16 replies to this topic

[Purple Tom]

Hey,

Stupid question, but what route does the oil take in an A-series engine?

I know it goes from the sump, through the pick-up pipe, to the oil pump, but where does it go after then?

Thanks!

Tom

[minimadjonesy]

around the engine??

[Purple Tom]

no you plonker! Does it go to the filter then through the mains, or through the mains then the filter, then via the pressure relief valve, I've been trying to figure it out but can't...

[Jammy]

I've always wanted to know this. I would hope it goes through the filter first, just in case anything gets up through the pick up pipe!

[minimadjonesy]

sorry, had to be done! bet Dan or GW will know though

[Dan]

Just saw the front off your engine block and you can see for yourself.

Ok, the oilway which leads out of the oil pump comes straight to the front of the engine block and ends at the oil pressure relief valve. Partway along it another oilway is drilled into it from above which leads up to the oil transfer outlet. Here it leaves the block and travels through the transfer pipe to the filter head where it gets filtered and re-enters the block through the centre of the filter head. From there it travels up to the main oil gallery which can be seen from the outside as it looks like a vein travelling along the front of the block. The oil pressure switch is in one end of this gallery. This gallery is drilled through with oilways which travel down into the main bearing housings from above. As you look at the main bearing housing you will see a channel cut into it with more than one oil port. This channel forms an extra oil gallery when the bearing shell is pressed against the front of it, closing it up. This extra gallery then has one inlet from the main gallery and two outlets, one formed by a hole in the bearing shell which allows oil to feed the bearing and one which leads to a further oilway travelling back up to the cam bearings. The oil feeding the main bearings then travels through the crank to also feed the big end bearings, while the oil feeding the front cam bearing travels around that bearing and up through the block into the head. It continues through the head and straight up into the front rocker post from where it fills the inside of the rocker shaft to feed all the rockers and in better rockers it also travels through the rocker to lubricate the adjuster thread and the pushrod cup. Then it all drips down the back of the engine back to the sump.

You may have noticed that the main oil gallery and the oil pressure relief valve occupy the same space inside the block due to the rear main bearing being further to the rear than the relief valve is. This is possible because of the pressure relief valve seat which allows oil to flow through the middle of it to the valve and around the outside of it in the gallery without the two mixing.

Everything else is fed by oil splash or drip/runoff.

The automatic and the MPi blocks are different.

[DANTOO]

I think oil is pick up from the sump, through the gauze filter. Past the pump to the filter , into the gallery. So yeah the oil goes to the filter before getting to the gallery.
Onto the main bearings, then up past the cam, to the rockers. Then back down to the gearbox. I think.

ohwww, yeah what Dan says lol

[Jammy]

Just saw the front off your engine block and you can see for yourself.

Ok, the oilway which leads out of the oil pump comes straight to the front of the engine block and ends at the oil pressure relief valve. Partway along it another oilway is drilled into it from above which leads up to the oil transfer outlet. Here it leaves the block and travels through the transfer pipe to the filter head where it gets filtered and re-enters the block through the centre of the filter head. From there it travels up to the main oil gallery which can be seen from the outside as it looks like a vein travelling along the front of the block. The oil pressure switch is in one end of this gallery. This gallery is drilled through with oilways which travel down into the main bearing housings from above. As you look at the main bearing housing you will see a channel cut into it with more than one oil port. This channel forms an extra oil gallery when the bearing shell is pressed against the front of it, closing it up. This extra gallery then has one inlet from the main gallery and two outlets, one formed by a hole in the bearing shell which allows oil to feed the bearing and one which leads to a further oilway travelling back up to the cam bearings. The oil feeding the main bearings then travels through the crank to also feed the big end bearings, while the oil feeding the front cam bearing travels around that bearing and up through the block into the head. It continues through the head and straight up into the front rocker post from where it fills the inside of the rocker shaft to feed all the rockers and in better rockers it also travels through the rocker to lubricate the adjuster thread and the pushrod cup. Then it all drips down the back of the engine back to the sump.

You may have noticed that the main oil gallery and the oil pressure relief valve occupy the same space inside the block due to the rear main bearing being further to the rear than the relief valve is. This is possible because of the pressure relief valve seat which allows oil to flow through the middle of it to the valve and around the outside of it in the gallery without the two mixing.

Everything else is fed by oil splash or drip/runoff.

The automatic and the MPi blocks are different.

Could of just said clockwise!

[minimadjonesy]

sorry, had to be done! bet Dan or GW will know though

Told Ya!

Could of just said clockwise!

[il-barba]

with a little simple words.....

where is oil needed for the rockers? and from where does it go down again? pushrods?

[Ethel]

The oil goes into the rocker shaft through a drilling up one of the pillars. The cam followers are fed by the oil tat escapes past the rocker bushes draining back down the pushrod holes.

Never did find out if there's a port above the followers or if all oil has to make it passed them.

[Big_Adam]

Questions?

[Sprocket]

Oil is fed to the rockers from cam bearing number one. cam bearing number one is fed from main bearing number one and main bearing number one is fed from the main oil gallery that runs horizontaly at the front of the block, the main gallery is fed from the oil filter housing, the oil filter housing is fed from the oil pump(the banjo bolt external oil feed pipe), oil pressure relief is also fed at this point.

There are two drain holes between the cam followers from the horizontal gallery at the back of the block, the oil would never get past the followers otherwise.

[Sprocket]

Is that picture big enough Adam??

[Big_Adam]

Is that picture big enough Adam??

1600x1200 desktop.

No image is big enough.

Edited by Big_Adam, 30 September 2007 - 06:28 PM.