TheSamba.com :: View topic - Engine runs for first time! (now, low oil pressure)

Wed Dec 09, 2009 9:20 am

Just an update, I dropped the oil control piston (easier than I thought) and took a look at it. It moved easily in the bore but the surface was quite rough so I smoothed it out with sandpaper on a flat surface, ending with 2000 grit.

Before:

After:

Unfortunately it did not seem to make much difference. Warm, at idle, it will still trip the warning light on the VDO gauge but not the light on the original switch. Going down the highway I still get 40-45 psi. This is with the 20W50 VR1 oil and very cool outdoor temperatures (my oil temp is maxing out around 150-160 degrees since it's in the 30's outside). I'm a bit worried what it's going to do in the summer.

I've also noticed a gentle oil leak from somewhere in the vicinity of the oil pump. Just enough to leave one or two drops on the ground after you shut it down. I'm not sure if it's the pump or the fan seal or something else (dipstick tube boot?)

Also, I talked to the machine shop that installed the oil pump. He says the pump had about .004 end play and he used the thin gasket that came with the Victor Reinz kit. That should add about another .004. Over in the "performance/engine" forum, they talk about either running with no gasket, just sealant, or decking the pump and gears together so the only clearance is the gasket. I'm not sure how much difference this would make, but removing the gasket would be easy enough to do without removing the pump (although I would have to remove the fan shroud).

Tue Dec 15, 2009 5:21 pm

WhirledTraveller wrote: machine shop that installed the oil pump says the pump had about .004 end play and he used the thin gasket that came with the Victor Reinz kit. That should add about another .004

That would be too much clearance if you are at .008"
The Bentley states that .004" is the wear limit as you measure the clearance between the gears and the edge of the housing.

That said, oil lights coming on at idle with aftermarket senders is a common occurrence. The factory sender triggers between 2-6 psi. If your aftermarket sender is triggered at 10 psi . . . well, there you go.
Colin

Tue Dec 15, 2009 6:15 pm

It sounds to me like you have a problem that you will need to deal with if you want this motor to last a long time. You say it is FI so I take that it is a T4 motor. Since you talk about an additional .004 clearance with the paper it is not the stock style pump but a modified T1 pump. Is this correct?

Tue Dec 15, 2009 9:55 pm

SGKent wrote: It sounds to me like you have a problem that you will need to deal with if you want this motor to last a long time. You say it is FI so I take that it is a T4 motor. Since you talk about an additional .004 clearance with the paper it is not the stock style pump but a modified T1 pump. Is this correct?

Raby engines come with a 30mm Shadek pump with the flat plate, IIRC
Colin

Wed Dec 16, 2009 12:48 pm

Amskeptic wrote: SGKent wrote: It sounds to me like you have a problem that you will need to deal with if you want this motor to last a long time. You say it is FI so I take that it is a T4 motor. Since you talk about an additional .004 clearance with the paper it is not the stock style pump but a modified T1 pump. Is this correct?

Raby engines come with a 30mm Shadek pump with the flat plate, IIRC
Colin

It is a 26mm Shadek type I pump which the machine shop modified to fit. The machine shop has said he'd be willing to blueprint and swap in a 30mm pump if I wish. Raby is also developing his own billet 30mm pump which should be available by spring.

If I have a chance, and the weather cooperates, I may pull the shroud and verify the end clearance with the pump in place. Removing the gasket may bring the pressure up. In the meantime, I don't think it is dangerously low. The real question is whether the pump is to blame or it's an open clearance in the engine. If it's the later, then no pump will really help. If it's the former, it's probably not a big deal as is especially in the winter with cold oil.

