Low oil psi 454 500HP
 

I have a 454 was previosly a 330hp now new cam, dome pistons . etc 500hp motor. I just fired it up and has low oil pressure, cold its 36psi but at 120f-140f its around 28psi.. I revved it up to 2000 rpms and its stays around 27 psi- I dont feel comfortable running the boat for the first time with these #s mercruiser says min 30 psi at 2000rpm
The boat has morel lifters and scorpions rockers, i am getting steady ticking out of them when my head is 2 feet from the motor, thinking its maybe the low oil pressure, i put my fingers on the rocker while running and it has a some oil but not squirting everywhere..
My plan is to put hv pump in this week, could it be any other issues?
using k n oil filter
put mechanical oil gauge

:eek:

I do not know if this is your problem but did you upgrade your oiling system?
Did you reverse the oil lines?
How about the valve on the oil pad?

i didnt update system or change the valve on oil pad. maybe it could be stuck open??

Did you replace the oil cooler and lines.. If not that is prob your problem.. Never re-use oil cooler and lines no matter who clean's them. If you blew up a motor before then it will have crap in it that will only ruin your new motor.

Chris

Teague on tech in powerboat just answered a very similar question last month. I dont have the mag handy though.

I never blew it up, it ran great just rebuilt and put in cam and new 781 heads.. Could it be the valve were original oil filter goes

Sounds like you missed a bunch of steps. If you are reusing the stock hardware from the 330 you will be breaking parts for a while. Upgrade your oiling system before you every launch the boat.

Spent 6 hours last night ripped motor or and replaced oil pump with a melling high volume. Which was the same pump in it. This motor use to have perfect oil pressure with the oil system it has, regardless the new pump did the exact same pressures, the boat is on the trailer now and staying cool 140f so I cant see that as a prob, were could the machine shop have left out oil gallery plugs???? Bc under valve cover there's some oil but not squirting.

What engine block do you have. There are three oil galley plugs behind the front timing chain upper gear. There also may be three plugs inside the lifter valley just above the camshaft. If these plugs are left out the oil pressure will be low, the oil will still be captured inside the engine and not leak out. Who assembled the engine, check with the machine shop that did the work and see if it is their practice to leave galley plugs out, or if they normally install all the galley plugs. Provide some information about the year and generation of the block you have. All other galley plugs will leak oil out of the engine. Good luck.

Did you ever try a mechanical gauge?

The May June issue of powerboat mag has an entire article about this. If you have checked for the oil galley plugs. Then the other two issues they cover are the oil pump which they say should be a mellings 10778-c which has grooves cut in the housing to prevent cavitation or they sead to use a 10778 mellings which is the same as above but with out the cavitation protection, but they both have the correct reef valve spring. The other issue they covered that I haven't seen mentioned in here is you bearing clearances. They say the main bearings should be .003 in on 1 through 4 mains, and .0034 on rear, and connecting .0027 to .003. Your bearings on the cam is something else to check. I am not sure what the clearances should be on those. Hope it's just the pump because the bearing can be a lot of work. Good luck Eric.

Yes mechanical and electric are both the same, i read about the ones under cam sprocket today and intake that is our next step.. Appreciate all the help guys...
The motor is a generation 6 with morel lifters and new pushrods.

The motor has only ran on a trailer 4 times now for 5 min sessions mainly cheacking this issure.
The boat is not in the water so there cant me cavitations issues, motor is basically level
The original oil pump was damn near laying on the bottom of pan, we riased it up a **** hair (3/8) lol and re shaped pan a bit..
Again original pump ran like a bat out of hell before rebuild.
We checked main tolerances when installing but they were fine before we rebuilt anyway. Motor only cam out to get new head and cam , but then said **** it and bored it .030 and through domed pistons in it with cometic gaskets .027 I think to got 9.3:1 compression. Has new timing chains thats why i cant see it missing oil galley plugs but well see, any one have pics of these plugs???????????/? thanks Adam

You still do not get it. I relize the small oil cooler, restrive fittings and lines are not the cause of your current problem of low oil pressure. That setup will not support more HP, you will run your oil hot and destroy your engine. I know thats one of the things I did wrong. After you blow it up you will blame everyone but yourself. :angry-smiley-038:

Here is what I did to improve oiling. I now have a 3" combo cooler from EMI, there are many other companies that make them. I switched out all the lines and fittings to 12AN, get a new filter relocator, I use the one from canton racing. Make sure the center valve on the oil pad is removed and the one on the side is plugged or has the 30psi valve. I also used a rotory tool and cleaned up the ports on the filter housing. Use a oversize oil filter and synthetic oil after break in. Hope this may help you. I have not had a engine failure since I did this.

Pantera on this forum the post "restrictors or plugs" He has pictures of the lifter valley plug locations. His question does not apply to you, hydraulic lifters cannot use restrictors.

Im going to check if the blogs are in the intake manifold and under cam gear?

Regarding the oil cooler ill look into changing it out, just want to get psi right and get backon water for a little while ill take it easy on the motor and install a oil temp gauge.

Did you have the crank ground. If so are you sure the correct bearings were used for reassembly. It's really starting to sound like you need to disassemble the entire engine and recheck all your bearing clearences.

Took of intake manifold today plugs were in :(. Will check for the ones in front of cam tomarrow...

Didnt do anything to crank, i did check bairing tollerances when assebled...

I am wondering if plugs are in front of motor can it be the bypass springs in oil filter?

Its pumping like a champ to the distributer housing when i spin with drill....

What clearance did you set the rods/mains? You should cut open the oil filter and look for metal before running it any more.

