All times are UTC - 8 hours

Post new topic Reply to topic  [ 8 posts ] 
Author Message
Offline
 Post subject: XPAG oil pump rebuild
PostPosted: Tue Jul 02, 2019 1:16 pm 

Posts: 87
I am in the process of rebuilding my oil pump and have a question: I have finished the new gears (they were oversize for my pump) and now have the correct clearance with the end plate in place however there is some end float on the driveshaft. Has anyone any experience of putting a washer/shim underneath the circlip on the end of the shaft to take out this end float or is this common and should I just leave it alone? Thanks. Tim.


 
 Profile  
 
Offline
 Post subject: Re: XPAG oil pump rebuild
PostPosted: Tue Jul 02, 2019 1:34 pm 
User avatar

Posts: 232
How much end float have you got? .002" is normal!


 
 Profile  
 
Offline
 Post subject: Re: XPAG oil pump rebuild
PostPosted: Tue Jul 02, 2019 2:38 pm 

Posts: 87
Hi Marv - the gears have .002" end float with the end plate fitted. There is however a gap between the gear that is driven by the cam and the pump (cant think how to describe this but if you take the pump end plate off you can move the spindle up and down by .025") With the pump built up I only have .002" float but don't know if the axial movement in the spindle with result in the gear digging in to the end plate?


 
 Profile  
 
Offline
 Post subject: Re: XPAG oil pump rebuild
PostPosted: Tue Jul 02, 2019 4:52 pm 
User avatar

Posts: 232
Hmm'm I just finished rebuilding my TC pump with new gears and a new spindle. I didn't have that problem. But if I understand what you are saying. if you were to place a .022 +/- shim under the snap ring, it would pull the shaft up so as not to have so much end float. You'd have to make sure the drive gear was seated deeper on the key to keep it proper to the driven gear and pump cavity.

First! Are you sure the shaft drive gear is the right way around on the spindle? There is a small oil groove at one end of the drive gear from the center hole out to a tooth space. Presumably to allow lubrication to the base of the gearset. I haven't seen notable mention in any publications on it but popular notion is that it is installed groove down.

Secondly! Your fear of axial movement of the spindle is probably not an issue. Due to the position of the oil pump, the rotation of the camshaft’s skew gear tries to draw the mating skew gear and drive spindle of the oil pump into the crank case. This axial force is resisted by the circlip retainer at the pump end of the drive shaft and prevents the drive shaft being pulled through the pump’s driving gear. It is probably more important to make sure you have a quality circlip installed than worry about axial movement grinding into the cover plate. Tales of failed circlips are ugly at best. :x


 
 Profile  
 
Offline
 Post subject: Re: XPAG oil pump rebuild
PostPosted: Thu Jul 04, 2019 3:08 am 

Posts: 87
Thanks Marv. I had thought that the drive would tend to pull the spindle inwards but it's nice to have someone else think the same way. I have a new circlip from the Octagon Club but the original looks stronger and may stay with that one.


 
 Profile  
 
Offline
 Post subject: Re: XPAG oil pump rebuild
PostPosted: Thu Jul 04, 2019 6:43 am 
User avatar

Posts: 232
You're welcome, Fill the ports and gear cavities with Petroleum Jelly or White Lithium Grease and button it up. Fill the filter with as much oil as you can without making a mess before installation. Both actions help achieve system pressure more quickly than starting with everything empty. Torque your NEW bolts carefully and you're good to go. Good Luck...


 
 Profile  
 
Offline
 Post subject: Re: XPAG oil pump rebuild
PostPosted: Wed Jul 17, 2019 8:05 am 
User avatar

Posts: 31
Location: GUILDFORD, Surrey, UK.
There's a bit more detail on the circlip problem in the web based Totally T-Type 2 Issue 54 June 2019. Try http://ttypes.org/ttt2/xpag-oil-pump-rebuild.
From your description you have an end float of just 2 thou. in the shaft, but what is the gap between the pump's body and the skew gear on the drive shaft? There's an implied gap of 25 thou. when the pump's end plate is fitted due to the shaft being pushed in. This suggests that the end of the shaft is in contact with the end plate. Is this the case?


 
 Profile  
 
Offline
 Post subject: Re: XPAG oil pump rebuild
PostPosted: Thu Jul 18, 2019 7:29 am 

Posts: 87
Thanks Eric - I have seen the ttt2 article. You are correct in that I have a clearance within the pump of 2 thou. I have now installed the old clip on the shaft and as it fills the groove it doesn't allow the shaft to be knocked/tapped further down as was the case with the thinner circlip I originally installed as a new replacement during the re-build - I hope this makes sense?


 
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic

All times are UTC - 8 hours

Who is online

Users browsing this forum: Google [Bot], MSN [Bot] and 12 guests

Powered by phpBB