The 93 octane 355 vortec headed motor I'm (slowly) :rolleyes: assembling will be driven to the track (20 min to 2 1/2 hours) and bracket raced 1/4 or 1/8 mile. 3.90 gear T-350 w/3000 stall 10" conv. Might get sprayed w/100-150 kit. I have cleaned out the two drain holes in the back of the valley floor area of the block. Then I lowered the bottom edge of the two drain holes in the front wall of the block (behind the timing cover) to where they are even with the valley floor. I also contoured the exit hole for the oil pump in the #5 main cap. My hopes are that this heavy pig (3750 w/me) will go a 12.70-12.80 on motor. I'm using a new Moroso #20191 pan (7 qt. w/built-in crank scraper &windage screen). Max rpm should be 6500-6600. My question is what to do about a pump ? Standard volume or hi-volume ? I'm willing to sacrifice a couple of horsepower for zero problems. But if there is no need to give up any thing then I won't. Should I reduce the amount of oil I run in the pan or stay with the 7 qts. (without filter) that the pan was designed for ? Thanks. Dave H

I have a very similar setup and have done what you have for oil return. Same pan and wind it to 7000 rpm. I use a M55 standard Melling pump. A lot depends on the bearing clearances you have. Mine are on the tightish side a just under .002". I think with .0025" you would be OK with a standard pump. Any more though and the HV might be needed. It is at idle that oil pressure is the biggest problem. Once the pump is spun up, maintaining pressure is rarely an issue.


I fill my pan to between the end of the dipstick and the "add" line. So that's between 1 and 2 qts low. If you use a HV pump, you might want to run a bit more oil in the pan but windage will be greater.

Also, I have one of the baffles that goes between the pump and the rear main. I "port matched' both the pump and the main to it.

A standard M55 Melling will work great. Good idea to remove the cover and verify the clearance between the gears and cover is close to the .002" specification.

After that, tack weld or braze the pickup tube, but I'm sure you were going to do that anyway.

Mike

Thanks for the reply Pat! graemlins/waving.gif I checked bearing clearance on the mains with plastigage. :rolleyes: Came up with .0025 plus or minus a ten-thousandth or so. I plan to switch to syn oil after a couple of months of street driving after initial break-in. My concern is in the heat of the summer with some miles on this that the standard volume may be kinda lacking at idle. I'm guessing idle will be around 850-900 rpm. Should I be concerned about pumping the pan dry with a hi-volume pump and only 6 quarts in the pan ? This was my reason for helping drainback conditions in the block. I don't want low(er) oil pressure at idle to contribute to killing the valvesprings prematurely either. I'm getting kinda funny about conserving energy these days- mine ! :D Must be this age thing. smile.gif Don't want to do this but once & don't own a trailer yet & probably won't for a while. Thanks for your help. Dave H

Hi Mike ! Thinking about a Moroso pump package too. Will definately tig pickup to pump if I don't purchase one already done.Thanks for your help. Dave H

if you have .0025 across the bottom end there's not any good reason to run an HV pump. If you have .0025 you won't have an issue with idle oil pressure anyway. Remember, at the 10lbs/1000rpm rate you only need 8 or 9 lbs at the idle speeds you're looking at.

Also, I have trouble understanding why valve springs would be damaged at idle speeds with or without oil. Now if they're run with no cooling oil at 7000, I can see where that would be a problem. If your motor has a reasonable cam and your planning to limit the RPM to the 6500 range you won't be running any edgy valve springs anyway.

Go with the standard pump with a 60lb Z-28 relief spring and you'll be fine.

Tom

Tom,thanks for the reply and the reason behind the answer! I'm probably overly paranoid about things I don't have any experience with (yet) smile.gif Dave H

Id go M55A, its the Z-28 pump. Ive had all 3 pumps in my car. The standard M55 wouldnt hold oil pressure up with the direct lube lifters so i went to a M55HV, the pressure was erratic with that, and frankly i didnt care for it. So i ditched the direct lubes, went with the M55A and pressure couldnt be better.

Whats a direct lube lifter? I've got solid lifters with the M55A pump/z28 spring.... and I can vouch for the oil literally flying out of the pushrod, so be careful with that! But pressure, thus, is awesome.

Hi Dave,
Most of the above ;)
M55A which is the standard pump with the HP spring.
You don't need 7 qts in the pan, run 5 or 6 at most.
Absolutely set the end play in the pump (.0015-.002 MAX) this will take care of low rpm pressure with reasonable bearing clearances.

Originally posted by Twilightoptics:
Whats a direct lube lifter? I've got solid lifters with the M55A pump/z28 spring.... and I can vouch for the oil literally flying out of the pushrod, so be careful with that! But pressure, thus, is awesome. =

It is a solid lifter with am EDM'd hole about .030" in the bottom to pressure lube the lifter/lobe contact area.

If I may I'd like to add one thing about this talk of oil pumps...

If you can , consider takeing it apart and after verifying it's clearence and such ... please wash it.... I have seen many oil pumps of most brands and most were filthy inside....It's amazing the junk that can be found in them.... mostly very fine oily dirt / metal.... IE the last stuff you ever want to pump right through your new engine..... It's very easy to do and worth the extra effort.

Thanks to all & : Nickel333,Twilightoptics,Wolfplace, & 69LS1 for your input & discussion of this matter! I appreciate everyone's contribution in helping me figure out what to do. Think I'll go M55A with the correct pickup for the pan. Once the pickup depth is set(I'll remove the relief spring first), I'll have a buddy TIG it in a few spots. But before I deal with the height of the pickup, I'll pull the cover off,check for trash & verify that the end play in the pump is .0015"-.002" MAX. Dave H

Originally posted by 69LS1:
If I may I'd like to add one thing about this talk of oil pumps...

If you can , consider takeing it apart and after verifying it's clearence and such ... please wash it.... I have seen many oil pumps of most brands and most were filthy inside....It's amazing the junk that can be found in them.... mostly very fine oily dirt / metal.... IE the last stuff you ever want to pump right through your new engine..... It's very easy to do and worth the extra effort. =
Thanks Al graemlins/thumbsup.gif

I tend to forget sometimes that even the obvious things probably should not go without saying,,,, :D

1, buy the pump
2, disassemble pump including pressure relief valve, inspect & set end clearance
3, recheck everything
4, check it again
5, aw hell,,, check it again :(
6, weld or braze pickup after verifying it is 3/8" to 1/2" off the bottom of the pan.
7. clean the pump
8, clean the pump again,,,,,
9, reassemble, prime & install the pump
10, recheck the pickup to pan clearance
11, torque the bolt
12 recheck everything

Ok,,, what did I miss??,,,, :D

Thanks Mike. :D Dave H

You'll probably have to use the Moroso pickup for that pan. It is an excellent unit with very heavy (10 ga or so) straps that bolt to the pump case.

Another thing I did, although it probably isn't necessary, is run sanding rolls through the outlet of the pump. This will smooth the inside surface and make a bit less resistance for the oil.

Thanks for the additional input Pat. smile.gif Dave H

I would remove pressure spring before you weld or tack on pick.Heat fron welding may weaken the pressure spring.

I would remove pressure spring before you weld or tack on oil pick up.Heat fron welding may weaken the pressure spring.