Ive just opened the new oil pump i have for my waterboxer engine, filled it with oil and have given it a few spins round. The two cogs slightly catch each other at a point rather than smoothly turning all the way round, here are two arrows on the cogs but no matter where i place them it doesnt seem to make a difference.
Is that normal, should i be ok fitting it?
Also does it matter which way round the pump sits?
Im sure i pulled it out with the cogs being vertical, but the haynes shows them horizontal. Also there is a big hole and a small hole in the sides of the pump, im not sure if it matters which way they go.
Im guessing the cog that you can spin round from the back slots into the camshaft, so aslong as thats in place the pump can be put in anyway round?
Thanks
New waterboxer oil pump slightly rough?
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tencentlife
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Re: New waterboxer oil pump slightly rough?
You're kidding, right, that Haynes shows the pump as horizontal?
The pump only goes in one way, the gears are one above the other, the driven gear is on top and engages the slot in the end of the camshaft.
Presumably you got the right pump for the type of camshaft, too, the wbx uses a late-style "dished" cam so it requires the long-reach pump. Hopefully your parts supplier knows the difference and supplied you the right part. If you have the wrong one, the driven gear tang won't reach the camshaft slot, but once you stuff it into the case to find out, you've bought it.
The arrows on the ends of the gears denote nothing, the gears just mesh together in whatever position. They should turn smoothly together all the way around, any perceptible binding would cause me to reject the pump.
You also must check the gears' endplay if you expect the engine to have good oil pressure. Presumably that's why you're replacing the pump anyway? So don't skip this step: put both gears in the pump body, all the way in, a lay a straightedge across the pump face. Use feeler gauges to check the freeplay between the end of the gears and the straightedge, at various angles. It should be between .002-.004", ideally .003". If so, then you will install the pump cover sans gasket. If there is zero endplay then you would use the thin paper gasket under the cover. Get the endplay wrong and you get an engine with low hot OP.
The pump only goes in one way, the gears are one above the other, the driven gear is on top and engages the slot in the end of the camshaft.
Presumably you got the right pump for the type of camshaft, too, the wbx uses a late-style "dished" cam so it requires the long-reach pump. Hopefully your parts supplier knows the difference and supplied you the right part. If you have the wrong one, the driven gear tang won't reach the camshaft slot, but once you stuff it into the case to find out, you've bought it.
The arrows on the ends of the gears denote nothing, the gears just mesh together in whatever position. They should turn smoothly together all the way around, any perceptible binding would cause me to reject the pump.
You also must check the gears' endplay if you expect the engine to have good oil pressure. Presumably that's why you're replacing the pump anyway? So don't skip this step: put both gears in the pump body, all the way in, a lay a straightedge across the pump face. Use feeler gauges to check the freeplay between the end of the gears and the straightedge, at various angles. It should be between .002-.004", ideally .003". If so, then you will install the pump cover sans gasket. If there is zero endplay then you would use the thin paper gasket under the cover. Get the endplay wrong and you get an engine with low hot OP.
Re: New waterboxer oil pump slightly rough?
Cheers for the reply
I havent got the haynes in front of me now but yes im sure it shows the gears horizontal, i thought it was strange as i thought the old one came out vertical.
Im replacing the pump as ive rebuilt the engine, and thought i might aswell put a new one in. Oh dear if the pumps abit naffed then thats a tenner down the pan and £25 for a new one, i bought it off a guy on here but its brand new and was sealed in a bag and in the box, its a Febi so not a cheapy brand im suprised its faulty. To be honest the gears on the old pump look fine, it might be worth seeing if i can switch a gear over to see if they turn smoothly.
When you say lay a straight edge across the pump face do you mean anything flat like a ruler, then measure the gap in between that and the gears? I thought both oil pump gaskets should be used regardless or it could leak?
Thanks
I havent got the haynes in front of me now but yes im sure it shows the gears horizontal, i thought it was strange as i thought the old one came out vertical.
