Jeep 225 V-6 Oil Pump Turns Hard

[bryanb]

Getting my 225 back together, not rebuilt, I just took it apart to look things over. Question I have is how difficult should my oil pump turn. I did put in a melling high volume kit a couple years ago, I just don't remember what it felt like. I wanted to confirm oil flow so I rigged up a priming tool, one handed is somewhat hard. I put it on my drill motor and it really makes the drill work to turn it. Definitely pumps oil (all the way across my garage) just a little concerned with the pump. Any thoughts?

[Moses Ludel]

bryanb...One concern with the Melling high volume oil pump for the Buick V-6 or an AMC V-8 is precise alignment of the kit's spacer with the timing cover/pump housing.  The high-volume pump is primarily longer gears.  The pump's spacer must align perfectly with the timing cover/oil pump housing to prevent the gears from dragging against the spacer or timing cover cavity.  (I illustrate this is the Jeep CJ Rebuilder's Manual: 1946-71.)

This pump installation uses a spring roll pin to align the spacer with the timing cover/pump housing.  If you believe the gears are dragging or that the spring roll pin is either not present or has become misaligned, inspect the assembly.  The spring roll pin centers the spacer, the pump bolts hold the assembly snugly in place.  There should always be precise oil pump gear clearance at the timing cover/housing wall and also between the oil pump spacer bores and the gears.  Gears must not contact the pump cavity wall or the spacer bores.

As far as drag on a drill motor, it does take considerable force to rotate an oil pump that is picking up oil from the pan.  That, in itself, is not unusual.  Weight of the oil plays a role here, too.  Also, if you packed the cavity with petroleum jelly, there may be additional drag until the oil flushes out the petroleum jelly.  What weight oil are you priming?

Moses

[bryanb]

Moses,

I am using just cheapo 10-40. A bit of history, I took this timing cover off a motor that I destroyed. #1 and #5 rods broke, destroyed the block broke the cam, timing gear ect ect. I am wondering if when the cam broke it may have jammed up the oil pump a bit. I just couldn't recall when I installed the high volume kit originally if it turned relatively easily by hand. I did use great care when I did the kit, using the spacers and such to locate the gears before I drilled for the spacer plate roll pins. I'm thinking a new timing cover and oil pump kit are in order. I'm pretty nervous about this one.

[Moses Ludel]

bryanb...Does the distributor shaft turn freely by itself?  Is the distributor drive gear and lower shaft running straight?

The camshaft front gear drives the distributor.  The distributor drives the oil pump.  It's conceivable that the broken camshaft could have placed a heavy side load on the distributor, perhaps enough to bend the oil pump's input shaft?  The oil pump's drive shaft could be binding, though you would likely have accompanying trouble with the distributor.  Worth checking but a stretch.

Describe or share a photo of the priming tool.  If not centered and running true, the priming tool could cause the bind you're describing.  The best priming tool is either a modified old distributor (drive gear teeth and centrifugal advance mechanism removed, just the distributor shaft, the remaining sleeve of the distributor's driven gear and the distributor housing) or a commercial tool with a fitted collar that centers at the distributor bore.  The sleeve of the distributor's driven gear (with teeth removed) captures the oil pump's drive end and helps keep the priming tool's shaft on center.

Here's an illustration of a quality priming tool, actually for Chevrolet V-type engines, but you'll get the idea.  (Buick is not mentioned here, it's unclear whether this could be used on a 225 Buick V-6, and dimensions would have to be compared.)  Note the way this keeps the shaft on center and the capture sleeve at the bottom of the shaft to align with the oil pump drive.  Enlarge the image for detail:

https://www.summitracing.com/parts/mel-pt13 [This is the Melling version.  There are less expensive knockoffs at Amazon and elsewhere.  Confirm fit for a Buick V-6.]

Moses