Connecting Rods.

On a scale of 1 to 10, (when compared to other foreign and domestic con rods), where do 4.0 con rods rate?

The thing that scares me the most about building a stroker is reliability. I range far from home on a regular basis, and I don't want to throw a rod 100 miles from the nearest paved road.

Are there aftermarket rods available? Are they worth the extra cost over the OEM units? And just how the hell does a shop resize a con rod, and what effect does that operation have on longevity?

CRASH

Resizing is easy,they grind the caps and then rebore the center.Ive never looked into engine parts but you could always polish and then shotpeen the stockers along with some ARP bolts.

Just go with Accurate or Hesco. You'll know they're right on and not have to worry about it.

You can spend your time working on fabulous new products.

Since my rig is the rolling catalogue of U.R.F. Inc. products, it has to be built right!

CRASH

The 4.0L rods are stronger than 4.2L rods, but also longer. If using the Accurate Power (or other) custom pistons this is not a problem. If trying to use stock pistons, the 4.0L rods will put the top of a stock piston at or above the top of the block. Not good.

Aftermarket rods are available. Check in on the Strokers group -- within the last couple of days someone posted a name and a source. Also available from Hesco ($$$$$$$), and from Clifford (????? Quality).

Let's look at this objectively. The 4.2L engine has a longer stroke than the 4.0L, weaker rods, and has been around since about 1970. These engines have been used in everything from drag racers to autocrossers to police cars to taxis to postal trucks. How many have you ever heard of breaking a rod? And the 4.0L rod is stronger.

IMHO, unless you plan to run very high RPM, or very LOW RPM under extreme loading, custom rods are a waste of money. Get a good set of 4.0L rods (buy new if you're really worried), have them shot peened, and go wheeling.

aftermarket rods

i sell the eagle I-beam rods for $159.50 they come with arp wave-lock bolts, and custom pistons for $500.00

scot

Scot,

Are the pistons dished to return the proper quench to the motor? Sounds quite interesting.......

CRASH

Scot, more info please. Who makes the pistons? Forged? What about the I-beam rods? Details. Oh, by the way, expect a call from Eagles copyright attorney about your clever name for the connecting rods.

Scot, is that $159 per rod, or for the set?

CRASH said:

Scot,

Are the pistons dished to return the proper quench to the motor? Sounds quite interesting.......

CRASH

Click to expand...

Quench is a function of rod length and pin height (basically, clearance between the head and the top of the piston), not dish. The stock 4.0L engine is technically not "quench compliant." What you are probably trying to ask is: if the custom rods and pistons result in a quench compliant piston height, are the pistons dished enough to bring the compression ratio back down to (or near) stock CR.

Are those rods in stock 4.0 / 2.5 lenght??? or are they short like the 4.2 rods??? I'll take my motor back apart to install real forged rods. I need the 4.0 / 2.5 lenght rods. I am running shotpeened stockers with good bolts right now..but the motor loves to rev..I have it chipped at 5500, I'd like to keep all the parts in the right places for as long as possible.



Quote from the Schnitz Racing cataloge...All parts have a lifetime...racing parts have a shorter one.

Inquiring minds want to know.

Eagle, when it comes to engine stuff, I'm a dope. Your correction is much appreciated, and your description of my desire for correct compression ratio at a decent quench height is right on.

Give up the info, xjjunkie.

CRASH

i mansge a speed shop in YORK, PA. have been a venolia dealer for more than 25 years, also a dealer for eagle products. the pistons are custom made by venolia, and the rods are eagle I-beam rods. the rods are $159.99 for a set of 6 rods. they are new, matched weight sets, have ARP wavelock rod bolts in them, the little end or pin end is a floater, meaning it has a bronze bushing in, so you have to use a piston with a locking wrist pin (like the venolias. rods are avalible know, pistons are 3 to 4 weeks out.

scot

If you assemble your con rods and pistons on a 4.2 crank, what is the final assembled compression ratio, and is the quench correct?

CRASH

Crash --

FYI, Ben "Stroker" from the NAC has been running an Accurate Power 4.6L engine since before the chapter was formed, and that was 3 years ago. Ben is, shall we say, not known for having a light right foot. He hasn't broken his yet ... therefore it is exceedingly unlikely that you could break one. I'm pretty sure Ben's engine uses the 4.0L rods with Accurate's forged pistons.

We have a guy in a local club that bought an Accurate power stroker and it blew up in less than a few mins! So not everything Accurate touches turns to gold. The Piston went into the head and the rod came out the bottom of the pan! This was on a complete motor built and assembled by Accurate.

They have been good about replacing it but, he had to ship the motor back and have them look at it and the turn around was not real fast if i remember correctly. Not baging on Accurate but a F*&^ up like that is 100% unacceptable in my book for the money he spent......and of course his time! I cant understand how someone makes a motor like that and doesnt check the clearance between the top of the piston and the head.....

Regards
Chewy

I'm interested in the same stuff. I bought a used (25K, 1 yr old) 4.6L very budget stroker, pretty cheap. It has stock 0.30 over pistons and 4.2L rods, with a compression ratio of 10 to 1. It's a Renix, so has the knock sensor, and he must have been fighting ping because it also has an adjustable MAP sensor.

I want to tear it down to inspect things before I put it in my rig, and I want to replace the pistons to correct the compression ratio. I'm wondering if there is enough of an advantage to spend the $$$ for 4.0L rods and custom pistons, verses just getting a set of the Silvolite 4.0L pistons and having them dished to the desired compression ratio. An advantage to me is a long life for the motor, overall increased reliability, and a guarantee of the proper quench height.

For you motor heads out there, when I get to tear this thing down, how do I determine what quench height I have, and what are the ways to correct it if it's wrong? How do I determine if this block has already been decked or not, and if so, how much?

One other thought that I've had through all of this stroker talk. The 4.2L motor, based on my experience and observations, is a 130K to 150K motor, before rebuild. The 4.0L motor is generally a 250K to 350K motor before rebuild. Why??

Quench clearance is basically the distance between the piston and the head...(we are dealing with flat top pistons) measure the deck height...measure or obtain the compressed thickness of the head gasket you will be using..if the pistons are below deck...add that amount to the gasket thickness... If above deck subtract the amount from the gasket thickness...around .040 is a good total clearance...I ended using a copper gasket from Clifford Performance because the stock gasket was too thick....one possible alternative to custom pistons, assuming you can get the deck height right is to have the pistons fly cut in the bowl area to bring the C.R. within range..

Poor quench can result in pockets of excessively rich mixture which aggrevate the preignition...also be sure that the entire combustion chamber including the valves and piston tops are deburred to smooth any sharp edges...I even spend a few extra minutes to deburr the electrodes on the plugs.

At least we arent dealing with poor plug placement or piston domes that inhibit proper flame propogation.

Eagle said:

Let's look at this objectively. The 4.2L engine has a longer stroke than the 4.0L, weaker rods, and has been around since about 1970. These engines have been used in everything from drag racers to autocrossers to police cars to taxis to postal trucks. How many have you ever heard of breaking a rod? And the 4.0L rod is stronger.

Click to expand...

Of course my 4.0 threw a rod (or 2?) driving down the road going home for spring break the other year.

Yes, throwing rods is my concern as well, our Sierrqa Chapter Prez threw a rod in his rig on level ground turning like 2200 rpm. These forged rods sound like a nice upgrade, and the price is very good.

xjjunkie, can you post a pic of one of your connecting rods in side profile, and give us some specs?

same with the pistons.

CRASH