Im replacing the pump as ive rebuilt the engine, and thought i might aswell put a new one in. Oh dear if the pumps abit naffed then thats a tenner down the pan and £25 for a new one, i bought it off a guy on here but its brand new and was sealed in a bag and in the box, its a Febi so not a cheapy brand im suprised its faulty. To be honest the gears on the old pump look fine, it might be worth seeing if i can switch a gear over to see if they turn smoothly.
When you say lay a straight edge across the pump face do you mean anything flat like a ruler, then measure the gap in between that and the gears? I thought both oil pump gaskets should be used regardless or it could leak?
Thanks
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tencentlife
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Re: New waterboxer oil pump slightly rough?
You use the gasket between the pump body and crankcase, but using the cover gasket or not depends on the pump gears' end clearance. The end clearance is the one factor pertaining to the pump that you can control as an assembler that will determine whether you have good hot OP or not, gasket notwithstanding.
Yes, you're measuring the difference between the length of the gears and the depth of the gear housing, speaking technically. The easy way to measure is as I've described, use the best straightedge you have (it doesn't have to be an expensive machinists tool, a good steel ruler that hasn't been used as a prybar will do), hold the pump body face up, drop the gears in the body as they would be installed, dry, lay the straightedge across the face of the body at various angles while you check the gap between the edge and the end of the gears for the clearance.
If you look in the Bentley official repair book (and by the way, I think you should burn that Haynes) you will see that no gasket was used under the wbx pump cover. I build this engine for my living, exclusively, and I use a new pump that has .003" gear end clearance, and I install the covers with only sealant, keeping it light and outside the circular groove on the face of the pump body.
There are two general approaches, depending on who makes the pump:
Some pumps have gears exactly the same length as the depth of the housing, so you would see zero clearance with the straightedge. With this type you would use a thin paper gasket that when compressed should set the endplay at between 2 and 4 thou.
Some pumps have gears a few thou shorter than the depth. If you used a gasket on this type you would end up with double the endplay and have poor hot OP, so don't use a gasket.
If you have the latter type but you're one of those old ladies that can't stomach the thought of there being no gasket there, then you can resurface the face of the pump body to make your pump into the former type. A waste of time, but there it is, except if you have the latter type but the end clearance is excessive (more than .004") then the body face can be resurfaced to bring the end clearance down to spec.
Just make sure, if you are using a gasket, to use the right one. There is one of thicker paper that has an inner circle cut out that will fit around the pump body itself; obviously this is the body-to-crankcase gasket. The other is of much thinner paper, and has an inner circle that is too small to go around the body. That is the right cover gasket to use. If you mistakenly used the one with the thicker paper (and I've seen it done) , you will once again have way too much gear end clearance.
This is all of course assuming you have a decent quality pump whose gears fit right and mesh smoothly with no binding at any position while turning the driven gear by hand (I've never see a pump that did not, though). Don't go swapping gears between pumps unless you know more about how to check other dimensional clearances that affect how it works; no offense but I think that kind of thing may be a bit above your pay grade.
For the small amount of money involved, vs. the time it takes to replace the pump on an installed engine (about 4 hours), if you're not happy with the pump you got such a good deal on, don't hesitate to throw down for a quality part instead. Having feeble hot OP and always wondering when you'll spin a bearing sucks.
Yes, you're measuring the difference between the length of the gears and the depth of the gear housing, speaking technically. The easy way to measure is as I've described, use the best straightedge you have (it doesn't have to be an expensive machinists tool, a good steel ruler that hasn't been used as a prybar will do), hold the pump body face up, drop the gears in the body as they would be installed, dry, lay the straightedge across the face of the body at various angles while you check the gap between the edge and the end of the gears for the clearance.
