Will removing the oil pump change my timing? Or can the rotor move since the distributor shaft connects to the pump?
No. It won't move. The distributor has a tang that goes in the slot in the intermediate shaft. That shaft has the distributor drive gear pinned to it. That shaft and gear goes in from the top. You can take the oil pump off and none of what is above it will move.
I took it off because my oil gauge has been reading low, like 20-15 psi at 40-50mph. Yesterday driving to my aunts it read 50 psi on the freeway but dropped low once i was in traffic. Almost down to 5psi at cruising but 20psi at idle. When I drove home on the freeway my pressure went down to 5psi(@about 65mph). So I pulled over on the freeway and at idle my gauge read 20psi but would drop lower as I spend up. The faster I went, the more psi I would drop.
I assume that your oil level was good. What weight of oil are you running? How long has the engine been in operation (miles)? Did this just start?
I use Mobil 1 vr racing zinc oil, maybe 10-40. The motor has 95k original miles. I’ve been driving this motor since nov ‘19, when I finished this car. I never noticed a problem before until recently. At initial start the pressure is high but once driving around it drops low. I thought the pump would be full of sludge but there wasn’t any inside the pump. Even took it apart to see what’s inside but it was clean. The pick up didn’t look bad but the was sludge at the bottom of the pan. I doubt it made its way th the pump because I had to scrape it off the pan.My sending unit is electric.
I would pull the valve covers and have a look at the oil drain back holes. They are in the lower corners of the head and they are not particularly large. If they are partially obstructed and they will block oil drain back at high speed. The only other way for oil they get back would be after enough of it made it into the heads for it to end up going back down the holes for the pushrods. Here are the oil drain back holes in the heads.
I got this block with a crank that had two spun rod bearings. All four oil drain back holes, shown in the picture below as the center of the three holes, the left being one of the head bolts, were nearly completely plugged by crud. That was at the block level. If you have your pan off you may need to run a welding rod or other suitable long rod down through the drain back holes, hose them out with carburetor cleaner, and then blow them dry and clean with compressed air. If you want to go with the extra mile, get a .38/.380 bore brush from your local firearm store.
I didn’t know that middle hole was a drain back hole. The oil pan is off, I’ll run a wire like you say.
For illustrative be purposes, I ran a 3/16 TIG rod all the way through the one in my chassis. You will note by the shape of the rod that it is not a straight path, so a little effort is required to push it through. The hole in both the block and head are straight, but there is a direction change at the deck surface. Check all 4 holes, 2-per head.
If you do find them to be containing crud, make sure that you get it all out. Leaving any behind will just attract more buildup. If the drain back holes are severely restricted or plugged, the cylinder heads and valve covers are fully capable of holding the entire contents of the oil capacity, running the bottom end totally dry, before the oil spills back down via the pushrod holes.
found this from awhile back. relevant? https://www.jalopyjournal.com/forum/threads/oil-bypass-plug-confusion-for-331-hemi-help.446062/
If you already have the oil pan off it is very cheap insurance to replace the oil pump. 90,000+ miles is not alot on a modern fuel injected engine but a older carburetor fueled engine that you do not know the complete history of it can be. Change the pump and sleep easier.
I used the 340 hp Dodge oil pump and made a pickup tube from a 360 Dodge and the adaptor was from one of the after market mfg's if you go that way you will need the hex end gear intermediate pump drive for 331/354 or something like the Hot Heads pump http://www.hothemiheads.com/oiling_system/hi_volume_340_oil_pumps.html
There are some rebuild 'kits' floating around which requires no additional mods. Also, the main can be modified slightly and you can run the 392 pump (melling m50) but it will require a new pickup. The 392 pump uses the oem drive shaft.
