I don't see how a dry sump Nascar engine can be compared to a wet sump 351M or C, kinda like apples to oranges.

 

Tech, if you care to re-read the quotation it is discussing pressure and clearances necessary to keep an engine alive not the type of construction of the oiling system.

 

There is a dedicated oil feed line to each main cap, also a return line, besides the trays and scrapers. No shaft to get broken. That's a whole different animal compared to oil being pushed through a series of bearings from one end of the block to the other.

 

Tech- Thanks for the info but the construction of the NASCAR scavenging system is of no importance. The pressure and clearances used were the point of the quotation. As in large clearances with high volume and pressure is not required and wastes power. Not much power but a continuous loss is a waste of $$ with the high cost of fuel.

Can you help user go-racing with his oil pump problem?

BTW, I am well aware of how the oiling systems are set up on high performance engines. It may be of interest to others tho. Maybe start a thread on high performance oiling systems in the General Engine Performance & Build forum or in the Oil & Lubrication forum.

 

It's obvious to me now that I've spoke again when I shouldn't( I didn't know I could do that online,) but no thank you, feel free to start your own thread, in the end you will probably be the only one that can help him, and don't give in to gas anxiety......

 

No problem, -Always question, and question...

 

Eric, where you are getting some of your ideas I can't imagine. The High Volume kits ford used to sell were indeed intended to be used on new engines. Ford's OHO manuals recommended the kits for High performance or heavy duty usage. I think Ford would consider the trailer pulling and load carrying some of us do in our trucks to be 'heavy duty' useage. I would love to know where you are getting the notion that HV pumps are not needed or recommended for a rebuilt engine, it would seem you are getting just someones opinion, rather than fact. There are lots of folks besides me that recommend the HV pump. The 'CYA' bit makes me wonder if you understand whats going on in the block......sure I, and any other machinist can build you an engine that has lots of pressure with the standard volume pump. But building an engine with tight clearances on the crank isn't usually a smart thing to do. Your oil does more than just lube things, it keeps the bearings and crank journals from becoming too hot. Even though it might have lower pressure than some setups, the extra volume of oil flowing over the bearings will keep things cool. Sure, you can set things up with .001~.0015 clearance and have lots of pressure with a standard pump. But if you set your clearances to .003~.0035 on the mains and .0025~.003 on the rods, and run the bigger pump, you'll still have enough pressure, and the bearings will be cool and happy. If this causes me to lose another 1/4 of 1 hp, I don't care, I can make it up elsewhere. I'm thinking of durability here, not the very last ounce of power. And as to TBO, I disagree that the extra 100,000 miles of life before an overhaul is 'a small amount of extra time'. That big oilpump will keep the customer happy about his oil pressure even as the engine's bearings wear another .001 bigger than when it left the shop. You guys who are thinking of running everything tight need to keep in mind the limitations of your factory cylinderblock. The mains don't sit still and the crank flexes, more than you might really want know. When you are pushing the stock block into the 500~600 hp range, the tight cleances aren't the safe way to go. If you want to run the standard pump, go ahead, but I wouldn't if it were mine. DF, @ his Dad's house

 

Finally got it disassembled today. The pump shaft didn't break, but it twisted itself a couple of wraps. Oil pump is locked up tight. I popped the cover off of the pump gear and while I couldn't find any contaminants in there, something definitely has it jammed and I can't free it.

Cleaned the oil pan (nothing to clean, really) got new oil pump, new oil pump shaft, plugged the distributor in, new oil and filter, and we're back in business. (Which is good, because my Tbird just lost a head gasket )

 

Dino I am well aware of what oil pumps do and their many functions. HV pumps are not required for any well built engine. Please read some more and learn about those old fashioned ideas. The days of HV and HP oil pumps being "needed" are long gone. We know better now. 40-50PSI is all that is required for any system and the systems are built with stock clearances so the stock pump will supply that pressure under load. Those OHO articles are kind of old, but they have some good reference info.

Josh- Sounds like some sort of particle made it past the screen and locked up the pump. Whatever it is the particle is down in between the lobes somewhere. If you can get it apart you will find it. Knowing what it was is always nice info to know to try to avoid the problem happening again. If some part is shedding metal or some gasket sealer is getting into the system it could kill your pump again.

BTW- The system worked as designed and when the oil pump locked up the drive pin sheared cutting off spark to the engine and saving it. If the oil pump shaft breaks and the distributor keeps on rotating keeping the engine running you could have serious problems before you noticed the oil pressure...

 

.0025-.003 on a rod & .003-.0035 main is a little much, even for a big pump. .0018-.0025 rod & .0025-.0032. main are the ranges I shoot for. I'm not saying it won't work, just too loose for my liking

 

When I build I shoot for minimum bearing clearances. They only get bigger, -never smaller...

 

I got my HV pump out and the stock replacement pump installed. I went with a Melling standard volume pump and I am using Shell Rotella 15-40W oil. Cruising down the road at 65 mph and the engine turning about 2600 RPM, I have 55 psi oil pressure. At idle, I have around 25 psi oil pressure.

With the HV pump I was about 70 psi oil pressure at 65 mph, and around 30 psi at idle. However, that was with 10-40W oil, not "much" difference than what oil weight I am using now.

I thought I would just relay my results.

 

That sounds like real good pressure! -Thanks for the info.

 

I thought it was good too and figured a few guys might like to hear about it