Installation of S&S M8 cam plate & pump
#51
07-06-2018, 03:23 PM
The stock pump has two scavenging pickups, one for the cam case and one for the sump in the crankcase. It only has one scavenging gerotor which is the pump pulling on both pickups. So if the cam case gets pumped dry the pump will suck air on that side which can cause it to lose prime on the crankcase side which will result in sumping. Try putting two soda straws in your mouth, one shorter than the other. When the liquid gets below the short straw it will be harder or impossible to suck liquid through the other straw as long as you are pulling through both.
The S&S pump has a gerotor or pump for each pickup which makes it more unlikely the sump side will lose its prime. The money invested in it when doing any upgrades or even if it is your only upgrade is well spent in my opinion.
On the TwinCam they managed to counter this by making the sump pickup longer and smaller which also helped counter the variances in crankcase pressure caused by the pistons going up and down. The M8 just has a big hole on the right case where the oil pump connects. Harley has tried making the oil pump pickup smaller, whether that is working I can't say. Also, that's why if you idle it on the side stand there may be some extra oil collect in the sump. The S&S won't keep that from happening, but it should clear it soon after you stand the bike up straight.
The S&S pump has a gerotor or pump for each pickup which makes it more unlikely the sump side will lose its prime. The money invested in it when doing any upgrades or even if it is your only upgrade is well spent in my opinion.
On the TwinCam they managed to counter this by making the sump pickup longer and smaller which also helped counter the variances in crankcase pressure caused by the pistons going up and down. The M8 just has a big hole on the right case where the oil pump connects. Harley has tried making the oil pump pickup smaller, whether that is working I can't say. Also, that's why if you idle it on the side stand there may be some extra oil collect in the sump. The S&S won't keep that from happening, but it should clear it soon after you stand the bike up straight.
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OzHD (07-07-2018)
#52
07-07-2018, 05:33 AM
Tourer
#53
07-07-2018, 08:32 AM
Club Member
Exactly. The space between the inner and outer rotors are measured with a feeler gauge. The inner ring is driven by the crank and the outer ring rotates in a precisely machined bore thats mounted to your crankcase. The runout on the crank will force the pump to move like an eccentric almost (exaggerated of course) in a way which will destroy the pump and the plate.
#54
07-07-2018, 02:00 PM
The stock pump has two scavenging pickups, one for the cam case and one for the sump in the crankcase. It only has one scavenging gerotor which is the pump pulling on both pickups. So if the cam case gets pumped dry the pump will suck air on that side which can cause it to lose prime on the crankcase side which will result in sumping. Try putting two soda straws in your mouth, one shorter than the other. When the liquid gets below the short straw it will be harder or impossible to suck liquid through the other straw as long as you are pulling through both.
The S&S pump has a gerotor or pump for each pickup which makes it more unlikely the sump side will lose its prime. The money invested in it when doing any upgrades or even if it is your only upgrade is well spent in my opinion.
On the TwinCam they managed to counter this by making the sump pickup longer and smaller which also helped counter the variances in crankcase pressure caused by the pistons going up and down. The M8 just has a big hole on the right case where the oil pump connects. Harley has tried making the oil pump pickup smaller, whether that is working I can't say. Also, that's why if you idle it on the side stand there may be some extra oil collect in the sump. The S&S won't keep that from happening, but it should clear it soon after you stand the bike up straight.
The S&S pump has a gerotor or pump for each pickup which makes it more unlikely the sump side will lose its prime. The money invested in it when doing any upgrades or even if it is your only upgrade is well spent in my opinion.
On the TwinCam they managed to counter this by making the sump pickup longer and smaller which also helped counter the variances in crankcase pressure caused by the pistons going up and down. The M8 just has a big hole on the right case where the oil pump connects. Harley has tried making the oil pump pickup smaller, whether that is working I can't say. Also, that's why if you idle it on the side stand there may be some extra oil collect in the sump. The S&S won't keep that from happening, but it should clear it soon after you stand the bike up straight.
So the S&S fixes the sumping problem? Now... would putting that on a new Harley invalidate the warranty? (I'm guessing that's "yes", but please say I'm wrong).
Hmm... will it fit on a trike OK?
#55
07-07-2018, 02:27 PM
Outstanding HDF Member
See no reason not to fit a trike.... I view it as good insurance. Would never take a bike back to a dealer for engine work anyway. Lucky they get tire pressures correct..lol. I have no idea why guys would even think about the BS stage crap with so many real engine builder out there. Why take it too a parts changer unless you can't afford it so you put it in your financing . Yikes
#56
07-07-2018, 02:41 PM
Makes sense.
Part of me feels that the dealer warranty should mean something. Why should they get away with crap service and quality while I pay extra for an after-market engine fixer?
I asked about the pump - which should very well fit OK - becasue I've been told by HD Australia that the Screaming Eagle upgrades from 107 to 114 or 114 to 117 won't fit a trike. Which is a bit of a ****. or were they lying? Anyone with a trike know for sure?
It's not a game killer for me buying a trike (losing the SE upgrades), just a mild disappoint.
(I don't finance, never have, I buy outright or not at all)
Part of me feels that the dealer warranty should mean something. Why should they get away with crap service and quality while I pay extra for an after-market engine fixer?
I asked about the pump - which should very well fit OK - becasue I've been told by HD Australia that the Screaming Eagle upgrades from 107 to 114 or 114 to 117 won't fit a trike. Which is a bit of a ****. or were they lying? Anyone with a trike know for sure?
It's not a game killer for me buying a trike (losing the SE upgrades), just a mild disappoint.
(I don't finance, never have, I buy outright or not at all)
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