Dauntless V6 Oil Pump Rebuild

Update

Even after shimming this pump out the oil pump continued to cause the distributor gear to wear. TA Performance advises that if you run a high volume oil pump, which they don’t recommend, that you use a “disposable” bronze gear since the extra drag tends to eat distributor gears (TA Peformance, 2005). I removed my high volume pump and replaced it with a stock pump. No more wear on the distributor gear. As such, I do not recommend using a high volume oil pump in your 225 unless you are absolutely sure you need it. 07/21/07 – This thread from V8buick.com backs up my assertations above from Buick V8 owners as well. A high volume oil pump is trouble and not necessary.

With the girdle and the adjustable pressure regulator the engine still maintains plenty of oil pressure.

The original article continues below.

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A Melling high volume oil pump was installed in this 225 when a new Edelbrock double rolling timing chain was installed. Unfortunately the clearance between the oil pump gears and oil pump cover were not correct. The gears were too tight, causing wear on the cover and eventually causing enough drag that the distributor gear gave way to the cam gear causing the Jeep to stop running. The cam gear was fine. The distributor was removed and oil pan dropped. Brake cleaner was used to flush out the timing cover cavity and oil pan. One tooth from the gear was found and some smaller pieces in the bottom of the oil pan. A new distributor drive gear was generously donated by Warloch from our forum here and installed to replace the one that had undesireable characteristics.

To remedy this a shim kit was ordered from TA Performance, phone: 480.922.6807, in Scottsdale Arizona to maintain the proper clearance, .002 to .003 inch, between the gears and cover. Along with the shim kit an adjustable pressure regulator was ordered and a thrust plate to cover the worn oil pump cover. Using a high volume oil pump kit along with these two items increases oil pressure in the 225 and oil flow. The pressure can be adjusted by turning a screw on the outside of the pressure regulator to attain the desired pressure. It is not recommended to use a high pressure spring in the pressure regulator. Use a stock rate spring or the adjustable that was used for this writeup which uses a stock rate spring.

The adjustable pressure regulator increases oil pressure off-idle while the thrust plate covers the worn oil pump cover, increases pressure at idle, and off-idle when the engine is warm by keeping the tolerances tighter. The aluminum cover expands when the engine is warmed up causing oil pressure to drop. The steel thrust plate acts as a girdle and prevents this from happening.

Click on any image to enlarge it, click on the image to close the new window that opens.

The Parts

Not shown are the oil pump gears, I reused the high volume oil pump previously installed.

The Tools

The Installation Process

Start by choosing the thinnest gasket in the shim kit and checking the clearance. Check the clearance by placing the straight edge over the gears and housing of the oil pump with the gasket in place. Make sure the gears are pushed into the housing all the way when checking the clearance. Keep adding shims until you are able to obtain .002 or .003 inches of clearance between the gears of the oil pump and the housing.

This is Courtesy of ObiWan, http://www.jedi.com/. It’s for an AMC V8, however the process is still the same.

For the first method, put a strip of red plastigauge (green only measures to .003″) across the end of the gears, then bolt on the pump cover & gasket. Remove the cover and check the width of the plastigauge with the scale on the package. For the first method, place a place a straight edge across the end of the pump gears and use a feeler gauge to measure the distance between the straight edge and the timing cover surface that mates to the pump cover. Subtract this distance from the thickness of your pump cover gasket (generally .010-.012″) to find your end clearance.

Once you have determined the proper gasket and shim combination you’re ready to assemble the oil pump. Pack the gears with petroleum jelly to prime the pump so when you start the vehicle it won’t run without oil pressure.

Assemble the oil pump by putting the gasket and shim in place. Make sure that the bolts do not extend more than 1/2 inch through the cover, thrust plate, and, if using a high volume oil pump, spacer plate into the housing. The shortest bolts were adequate in most of the holes with the second shortest bolts working where longer bolts were necessary. This ensured that no bolts were too long. Torque the bolts to 8-10 ft. lbs. of torque.

Double check with the distributor pulled that you can spin the oil pump easily using a flat head screwdriver. With the proper clearance it should spin with some drag but not be so tight that it takes great effort to spin it.

Be sure to have a mechanical oil pressure gauge hooked up and keep an eye on it. If the pressure doesn’t come up when you start the Jeep shut it down and recheck the oil pump!

The end result appears to be a leak free, tuneable oil pump now with proper clearance. It cost a few extra dollars but an oil pump isn’t something that should be skimped on. So far the Jeep appears to have plenty of oil pressure, I’ve not adjusted the regulator at all. Hopefully this will alleviate the issues this Jeep had with the oil pump dragging and destroying the distributor gear.

From Jerry Fulmer via the forums here:

TAperformance (the company that has the different gasket thickness kits) does NOT let you purchase over the phone if your credit card “is linked to your checking account,” they only accept a conventional credit card. Also, if you send in a personal check (the parts shipped to MI are under $20), it will take “approx 10 working days to process the check through the bank system.”

References

TA Peformance, Winter 2005 Master Catalog and Reference. Scottsdale: TA Performance, 2005.

Kaiser Jeep Corporation. Service Manual Jeepster Series Vehicles. Toledo: Kaiser Jeep Corporation, 1969.