Oil pump driveshaft length?

Zero Signal · Aug 16, 2011

I dropped an ARP oil pump drive shaft into the block today and found it too short for some reason I compared it to stock and it's the same length as stock. This is in an original-block 347 with a Melling M68 oil pump. Does this oil pump require a longer driveshaft?? It's just kind of dangling in there on the clip without engaging the pump. Sliding the clip up doesn't take up enough slack to get it in there and also engage the distributor.

Zero Signal · Aug 16, 2011

I'm thinking I screwed up and need to drop the oil pan to install this thing. I think it's upside down.

Adam95GT · Aug 16, 2011

Skirt goes on the bottom to keep the shaft from coming out when your pull the ditsy and falling in to the pan.

Zero Signal · Aug 17, 2011

I guess I could probably run it without the clip, but I'd probably have the luck of dropping the shaft into the pan in the process of pulling the distributor out in the future. I'm just gonna drop the pan and put it in properly

Rick 91GT · Aug 17, 2011

The ARP shaft isnt relieved enough and bottoms out on MSD dists, one reason I use the Ford Racing shafts... Just something to keep in mind if your going back in the motor. I end up trimming the dist to gain the clearance is a ARP shaft is used.

Zero Signal · Aug 17, 2011

The distributor is a stock replacement, but it may still need to be trimmed. I wonder how far off it may end up? I hate to trim the distributor shaft and possibly throw it out of balance. I don't plan on doing anything crazy with this engine (stock heads, long story), so I might just use the stock shaft.

revhead347 · Aug 17, 2011

Yeah, I would just switch to a FMS hardened shaft. You do need to put it in with the oil pan off. It needs to go in from the bottom with the little ring on it to keep it from pulling out. If you don't put that ring on it, you will inevitably pull the distributer out later, and it will come up with the distributer, and then drop into your oil pan. It's like one of those things that Murphy's law dictates will happen. So you have to pull the oil pump back off to put it in too.

Kurt

Last5.0 · Aug 17, 2011

I forgot to install that clip years ago when I had my motor out redoing it. I've been lucky so far. I usually remember that it's not there whenever I pull the dizzy and just give it a little shake before pulling it all the way out so the driveshaft will drop out of it.

I wish they mad a spring activated clip that you put on the shaft and install from the top and once it's through the hole it springs out....like the carriage bolts you put into drywall to hang stuff

revhead347 · Aug 17, 2011

Installing that damn clip on the oil pump shaft is a multiple curse word event. You kind of have to stab it in there.

Kurt

Zero Signal · Aug 17, 2011

It seems to me, that one could strategically trim some side meat off the clip in such a way that it could be hammered through the opening. Once it's through, it should just splay out to it's original position. I'm sure it's made of spring steel, it's the only way it can hold itself on there so well.

I doubt I will go there though. I've already accepted the idea of dropping the pan again.

My main concern right now is whether or not the stock shaft will be ok with the M68HV pump. I have no way of trimming the bottom of the distributor to fit the ARP shaft.

revhead347 · Aug 17, 2011

I have no problem with an M68HV. The drive section should be the same distance from the distributer. Like earlier stated, you're probably better off just getting the FRP hardened shaft. Honestly, I don't know what's wrong with the regular shaft that comes with the pump. I have a stack of those somewhere. If the pump locks up, the shaft seems to twizzler up whether it's hardened or not.

Kurt

Adam95GT · Aug 17, 2011

Are you running the stock pan with the HV pump... I had clearance issues and it pushed a hole in my pan.

Zero Signal · Aug 18, 2011

I bit the bullet tonight and dropped the pan. My RTV job on the front and back kept the gasket stuck nicely to the block, so it was pretty much cake. Keep in mind, the engine is still on a stand.

The ARP shaft fit just fine with the distributor afterall. I had to bottom the clip out against the rounded part of the shaft, but it was fine and won't lift out. I didn't have to remove the pump to get it in, just aim it up in there just right and popped it in. This is starting to sound kind of dirty . . .

Also, it turns out it's not the HV pump, just the M68A. Seems to fit like the stock one. I have a rebuilt factory distributor and it sits perfectly. The driveshaft doesn't have too much play, but it's not tight either, so I sealed it back up.

revhead347 · Aug 18, 2011

If you get that really nice Felpro one piece gasket, you don't need any RTV on the oil pan. It's reusable too, and will probably last a good 10 years.

Kurt

Oil pump driveshaft length?

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Apparently my ex-husband made that mistake.

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Apparently my ex-husband made that mistake.

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Apparently my ex-husband made that mistake.

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Oil pump driveshaft length?

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