The bearing clearences on the crank, mains and rods pretty much determine your oil pressure, of course unless a plug was left out. As blue thunder suggested you may want to cut open your oil filter. You may have spun a bearing and now have excess clearence there. Or the worn crank ate up the new bearings.

I assume you put new bearings in it. New bearings on a worn crank don't always work out well.
Kind of like putting new brake pads on a old worn out rotor.

I'll cut the filter open but I took belly pan off last night to put in new oil pump and I didn't see any steel.

No metal in the pan is a good sign. What oil are you running?

40 weight, when i took of intake manifold i notieced a loose push rod, could loose push rods be messing up oil pressure?

I was able to get the valve cover off with exhasue manifold still on so i am going to start the motor and adjust valves while running, the zero lash and half turn must have not done it properly, plus a lifter could have collapsed

A loose pushrod wouldn't do it. Readjusting them isn't going to make a difference either.

What exactly do you mean by "raised it up a bit"? The Pick-up should be approx 3/8" off the bottom of the pan and should be perfectly square with the bottom as well.

"reshaped the Pan a bit"??????:eek:

How much oil do you have in it? Too much oil can make it have low Oil Pressure as well as not having enough

You stated this was originally a 330. Was there such a thing as a 330 gen 6? Is this carb or fuel injection? Also see you have 781 heads which are mark lV heads.



Eliminator28, you stated that too much oil can make it have low oil pressure. Can you elaborate on this.

The crank will hit the oil if the level it too high and can create air voids in the pan for the pump to suck up. This would be erratic OP though not consistently low. Unless done enough to take out the mains, then consistently low.

I've never had it happen to me, but I think a bad lifter could create a major internal oil leak.

Just saw this, sorry I cant be of much help when it comes to BB stuff, especially oil pressure issues. I agree though to check the pickup height, and reshaping of the pan?? When you say 40 weight, is it straight 40, or like a 15w40 rotella?

Like Blue Thunder said.. With the oil level too high the crank counterweights hitting the oil will airate it, making OP eratic.

IMHO, I would take a few steps back at this point and go back to triple checking bearing clearances on the mains and rods. You are looking for a simple smoking gun and not finding it. I know you want to be in the water tomorrow, but it will be easier to find the problem by checking all the what if's now rather than blowing it up later. Just my .02

http://youtu.be/7IpJlYssvkM

Listen close starting at :56

The pan had a slight dent in it nothing insane, so we tapped it out and the old pickup had touched the dented service, so we fixed pan and adjusted the new one a little higher , measuring to keep it 3/8 of the bottom...

Since the rockers were loose the motor was making a ticking noise, so were going to adjust with motor running to get rid of that problem, the oil is straight 40 weight, used in diesal trucks, we put this in after trying the 15w40 and haveing low psi

Pantera,

You are missing something very simple. I think as much as you dont want to, you need to pull the engine down one more time and triple check ALL of the bearing clearances. If the engine had good oil pressure before, and nothing was done to the crankshaft, then it should have good oil pressure now.

One thing to check first .... are the lifters the same ones that were in the engine before ??? If not, or maybe even if they are, is the oil hole in the lifter either coming up too far or going down too far and getting uncovered during operation ? That will certainly bleed off oil pressure and cause a similar problem. If the cam is ground with a smaller base circle and the lifters are not correct, they can go down too far and uncover the oil hole.

Other than that, you really need to go back to basics and forget about all of the trick issues. It is somthing very simple causing the problem.

Bill Koustenis
Advanced Automotive Machine
Waldorf Md

The symptoms are exactly what I experienced when I replaced the stock shrouded hydraulic roller lifters with unshrouded Crane lifters in a Gen 7 (496HO) engine with non stock cam. At max cam lift the top of the slot in the Crane lifter (that the roller sits in) would breech the bottom edge of the lifter oil gally ~0.030" and release oil past the roller and back into the crankcase. Oil pressure was great before the Cranes and after I put stock lifters back in.

These are very good reply's, and sound like the most plausible suspect based on the symptoms (ticking and little oil coming out on the rocker end).

You know what?
I took a brand new race engine apart one time because of low oil pressure. turned out to be a faulty oil filter.
I would change the oil filter and try that before I pulled the engine again. Just sayin.!!!!


Thank You FRAM. :(

I adjusted rockers today no more noise...
the pushrod is sending oil though up to the rocker there is a puddle there, @ 800rpm 20-30psi, but its not filling up enough to go through the next hole which is the front bairing rolling on the valve stem..

the lifters are morel from marine kinetics and so is the cam..
It could be possible that the oil hole isnt lining up... If we modify a distributer cap so the oil will run to the lifter gallery we can see if its leaking..

Maybe i do need to try a set of stock lifters are they the same size?? so i could use my new custom pushrods ? I dont have a morel to measure bc there in the motor..

Do i need to run the 1/6 inch piece of steel that covers cam under intake manifold or it doesnt make a difference.??

Will putting the boat in the water with a load on it maybe change anything? im getting 35psi when rev to 3000rpm on trailer dont think it would hurt for a 20 min low rpm test

You should have 80lbs. cold at idle with that pump and 40+ at idle hot. If Bob set you up with that cam and lifters than I doubt that is the problem.

Have no idea what your talking about with modifing a distributer cap.

The 1/6 inch piece of steel under the manifold?

Putting it in the water won't change anything. Don't waste your time and engine.

Are you sure this is a gen 6 block. Is it a carb engine? Does it have the fuel pump on the block or on the waterpump or electric pump?

What part number oil pump are you running?

I asked this question a long time ago, but did you make sure you do not have the oil lines reversed?