oil pump leaking, suggestions on a replacement Options

[scottb]

mine has been leaking since i got the car and now that my clutch is going wacky, i am going to fix everything starting at the front.

so..... i need a new oil pump. i have searched the threads and there seem to be 3 types

- iron one that leaks (not going there)

- aluminum one that doesn't leak (but need to machine the shaft IIRC)

- type 1 conversion (still with shaft machining?)


anyone who has this lately speak up as i am looking for input and assistance.

after the oil pump, comes the valve adjustment then the clutch.

thanks in advance (IMG:http://www.914world.com/bbs2/html/emoticons/beerchug.gif) (IMG:http://www.914world.com/bbs2/html/emoticons/beerchug.gif)

[Allan]

I have a steel Melling HD pump that does'nt leak a drop but I spent alot of time making sure everything was nice and flat.

IIRC the T-1 pump only needs the cover modified to fit. Grinding off a corner or something.

[Jake Raby]

The TI is NOT a wise choice if your engine is assembled- The correct retrofit of the TI pump requires a modified cam gear and oil pump body to work- not just a modified cover..

The Melling would be your best choice for that scenario (damn I hate to recommend a Melling for any reason)

I don't sell the Melling pump.

[scottb]

QUOTE (Jake Raby @ Aug 26 2005, 07:02 PM)

The TI is NOT a wise choice if your engine is assembled- The correct retrofit of the TI pump requires a modified cam gear and oil pump body to work- not just a modified cover.. The Melling would be your best choice for that scenario (damn I hate to recommend a Melling for any reason) I don't sell the Melling pump.

thanks for the input guys.

jake, i sent a message through your TIV site. since my engine is assembled, suppose you can ignore it until i need a rebuild... (IMG:http://www.914world.com/bbs2/html/emoticons/wink.gif)

[Aaron Cox]

i got a 38mm aluminum pump, to help with a front oil cooler. my cam gear had already been modded.....

[dmenche914]

The steel Melling pump has its share of problems. However the leaking issue has to do with the flat cover plate. This steel cover plate does NOT remain flat when the four bolts are torqued down. The middle bows uot several thousands of an inch. To fix that problem, you will need to install a stock VW oil pump cover. This cover has raised edges on all four sides that totally prevents this bowing, and hence the leaks. Slight grinding on the top raised edge is needed to clear the 914 engine case, but is minor. That is the fix for the leaky meeling pump with the flat cover.

You could also go for a used stock 914 pump, if in good shape, that will be fine for a stock motor.

The Melling is basically a type I pump, just it is an aftermarket Type I pump.

What ever pump you get, be sure that the cover plate has raised edges. (type I)

that the cover plate is lapped flat using fine wet / dry sand paper on a flat surface. (Type I)

That the pump body is lapped to be flush (zero clearance) with the pump gears. (type I)

Be sure the clearance between the gears and the body is within limits use a feeler gage for this (both type IV and I pumps)

be sure the cover plate gasket is the ultra thin one (only a few thousands inch) (Type I )

Be sure that the inlet and outlet holes on the pump body line up with the correspounding holes int he engine case (they have been known to be off for certain pumps) (type I and IV)

Use sealant between pump body and the engine case (type I and IV)

be sure that there is clearance between the pump drive tang, and the cam gear, you do not want any thrust load on the cam gear, yet make sure the tang is engages enough. The tang can be ground down a little if pushes on the cam gear and /or pressed further into the drive gear

Check specs and make sure there is not too much backlash int he gears (worn or improperly made gears)

To be sure everthing is right, do the above, this will require use of feller gages, a flat surface, and some clay or layout dye (to check tang to cam gear clearance) and or careful measurements with a caliper.

If you use the VW type one pump, you can find the gear clearance and back lash specs in a VW book, or ask here again and someone can look it up for you

You do not need spend a ton of money on a fancy pump If you take the time to measure and "blue print" the pump. At the store bring your feeler gage to check the pumps gear to body clearance, and backlash before you buy it, the other items require assembly and lapping to get right.
Pump body to pump gear clearance, and gear back lash can not be corrected (well nothing is impossible, but you sure wouldn't want to have to try to correct it, so besure those are in spec before purchase)

good luck

[Cap'n Krusty]

Nothing wrong with a stock pump in a stock or mildly modded motor. They never leak, either. The Cap'n

[scottb]

QUOTE

However the leaking issue has to do with the flat cover plate. This steel cover plate does NOT remain flat when the four bolts are torqued down. The middle bows uot several thousands of an inch. To fix that problem, you will need to install a stock VW oil pump cover.

so perhaps, i don't need to replace the pump but replace the oil cover plate? i am i making this too simple? if not, where can i buy one without going to my local pick-a-part?

thanks for all the input folks......

[scottb]

is this what i need for a cover?

[MattR]

QUOTE (scottb @ Aug 26 2005, 04:58 PM)

is this what i need for a cover?

Yep. That looks right. You have to grind off an ear of the cover to clear a boss on the case. You'll see when its in there... its really easy.

[dmenche914]

Any aircooled VW / buggy shopor rebuilder out to have these covers, new or used (they sell them new in ads in Hot VW's magazine) just be sure to lap them flat, as even new ones may not be perfect. the other posters phot is right on, that the one to get. be sure to use sealant around the body of the pump if you pull the body out that is. Remember use one thin gasket unde rthe cover (about .003 inch thick as i recall ) do not use the near identical thicker gasket, as that one is used between the engine and the pump body. The tin gasket, after you lap every thing flat is the only gap (clearance) betweent eh cover and the gears. The more clearance, the more pressure loss.