more later

Compedgemearine:

The two different comments about bearings are not directly related.
First, the stock crankshafts in GM engines and the newer Gen 6, Gen 7 (8.1L-496) engines have small rolled fillets on the journals unlike most afgtermarket crankshafts which have larger radius fillets ground into them that require a bearing that is champferd on each side edge to keep the bearing surface rom riding up on this larger radius fillets on the crankshaft journals. These crankshafts need to be fitted with the H-series bearings which have these larger champfers (narrower bearing surface width). However if these narrower bearing surface H-series bearings get used on the small almost no- existant fillet crankshafts the mating will create a big side void and the bearing will allow a great deal more oil to be thrown out the side of the main bearing or rod bearing. This can also greatly reduce oil pressure, create reduced volume of oil to required oiling areas and other windage and oil consumption issues in the engine improperly equipped.
Second: "Alumina" series bearings are bearings that have been developed to get rid of lead babbit material backings in older engine bearings that had to be removed for hazordus materials laws and regulations. The alumina series engine bearings use an aluminum alloy with high silicone contnet to create better surface hardness on the bearing. As it turns out the new manufacturing technology in thse bearings also creates some new benifits which we have found and believe are beneficial in the newer engine types. The surface of these bearings actuall y have a micro-grooved surface that actually aids in oil retention on the bearing surface to create a better oil "cushion" between the bearing surface and the surface of the crankshaft bearings. Older smooth surface bearings have a difficult time maintaining this oil 'cushion bearing and are more prone to blowing oil off the bearing and allowing more surface to surface contact.
The newer crankshafts being produced today have great induction harfened surfaces going as much as +060" deep into the journal material. When a crankshaft like this is straight and the journals are exactly round and uniform dimensions when it had the harder surface alumina bearing the crankshaft surface tends to show almost no normal grooving and irregularities and the journals tend to get micro-polished by the bearing. The next added benefit is the harder surface of the bearing does not allow much if any particle dirt, soft metals and carbon imbedment in the bearing surface like we would see in the older Tri-Metal bearings. This debris in a correct rotating assembly equipped with the "alumina" bearings tends to be spit out into the oil where the filter can remove them instead of them staying on the surface of the softer bearing and etching and grooving the bearing and journal surfaces. This I feel is why when you breakdown some of these new so equipped engines today you tend to see in undamaged engines bearing journals on the crankshaft with nominal wear and jounals that look almost like new.
I think much of this is an un-intended side benefit of the new required bearing materials. We use them exclusively in the 496-8.1L and LSX series engines we build , with many years now of excellent results and reliability.
Kind of a wordy explanation, but its important to explain the real technology here for all.

Best Regards,
Ray @ Raylar

thanks Ray, I have built a lot of engines but all older MK4 and small blocks and Olds and Pontiac stuff. I have never played with any of the new 8.1's but I always like learning new things so I appreciate the wordy answer. never too old to learn something new.
steve

SD Fever,

Thanks for your input.

I seem to recall a conversation that we had a while back about engine oil temperature where I thought you said that your's did not get too hot because when it got to ~250F I think it was you just reduced from WOT and that you never ran at WOT 15 min. Am I remembering correctly or not?

First of all your pictures show a beautiful engine and paint job. I am jealous.

However what I also see is the stock Merc 496HO (425hp oil cooler) still there with your Raylar HO600 600hp+ engine upgrade. Are you nuts? No wonder you have to shut down WOT runs early. I ran my 625hp engine with that stock oil cooler and during extended WOT runs ( that you do not do because the oil temp spikes) I melted lots of things and oil pressure went down the toilet. That is why I installed the 700hp Hardin Marine 3x18 oil cooler ( I wish I had picked the 1000hp unit) and AN10 lines and fittings. I can not believe that Raylar did not tell you that the stock Merc 496HO oil cooler and lines and fittings were inadequate. So much for state of the art engineering.

Interesting. Federal-Mogul would be pleased (my former employer and the OEM Alumina Silica bearing manufacturer of which you speak). Since I am using your Raylar aftermarket SCAT forged stroker crank and not the OEM crank of which you speak I guess all this high tech does not apply to me and my issues described in this thread. Nice advertisement though.

The alumina silica bearings are hard as a rock the tri metal bearings are more tolerant (protect the crank)of metal to metal contact.

Hey man thanks a lot for this info!!!!!!!!!!!!!!!!!!!!!1

I checked it . It is working properly.

Thanks. Right now I am in Florida and the boat/engine is in Missouri. Later.

Since the oil flow rate would still be the same with the main oil pump system do to the bearing clearances and the current cooler is already cooling the oil that goes through it now to the thermostat setting of 190F regardless of how hot the oil is going into it so a bigger cooler would do nothing but take up more space and $$$$.