I believe you are right. I think all of the new ones are already higher volume than the standard pumps. Then there is a high volume pump that is even more high volume. If that makes sense?
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| Best Oil Pump for HP Street Use? https://slantsix.org/forum/viewtopic.php?t=61748 |
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| Author: | csheehy [ Wed Dec 20, 2017 7:01 am ] |
| Post subject: | Best Oil Pump for HP Street Use? |
I'm looking for oil pump recommendations for a spring 230+ HP rebuild. All the pumps look the same to me, perhaps some of you have had experiences with most of them and can vote your fave? Stuff I think you should know: mechanical lifter engine, I will be grooving lifter bores, using lifters with oiling hole on the face, KB-239 pistons, chamfered crank bearing for timing chain oiling, around 3.5" bore, moly rings, and considering zero-gap for #2 ring since this is a non-racing engine. Skirts and cam will be dry film coasted. Did I miss anything? Thanks all! -Chris |
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| Author: | Dart270 [ Wed Dec 20, 2017 8:18 am ] |
| Post subject: | Re: Best Oil Pump for HP Street Use? |
Sounds like you are being careful here on many points. This may sound funny, but we still do not know if ANY aftermarket/rebuilt pumps will be reliable in a Slant 6 engine due to the oil pump gear problem (hardness...?) that cropped up in the late 1990s or early 2000s. One possibility would be to pick up a stock or HV pump (new or rebuilt) and send it to Doctor Dodge for installation of a hardened gear. Personally, I like things simple and things that work. If you have a USED pump that you know was working well and the gear looks good, just use that. Shim up the relief spring with 1/16" to 1/8" of washers to get 60 psi at 2500+ RPM and go with it. Nothing fancy is needed here. Also, if you are building an engine you will rev above 5000 RPM, then I suggest using an oil pump WITHOUT the standpipe for better flow. The two engines that I have ever observed oil pressure problems or had bearing issues had the standpipe, and all my other performance engines do not ("do" means they are still running 15-30 yrs after being built!). A stock or high volume pump should work fine, as long as it has been run in an engine and has a good gear. What bearing clearances will you request from your shop? Is this a cast crank or forged crank motor? Assuming forged, I recommend 0.0020 - 0.0022" on the rods and 0.0018-0.002" on the mains for such a build. Hope this helps, Lou |
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| Author: | SpaceFrank [ Wed Dec 20, 2017 8:20 am ] |
| Post subject: | Re: Best Oil Pump for HP Street Use? |
I wouldn't go zero gap on any of your rings unless you want them broken as soon as the engine gets even a little warm. Even in a stock motor there are gap specs for a reason. I've used the Melling 66C with success, but I may have been lucky with gear meshing and a well-made cam gear. |
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| Author: | Joshie225 [ Wed Dec 20, 2017 9:58 am ] |
| Post subject: | Re: Best Oil Pump for HP Street Use? |
Lifters with EDM holes in their faces will do you zero good as there is no pressure to force oil through the hole. Save your money. |
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| Author: | Dart270 [ Wed Dec 20, 2017 10:12 am ] |
| Post subject: | Re: Best Oil Pump for HP Street Use? |
Good catch, Josh. Stock lifters will do just fine. Lou |
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| Author: | afastcuda1970 [ Wed Dec 20, 2017 10:20 am ] |
| Post subject: | Re: Best Oil Pump for HP Street Use? |
I have to wonder how many companies are actually manufacturing an oil pump for a slant. How many are just slapping their sticker on the box? I haven't researched it but it doesn't make sense that so many different companies are making such a low demand part. |
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| Author: | csheehy [ Wed Dec 20, 2017 12:25 pm ] |
| Post subject: | Re: Best Oil Pump for HP Street Use? |
Quote: Lifters with EDM holes in their faces will do you zero good as there is no pressure to force oil through the hole.