If you look in the Bentley official repair book (and by the way, I think you should burn that Haynes) you will see that no gasket was used under the wbx pump cover. I build this engine for my living, exclusively, and I use a new pump that has .003" gear end clearance, and I install the covers with only sealant, keeping it light and outside the circular groove on the face of the pump body.
There are two general approaches, depending on who makes the pump:
Some pumps have gears exactly the same length as the depth of the housing, so you would see zero clearance with the straightedge. With this type you would use a thin paper gasket that when compressed should set the endplay at between 2 and 4 thou.
Some pumps have gears a few thou shorter than the depth. If you used a gasket on this type you would end up with double the endplay and have poor hot OP, so don't use a gasket.
If you have the latter type but you're one of those old ladies that can't stomach the thought of there being no gasket there, then you can resurface the face of the pump body to make your pump into the former type. A waste of time, but there it is, except if you have the latter type but the end clearance is excessive (more than .004") then the body face can be resurfaced to bring the end clearance down to spec.
Just make sure, if you are using a gasket, to use the right one. There is one of thicker paper that has an inner circle cut out that will fit around the pump body itself; obviously this is the body-to-crankcase gasket. The other is of much thinner paper, and has an inner circle that is too small to go around the body. That is the right cover gasket to use. If you mistakenly used the one with the thicker paper (and I've seen it done) , you will once again have way too much gear end clearance.
This is all of course assuming you have a decent quality pump whose gears fit right and mesh smoothly with no binding at any position while turning the driven gear by hand (I've never see a pump that did not, though). Don't go swapping gears between pumps unless you know more about how to check other dimensional clearances that affect how it works; no offense but I think that kind of thing may be a bit above your pay grade.
For the small amount of money involved, vs. the time it takes to replace the pump on an installed engine (about 4 hours), if you're not happy with the pump you got such a good deal on, don't hesitate to throw down for a quality part instead. Having feeble hot OP and always wondering when you'll spin a bearing sucks.
Re: New waterboxer oil pump slightly rough?
I get what you mean,ive ordered another pump and will pick it up tomorrow.
The rubbish haynes also says to lube up the gears, where as you say leave them dry. I have got a Bentley manual in pdf but it didnt really explain much about fitting an oil pump, unless ive missed it.
I will watch out to make sure i use the correct gasket, you say about not always needing an outside gasket but surely metal on metal wont seal properly?
The rubbish haynes also says to lube up the gears, where as you say leave them dry. I have got a Bentley manual in pdf but it didnt really explain much about fitting an oil pump, unless ive missed it.
I will watch out to make sure i use the correct gasket, you say about not always needing an outside gasket but surely metal on metal wont seal properly?
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tencentlife
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Re: New waterboxer oil pump slightly rough?
Why wouldn't it? The case halves seal together using only sealant, other places too. It's not metal on metal anyway, it's metal on sealant on metal, but the sealant will compress to much thinner than any gasket, too thin to measure.
I think like many you misconstrue the purpose of a gasket. In most locations a gasket's real purpose is to level out and cushion imperfections in mating surfaces. If the surfaces are good and flat there is no a need for a gasket, a little sealant will suffice. When surfaces are truly flat and mate perfectly, even sealant is superfluous. But that quality of machining is seldom found in budget cars like VW.
There is another reason, and this was the modus operandi of the OEM oil pump cover gasket VW always used on the boxers. That thin paper gasket was put in dry, but it was made of a paper that would soak up oil and swell to make a seal.
But the endplay of the oil pump gears is far more important that the presence of a gasket there, if the endplay is excessive the hot OP will suck. So observe my warnings above.
Use only a steel pump cover, and if it is used, dress it flat by rubbing it in a circular motion flat on a sheet of medium-grit emery cloth over a piece of plate glass or a very flat tabletop. Use plenty of WD40, kerosene (paraffin by your lights) or very light oil on the abrasive paper. Rinse and clean thoroughly with solvent after honing that way.
