Just my luck...

[Joseph Upson]

I have been hearing more and more lately of guys going to 0W30 on these engines to avoid the slow oil pressure build up.

Any thoughts on this?

And hey Dave. My buddy has a 3400 auto '89 Cavy and may be looking for a chip.

How much and what other info do you need?

asylummotorsports@yahoo.ca

I was thinking going even lower than that 0W-15 but I believe it depends on how tight your engine is in that with the decreased viscosity you'll have easier flow and lower oil pressure. I recall it from a performance oil test that measured horsepower loss based on oil viscosity and faintly remember as much as a 5hp difference between it and 20W50.

That being said as long as oil pressure meets or exceeds by a small amount the demands of the engine there is a lot of benefit to it particularly from a fuel efficiency standpoint.

The downside is the valve components are likely to be louder, haven't heard anything on dependability pros/cons.

Found my answer, and make that 10 hp difference though this is not the article I referred to earlier;

http://www.hotrod.com/shop4parts/hrdp_0404_hot_rod_product_testing/index.html

[merlot566jka]

it happens to the best of us

[IsaacHayes]

Whats that from????

[onefastV6]

Did GM cheap out on bearings with the 3500?

[3400-95-Modified]

the fractured 3500 cap still has those notches to prevent the bearing from spinning correct?

[ForcedFirebird]

the fractured 3500 cap still has those notches to prevent the bearing from spinning correct?

Yes, but as I mentioned earlier, I spun the same bearing twice, those tabs don't hold in the case of detonation

[discostu]

Delete me.

[discostu]

I have been hearing more and more lately of guys going to 0W30 on these engines to avoid the slow oil pressure build up.

Any thoughts on this?

This is absolutely 100% correct. I just finished my 1st year of schooling for the Parts Technician apprenticeship a couple months ago. In class we watched a video of a Cold Weather Testing Facility where they test engines and oils in cold temperatures.

They showed an OHC engine with the valve cover replaced by a clear plastic cover that had been in -20C for 12 hours (basically sitting overnight). It showed that it can take anywhere between 20 seconds to OVER 1 MINUTE for some 5W30 oils to reach the cam bearings. They did the same for a 10W30 oil and the engine started smoking under the plastic valve cover and screeching loudly from the metal to metal contact.

They also showed a pour test of different weight oils that had been cold for different lengths of time, they had bottles of oil and flipped them over at the same time on a little rack. It's crazy how slow the oil even POURS when it's that cold. 0W30 was pouring immediately, but even 5W30 took like 10 seconds to pour. 20W50 took like 45 seconds to even pour out of the bottle at that temperature, and it looked like a big gob of goo coming out of the bottle.

I personally will NEVER run any less then 0W30 in the winter, in any vehicle. Not even 5W30 is enough to satisfy me.

[Monzsta]

I run 0-40 M1 synthetic myself. 30w is a little thin with the punishment I dish out. The SAE designation of 30w is measured at 212°F. As your oil heats up, the viscosity thins out, and the only difference between a 30w and a 20w is about 50 degrees! Being it's not too hard to see 300 degrees oil temperature hot lapping the car at the track, you're looking at a realistic viscosity of 10W at 300 degrees for a 10w-30. Run the thicker stuff. If I had Dave's build, I'd have 20W-50 in it.

[Monzsta]

Did GM cheap out on bearings with the 3500?

They made the crank rod journal so large in diameter the rod is probably weaker, and the big end is streatching, pinching the bearings onto the crank at the parting line. Once the oil film is broken and the metal begins to friction weld to the crank it simply overcomes the little tangs and goes for a spin.

