Very tight valve clearance on rebuilt engine

[Wildthings]

[richparker]

Not sure of your location but up here (7700') there seems to be a lot of unnecessary crap added to the fuel in the winter. Unnecessary for carbs, that's for sure.
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[SGKent]

as you go up in altitude air molecules are farther apart. This slows how fast fuel burns. That is why the timing can be advanced a couple degrees at altitude, or the octane reduced.
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[orwell84]

So in rebuilding my engine, I noticed that when I torqued the oil pump down, it made the engine very hard to turn by hand. Its a cb performance pump and I have run it without issues., but it was installed after the engine was in so no hand turning without compression. When I disassembled the engine noticed no clearance issues with intetference with the cam. When assembling did not notice any clearance isaues either. There was some slight scoring on the cover plate from the gear that engages the cam after 300 miles. Any thoughts? Don't think its normal for the drive gear to put that much pressureon the cam. Thanks for the help.

[SGKent]

if tightening the 4 nuts causes the engine to bind, pull the gear out of the pump and see if the binding goes away. Be sure that you used the thin gasket between the pump and cover because that is what gives the gear clearance. The thick gasket goes between the pump body and case, and the thin gasket between the body and cover. The specs on how to verify clearance is in Bentley.
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[orwell84]

Pretty sure its the gear. Pumpbody and bolts are nowhere near the cam gear. Sorry I'm away from home and wirhout my Bentley for a week. Would assume clearancing involves removing material from the tang end or the back of the gear. If you could point me to an explanation on the net it would be much appreciated. I almost never leave home without my Bentley...

Thanks!

[Tcash]

http://www.thesamba.com/vw/forum/viewtopic.php?t=586716

https://www.youtube.com/watch?v=Re9DZ9TBOKY

[SGKent]

[orwell84]

Thanks for the help.

[orwell84]

Definitely not interference with the pump body. Mocked it up without the thick gasket on my second rebuild before assembling case halves and no interference then. When this pump came out of the engine after 300 miles, cam bolts, pump body, etc all looked perfect. had worried that this was the source of debris I found. Drive gear tang was also fine as was slot in cam gear. Only thing i noticed was scoring on the cover plate from the back of the pump drive gear. Would using a thicker gasket for the cover plate help?

[aeromech]

Light scoring is normal. Can you show us a pic?
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[Tcash]

Would using a thicker gasket for the cover plate help?
No, that would increase the running clearance of the gears and reduce oil pressure.

[SGKent]

you are on the right path. Hang in there.

There are two gaskets that go with a T1 pump even on a T4. The thin one goes between the pump body and cover. Try putting that assembly together out of the case with 4 bolts and nuts - see how much force it takes to turn the pump out of the engine. Anytime there is debris in the engine the character of the debris should give away something about where it came from. For example can a magnet pick it up?

You can also look at the cam gear and see if the tang has been bottoming out.

The thin left hand gasket goes between the pump body and cover. The right hand one (or Loctite anaerobic sealer) goes between the pump body and case.

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

[orwell84]

Ok, thank you. I am on vacation for the rest of the week, so the rest will have to wait. BTW, In doing the second rebuild of this engine, I split the case, cleaned it thoroughly and started from scratch. Debris was determined to be something dropped down the intake. Debris found on the first occasion was likely from a valve adjustment screw hitting the inside of the rocker cover. This was occurring even before I rebuilt the engine the first time. This go-around I know a lot more and am using better parts, HAM heads, etc. Also will be paying careful attention to deck height and valve geometry. Especially attentive to working clean, keeping the engine covered at all times, keeping the space around me clean and uncluttered, accounting for dropped parts immediately...

[orwell84]

Yes, I get it now about not using a thicker gasket. Increasing gear clearance excessively reduces pump efficiency and oil pressure...Wish it just bolyed in with no issues, but way better to find out while its on the bench.

[orwell84]

Ok. So I assembled the pump torqued to specs outside of the engine; smooth and no binding. Torqued it to spec in the case minus the drive gear; no binding. Tried it again with the drive gear in, the pump in the case,; got some binding. I did put the gaskets in the right place; fat one between the pump body and the case, paper thin one under the cover plate. Would post photos, but there is nothing to see...no scoring on anything....As I mentioned before, I have run this pump, but would not have noticed binding as the engine was in the bus...

Where do I go from here? Thanks as always for the help...

[Tcash]

If you have a bolt on cam. The cam bolts may be hitting the pump.
Could the oil pump drive gear be bottoming out in the cam slot.
Put some grease in the cam slot install the oil pump housing install the drive gear. Push in the gear. Carefully remove the gear and pump housing. See how far the drive gear tang is locating in the cam.
Put the gears in the pump and with a straight edge and feeler gauge measure the end play. The gap between the straight edge and the gears.
Rotate the gears by hand is there binding.

Good luck
Tcash

[orwell84]

Thank you. Cam bolts are most definately not hitting the pump. That's why it it turns nicely with the drive gear removed. It's the drive gear. Will check as instructed. Thanks...

[orwell84]

Might it be normal for the engine to turn stiffly with the oil pump installed? It's just the rods, case, drive plate...

[Tcash]