Check the returns like has been suggested. The pump might be perfectly fine,,,,,just running out of oil . Like some realize already,,,,certain replacement pumps are hard to come by,,,unless going to the trouble of making another model fit . Like Gary suggested,,,the 392 piece is a great pump,,,,but needs a pickup . Tommy
I am taking down all this advice for my next hemi build- great info. Had anyone tried the rev engineering intermediate shaft/la oil pump kits- it appears they use the M72 HV pump with hex drive and cut an intermediate shaft with hex instead of the modified tang that seems to fail on the hot heads setup. The rev engineering intermediate shaft reminds me of a product that Kent Redd made for a while.
The HEMI Tech pages are a good source of oil pump stuff. HEMI Tech: Oil systems- filters, pumps, pans | The H.A.M.B. (jalopyjournal.com) Again, for anyone with a 331 needing a new oil pump, the M50 can be fitted without an adapter. Start reading at post 117
If your pump is in ok shape (no wear, no big scratches) then it is probably low oil viscosity or more likely a broken bypass spring causing the lower readings. Since your problem just showed up, I suspect a bypass spring failure. Positive displacement pumps like your oil pump either put out the exact designed volume or break something trying. They can't modulate, that's why they use the bypass unit so nothing breaks if flow is blocked. There are a lot of misunderstadings about oiling. Your engine needs volume but not pressure for good oiling. Engines use bushings (insert bearings) not roller or ball bearings. These bushings depend on hydrodynamic lube which is not dependent on oil pressure from the pump. With oil flooding the shaft/bearing clearance, as the shaft rotates there is a bank of oil that builds up ahead of the squeeze zone where the two components try to contact each other. This oil build up is a few molecules thick but reaches several thousand psi which easily suspends the shaft over the bearing surface. Thus the few 10s of psi that the pump supplies is irrelavent to the lubrication mechanism. As long as your pump gets the oil there, physics of hydrodynamic lubrication does the work. Oil pressure at the gauge is a representation of friction losses in the passages and resistance to flow into the bearing, not lube function. Installing a 'high pressure, high volume' pump just wastes hp and causes more wear in the pump, not better lube. This phenomenon was discovered in the early days of railroad engineering. Early rail car axles were bushings lubed with animal fat grease. They put in wood plugs on top of the bearing holders but they kept popping out no matter how tightly they were installed. They finally determined it was the extreme hydrodynamic pressures doing the deed. What year is your hemi? As stated above '51 thru '53 extended bell 331s have the bypass in the aluminum filter canister, not in the block. There is a 3rd small hole in the filter canister mounting pad to flow the bypassed oil back to the pan. The small hole on the left is the bypass port. The bypass piston and spring are under the big hex plug on the right. The bypass piston and spring are under the big hex plug on the upper right side of the filter can in this pic.
Yes THANK YOU! I’m sorry I didn’t post an update. I clean out the returns, they weren’t bad but my pressure is consistent so I’m happy. I bought the pump from hot heads. I don’t know what kind it is, it’s been modified to fit my motor. But fit perfect. On to another note i was going to message you about. I sold my other project roadster to fund a 33 5 window. I have a 9inch I want to use and it has some 36 rear bones welded to it. I plan to use a mild motor nothing over 250hp maybe a Y block or early 283. Will those bones hold up?
Most likely, yes, but I am a big fan of a simple torque arm, shackle at the leading end. They are not hard to make, and the steel 9-inch housing allows of veritable multitude mounting positions. For a 9, I like to do what looks like a single ladder barn, to the driver's side of the drive shaft, or essentially centered on the housing. This makes for good handling characteristics. You might not need the torque arm, but finding out the hard way means spending more money and time that building one.
My 33 frame has the 4link brackets welded on. You think that’s a smarter route, with coilovers and a pan hard bar?
Either one will work. The 4-link and coils will have a move "civilized" ride, assuming that the spring rate and shock valving is correct. The 4-link can move more, without restriction that split wishbones can. That said, a '33 won't have, or need all that much suspension travel, especially in the rear, so it is hard to say how much the difference would be noticeable. I guess it all depends on how much you want to fabricate.
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