Oil Pump again

[Lin]

Last week I enquired about whether I should replace my oil pump with the engine rebuild. Most responders said to definitely replace - a few said inspect and if OK reinstall. While I think I will accept the advise to replace, I am curious so I took mine out tonight.

I have a gear pump, not the earlier rotary. The bush on the top does have some scoring, not deep but evident. Is that the primary concern?

The tolerances around the gears seem pretty tight (less than .002). Do I just check the gap between the gear teeth and the wall?

Most everyone claims that the rotary pump is better. Should I order a rotary type even though it was not original to my car? I assume the fit is interchangeable.

Finally, How are the two pipes (valve drain pipe and I don't know what the other one is called) removed? Do they unscrew? If so, with what - vice grips?

Thanks as always!!

Lin
1960 BT7 in restoration
1959 Bugeye

 

[Keoke]

Hi Lin, IMOP the gear pump is the best pump. Maximum Tolerances on the internal parts are:
End float=0.0016"
Gears to pump Body =0.005"

Vise Grips!!-- /ubbthreads/images/graemlins/nonono.gif-??

Fwiw---Keoke-

 

[Randy Forbes]

[ QUOTE ]
Last week I enquired about whether I should replace my oil pump with the engine rebuild. Most responders said to definitely replace - a few said inspect and if OK reinstall. While I think I will accept the advise to replace, I am curious so I took mine out tonight.

I have a gear pump, not the earlier rotary. The bush on the top does have some scoring, not deep but evident. Is that the primary concern?

The tolerances around the gears seem pretty tight (less than .002). Do I just check the gap between the gear teeth and the wall?

Most everyone claims that the rotary pump is better. Should I order a rotary type even though it was not original to my car? I assume the fit is interchangeable.

Finally, How are the two pipes (valve drain pipe and I don't know what the other one is called) removed? Do they unscrew? If so, with what - vice grips?

Thanks as always!!

Lin
1960 BT7 in restoration
1959 Bugeye

[/ QUOTE ]
I was told a couple decades ago, by the folks at Southern Carburettors, that the rotary pump was preferred for sustained high RPMs. I have no dyno proof to back that up, but the several annual tear-downs from when I used to compete with my car seemed to bear that out (while they were always replaced, I kept the main & rod bearings removed during those inspections because they still looked like new). Another plug for Castrol GTX 20w/50 too /ubbthreads/images/graemlins/wink.gif

Yes, the two (2) tubes unscrew (standard RH threads, nothing funny).

 

[Terry_Geiger]

The BPNW site seems to indicate the rotary pump is better for street driving (better oil pressure at lower RPM) and the gear pump is better at high RPM (more oil pressure at higher RPM). I have no proof if this is true or false, only reporting what I found. Can someone look in the Bentley manual and see what the differences are? I'm working from memory (which is a dangerous thing for me) but I believe the gear pump equipped engines were expected to run 20PSI at hot idle and the rotary oil pump equipped engines were expected 25 PSI at hot idle, which would tend to support the theory that the rotary is better at lower RPMs.

I'm waist deep in a 3000 engine rebuild right now and it has a gear pump. The engine was torn down due to low oil pressure. The gears are heavily worn with a lot of play between the gears and the wall of the oil pump. Also, you can see where the gears are not making full contact with each other which is causing some loss in the gear pump. I'm interested to see where this thread goes as we'll be purchasing an oil pump soon and I'd like to go with what makes sense in a street engine.

See this link: BPNW Oil Pumps for AH 3000

[ QUOTE ]
I was told a couple decades ago, by the folks at Southern Carburettors, that the rotary pump was preferred for sustained high RPMs. I have no dyno proof to back that up, but the several annual tear-downs from when I used to compete with my car seemed to bear that out (while they were always replaced, I kept the main & rod bearings removed during those inspections because they still looked like new). Another plug for Castrol GTX 20w/50 too /ubbthreads/images/graemlins/wink.gif

Yes, the two (2) tubes unscrew (standard RH threads, nothing funny).

[/ QUOTE ]