Lost a Motor last night.

Originally Posted by n2omike

351W's NEED extra bearing clearance because of their huge 3" size. I would look for 0.003" and would be using 3/4 groove racing bearings. Unless you are using watery thin oil, I would look for between 0.0030" and 0.0035" on the mains. 0.0025" on the rods.

Install a high volume pump for insurance, and add a large BAFFLED oil pan that will provide a total capacity of around 8 quarts. Canton makes some nice units. Get one that is either DEEP and narrow, or has the 'roadrace' baffles. 'T' pans with wide bottoms and no baffles are NOT good when the oil gets sloshed around.

As for the accumulator... not a bad idea, but address the above first.

Good Luck!

Thanks, we had all of above. The pan was seven quart though.
One thing, the 3" mains looked perfect. It was the number two rod
bearing that failed.

Originally Posted by n2omike

351W's NEED extra bearing clearance because of their huge 3" size. I would look for 0.003" and would be using 3/4 groove racing bearings. Unless you are using watery thin oil, I would look for between 0.0030" and 0.0035" on the mains. 0.0025" on the rods.

Install a high volume pump for insurance, and add a large BAFFLED oil pan that will provide a total capacity of around 8 quarts. Canton makes some nice units. Get one that is either DEEP and narrow, or has the 'roadrace' baffles. 'T' pans with wide bottoms and no baffles are NOT good when the oil gets sloshed around.

As for the accumulator... not a bad idea, but address the above first.

Good Luck!

Just a point that we learned.
We have had problems running a high volume pumps at high rpm sheering the pin on the distributor gear. There is really no need to run a high volume unless your running coolers. We have switch to a HIGH PRESSURE, to insure we have 10lbs per 1000 rpm of engine speed. Havn't lost a engine to bearing failure in 10 years. It's pressure that maintains the oil clearance at RPM not volume. Just what works for us.

Jeff

Originally Posted by JN-Motorsports

Just a point that we learned.
We have had problems running a high volume pumps at high rpm sheering the pin on the distributor gear. There is really no need to run a high volume unless your running coolers. We have switch to a HIGH PRESSURE, to insure we have 10lbs per 1000 rpm of engine speed. Havn't lost a engine to bearing failure in 10 years. It's pressure that maintains the oil clearance at RPM not volume. Just what works for us.

Jeff

I worried about the dist pin, I changed the Duraspark oem gear to a steel gear to be compatable with the solid roller cam. MSD supplied an 1/8" roll pin,
the OEM was bigger.

We did have a high volume-standard pressure pump, it didn't shear the the dist gear, but I wonder about the point you made. There may have been a lack of pressure at high rpms. Something caused our bearing failure, I need to
prevent it from happening again.

Greg,
What we found just by chance is the amount of drag and hp anchor it is to spin a High Volume pump and it gets terrible if you put a high pressure spring in a H/V pump. We had a 10hp gain by going to a high pressure pump. The 10lb per 1000rpm rule is something we've used for years. There are a lot of racers that say since synthics have emerged that rule dosn't apply anymore. Don't care, the 10 per 1000 rule has save my wallet.

Jeff

Originally Posted by JN-Motorsports

Greg,
What we found just by chance is the amount of drag and hp anchor it is to spin a High Volume pump and it gets terrible if you put a high pressure spring in a H/V pump. We had a 10hp gain by going to a high pressure pump. The 10lb per 1000rpm rule is something we've used for years. There are a lot of racers that say since synthics have emerged that rule dosn't apply anymore. Don't care, the 10 per 1000 rule has save my wallet.

Jeff

Jeff,
I was aware of the rule. I did not expect this motor to wind up with such ease. I figured it would be done by 5500-6000 rpms. We were just running regular 10-30W oil, no synthetic's. I think a high pressure pump is one of the change's we will definately make.
I am considering a higher strength rod than the Probes we had last time also.

What are you doing for your next motor?


This post is getting way long, and I still need some insite on other damaged engine parts that happened when we lost our motor so I think I will start a new post on those subjects.

Thanks for all of your help,
Gregg

Greg,
This is our last probe rod in a 13.5:1 358 Cleveland, after three passes, 8740 bolts and came apart at 7200... Called ARP and they will tell you that 8740 bolts are only good to 7000. We run Olivers now with 2000 series bolts. Will never run a probe product again.

Jeff

Wow! Our rod bolts lived but the big end broke of like yours.

The Nascar boys run the RPMs way up. Our motor pulled like nothing I have been around, I think we got very lucky on the combination and
you had way better rods than my son and I, and we were bouncing this thing off the 7000 rpm chip with ease. No valve float, no problem.

I wonder now....do we need ultra high buck rods?

Everyone needs to do what they are comfortable with, but I do not understand why people are affraid of a HV pump vs HP pump.
The spring is what dictates the pressure, it has nothing to do with the 25% extra volume that a HV pump is capable of suppying. If you set a standard pump, a HP pump and a HV pump all to 65PSI, it will take the same amount of energy to spin all 3.
The reason I like a HV pump set up properly is, if the bearings clearence is loose, the oil gets thin and the engine needs some extra volume to keep the clearences filled with oil, at least the HV pump is capable of suppying extra oil, where as a HP or standard pump may run out of volume.
I do not like running HV pumps with stock pans, only if the pan capasity has been increased or if an accumulator is used.
Not trying to start an arguement, just throwing in my 2 cents.
Rick

Originally Posted by Bfast

Everyone needs to do what they are comfortable with, but I do not understand why people are affraid of a HV pump vs HP pump.
The spring is what dictates the pressure, it has nothing to do with the 25% extra volume that a HV pump is capable of suppying. If you set a standard pump, a HP pump and a HV pump all to 65PSI, it will take the same amount of energy to spin all 3.
The reason I like a HV pump set up properly is, if the bearings clearence is loose, the oil gets thin and the engine needs some extra volume to keep the clearences filled with oil, at least the HV pump is capable of suppying extra oil, where as a HP or standard pump may run out of volume.
I do not like running HV pumps with stock pans, only if the pan capasity has been increased or if an accumulator is used.
Not trying to start an arguement, just throwing in my 2 cents.
Rick

Yep +1

Originally Posted by Bfast

Everyone needs to do what they are comfortable with, but I do not understand why people are affraid of a HV pump vs HP pump.
The spring is what dictates the pressure, it has nothing to do with the 25% extra volume that a HV pump is capable of suppying. If you set a standard pump, a HP pump and a HV pump all to 65PSI, it will take the same amount of energy to spin all 3.
The reason I like a HV pump set up properly is, if the bearings clearence is loose, the oil gets thin and the engine needs some extra volume to keep the clearences filled with oil, at least the HV pump is capable of suppying extra oil, where as a HP or standard pump may run out of volume.
I do not like running HV pumps with stock pans, only if the pan capasity has been increased or if an accumulator is used.
Not trying to start an arguement, just throwing in my 2 cents.
Rick

Well, I hate to say this. but I beg to differ. H/V oil pumps have a larger (taller) gear set than a stock pump there for more contact surface which mean more drag requiring more effort to turn the gear. You can feel this if you have ever primed a engine by hand. Then place a 100lb spring on a H/V pump and hand prime an engine and you'll go holy cow!
If your in a habit of blueprinting an engine then your oil clearances will be fine for a stock pump with a higher pressure spring. I have had experiences at high rpm with a 25% increase volume H/P pump bending the spring pin on the distributor gear changing my timing by 15 degrees..
To each thier own.. I know what works for us and we run some 650hp 408 clevelands at 8500 rpm every pass.

Jeff