And, I never said to install the pump gears dry, I said to check them for endplay dry. You don't check tight clearances with lube in place because the lube takes up space and will give you false measurements. The clearance you are measuring is the space the lube fills once things are running. This goes for bearings, crank thrust measurements, most of the fitments of moving parts in an engine; measure dry, assemble with lube.
So you can get a quick pump prime once you begin to crank the engine on the first start, you definitely want some lube in the pump. But, if you put oil in the gears, it will dribble out (unless you stand the engine on its flywheel) and make it impossible to get a good cover seal using sealant. So, on the final assembly, dip the engine end of both gears into some grease, only deep enough to get up the gear teeth about 1/4" at most, and slip the gears into place. That way there is a wad of grease in there, but none at the face of the pump body where you need to apply sealant. Then once it's sealed and oil put in, the grease will spread around as the pump gears turn and make it suck air, which will suck oil, and the pump will prime quickly. Another tip is to wait at least an hour after filling the oil with the van on level ground, which will give the oil time to seep into the pump and partially prefill it. Also never crank the engine with the rear end of the van lifted when you need the pump to prime fast.
I think like many you misconstrue the purpose of a gasket. In most locations a gasket's real purpose is to level out and cushion imperfections in mating surfaces. If the surfaces are good and flat there is no a need for a gasket, a little sealant will suffice. When surfaces are truly flat and mate perfectly, even sealant is superfluous. But that quality of machining is seldom found in budget cars like VW.
There is another reason, and this was the modus operandi of the OEM oil pump cover gasket VW always used on the boxers. That thin paper gasket was put in dry, but it was made of a paper that would soak up oil and swell to make a seal.
But the endplay of the oil pump gears is far more important that the presence of a gasket there, if the endplay is excessive the hot OP will suck. So observe my warnings above.
Use only a steel pump cover, and if it is used, dress it flat by rubbing it in a circular motion flat on a sheet of medium-grit emery cloth over a piece of plate glass or a very flat tabletop. Use plenty of WD40, kerosene (paraffin by your lights) or very light oil on the abrasive paper. Rinse and clean thoroughly with solvent after honing that way.
And, I never said to install the pump gears dry, I said to check them for endplay dry. You don't check tight clearances with lube in place because the lube takes up space and will give you false measurements. The clearance you are measuring is the space the lube fills once things are running. This goes for bearings, crank thrust measurements, most of the fitments of moving parts in an engine; measure dry, assemble with lube.
So you can get a quick pump prime once you begin to crank the engine on the first start, you definitely want some lube in the pump. But, if you put oil in the gears, it will dribble out (unless you stand the engine on its flywheel) and make it impossible to get a good cover seal using sealant. So, on the final assembly, dip the engine end of both gears into some grease, only deep enough to get up the gear teeth about 1/4" at most, and slip the gears into place. That way there is a wad of grease in there, but none at the face of the pump body where you need to apply sealant. Then once it's sealed and oil put in, the grease will spread around as the pump gears turn and make it suck air, which will suck oil, and the pump will prime quickly. Another tip is to wait at least an hour after filling the oil with the van on level ground, which will give the oil time to seep into the pump and partially prefill it. Also never crank the engine with the rear end of the van lifted when you need the pump to prime fast.
Re: New waterboxer oil pump slightly rough?
Ah i thought you meant just use nothing not even any sealant.
I got the new oil pump today and measured between the gears and a flat surface, the smallest feeler gauge i has was .004 and i couldnt get it all the way in. So i wont use a paper gasket and will just put some sealant round the pump instead.
The new pump turns fine no roughness at all, ill get abit of grease in the gears and get it sealed up tomorrow
I got the new oil pump today and measured between the gears and a flat surface, the smallest feeler gauge i has was .004 and i couldnt get it all the way in. So i wont use a paper gasket and will just put some sealant round the pump instead.
The new pump turns fine no roughness at all, ill get abit of grease in the gears and get it sealed up tomorrow