"H" vs. "I" connecting rods

[2003 MIB]

Okay gearheads- Which is better?
The engine will eventually have the Trilogy blower kit. I'm not ever going to run nitrous. I'm seeking the most reliable combo.

What do you think?

[TAF]

Certainly not my opinion, Dan...but, the opinion of experts who know our engines...H-Beam...most definitely.

[Logan]

What he said.

[2003 MIB]

Certainly not my opinion, Dan...but, the opinion of experts who know our engines...H-Beam...most definitely.
Thank you Sir- I thought you might have an idea... H rods it is!

[martyo]

Thank you Sir- I thought you might have an idea... H rods it is!

Dan: Shall we take it that the news from the dealer was not good?

[BillyGman]

H-beams are very popular, but some of the best connecting rods made are infact Oliver rods which are I-beam rods. The design of these rods are superior to other I-beam rod designs, and I recommend them. They're definately what I'd use should I ever decide to rebuild the bottom end of my Marauder engine. Here's a link to their site....


http://www.oliver-rods.com/

[SergntMac]

What is "best" in anything is often not easy to define, or agree upon.

Seems to me that H or I beam style is less important than construction material and production quality. You may have to shop around a bit, but you can get very high quality connecting rods in either style from the major manfacturers. For example, Manley 4340 H beam rods are available for little as 469.00 a set, and their Billet I beam rod kits sell for around 1250.00 a set. Either set will work just fine in your application, the fact that Manley produces a high quality rod in both styles, renders science to personal preferrence...IMHO.

[2003 MIB]

What is "best" in anything is often not easy to define, or agree upon.

Seems to me that H or I beam style is less important than construction material and production quality. You may have to shop around a bit, but you can get very high quality connecting rods in either style from the major manfacturers. For example, Manley 4340 H beam rods are available for little as 469.00 a set, and their Billet I beam rod kits sell for around 1250.00 a set. Either set will work just fine in your application, the fact that Manley produces a high quality rod in both styles, renders science to personal preferrence...IMHO.
Thanks Mac!!!!!!

[2003 MIB]

Dan: Shall we take it that the news from the dealer was not good?

No, not good but the sky isn't falling either, Marty. See "Rod Knock" thread for deatails. I'm cool with the turnout and it gives me an excuse to beef things up a bit.

[BillyGman]

I agree w/what MAC said about the materials and quality control of the rods in question. That's a good point. I have an engine building video which displays different hi-perf parts that are available. The narrator of the video who is a circle track racer (Mike Colletti)shows why Oliver rods were used in his engine. he has a few sets of connecting rods sitting on the bench, one of them being the Oliver rods. All the caps are removed from the rods so that he can show you just some of the reasons why the Oliver rods are superior in their design.


Out of the three rods that are displayed in that video, the Oliver rods were the only ones that have an alignment pilot which protrudes, so that it actually inserts into the bolt holes of the rod caps which keeps the caps aligned on the rod. So in addition to the torque placed on the rod bolts, which holds the caps in place on the rods themselves, the alignment pilot on each side also prevents any side to side movement of the cap. I don't know if any other rod has that, but I do know that many of them do NOT, and that Oliver rods do.

I'm not saying that this is the only thing to consider while choosing which connecting rod to purchase, but Oliver rods are no joke. And again, I agree w/MAC that for your application, billet rods are NOT needed. it would be different if you're planning on running over 600 HP through your drivetrain, but my guess is this isn't the case. So forged rods can be had for about $700 a set. And that would buy you a premium set of forged rods which will be stronger than your engine would ever require, even if you plan on Nitrous oxide, a Trilogy S/Cer, or a Reinhart S/Cer.

[TripleTransAm]

No, not good but the sky isn't falling either, Marty. See "Rod Knock" thread for deatails. I'm cool with the turnout and it gives me an excuse to beef things up a bit.


Do you think this rod failure might have had something to do with spark knock in a cylinder that might have been running a little hot to begin with? Isn't that one of the cylinders that tends to run a little on the steamy side?

I remember someone posting a warning thread a while back about Marauders and how they were "all dying (busted bottom ends) at a certain mileage." Does anyone know if these reports all dealt with that same (or nearby) cylinder?

[BillyGman]

Gee, I don't remember seeing that claim from anyone on here Steve. I must have missed it. Now you have my curiosity on that. But as far as the detonation, or "knock" being a cause, I would think that the piston in that cylinder would be melted or cracked waaay before the rod would break due to knocking. As far as I know, the head gaskets, and pistons are the first to go from detonation.

[TripleTransAm]

Yes, I agree... I too would think that the pistons would take the beating first and foremost. Just trying to find some sort of link... I'm "sensitive" to issues on that part of that cylinder bank ;) and so have some interest in looking into anything that goes wrong with them.

The 'sky is falling' issue with the failing bottom ends was posted a while back, several months ago perhaps? No substantial data to back it up, though, so while I cannot disprove it (we are but 1000 or so owners out of 10000?) I am keeping my ears open.

Wouldn't someone within the Ford service organization (dealers, parts dept, technicians?) be able to delve into Ford's data and call up the number of Marauder engine failures per failure type?

[BillyGman]

The 'sky is falling' issue with the failing bottom ends was posted a while back, several months ago perhaps? No substantial data to back it up, though, so while I cannot disprove it (we are but 1000 or so owners out of 10000?) I am keeping my ears open.

Wouldn't someone within the Ford service organization (dealers, parts dept, technicians?) be able to delve into Ford's data and call up the number of Marauder engine failures per failure type?
Good question Steve.....

[David Morton]

Do you think this rod failure might have had something to do with spark knock in a cylinder that might have been running a little hot to begin with? Isn't that one of the cylinders that tends to run a little on the steamy side?

I remember someone posting a warning thread a while back about Marauders and how they were "all dying (busted bottom ends) at a certain mileage." Does anyone know if these reports all dealt with that same (or nearby) cylinder?Intermittent knock could cause wrist-pin failure on the piston most probably but I seriously doubt the big end is going to knock out from detonation.

A nice builder tip when torqueing the rod caps is to put a feeler guage into the journal to take up the thrust so that when you tighten the nuts the rods don't 'twist' any. This will save the bearing inserts from any edge contact that causes damage to the insert. Also, measure the journal widths on the crankshaft, and then the widths of the rods, and 'map' out the rod placement so each journal has as close as possible a match of the others.

If you're using a cheap micrometer that can't measure 1/10,000 inch, forget what I just said. Also, don't try to build any racing engines either, you probably won't make very many reliable ones and will spend a lot of time blaming vendors for the failures.

[rumble]

I remember someone posting a warning thread a while back about Marauders and how they were "all dying (busted bottom ends) at a certain mileage." Does anyone know if these reports all dealt with that same (or nearby) cylinder?

Here ya go;


http://www.mercurymarauder.net/forums/showthread.php?t=9995&highlight=CRANKSHAFT

[merc406]

Toss a coin, for what you need them for they are both good choices.