Just my luck...

[3400-95-Modified]

Well there is a good solution... you would also need to have the bore re-bored correct?

The more and more I read about the fractured cap I find that this was only done to take a 20 step process of making a rod and cut that down to a 10 step process... I'm not so sure the process was created to make them stronger or better in any way.

[Joseph Upson]

The machinist also said that some newer rods don't even have the notches and since rod bearings were spinning long before powder metal rods were invented, it's safe to say that the traditional configuration guarantees nothing if the conditions favoring a spun bearing presents itself.

The connecting rod I have on my desk right now would loose more than .100" from the crank pin end diameter if the cap surfaces were machined flush because it is a diagonal fracture. That leaves a lot of metal to bore out compared to normal rod reconditioning.

Lets not forget this is a combination of 1000 rpm above stock fuel cutoff for the non-VVT 3500 and a larger crank pin diameter which is documented to cause more friction as a result, and possibly a heavy piston. The total weight difference between my stock and forged piston is right at 50 grams. All of those factors come into play, GM engineers are not stupid and although hard to believe I'm sure the rod bearing tab design is not a problem for the limits they set.

We'll have to figure out how to create a firmer bearing hold or bring the revs down.

[gectek]

Yah then the rod would be rebored to stock spec...my shop calls it a competition cut. i had that done to my rods. i would def try the arp bolts, they are beautiful pieces. they would help the clamping pressure stay constant and high, instead of stretching. i just dont like the fact of the tangs facing each other and thats it. i would look at flipping the cap, machining it true and going from there.

[project89]

why not pin the bearings like i sugested earlier? its a simple small dowel pin in the rod cap with a locating hole in the bearing.

ill have to see if i can find one of the rods from the dragster and take some pics

[Joseph Upson]

Yah then the rod would be rebored to stock spec...my shop calls it a competition cut. i had that done to my rods. i would def try the arp bolts, they are beautiful pieces. they would help the clamping pressure stay constant and high, instead of stretching. i just dont like the fact of the tangs facing each other and thats it. i would look at flipping the cap, machining it true and going from there.

Another issue with the amount of metal that would have to be shaved off the cap ends of a powder metal rod before they are flush, is that the big end would have to be offset bored afterwards in order to maintain the relative rod length which will make the cap perimeter much thinner than stock and that will surely weaken the rod and make it even more prone to stretch at TDC during high revs.

I looked at my connecting rod again and I'm sure at a minimum a total of at least .100" would need to be removed from the ends reducing the diameter and at least that much would have to be restored by offset boring towards the cap making the cap that much thinner.

Take the pistons and have them lightened a few grams.

There's a lot of thought having to go in something that seemed as simple as stronger valve springs and raising the rev limit to get to the next level. Think I'll stop at 6500.

[Superdave]

The new 3500 got here today, it's from a '04 Malibu and has 53K on it. It has the 7484 crank and so far the main bearings look like new.

It has an AC Delco oil filter on it so it apepars that it was well maintained.

I also got the complete wiring harness and a few things my other 3500 was missing..

[FallenZ24]

Good to hear Dave. How much did you end up paying for that low-milage 3500?

BTW, You want to donate some 3500 heads & lim to my 3400 build?

-Joseph

[Superdave]

the first one was $610 with under 700 miles.. this one was $475 with 53K.

Right now the 3500 heads are spoken for, if he decides against them i'll consider other options.. I'd like to sell them.. but i've also been thinking about tossing in this stock 3500 and trying to see how good of gas mileage i can get.

[kflo 93 gt]

Do you have that spare waterpump outlet pipe that goes from the top of the pump and around the engine, under the throttle body, and etc? I think the 3500 one is what I'm going to have to use with my headers. The 31/3400 one just runs right into them.

[3400-95-Modified]

I may have that pipe, I'll look when I get home.

[Superdave]

I have it, i'll snap a pic later...

[IsaacHayes]

Kurt, can't you use the 3.1 pipe?

[Superdave]

Found something weird.. the #3 main bearing, cap side didn't have a tang on it.. the bearings in this engine are dated '03 while the ones from mine are dated '04. My old one has a tang.. and was in better shape so it got used.

Engine is coming to gether now, gotta torque it all down, slap the pan on and then bolt the tranny to it and drop it in.

[IsaacHayes]

Hmm. I wonder if they were revising them along the way. What was the last year for the 3500 LX9? Might want to grab one of those if I ever do a turbo 3500 LOL

[Superdave]

Hmm. I wonder if they were revising them along the way. What was the last year for the 3500 LX9? Might want to grab one of those if I ever do a turbo 3500 LOL

Both these engines were from a 2004 Malibu.. i'm guessing the latest one was a very early '04 model.


Engine is assembled and in the car, just gotta put the headers in, hook up the coolant and fuel lines and plug in everything.. i hope to have it fired up tomorrow evening.

Oh, and on a sad note.. i had to use the tining chain setup from the 3500 instead of my nice pre-99 chain. The crank gear was stuck on the old crank.. and it's at the machine shop. i used my 700 mile chain atleast.. it was in much better shape than the 50K one.


06 or 07 was the last year for the LX9..