Wed Dec 16, 2009 1:30 pm

just be aware that on some of theT4 forums there has been complaint that a whole batch of shadek pumps lost quality control and the OD of the pump body is too small. I measured one I bought from GS and it is very close to the T4 pumps. We found enough mention of this issue on several T4 forums that we ordered a new T4 pump in from Europe and used it. All our collected T4 pumps are out being remanufactured right now or I'd offer you one of those. VWHeritage,com shows remanufactured T4 pumps on their site for a pretty reasonable price. I have never handled one. http://vwheritage.com/vwh/VW-Camper-Van-Parts/Bus-...lateID=vwh

Wed Dec 16, 2009 3:09 pm

SGKent wrote: just be aware that on some of theT4 forums there has been complaint that a whole batch of shadek pumps lost quality control and the OD of the pump body is too small. I measured one I bought from GS and it is very close to the T4 pumps. We found enough mention of this issue on several T4 forums that we ordered a new T4 pump in from Europe and used it. All our collected T4 pumps are out being remanufactured right now or I'd offer you one of those. VWHeritage,com shows remanufactured T4 pumps on their site for a pretty reasonable price. I have never handled one. http://vwheritage.com/vwh/VW-Camper-Van-Parts/Bus-...lateID=vwh

I heard about this and mentioned it to the machinist. He said the pump was a normal/tight fit, that he had to tap it in "just like usual". I actually have the old T4 pump which we removed, and the machinist claims says the clearances on that are within limits. We had decided to go with the T1 pump just so we could have the peace of mind of a new pump. Do you know of anybody not in Europe who rebuilds these pumps?

Anyway, as I said, I'm measuring about 5 psi hot idle at 800 rpm and 40-45 psi at 4000 rpm so I think the bearings will be fine. I am going to take a closer look at it but I'm not in a hurry and I don't feel like doing a lot of work on the motor in the wintertime.

Wed Dec 16, 2009 5:30 pm

Phil does them when he has time but it is as expensive as a new T1 pump.

Wed Dec 16, 2009 11:41 pm

WhirledTraveller wrote:
I'm measuring about 5 psi hot idle at 800 rpm and 40-45 psi at 4000 rpm so I think the bearings will be fine. I am going to take a closer look at it but I'm not in a hurry and I don't feel like doing a lot of work on the motor in the wintertime.

That seems OK. I will be in Boston/Brookline/Cambridge>Harvard Sq Grendel's Den December 23/4th. Be sure to wave when I pass by.
Colin

Mon Feb 15, 2010 2:40 pm

Update... finally got a decent day (40 Degrees!) to work outside, and decided to pull the oil pump and see what's up.

I managed to get the shroud off without too much difficulty, left the alternator in place and loosened the heat exchanger at the "U" pipes so that the whole exhaust would droop enough. Had to loosed the engine mounts and rotate them a bit to get the oil pump cover plate clear. I also found the source of my oil drip, it was the dipstick tube boot (broken).

After loosening the 4 case bolts closest to the pump, I prepared my puller. After a couple of turns (breaking the seal of the gasket) the pump practically leaped out at me... not good. It required almost zero effort.

This is what the pump looked like:

As you can see, it seems to be covered in a thin coat of what appears to be clear RTV. It has that rubbery, stretchy feel.

After I cleaned off the goop, and retorqued the case bolts, I was able to insert and remove the pump with my hand, easily.

I attempted to get some measurements, but found the bore tricky to measure. Nonetheless, the average of my measurements is 2.7564". The average measurement of the pump diameter is 2.7556". So the pump is, on average, 0.0008" smaller than the bore in the case.

I suspect this to be the source of my low oil pressure problems. The end play and backlash on the gears seems very low.

Now my only question is what to do about it... I really hope Raby starts selling his pumps very, very soon. I'd reinstall the original type 4 pump, but it is currently in the possession of Import Machine and Dana is out of town until March 8th.

Mon Feb 15, 2010 4:02 pm

It looks as though you're onto something there but might be worth laying a straight edge across the pump cover also to see if it's at all dished. Even genuine VW pump covers (sold here in the UK) have not been anywhere near flat in my opinion, just dragged across a belt sander for 5 seconds from the look of them.

I've had low oil pressure problems on a couple of type one engines, one of them I'd given up for dead (symptoms you've described) but a new well fitting shadek pump with a genuine cover (lapped by hand) and the pressure came back to life. CB performance sell a modified type 1 pump & cover for use in a type 4 engine if you need to get on the road quickly

item 23 on this page

http://www.vwheritage.com/vwh/VW-Camper-Van-Parts/...lateID=vwh

I can't see this described on CB's own site though :? maybe I missed it.

Ant

Mon Feb 15, 2010 4:15 pm

Thanks for that link, I found it on CB's site (part #1829 here http://www.cbperformance.com/catalog.asp?ProductID=195)

However I can't seem to find any reviews/experiences with this pump in a type 4.

