TheSamba.com :: View topic - O-Ringed Melling Pump

Tue Aug 18, 2015 2:45 pm

I've never run a Melling, but I'm in the market for a quality 21mm pump and I've got a line on a NOS one. If I had it O-ringed, do you think it would be susceptible to the leaking issues of running a cast iron pump?

Tue Aug 18, 2015 2:51 pm

sounds like a good plan.
I wasn't aware that Melling made a 21mm pump

Tue Aug 18, 2015 3:38 pm

I wasn't aware that Melling oil pumps leak.... who started that rumor...

Tue Aug 18, 2015 4:46 pm

why a 21mm pump??

Tue Aug 18, 2015 4:50 pm

mark tucker wrote: why a 21mm pump??

Why not?

Tue Aug 18, 2015 5:23 pm

It looks like they are still made too. Google Melling 79A
The guy I'm buying it from measured the gears and oil holes.
Made for a flat cam, Gears are 22.5ish - One oil hole is 16 mm and the other is 12.5 mm

Tue Aug 18, 2015 5:26 pm

jfats808 wrote: I wasn't aware that Melling oil pumps leak.... who started that rumor...

Internal pressure and suction leak. Yes the o-ring is a good idea.

Dan

Tue Aug 18, 2015 6:25 pm

LivinInnaVWBus wrote: mark tucker wrote: why a 21mm pump??

Why not? I like my engines to live a long hard life.....and they do.30mm pumps for me.

Tue Aug 18, 2015 7:07 pm

mark tucker wrote: LivinInnaVWBus wrote: mark tucker wrote: why a 21mm pump??

Why not? I like my engines to live a long hard life.....and they do.30mm pumps for me.

It's for an under powered fuel economy build.

Wed Aug 19, 2015 4:24 am

Does it come with its O ring?

Wed Aug 19, 2015 11:21 am

oh so underpowered dont need good oil flow.I wasent aware of that. I feal stupid now. stupid.

Thu Aug 20, 2015 12:13 am

mark tucker wrote: oh so underpowered dont need good oil flow.I wasent aware of that. I feal stupid now. stupid.

A built engine with tight clearences (tighter than stock) doesn't need a 30mm pump. And if the engine isn't going to be revved the hell out of, it doesn't even need the 26mm. IF built correctly.

Thu Aug 20, 2015 7:28 am

so... tighter than stock is...built correctly?with insufficient oil pressure and is supposed to live longer.especialy at lower rpm where the oil pump is pumping even less.......wow boy do I feal realy stupid now.makes me wonder how my stuff ever gets to the gas station. :shock: it seems I learn something new almost every time I log on. Ive always likes a lot of pumping and on the loose side .

Thu Aug 20, 2015 8:20 am

Quote: Shocked it seems I learn something new almost every time I log on. Ive always likes a lot of pumping and on the loose side

Yep if its on the loose side it will take more pumping :lol:
Terry

Thu Aug 20, 2015 9:45 am

Interesting how these pumps surface every once in a while. They were banned from my shop 20 years ago due to too many durability and expansion issues.

T

Fri Aug 21, 2015 6:50 am

I never had an issue with the one I used,,,or was that 2 I used.... funny how they get mfed for being iron, but the junk 010 dist gets high dollar.... :shock: ( yess I think the aluminum pump is a better /wizer choice)

Fri Aug 21, 2015 11:19 am

Mark, your unfriendly and demeaning approach is less that desirable and though I didn't ask for any opinions on gear size, I'll humor you.

I've been using strictly 21 and 26mm oil pumps since 2006 on my daily drivers which typically see near 50k a year with 0 issues to report to date.
I just tore into the 1500sp in my 68' bus with well over 100k miles on it since the last time I took it down, I reused the entire rotating assembly and 21mm oil pump.

This build is a 1679 single port running a stock carb, 1:1:1 rockers and this cam http://www.cbperformance.com/ProductDetails.asp?ProductCode=2229

All minute things are taken into consideration with this engine for the best chance at better mileage. Straight cut gears, relatively low pressure valve springs, straight cut gears, race spec dynamically balanced rotating assembly, lightweight lifters/pushrods, CW crank and a smaller oil pump for less resistance. If the engine likes it, I'll be using 0w30 oil. Everything helps and in my experience, a 21mm pump will be more than sufficient.

Fri Aug 21, 2015 5:43 pm

For 0-30 weight it wohnt. Stay at 10w-40 at least or you will be in the dangerzone with both quantity and oil film strength, even for a detuned engine. Just get an oil that has the properties needed for these engines and has a HTHS value higher than 3,50 and a flow viscosity index around 150 Then you should be on the safe side. (Ever wondered why 1500 engine always lost the rod bearing on cylinder 3 ?)

T

Fri Aug 21, 2015 6:25 pm

Alstrup wrote: For 0-30 weight it wohnt. Stay at 10w-40 at least or you will be in the dangerzone with both quantity and oil film strength, even for a detuned engine. Just get an oil that has the properties needed for these engines and has a HTHS value higher than 3,50 and a flow viscosity index around 150 Then you should be on the safe side. (Ever wondered why 1500 engine always lost the rod bearing on cylinder 3 ?)

T

0w30 used in this engines entire life except the last month before I broke it down which I used 10w30 to bump the oil pressure. These bearings and everything else in the long block except the gasket kit and oil pump were used and unmachined. I personally clocked over 100k on this engine since I assembled it with these used parts.

I let my engines tell me what they want. After the initial break in, I baby the engine for 1k miles and change the oil between 4 and 5 times during that period. After that, I start at 0w30 and work my way up logging the oil temperatures. With this engine, it liked 0w30. I was able to cruise at 65 all day with the ambient temps over 90 degrees and my oil temp at the sump would stay near 215. With just the next heavier weight, it put the temps up 15 degrees.
I'd say over 100k on an 1500cc air cooled engine in a fully loaded camper using a 21mm oil pump and 0w30 oil is a success. I reassembled this engine using only new bearings, gaskets and a different intake manifold. Here it is now after reassembly, a cold start after sitting all night and I didn't even have it fully tuned at this point.
Don't mind the zoom tube, I wouldn't be using it if it wasn't a last resort option.

Sat Aug 22, 2015 7:30 am

those bearing are dead totaly dead, and also some are full of debris.how much power does it take to turn a crank in bearings that scrub on the crank?? how much power does a pump use with extra tight clearances ?how much for a biger pump with big clearance's and extra oiling mods done so the oil flows more freely and the crank isant scrubbing or gaullding the bearings? not unfrendly or demending. thats in you head. I see no humor at all in engines being built so they look like that when they come appart.or in trying to see just how much can be done untill they give up the ghost. I do however under stand mpg and a long lasting powerful fun engine.