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Oil Pan Depth Survey
Oil Pan Survey
Background : Group member Jimmy Bennick recently experienced an engine failure on his 71 429 CJ Mach 1. Upon disassembly of the engine, Jimmy discovered that the oil pump pickup was flush against the bottom of his oil pan resulting in a severe restriction of oil flow to his engine (see the witness mark from the pickup on the inside of the oil pan in the photo above). Jimmy, assuming the incorrect pickup had been installed, ordered a new oil pump and pickup from a major supplier designed for use on the 70/71 429 CJ/SCJ (as indicated in the parts catalog). He found this to be the same part as the previously installed pump and pickup with the same improper clearance to the bottom of the oil pan!
(Note: Click thumbnails to enlarge pictures.)
What This Means To You
Many of us at some point will need a new oil pump/pickup for our 429 CJ/SCJ engines. It is in all of our best interest to get to the bottom of this problem so the cause of the pan/pickup interference is understood. One possibility of the cause of this problem is oil pan depth. Are all 429 CJ/SCJ oil pans the same, or were there different depth pans? Maybe some 429CJ’s over the years have truck or passenger car pans on them? We would like to establish the depth of 429 CJ/SCJ pans out there to see if there is significant variation in depth and if so, how much it is.
How You Can Help
Measure the depth of your pan for us (either on or off your car! ). Once we understand the cause, we will try to make a recommendation on how to avoid this issue.
Measuring Pan Depth on the Car
Place a straight edge on the bottom of your oil pan that extends out past the sides. Measure up from the straight edge to the pan rail close to the 3rd bolt back from the front. Report your findings to the nearest 1/8″.
Measuring Pan Depth off the Car
Lay a straight edge across the pan rails at the 3rd bolt hole back from the front. Measure down from it to the bottom of the pan. Report your findings to the nearest 1/8″.
| Survey Results – 1/6/03 | ||
|---|---|---|
| Data Supplied By | Measured ON Car | Measured OFF Car |
| Greg Wong | 8 1/2″ | – |
| Don Brasier | – | 8 1/4″ |
| Jay Pape | – | 8 3/16″ |
| Jim Scott | 8 1/2″ | – |
| Jess Brin | 8 1/2″ | – |
| Robert Sullivan | – | 8 1/4″ |
| Fred Coyner | 8 4/8″ | – |
| John Blair | 8 1/2″ | – |
Resolution
From Rich:
Melling makes the two pumps/pickup assmeblies…one short one and one taller.
As Jimmy showed us in the list Melling sent him, both pumps say “CJ”, but one is for a short pan, and the other for a deeper pan.
Jimmy ordered his pumps from Summit Racing. Summits catalog list both pumps, but only has the “CJ ” engine pump assm listed for the deeper oil pan, so Jimmy ordered their TALLER CJ pump, and I also agreed with him at that time it was the correct pump, from my Summit catalog, based on Summit’s “CJ” listing.
What CJ owners have to do if ordring from Summit, or anywhere else, is to make sure they get the pump for the short pan, which is the correct CJ pump. That will insure the correct space between the pan and pickup then.
If Summit used the “CJ” name under both listings, then a buyer would just choose the correct pan depth to order the correct pump.,,,but since /Summit only has one pump listed as being “CJ”, that’s where the problem lies, and CJ people then order the wrong pump.
(Still don’t know what that long pump/ pick-up and deeper pan were used on……maybe some sort of truck or motor home maybe??)
From Jimmy:
It looks good to me. I think we all came up with mostly the same results. So if any of us order an oil pump for a S/CJ for our Cougar, Mustang, Torino, Cyclone, Montiego, etc. You will get the wrong one. It will be too deep.
It looks like the Melling high volume oil pump # M84BHVS for the “(standard)” 429-460 is the one that fits. It is marked “EXCEPT CJ” in all the catalogs. The Summit Racing catalog lists the std pump as 8-1/4″ deep and the CJ pump as 8- 5/8″ deep. I guess they got back so many they started stating the depth.
