Just my luck...

[merlot566jka]

Whats that from????

one of the three 3.4 iron heads i had in the fiero. all iron head engines were lost due to bearing failure. cam bearings, rod, main, you name it...it failed. thats with rotella and crane break in lube.

i even had the last 3500 spin a rod bearing, but that was a combo of fuel diluted oil and piston to head contact (who woulda thought rods stretch at 7K enough to allow a piston to define its .020 quench area??)

[3400-95-Modified]

I've read a few other places, that Rotella, yes has the extra zinc but its not made for high rpm motors, the structure of the oil is setup right to protect bearings and such against high loads of a higher RPM since its engineered to be in a motor that ranges from probably 1-4k on a daily basis.

We used to run Rotella in our race motor and we had problem after problem with it... or at least it appeared that way to me. Valve guides would constantly wear out in 2 weeks... bearings wouldn't last that long, lifters would keep breaking, and then finally a wristpin let go on one of the pistons, never lost a cam lobe tho ... Now with our crate motor we run whats recommended, the 15w 50 Mobil 1

[Joseph Upson]

i even had the last 3500 spin a rod bearing, but that was a combo of fuel diluted oil and piston to head contact (who woulda thought rods stretch at 7K enough to allow a piston to define its .020 quench area??)

I resently read that piston to valve clearance should be around .100 although it wasn't specific for the V6, are you sure the piston to head contact didn't occur as a result of the bearing wearing out? Perhaps oil pressure should be raised a little with more tension on the pump spring.

[pocket-rocket]

I've read a few other places, that Rotella, yes has the extra zinc but its not made for high rpm motors, the structure of the oil is setup right to protect bearings and such against high loads of a higher RPM since its engineered to be in a motor that ranges from probably 1-4k on a daily basis.

The Detroit Diesel in the Century Class Freightliner I drove for Arrow Trucking redlined at ~2300 rpm IIRC, although they always told us to stay away from Rotella for some reason but I don't remember why.

[ForcedFirebird]

I resently read that piston to valve clearance should be around .100 although it wasn't specific for the V6, are you sure the piston to head contact didn't occur as a result of the bearing wearing out? Perhaps oil pressure should be raised a little with more tension on the pump spring.

I believe he had piston to head clearance issues with the .020" quench, that would sure kill a bearing at 7k rpm.

[gpse3400]

I have built my fair share for high RPM GEN 3s..Only one of them lasted an appriecable amount of time. The only thing that was different was the usage of matched pistons on one engine as opposed to the other. If the Twin Cam can last running up to the 7K and get 200K+ accumulated milage so can the pushrod motors...What I'm getting at is that the Twin Cam was probably balanced out to wind that high. That's what the the pushrod motor needs if you are going to increase the operating range. The next time I build an engine..if I even bother to change the cam I will get it balanced out. BTW an HV HP oil pump will not solve this problem.

A good practice is to toss the rod if the bearing spun in it as you not only change the ID but you sctratch it all up an induce an uneven load surface. Of coarse if you remove the the con rod an install another the factory balance is gone. I really feel this is very important. Nominal engine speed is up 6000 on the GEN 4. I guess we can call it that now? Maybe 3.5? Out of balance at 7000 is exponentially worse.

[Joseph Upson]

I have built my fair share for high RPM GEN 3s..Only one of them lasted an appriecable amount of time. The only thing that was different was the usage of matched pistons on one engine as opposed to the other. If the Twin Cam can last running up to the 7K and get 200K+ accumulated milage so can the pushrod motors...What I'm getting at is that the Twin Cam was probably balanced out to wind that high. That's what the the pushrod motor needs if you are going to increase the operating range. The next time I build an engine..if I even bother to change the cam I will get it balanced out. BTW an HV HP oil pump will not solve this problem.

A good practice is to toss the rod if the bearing spun in it as you not only change the ID but you sctratch it all up an induce an uneven load surface. Of coarse if you remove the the con rod an install another the factory balance is gone. I really feel this is very important. Nominal engine speed is up 6000 on the GEN 4. I guess we can call it that now? Maybe 3.5? Out of balance at 7000 is exponentially worse.

Very good point, especially when considering mass produced engines which are at the mercy of the machining equipment and factory allowable tolerance for moderate performance.

I noticed the crankshaft in my current engine when installing the 7x ring had an obvious bluish area indicating the crank got very hot at that location. Since the engine had about 3k on it and another identical low mileage crank 6k, did not have any blemishes at all characteristic of an overheated area, I had to conclude the machining equipment was to blame.

An episode of How It's Made showed the machining process and made it clear that this is a very real possibility. Who knows how hard times is affecting production.

[TurboGTU]

Only other way of spining a bearing is from too much knock. The old ford OHC 4.6l had that problem. On thise it could be from load and knock during tunning. Not saying thats what caused it but a possibility. The other is from oil starvation during hard acceleration or turning.

