste of things already said, and adds nothing to the discussion. Let me guess, aluminum rods would be a better choice?