24 replies to this topic

[super6al]

Hi everyone

After several months inactivity, I'm starting my 1275 A+ rebuild, starting with cleaning the oil ways. So question is - does the 3rd (rear) main bearing oil way drilling go straight through to the main oil gallery?

I've checked 1 & 2 with a length of mig wire & if I poke the wire from the main bearing housing I can see the wire in the main gallery, however on the 3rd oil way the wire seems to stop about an inch before the gallery. If I use an air line I can feel air coming out through the gallery.

Thanks

Alan

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[unburntfuelinthemorning]

All the main bearing journals are supplied with oil from the main oil gallery.

[DeadSquare]

Don't forget that at that end of the gallery, the dumbell shaped pressure relief valve seat may be obscuring the view.

[Spider]

Don't forget that at that end of the gallery, the dumbell shaped pressure relief valve seat may be obscuring the view.

 

Yes, this crosses over the Main Gallery.

 

You really should pull the Oil Pressure Relief Valve Seat out in in case so you can clean the galleries properly, there's like some sheep of cows hiding in there!

[Retroman]

This might help

 

[super6al]

Thanks everyone,

I had a look & also found a photo on the forum of a cut away section of block that shows it clearly. 

I tried to remove the valve seat today without success - don't really want to tap & screw it if possible.

Alan 

[super6al]

Just seen the above before i posted - Haha thats the very photo !!

[RooBoonix]

Thanks everyone,
I had a look & also found a photo on the forum of a cut away section of block that shows it clearly.
I tried to remove the valve seat today without success - don't really want to tap & screw it if possible.
Alan

Why not? They're cheap enough to replace, which whilst you're there is worth doing, along with the plunger

[Spider]

I tried to remove the valve seat today without success - don't really want to tap & screw it if possible.

Alan 

 

They are in VERY tight so that the Oil Pressure doesn't displace it.

 

The only way I've ever been able to get them out is to tap them - I find a 3/8" UNC Tap does the job, and a Head Stud screwed in to that.

[DeadSquare]

If it isn't bust........................... DON'T FIX IT.

 

Any swarf that might have been in there has been washed out years ago.

 

If you really really feel that you must do something, steam clean the oil ways, but if you haven't got a steam cleaner, pour paraffin through the block and blow it out with an air line

[super6al]

Main reason not to remove the seat is I don't have a suitable tap!

I've washed the block 3 times & had WD40 down there & blasted with the air line. Nothing came out, however I take the point there maybe swarf trapped behind the seat.

I bought a new valve as the old one was scored.

I've ordered some cleaning brushes, so will see if anything comes out with those. 

[DeadSquare]

Main reason not to remove the seat is I don't have a suitable tap!

I've washed the block 3 times & had WD40 down there & blasted with the air line. Nothing came out, however I take the point there maybe swarf trapped behind the seat.

I bought a new valve as the old one was scored.

I've ordered some cleaning brushes, so will see if anything comes out with those. 

 

 

1)  Has your crank been so badly scored, that you need all this cleaning ?

 

2)  Was the oil pump very badly scored ?

 

3)  How much foreign material did you get out of the other galleries when you cleaned them ?

 

An advantage of the replaceable filter element is that a warning of damage can sometimes be gleaned from examination of anything that might be in the bottom of the bowl.

[Spider]

Just to go the other way, I wouldn't do a build without pulling the seat. If you look carefully at the cut away photo that Retro kindly posted up, you can see there's a lot of 'dead' area around the seat and often, there's all kinds of crud and half the dead sea residing in there.

 

You can leave it and run the gauntlet but if you do pull it out, then you can see and you'll know for sure.

[Rorf]

I was under the impression that the oil pressure relief valve was before the oil filter and so any debris, swarf that might be hidden there would be prevented from going in to bearing journals.

 

The major side effect though could be the oil pressure relief valve shuttle cup being prevented from closing properly due to the swarf, but judging by the score marks usually seen on this shuttle, the swarf probably is forced through and back into the gearbox anyway.

[DeadSquare]

You are correct.

 

The lurking 1/2 of "The Dead Sea" has either been there since manufacture, or by-passed a blocked oil filter.

Edited by DeadSquare, 22 August 2019 - 06:24 AM.