[Superdave]

Considering it happened while going 0 to 105 MPH in 13 sec i'm pretty sure it was oil starvation.. lol

I've never had a problem with knock in PE mode, just the occasional one if i revved up the car no load or hit the rev limiter (didn't happen on the track).

what do you guys think about running something like Slick-50 or another additive to help out incase it tries to happen again?

Currently it's got Penzoil 5W30 in it...

[3400-95-Modified]

You might want to run a heavier oil with more additives in it... I'm running Mobil 1 15w50 currently. It might work better than the Slick-50. I've heard good things about that but its not the fix all.

[Joseph Upson]

Considering it happened while going 0 to 105 MPH in 13 sec i'm pretty sure it was oil starvation.. lol

I've never had a problem with knock in PE mode, just the occasional one if i revved up the car no load or hit the rev limiter (didn't happen on the track).

what do you guys think about running something like Slick-50 or another additive to help out incase it tries to happen again?

Currently it's got Penzoil 5W30 in it...

What is the possibility that such an high rpm is actually pumping the pan low enough to cause starvation. Also who knows what combined effect the oil squirter bleed off may have at high rpms with the stock pump. The oil pump for the 3900 is bigger than any other I've seen. I didn't think to take a picture of it when I had the pan off. I know it has to compensate for any pressure loss due to VVT but I'm not sure if the VVT phaser causes as much a drop in oil pressure due to its need for a resisting outflow to work properly compared to the squirters which start to do their thing at certain oil pressure. That is basically a regulator type function which can actually limit the amount of pressure you can build. Perhaps as I mentioned earlier switching to Mobil 1 as used in the high revving 3.6L and a heavier oil is necessary.

[pocket-rocket]

I remember reading about a speed shop having problems with the 4G63 engines in the turbo DSM's. No matter what they did the engines developed crank walk, even after 5k miles. They ended finding out that the oil squriters were supplied off the main oil gallery and that the springs that were supposed to keep them closed below a certain pressure was worn out causing them to open at a much earlier pressure, starving the crank of oil. I have no idea if this is related/helps but it's something I remembered about when oil starvation was mentioned.

[Monzsta]

Very good point, especially when considering mass produced engines which are at the mercy of the machining equipment and factory allowable tolerance for moderate performance.

I noticed the crankshaft in my current engine when installing the 7x ring had an obvious bluish area indicating the crank got very hot at that location. Since the engine had about 3k on it and another identical low mileage crank 6k, did not have any blemishes at all characteristic of an overheated area, I had to conclude the machining equipment was to blame.

An episode of How It's Made showed the machining process and made it clear that this is a very real possibility. Who knows how hard times is affecting production.

The bluish area you are seeing on the journals is probably from the induction hardening process. This electrically heats the bearing surfaces, then the crank is quenched to increase the hardness of the surface, leaving the metal at the cheeks blued. Usually the blueing is removed with media blasting or subsequent heat treatings, but most time it remains. If a journal actually welds in service the metal turns black with charred oil.

You can see the blueing on the cheeks of the throws from the hardening. Iron cranks don't undergo this process.

[gpse3400]

Considering it happened while going 0 to 105 MPH in 13 sec i'm pretty sure it was oil starvation.. lol

I've never had a problem with knock in PE mode, just the occasional one if i revved up the car no load or hit the rev limiter (didn't happen on the track).

what do you guys think about running something like Slick-50 or another additive to help out incase it tries to happen again?

Currently it's got Penzoil 5W30 in it...

I have to disagree with you/ Respectfully I think your engine failed because you exceed the bottom end speed of the engine. You put in an HV HP pump, it will just happen again plus you will lose power to running that. Thicker oil may help some but 7000RPM + is just way more than what the factory wanted that engine to run. Power output is relevant but not the whole reason. I really recommend you balance that motor out. If you do not it will fail again and sooner. If you haven't done so I'd be checking the other bearings as well. Dont be so quick to button this all up, you have nice setup, make it work well. I'd also take a look at those cam bearings too.

[Superdave]

i'm not running a HV pump.. it's the stock pump from the 3500.


LOTS of people rev these engines up to 7K, I've seen them pushed to 8K before.

the stock rev limiter is like 6400 RPM, at the track i shift at around 6500-6700 so it's not like i'm exceeding any limits of the engine. When i re-ported the heads this year the engine seems to have a different RPM range, last year it would pull like crazy to the limiter and this year it pulls even harder till about 6500 ish then drops off. It seems to have helped my track times.. .7 faster with some adjusted heads and a larger TB isn't bad...

Either way, the engine is coming out before next season.. but i fully plan on pushing it hard till the tracks close. If it breaks, I won't be upset.. It's just a toy.

I'll be changing the oil tonight with RP 15W40 and a new Delco filter.