Spilling the Beans...2L rod/bearing options

Stripped66 · Post by **Stripped66** » Wed Oct 12, 2005 10:59 pm

Here is the data I can share at this time. Keep in mind, none of these options "bolt together." However, all of these options provide the means, within reason, to have a non-consumable (rods) modified to allow use of a consumable (bearings). These options have been explored from the standpoint that the main problem with the 2L rod journals (found on either stock 71mm cranks or aftermarket strokers) is the poor bearings available. By all means, if a Chevy or Type 1 journal is available, it is likely a cheaper/easier option. However, for the rest of us who wish to keep the 2L journals, keep reading:

Bearing option:

Late 80's Dodge Daytona Shelby (2.2L Turbo).
Clevite tri-metal p/n: CB1269P

The bearing is 20mm wide; the 2.2L rod journal is 50mm, like the 2L T4.

Modifications: the bearing tangs are on the wrong side. The 2L rod will need to have the current retaining grooves welded up. The big end diameter needs to be bored to 53mm (+/- 0.05mm); in inches, the stock 2L rod is 2.079", it needs to be bored out to 2.0866"...about 0.007" overbored. The bearing retaining grooves then need to be filed on the opposite side. If you are considering this, you are likely having your 2L rods rebuilt anyway.

Rod options:

Dodge 2.2L, same application as above
Length: 151mm (5.944")
Big-End Diameter: 53mm (2.0866")
Big-end Width: 25.75mm (1.013")
Wrist-pin bore: 22.85mm (0.8996")

This is a long rod, not sure about the composition (maybe forged, maybe powdered-metal). The big end diameter is correct for the bearing option, the big end width is about 0.003" wider than the stock 2L rod. The wrist-pin bushing will need to be pressed out and/or honed for proper bushing (either 22 or 24mm).

Dodge Neon 420a (non-turbo Talon/Eclipse)
Length: 5.428" long
Big-End Diameter: ?
Rod journal diameter: 1.889"
Big-End Width: 1.055"
Wrist-Pin Diameter: 0.865"

Toyota 3SGTE (MR2 turbo, Celica All-Trac)
Length: 5.472" long
Big-End Diameter: ?
Rod journal diameter: 1.889"
Big-End Width: 1.032"
Wrist-Pin Diameter: 0.826"

Both of these rods need the big-end narrowed to 1.010", the big-end diameter bored to 2.0866" (this would remove about 1mm of metal along the perimeter of the rod and cap), and the wrist-pin bored for either a 22 or 24mm bushing. The rod length is certainly attractive.

Other problems with these rods: the rod bolts need to be flipped for clearance (more so with strokers). The stock Neon rods are definitely powdered-metal (they suck), but the Toyota 3SGTE rods are plenty strong for whatever we can throw at 'em. Eagle does make H-beam rods for the Dodge Neon and Toyota 3SGTE, which may be a suitable hi-po starting point.

I have contacted Eagle about possibly pulling a set of 3SGTE rods out of the production line prior to finish machine work (e.g. before bushing the wrist-pin bore, filing bearing-retaining grooves, drilling/threading rod-bolt holes/threads in rod and cap, etc) so that I could have a machine shop finish them to my specifications. So far, no response

Other than that, I'm keeping my eyes open for a set of Pauters

so I can at least modify a quality rod for the quality Clevite rod bearing.

One last thought: if we can ever drum up enough interest to seriously pursue a production run of 2L rods, I hope we would consider designing the big-end to accomodate this Dodge 2.2L bearing. A much better bearing, inexpensive and readily available, and width/diameter are fine for the 2L journal. FWIW, the Dodge 2.2L turbo (Daytona Shelby) and Toyota 3SGTE (MR2 turbo and Celical All-Trac) both can produce big, big power using the stock bottom-end...more than we'll ever see in a T4; just a comment on the quality of the rods and bearings.

Anyway, use this info as you'd like. As I've stated in the other thread, I'm going to use this bearing. Period.

MASSIVE TYPE IV · Post by **MASSIVE TYPE IV** » Wed Oct 12, 2005 11:03 pm

dstar · Post by **dstar** » Thu Oct 13, 2005 9:52 am

You forgot the 292 Chebbie rods.......AND they come in a 6 pack!

Don

Stripped66 · Post by **Stripped66** » Thu Oct 13, 2005 10:15 am

dstar wrote:You forgot the 292 Chebbie rods.......AND they come in a 6 pack!

Don

I guess I did

However, aren't they for a 2.000" rod journal?

dstar · Post by **dstar** » Thu Oct 13, 2005 11:02 am

Well, every rod you listed has to have *some* type of work done
to it to work on the STD Type 4 journal, so I thought it should be
included?

Your call!

