Type 4 engine rebuild: take 3

[orwell84]

I'm trying not to create new threads as I have many threads asking the same question. I picked up where I left off on one of my favourite topics, oil pumps.

I really wish I had taken pics of the stock oil pump I took out in bits, but shame prevented me from doing so.

As many of you have found, the CB performance pump delivers insufficient oil pressure unless you run 50 wt or keep the oil below 190*F. Bought a full flow 30mm pump from the Type 4 store thinking...mmm..great, big gears, more pressure. I have since learned that they can put out too much pressure and that they are meant for installation of an external oil cooler.

I would like to go back to a stock oil pump, unless the aftermarket oil situation has miraculously improved.

I have found rebuilt pumps at EVW and there a few in the classifieds. Although the EVW pumps are more expensive, I'm fine with paying more as long as it is actually a quality rebuilt pump. Would I do just as well trying my luck in the classifieds? Any thoughts?

Thanks for the help.

[Danwvw]

Do it all man disassemble that engine and put in new bearing too.
_________________
1960 Beetle And 1679cc DP W-100 & Dual Zeniths!

[raygreenwood]

[orwell84]

If its really "rebuilt".....its worth the money. Actual rebuilding means removal of all tye studs and locating collar (not a time or cost factor)....then lapping the inside deck, the top deck, and possibly shuffling other gears from other pumps to get a good fit, lapping the gears to correct height, staking or pinning the shafts.....and in some cases actually hard anodizimy the case to tighten tolerances.
Its a lot of labor.

If all of that is done....its worth it. So.....if you buy one...please spend five minutes and crack it open and measure so we can get an idea of what the specs are.

I have about four pumps going out soon for anodizing that I am about to start rebuilds on. Ray[/quote]

Right. It's anybody's guess what they do to rebuild these pumps, so I would be inspecting it anyway as I would a new aftermarket pump. I would be interested in buying one of your rebuilt pumps if they are for sale.

Thank you

[raygreenwood]

[orwell84]

Ok, thanks. Please keep me posted if you have something available.

[orwell84]

So I bought 2 used oil pumps from the classifieds at a reasonable price and a rebuilt pump from Mofoco. Hopefully I will be able to put together a good pump. I might just get lucky. Like so many other things required to keep an old bus alive, there is no substitute for learning how to do it yourself. I was curious about hard anodizing and what direction to go in in having a pump done. I'm also looking for a comprehensive thread on oil pump blueprinting/rebuilding. Thanks as always.

[orwell84]

So here is an excellent discussion on this very topic. It comes up often in the process of rebuilding T4 engines.

https://www.thesamba.com/vw/forum/viewtopic.php?t=...mp;start=0

Since starting the original thread, I did another rebuild of my engine using HAM heads. I am currently running the CB performance pump and like many have found the fit to be a bit loose compared to the stock pump which was too tight to remove without splitting the case. Oil pressure is great until the oil temp gets above 190*F. After this point it is about 10 psi too low at the higher end of the rpm range according to my VDO gauges. I question whether I truly have insufficient oil pressure, but am concerned enough to attempt running a stock pump again. Another observation: At high temps my warning light would sometimes flicker at idle on hot days using the VDO sender. I did replace the rod and main bearings during my rebuild, even though they were not worn. I never had oil pressure issues that I was aware of before rebuilding, but did not have a pressure gauge until after I rebuilt. I switched to using the something or other /42 hose and fitting with the stock sender. It has never lit up the warning light at idle since.

[orwell84]

First of 3 oil pumps coming in. This one was from the classifieds...

I haven't spent much time looking at oil pumps. This is the worst of the scoring.

Battery died on my calipers, but it's under .005 with feeler gauges. That's the thinnest one I have on hand.

Just for comparative purposes, how worn is this?

Thanks

[Bulli Klinik]

Why would anyone think that they can sell parts like this? You would find that part in the garbage of my shop upon tear-down.

Did you ever find out why you weren't making oil pressure? As mentioned earlier in the thread, even a worn out pump will give you some pressure. I'm assuming that the dog wasn't engaged in the cam for whatever reason. Did the gears turn when the motor was turned over with the cover off but the pump installed? Did you hook up a pressure gauge prior to taking out the old pump?
_________________
I've never met a Bus I didn't like.
Mike K
Bulli Klinik
Colorado Springs

[orwell84]

We never found out for sure. Either the drive dog not engaged in the cam or because it was packed with vasoline clogging it. We tried heating the pump to thin out the vasoline but no luck. When we switched to the maxi pump it pumped right up. The pump in the pictures was $25. Waiting on a rebuilt from Mofoco and another cheapie from the classifieds.

Thanks for the help

[Wildthings]

How about a close up shot of the gears. If you have obvious abrasion of the wear surfaces on the gears I would say that the oil pump saw erosive materials passing through it. Otherwise you may just have a pump that was poorly machined. The thrust wear looks minimal, while the wall scoring doesn't look that much different for the machining done on the none wearing surfaces.

[SGKent]

late cases with the loopback from the overpressure to the oil pump will cavitate when there is any air in the pump. Literally you can pressurize the system with a device, turn the key to start the bus and it won't make oil pressure. Remove the filter or oil pressure switch and it will pour oil out in 1 second. Put the filter or sender back and you'll have pressure. Let it sit a few days where a little air gets into it and it will cavitate again. The simplest solution then is to start it for about 4 seconds, turn it off for about 10 seconds and start it again. Oil pressure will come up almost right away. While I can't see inside the pump it acts like air in the pump frothing the oil into a foam. You an see the change here.

_________________
“Most people don’t know what they’re doing, and a lot of them are really good at it.” - George Carlin

[orwell84]

[orwell84]

Here are some more photos for oil pump number 1. The clearance from the top of the gears to deck was about .005

[SGKent]

.0015" to .0030" would be better but .0050" is still acceptable. Basically you have .0025" on top and bottom instead of .0010" - .0015".

Steve
_________________
“Most people don’t know what they’re doing, and a lot of them are really good at it.” - George Carlin

[orwell84]

Pump number 2 arrived in the mail today. Also from the classifieds, same price range. It looks a lot more promising. To me it looks like minimal wear and scoring on the gears, bores and thrust faces. Gear deck clearance measures the same but eyeballs less. I don't think I am measuring accurately. I am using the depth gauge on the calipers and measurements are all over the place. From the lack of wear, I am assuming the clearances are probably good?

To my untrained eye, it looks only minimally worn with no obvious scoring from dirty oil. Did I get lucky?

Thanks for bearing with me. Though it's a means to an end, I enjoy learning about this stuff for its own sake.

[raygreenwood]

[raygreenwood]

[Wildthings]