Here's an interesting set of videos that show the stresses in an engine.

http://images.google.com/imgres?imgurl=http://www.vrvis.at/scivis/IASTED2004/images/crankshaft-withglobal.gif&imgrefurl=http://www.vrvis.at/scivis/IASTED2004/&h=480&w=640&sz=112&hl=en&start=11&um=1&usg=__sq4ScdfNDxRoTo6xkQru3GIbzJA=&tbnid=qOcD_7F7-NTjtM:&tbnh=103&tbnw=137&prev=/images%3Fq%3Dcrankshaft%26um%3D1%26hl%3Den%26safe%3Doff%26client%3Dfirefox-a%26rls%3Dorg.mozilla:en-US:official%26sa%3DG

[3400-95-Modified]

I run 15w-50 Mobil 1 in my toy car now too... The 5w-30 was making too much valve chatter when warmed up

[Joseph Upson]

They made the crank rod journal so large in diameter the rod is probably weaker, and the big end is streatching, pinching the bearings onto the crank at the parting line. Once the oil film is broken and the metal begins to friction weld to the crank it simply overcomes the little tangs and goes for a spin.

Here's an interesting set of videos that show the stresses in an engine.

http://images.google.com/imgres?imgu...icial%26sa%3DG

There is some good dialogue going on here that's lending lots of credibility to my planed upgrades, oil cooler, bigger radiator 180 degree max engine and oil temps.

I doubt the rods are weaker given the powder forging info I have read says they are stronger than the previous production con rods and GM trusts them to about 6400 rpm in stock settings so there is something else possibly causing the problem.

I felt the rod might be a little reduced in strength due to the increased length, but when I did the calculation taking into consideration that in order to increase the big end and small end diameters of the rod, you have to take away metal from the rod in between those two points.

On the 3900 at least since it has a bushed pin I calculated a center to center increase in load bearing rod length (center section connecting the ends) of .016, so the larger pin holes are responsible for the bulk of the length increase.

The larger journal causes more drag because the speed at which the pin surface turns past the bearing surface is much faster as a result of the increase in centripetal speed. Perhaps its an oiling issue at the higher rpm and pressure needs to be increased.

I say compare the type of bearings used in the 3.6 with a 7k fuel cutoff to those used in the 3500.

Note also that the 7k version is only found in the Cadillac and unlike the other applications the cadillac has a GM recommended synthetic oil application and as mentioned regarding how viscosity decreases linearly and inversely with heat increase which I imagine is pretty hot between the bearing surfaces at 7k, perhaps a switch to synthetic is in order.

And as mentioned earlier, maybe the timing is to aggressive at the higher rpm or possibly a mix of that with the inability to even control timing and other factors at that level depending on the code being used.

[Superdave]

it could just have been a simple piece of contaminate that got through the filter and was in the #1 bearing at the wrong time...

Anything is possible and we'll never know. It runs now and hopefully it'll stay running till the end of the year.

[Wiz85]

I've spun a few bearings in my day and I came across an article in my CHP magazine that said that in the past couple of years, EPA for some odd reason took phosphorus and zinc content out of "off the shelf" engine oils. Which is making old hot rodders cams go flat and bearings spun. Their solution, easiest is to run diesel oil (still has zinc), or use aftermarket race oil like Amsoil, Joe Gibbs oil, Royal Purple race, etc., or use oil additives like PX3, Lucas, Z-max, etc. In the past for me and still this way, I am running a 50/50 ratio of SAE 30 oil with 15W-40 diesel oil, that way I have the advantages of low viscosity and zinc. There my been a better solution than what I got and could be wrong on some info, but it's worked so far.

[3400-95-Modified]

Zinc being reduced, not removed is a true statement, we run into that issue with the race motors we run... We are told to use diesel oil too, but the new crate motor says to run 15w50 Mobil 1, so we may have to find a zinc additive to just have that piece of mind.

just found out 15w50 has 1200ppm of phosphorous, where the standard 5w30 oil has 800ppm.... so maybe the 15w50 is comparable to the diesel oil's

Rotella-T is also now only testing at 1200-1100 PPM of phosphorous, so according to those numbers the Mobil 1 15w50 is comparable to Rotellla-T, that weight of Mobil 1 is also recommended for flat tappet applications since zinc is really necessary and desired in those types of cam motors. FYI you 3.1 guys