It's what I have Josh. Lifter selection was made for a bunch of other reasons; I added it here in case someone knew of a way to benefiting from it. I'd have to think that if I were able to get oil into lifter reservoir, the upward movement would get (at least) some of the oil out and onto the cam. Galley standoffs and bore grooving were already planned, so oil will be readily available to the lifter - although unpressurized. But I'm wondering if, in addition to a full-length groove on the uphill side of the bore, adding a second groove on the downhill side, and only halfway down, will be enough to get oil to the lifter waist area and fill the reservoir? The hole is there - any benefit received would be a positive one. Thanks to all for your input - great stuff to kick around! -C |
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| Author: | Dart270 [ Wed Dec 20, 2017 2:02 pm ] |
| Post subject: | Re: Best Oil Pump for HP Street Use? |
Hmmm. I am not aware that anyone has had trouble with lifter/cam oiling on a flat tappet Slant motor. I just hone the bores lightly to clean them up and all is good. I have never used standpipes and have run cams up to 255@0.050" and 0.570" lift - no issues. Just another 2 cents... Lou |
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| Author: | csheehy [ Wed Dec 20, 2017 2:44 pm ] |
| Post subject: | Re: Best Oil Pump for HP Street Use? |
Quote: I have never used standpipes and...
Lou, I'm a V8 convert, the Slant stuff is new to me. Much of what works for a V8 carries over but do find the nuances fascinating and challenging — which I enjoy as much as I think any slant-head does. I read about the standpipes (maybe that's the wrong word) in posts by Doug (https://goo.gl/12sNeK & https://goo.gl/rGmC3h) — whom I find to be progressive with these mills, as are you. I doubt too that there's an inherent problem with cam/lifter oiling and I'm sure the stock lifters are sufficient, but I thought Doug's approach could benefit my specific design and intended use. It's probably (most likely) overkill, this I acknowledge.Lou The lifter will work fine as is, but if any oil can come from face hole - I'd be ahead of the game. I'm enjoying the convo on lifters, gaining knowledge as I read the replies, but my interest in posting the poll was on oil pumps. Which all seem the same to me but with different box stickers and body markings. Are any brands better engineered than others? Advice on that front is still welcome. -C |
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| Author: | Rick Covalt [ Wed Dec 20, 2017 3:08 pm ] |
| Post subject: | Re: Best Oil Pump for HP Street Use? |
A known good used oil pump and gear (Especially if you have the matching cam to regrind) is much preferred to a unknown new pump and gear. I'm guessing any of the new pumps will be fine, but you don't want the high volume one from anyone, because it loads the gears even more. Also look at the openings and casting flash on any new pump to make sure the passages are open as they should be. Rick |
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| Author: | DusterIdiot [ Wed Dec 20, 2017 4:57 pm ] |
| Post subject: | Re: Best Oil Pump for HP Street Use? |
Ditto. A good stock one within specs is fine... if not available the Melling standard unit works well. I have used the Melling HV unit and it is not necessary, I didn't have a problem with it, but it added the problem of not being able to be pulled from an engine for replacement in any late A-body without removing the engine, damaging the body to do it. Get one of Doc's hardened gears, it's good insurance, you will have to determine the type I have two types of oil pump rotor shafts in my inventory and some are interference fit, a few others have a small shaft key. |
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| Author: | Dart270 [ Thu Dec 21, 2017 5:04 am ] |
| Post subject: | Re: Best Oil Pump for HP Street Use? |
It may be hard to find a stock low vol pump in the aftermarket offerings. At one point, about all of the "new" ones were HV. I may be out of date. Lou |
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| Author: | Rick Covalt [ Thu Dec 21, 2017 9:39 am ] |
| Post subject: | Re: Best Oil Pump for HP Street Use? |
I believe you are right. I think all of the new ones are already higher volume than the standard pumps. Then there is a high volume pump that is even more high volume. If that makes sense?
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| Author: | DadTruck [ Thu Dec 21, 2017 10:35 am ] |
| Post subject: | Re: Best Oil Pump for HP Street Use? |
Quote: higher volume than the standard pumps
I believe the new stock replacement slant six oil pumps available today match up to the 1981 and after rotor thickness that went into use with hydraulic lifters. MY '83 FSM has the oil pump rotor thickness listed as .825 minimum. There may be HV slant six oil pumps available that have a noticeably thicker rotor. So a new replacement oil pump used on a slant with mechanical valve train would have additional pumping capacity. |
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| Author: | Doctor Dodge [ Thu Dec 21, 2017 10:38 am ] |
| Post subject: | Re: Best Oil Pump for HP Street Use? |
5/8", 7/8" and 1 inch impeller sizes were offered. Most all of the replacement pumps (Melling M66) are the 7/8 size. (I think Melling is the last true manufacturer these days) In the past I have been able to get rebuild kits for the factory 5/8" pump but those may-be hard to get these days. DD  http://www.slantsix.org/articles/oil-pu ... report.htm |
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