Don

Stripped66 · Post by **Stripped66** » Thu Oct 13, 2005 11:17 am

dstar wrote:Well, every rod you listed has to have *some* type of work done
to it to work on the STD Type 4 journal, so I thought it should be
included?

Your call!

Don

Damn right it's my call...

IMO, it's easier to bore something to size than it is to make smaller...though I guess with the Chebbie rods, you could mill the mating surface of the rod and cap, then rebore it to the 53mm diameter.
How wide are the 292 rods? I would trust the machine work to make an oversized bore smaller, but I would not be so keen on making a narrow rod wider.

Post by **Piledriver** » Fri Oct 14, 2005 12:42 am

Thanks, Stripped66.

As my planned RPM range is essentially the stock one (914) and the stock 2.0 rods are exactly (what "some people" consider--T.O.O. et al) the ideal length for that (1.85:1 RR w/71 crank) the decent bearing mod is more than welcome with the planned blower (Miller Cycle) setup, altho I may have to go with Squishies to get the CR I want...

Jake always insists the stock 2.0 rods are too short, even for a stock engine, and that MAY be true if you only run between 6-8K

I'm not sure if this link has been posted before, of if I stumbled upon it, but it has pretty graphs and spreadsheets to calculate exactly how much the longer rod is getting you.
(It doesn't calculate airflow improvements, sadly)
http://e30m3performance.com/tech_articl ... o/kin2.htm

dstar · Post by **dstar** » Fri Oct 14, 2005 6:48 am

Piledriver wrote:-------
(It doesn't calculate airflow improvements, sadly)
-----

Only headwork can improve *airflow*!

Sorry to be so *pointed*, but rod ratio does NOT *improve* airflow,
it just moves the RPM band that the engine CAN breath to before
maxing out, up the RPM scale.

Air cannot be moved supersonically, so physical dimensions of the
air path (and PHYSICS!

) are the limiting factor.

Don

speedy57tub · Post by **speedy57tub** » Fri Oct 14, 2005 7:40 am

Dstar,
Yup!

Post by **Piledriver** » Fri Oct 14, 2005 9:13 am

Only headwork can improve *airflow*!

Ummmm... Stop and think about it for a moment, gentlemen...

How exactly does the longer RR improve HP in the upper band if NOT by improving airflow?
(It isn't leverage, so...)

It increases the peak velocity, reduces the accelleration, and spreads out the effective flow, allowing a given port to work better at higher rpms than with short rods.

Short rod==high accelleration, low peak velocity==runs out of flow at high RPM.

If it wasn't for this effect, there would be NO POINT in installing long rods in engines, except to reduce wear a little.

How much it really helps, and what RPM range you will actually run the engine in (in reality) are the questions.

dstar · Post by **dstar** » Fri Oct 14, 2005 9:56 am

Again, airflow is not improved......

A short rod sucks hard on the heads at low RPM, whilst a long rod
has to get UP in the rpms before it sucks that hard.

Got your attention yet?

A vacume guage can show this......

Don

Stripped66 · Post by **Stripped66** » Fri Oct 14, 2005 10:33 am

I think you guys are saying the same thing, there is just a breakdown in terminology.

WRT vacuum, as you said Don, a short rods SUCKS hard on the heads at low RPM. When you take a look at a head flow chart, what parameter do you look for? VACUUM. A head that was flowed at 25" H20 is going to show lower flow rates than a head flowed at 28" H20.

The point Piledriver is making ISN'T that the shorter rod is going to get the head to EXCEED it's flow capabilities, but that, at least at the lower RPM range, the shorter rod will make better use of the head's flow capabilities. Thus, for a low range in RPM, a shorter rod may facilitate more flow through the head than a longer rod. Absolute maximal flow capability of the head has not changed, but the relative flow due to rod length and RPM has.

Don't forget that air has mass, and therefore moving air has momentum. The greater flow you can generate at low valve-lift is going to help build the intake-charge momentum, very important as the piston passes BTD and is moving back up...

dstar · Post by **dstar** » Fri Oct 14, 2005 11:17 am

SHORT RODS RULE for a good flowing head!
(keeps the velocity up at low RPMs)

At least that is what I tell my girlfriend.........

For my 2316 with over 300 duration, and a 6500RPM limit, 1.65:1
will do just that!

Long rods are used to get UP in the RPM range, with heads that
normally wouldn't let you get there. Like a type I.

Look at the factory 1.99:1 ratio, and it has the worst flowing intake
I have EVER seen!

Where is Len when you need him? He can straighten this out.

Don

Post by **Piledriver** » Fri Oct 14, 2005 9:41 pm

Thanks, Don, I always wondered what Mountain Dew would feel like in my nose...

jonas_linder · Post by **jonas_linder** » Sat Oct 15, 2005 12:28 am

A engine doesn't suck the air in.. it's the atmospheric(spelling?

) pressure that push the air in!

only .... suck