Hey guys I was looking for a good upgrade for our connecting rods. I found some good ones but they say for the Holden L67. I am assuming that we can use parts from those seeing as how they are a L67. Is this correct? Below is the link.



Holden L67 V6 3 8L Supercharged H Beam Connecting Rods | eBay

 

I have never seen a set up need anything stronger then stock.

 

Well with this being the 3RD engine build I just want to not hold back on anything. And I am doing forged pistons so figured why not forged rods as well. I need new ones anyways. I just need to make sure these will work.

 

You would have to check this, but to my understanding, GM used forged connecting rods in the '05+ series 3 3800's (but not in the '04). Perhaps a series 3 donor would be the way to go. Just a thought.

 

You don't need 'upgraded' connecting rods... seriously. From what I remember from the other thread, you're planning to run an M90, so you will never have to worry about a connecting rod failing from too much power.

You want some hardcore bulletproof rods- you can call up any of the big rod shops, and they'll make you some really hardcore rods if you've just got tons of money to blow. Heck, may as well go with that $4k stroker kit with the forged crank too (sarcasm). But the simple fact is that you don't need them.

I really doubt you're blowing all these engines from too much power- something else is wrong here. There was a building error, tuning error, mechanical problem (ie dying fuel pump, etc). Mildly modded 3800s just don't come apart like that (well not unless they've had the bottom end opened up). Sure you'll get a oddball OEM failure here and there- but if you've blown 3 3800s, something else is seriously wrong- nobody else is blowing that many engines.

Also, skip the forged pistons- seriously. You don't need them either. Keep the car from knocking itself to death and you won't have to worry about them chipping apart at the ring lands. People have made HUGE power on stock pistons. Plus, if you go that route, now you've got to have the bottom end rebuilt- which again is bad news for a 3800- especially with the recent experiences you have.


Honestly, before you waste all kinds of money building a 4th engine- my recommendation is the same as the other thread- get a GM replacement engine, get an experienced mechanic to install it, and just drive the car as it is. You don't want to go the route of another questionable rebuild. I would normally recommend getting a used OEM engine, but I know how against that you are. You want a bottom end that has never been opened up though- by anyone, used or new.

I'd just be real careful- with how much money you've got in rebuilt engines and such- you probably have more than the car is worth just tied in engine rebuilds?

My point is- let history be your guide. There are a lot of other people that have went down that same path you have of thinking that they're going to build some crazy bottom end, but at the end of the day, you'll have a less reliable engine- and will spend tons of money for no more power...


Not true. The series 3 engines got powdered metal rods, which could be loosely interpreted as being 'forged' together- but the strength is nowhere near a real forged rod. In fact, the L26 rods are known to be the weakest rods available in a series 2/3 3800. L32 rods aren't as terrible- but I certainly wouldn't rebuild a bottom end to install them.

 

Well when they all fail under high speeds. They are fine off the line and anything under 120. as soon as I hold it at 140 or more for a little bit they go.

 

How much knock are you getting at 140?

 

I have no guages to read it. I know I should get some. But I cant imagine that much if when it spends hours on the dyno it gets 0-1.

 

I'm confused here. You're trying to say when you hold the car over 140 mph, the rods fail? That doesn't make any sense... There are 3800s on stock bottom ends that do over 120 in the 1/4 mile alone- why don't they seem to have any issues?

My second question is why are you holding over 140? These engines have a terrible top end, especially with the M90- I just don't see the point in holding it that fast, and pushing it that hard. Especially if you're doing this multiple times- it sounds to me like you're just beating on the engine for no reason.


That doesn't make any sense either- you're looking at $750+ in aftermarket rods on ebay, but don't have a simple way of monitoring KR? Looking at your mod list, you have thousands of dollars invested between the sound system, two sets of wheels/tires, appearance mods, and a ton of engine mods. Seriously- sell the lifters or aluminum valve covers or something that isn't adding power, and get a cheapo used aeroforce or something.

Plus, dyno tuning doesn't do a good job at simulating crazy high speed runs- running 140+ as you claim, all that wind resistance is really increasing the load on the engine- and sitting there 'holding it', you're increasing the temps on all the parts and such that are already under extreme load.


I pulled up your old posts to see if you posted why your last 2 engines failed, and here is what I found:

Engine 1: 3/1/12
Engine 2: 1/23/13

Sounds to me like rods are the least of your concern. Your first engine was destroyed by abuse from the sounds of it, and the second one sounds like a valve issue.

So, I don't understand where this huge issue of rods failing over 140 mph comes from, same for the forged pistons too... If you're trying to go that fast- seriously just buy a car that is built to do that kind of speed- pick up a used C5 or C6 or something- just keep in mind that no car is going to last being beaten on.

 

Its obvious that something is up if you blew up 3 3800's. They only fail if you abuse, just like every other good car out there. If your going to tune, do it right. Start off slow & don't do unnecessary things. (such as rods that don't need to be replaced)
Plus, 140MPH for any amount of time for these cars is just...crazy! Yea, I love the thrill & all of triple digits but I would never push it longer than a few seconds!