oil flow

[jeff dewberry]

i was wonder in what order does oil flow through an engine

[Beefy's Bronco]

I think it depends on the engine. What engine do you have?

[towtrucks]

Basically, the oil is picked up by the oil pump, then pumped to the crankshaft where it then goes to the crank bearings, then the rod bearings, then he cam bearings. The oil also travels up the block to the lifters and up the push rods, this is also where the pressure is recieved by the oil pressure switch.

[Gearhead52]

Chevy, SB...Cam then crank. BB....both..oil gallery down skirt of block then to crank, plus oils up the back of the engine to the rear cam journal then along each lifter. Both feed the cam and overhead at the same time.

Ford is usually to the crank then to the lifters which feed the valve train.

Dodge....not sure. I do know they still use rocker shafts so they oil these through a oil gallery port from the block to the head....I think.

[jeff dewberry]

i have a 70 sb chevy
with low oil presure and i was wondering if the oil was getting to everything before it got to the sending unit and it sounds like it does like it oils the cam bareings last and that is where it takes the presure from

what are the dangers of low oil presure
what is the lowest oil presure a sbc can have w/o to much damage

i am sure that my bareings are bad but i cant pull the motor due to time and money for about four months and i need to drive the car until then.
what other stuff will i damage by doing this?

[Beefy's Bronco]

I've heard it said that a performance small block Chevy needs only 10 lbs per 1000 rpm. Thats from either Hod Rod or Car Craft magazine. If its not knocking or clattering I wouldn't worry to much about it. Gauges are usually inaccurate and I only use them for relative purposes ie: usually reads 60 psi, now only 30. Maybe there is a problem.

[elbi_chorrea]

Originally posted by towtrucks
Basically, the oil is picked up by the oil pump, then pumped to the crankshaft where it then goes to the crank bearings, then the rod bearings, then he cam bearings. The oil also travels up the block to the lifters and up the push rods, this is also where the pressure is recieved by the oil pressure switch.

what about the valve springs??, and all that stuff?

[Gearhead52]

JD,

Like I said earlier the SBC oils from the CAMSHAFT to the crank.......the presure sensor is first in the circut.

Beefy is correct on 10 lb per 1,000 rpm for the SBC.

Run heavy weight oil until you get the chance to rebuild it. You'll notice the oil presure come up and stay there a little better.

Without the oil presure to keep a cusion of oil between the bearing surfaces the metal to metal contact possibility is greater. The heavy oil will not pass through the loose bearings as quick. Helps cusion the metal parts.


elbi,

The overhead valve system on the small block chevy get oil from the lifter and a hollow push rod up to the rocker then the springs and valves.

Some of this also covered in earlier post.........

[jeff dewberry]

thanks for the help everyone
i think i will be fine until i can rebuild
i am using 20w 50 right now and am keeping about 10p per 1000rpm but once the temp warms up this summer i think i will have to rebuild.

once again thanks

[Beefy's Bronco]

Oh thats right. Its a Chebby. It is gonna have lifters banging. LOL

[Gearhead52]

If you are running 20 W 50 now and getting 10 psi per 1,000 rpm....I think you need to look for a good core and start rebuilding it while the other is still running.......

You ain't got much time.

[jeff dewberry]

when rebuilding this one will i need to replace more than the bearings

[Beefy's Bronco]

It is false economics to just replace one part of an engine once you have it apart. All the parts have the same mileage on them and you really should tear it down and ship it all off to the machine shop to have it all inspected and checked (I let my machine shop clean everything too). Some times you can get by with new rings and bearings, but always replace things like the oil pump, timing chain, frost plugs etc.

[Daniel Wood]

Is this going to be your first engine rebuild, if so go to www.compcams.com and click on SB Chevy engine build up and there's a tape I highly recommend that you get it. It's very educational and takes the fear out of working on your own engine.


But if you're motor needs boring out or have to replace a camshaft it can get pretty expensive. Sometimes it's cheaper now to buy a crate motor. By the time you buy pistons, machine work on your block, valve job among other things you could have bought that crate motor with a warranty. You can go to www.jegs.com and talk to a tech. Or shop around on any web site for prices.

But there's nothing like getting satisfaction of rebuilding your own motor, you can go as far as your wallet will let you

[jeff dewberry]

i have had this motor rebuilt many times it does not have that many hours on it and it has many new parts.
the problem is that i wore a lobe down on the cam. from the aproximate time it started to wear till the time i took the cam out it had an hour may be an hour and a half of run time i put in a new cam and lifters and prayed that the bearings would be ok.
but it looks as if the damage was done.

when i do tear it down i will replace anything that needs to be replaced but what i really want to know is if by driveing it for a little while will damage more parts and cost me more money.

what are the chances that this will ruin my new cam it is a hydrolic roller cam?

[Beefy's Bronco]

I don't know how ya figure all that Mr Wood. I rebuilt my 300 six and I paid 400 bucks for a Master kit. (crank and everything) and 600 at the machine shop (including labor to rebuild my head). I priced crate engines and the best price I could find was 1600 bucks. The warranties are a joke, you provide or pay for the labor, some re-builders require you to use a shop specified by them to even get a warranty, and you pay to ship the engine back to them, and then you pay again to reinstall or do it yourself. Personally, I would prefer to take my time, use a machine shop I trust, and build it right the first time.

This is just my Opinion, I just choose to trust myself and not some minimum wage nose picker that you know has to assemble your new engine in X amount of time to keep his job. I know that I will do my best to do it right. If I make a mistake, and I've made many' I have no one to blame but myself. If you shop around and do the work yourself you can save a bunch of money.
By the way I am not a mechanic, and working on my vehicles is a hobby, so I cannot charge myself for my labor. Lot of guys want you to add your labor to the total cost. I think thats nuts. Gonna charge yourself. ROFLMAO