View Full Version : Oil pump and check valve. 351 w

Mike Ingram
08-12-2012, 10:56 PM
Guys. I went ahead and pulled the engine tonight. No sludge to my surprise. No metal shavings. I did remove the oil pump. Pick up tube and screen. It all looked clean though. How would I know if my pump was bad and how do I locate the check valve. I saw something inside the pump. Not sure of that's it though.

Pimp is a ford pump. Was going to go ahead and replace it all. Do I need the stick pump r should I go with the high volume pump.

Thanks for all the help.

08-12-2012, 11:08 PM
Your preference, imo the stock pump will do just fine for your application

http://www.summitracing.com/parts/MEL-M83/?rtype=4 please watch this video...

Mike Ingram
08-12-2012, 11:20 PM
I'm thinking that too. As far as I know there are no performance upgrades in the motor. I think the pump was pumping good but the check valve may have been faulty as I had no pressure at idol. Just a touch of the gas an pressure would be back up to 25-30 lbs. If this isn't it I guess it's on to the bearings.

Wondering of te high volume pump would help with any worn parts.

08-12-2012, 11:23 PM
the high volume is $15-20 higher it won't hurt nothing to try it, but i still think your issue is the bearings, since you already have the engine out, why don't you plastigage the main and rod bearings, if the bearings are worn but the hard parts are not damaged you could roll some new bearings right in there...

Mike Ingram
08-12-2012, 11:30 PM
Yeah. I'm fearing it myself. May get lucky. How do you know if the pressure valve is bad. So will the high volume pump increase overall pressure or volume at all Roma. Just don't know much about them.

08-12-2012, 11:41 PM
High volume pump will just increase the volume of oil flow about 25% more and do nothing for actual oil pressure however it might provide enough flow to fill the excessive clearances and provide you with some pressure at idle, iirc the releif valve is built into the pump itself. if going to a high volume you might need to run a hardened oil pump drive depending on which mfg you go with.

Mike Ingram
08-12-2012, 11:57 PM
Thanks for the info. The parts stores around here carry melling pumps.

08-13-2012, 12:22 AM
I reckon Mike is pretty keen to change the pump and maybe not check those clearances!!!

Mike Ingram
08-13-2012, 12:37 AM
Unfortunately I don't even know where to begin to check clearances. What would that tell me. Rebuild or not. How can I go about that. Any tips would be appreciated as new to the engine internals. If it weren't for this forum I be lost.

08-13-2012, 12:43 AM

Mike Ingram
08-13-2012, 12:52 AM
Thanks. I've never seen one of those. Are they readily available. Can I just remove a main cap and measure it with the engine lifted and pan off. Looks fairly simple. Thanks much. I guess If there is excessive wear then the ony answer is rebuild.

08-13-2012, 01:06 AM
Yes your local auto parts should have it, no real need for a "rebuild" if the bearings are worn but the crank, caps and rods are smooth and doesn't show any damage then you can just replace the bearings one by one and then recheck your clearances. All this can be done with the engine hanging with the oil pan and pump removed and no need in removing the crankshaft, heads, pistons etc. You will need the factory specs and a torque wrench and a little bit of patience.

08-13-2012, 01:14 AM
Torque specs
Main cap bolts 95-105 ft.-lbs. Connecting rod bolts 40-45 ft.-lbs. Cylinder head bolts 90-100 ft.-lbs. Rocker arms 17-23 ft.-lbs. Intake manifold bolts 23-25 ft.-lbs. Oil pump bolt 23-28 ft.-lbs. Cam bolts 40-45 ft.-lbs. Cam thrust plate bolts 8-10 ft.-lbs. Harmonic damper bolt 70-90 ft.-lbs. Flywheel/flexplate bolts 75-85 ft.-lbs. Front cover bolts 12-15 ft.-lbs

Oil clearances should be main bearing .001-.00125 and rod bearing .002-.0025

Mike Ingram
08-13-2012, 01:26 AM
Thanks for all the help. I will give it a try. I'll keep you posted.

Mike Ingram
08-14-2012, 12:52 AM
Checked bottom end clearances with plastigage. That stuff is cool. got enough left for a lifetime. they were in the range for the main bearings. Replaced the pump with melli g high volume. New gaskets etc. have no idea about cam bearing condition. Did notice the timing chain had some play in it. Is that normal. Could be an issue of top end troubles. Anyway. I'm adding oils back. Used vr1. 20w 50. Mobile 1 filter. (long one ). Topped off filter with about 1/2 qt. then added 3 quarts to engine and says its at full line. Also bled off drain hose kit so it's full too.

I assume when I crank it it will show low and I'll need to add the other quart or so. I can imagine it only holding 3 quarts. Any ideas. Thanks again.

08-14-2012, 01:32 AM
1/2" deflection or less is within specs, anything over is considered stretched.

Mike Ingram
08-14-2012, 07:25 AM
Ok then that's about right then.