Tue Feb 16, 2010 1:36 am

If your oil pump bore ID matches what I have here in the way of billet pumps from the last batch I **may** sell you one. I'd like to see what the pump does when applied to an engine built off site that has had low oil pressure.

The problem is measuring the case bore accurately and matching that to one of my standard, oversize or undersize pump bodies for the tightest fit.

Tue Feb 16, 2010 1:26 pm

I went to install the modified T1 oil pump that CB Performace sells into a 2L and was a loose fit in the case too.. Then I ordered a reman T4 pump from evwparts.com.. Looked good, was within specs and fit in there like its suppose to.. Haven't run it yet but I was happy to find them available..

Wed Feb 17, 2010 1:25 pm

I don't know if anybody is interested but I made a video showing how loose it is.

http://www.youtube.com/watch?v=7c2rvikCHa0

I also re-measured the bore in the case more carefully, and now that I've figured out how to properly use the telescopic gauges I'm averaging around 2.760" or so... about .003 over the Bentley spec.

Wed Feb 17, 2010 1:54 pm

Are you thinking that as the engine warms up the oil pump "gap" becomes larger and thus less OP after everything warms up?

Interesting. Keep us posted.

Wed Feb 17, 2010 2:51 pm

Randy in Maine wrote: Are you thinking that as the engine warms up the oil pump "gap" becomes larger and thus less OP after everything warms up?

Interesting. Keep us posted.

I would assume that the gap stays relatively constant since the case and the pump should expand at the same rate. I think the warm OP is low because I am either squirting oil through the pump bore back into the case or sucking air into the oil, or both... probably when the oil is cold it doesn't squeeze as well through the gap.

Mon Mar 08, 2010 5:45 pm

One more update. I have hesitated to post because of so much conflicting information. The bus has been out of commission this whole time. I have measured and remeasured everything, I have purchased a proper electronic bore indicator, and I've taken everything including my micrometers to the local machine shop to get my measurements checked and my micrometer checked vs. gauge blocks. I can now give these measurements with confidence.

First off: The Shadek pump which is loose in the case measures 2.7550, the average of 12 measurements at various points.

The original T4 pump which was in my engine measures 2.7594, again an average of 12 measurements.

Another well used T4 pump which I bought for $20 out of the classifieds measures 2.7583 on average.

The case itself measures 2.7586, again the average of 12 measurements.

Now, I have all sorts of conflicting information about what the case is supposed to measure, and what the pump is supposed to measure.

When I visited the machine shop, the guy had a T1 motor being assembled. He took my "too small" Shadek and tried it in that case, it was a reasonably snug fit. Jake Raby says they took a crate full of old T4 pumps, measured them all, and came up with an average of 2.7550 (same as my Shadek). The Bentley spec for the case bore is 2.7559 to 2.7570. Aircooled.net website says the pump should be 2.7570 and the case should be 2.7535. SGKent says he measured his brand new T4 pump from Germany and it was the same as his Shadek, around 2.7555.

All these numbers are all different and leave me scratching my head for sure.

The only thing I can say with certainty is that my *original* T4 pump is larger than my case bore and is an interference fit. It also has minimal wear and about .004 end-play.

My plan is to run the original pump. After all that!

Mon Mar 08, 2010 8:29 pm

we are using 20/50 and oil pressure is holding well. You need 10 psi of oil pressure per 1000 rpm. That pressure to RPM ratio is a standard. Less and you will have trouble.

Mon Mar 08, 2010 11:26 pm

Want to really get confused?? Warm the case and oil pump to 200F and then measure it as quickly as possible.

You'll see that at temperature the components don't have the same size differentials that they do at ambient.

What the case was supposed to measure was written prior to 3+ decades of service. The oil pump bore is at the parting line and is fairly large in diameter. This area in most applications has been subjected to heat from the exhaust system, overheated oil, etc, etc so if you expect it to measure dead nuts on you'll be sorely disappointed. I have measured NOS cases that were outside of the "spec" as posted in "The Book".

This is why we have had to make pumps and soon we'll be having to alter pump bores through insane procedures. This is a common issue with 911 engines as well, not limited to the TIV.