Main bearing oil feed question...

[Exminiman]

Hi folks

Cleaning the main bearing oil feed nearest to oil pump as far as i can see it gets it supply from one of the two main gallerys , as the other main bearings.

Question i am assuming i is should i be able to get brush from main bearing all the way until it shows in oil gallery, is this right ?

Have also tried strimmer nylon without luck -paraffin does get through though.

The main oil galleries have been tapped by machine shop for threaded plugs - my concern, maybe unfounded, that this might of blocked oil way.....

Appreciate some opinions......

[Herbert]

Have you tried to blow compressed air in it? Put a rag on all the other exit holes and see what comes out....good luck

[imack]

You'll need to remove the oil pressure relief valve seat to be able to pass a brush from the main bearing through to the oil gallery.

[Spider]

You'll need to remove the oil pressure relief valve seat to be able to pass a brush from the main bearing through to the oil gallery.

You really should be doing this to get the block proper clean, there's often 1/2 the dead sea in behind it - and that's on the filtered side.

[Exminiman]

You'll need to remove the oil pressure relief valve seat to be able to pass a brush from the main bearing through to the oil gallery.

You really should be doing this to get the block proper clean, there's often 1/2 the dead sea in behind it - and that's on the filtered side.

Next job is to pull out old seat and replace it.......didn’t think this was connected to this oil way though, am i wrong ?

[Oneball]

Here’s a x section

[Exminiman]

Cheers for that, makes sense now! so the oil passes around the recess machined into relief valve seat?

[Dearg1275]

You'll need to remove the oil pressure relief valve seat to be able to pass a brush from the main bearing through to the oil gallery.

You really should be doing this to get the block proper clean, there's often 1/2 the dead sea in behind it - and that's on the filtered side.

Is there a source for the relief valve seats. I thought they were NLA!

D

[Exminiman]

You'll need to remove the oil pressure relief valve seat to be able to pass a brush from the main bearing through to the oil gallery.

You really should be doing this to get the block proper clean, there's often 1/2 the dead sea in behind it - and that's on the filtered side.

Is there a source for the relief valve seats. I thought they were NLA!

D

Yes, bought two recently from Tim at Minimail or there is someone on ebay also.....they want silly prices though.

[bwaminispeed]

Oil goes to/through the relief valve almost directly from the pump.........

Then out the block (what doesn't get dumped back to the sump), to the filter, to the front main gallery, THEN, it goes around the relief valve seat to the rear main bearing, you're thinking it backwards...........

[Spider]

You'll need to remove the oil pressure relief valve seat to be able to pass a brush from the main bearing through to the oil gallery.

You really should be doing this to get the block proper clean, there's often 1/2 the dead sea in behind it - and that's on the filtered side.

Is there a source for the relief valve seats. I thought they were NLA!

D

You'll need to look hard, but yes, they are available. 99 times out of 100, I refit the one I've taken out. It's usually only if it's had the ball bearing relief valve in there that they need replacing.

[Exminiman]

how do you re-fit ?

has assumed by time it was threaded and pulled out, it would be knackered

[CooperTune]

Since the bore only feeds the relief valve it's not to important. As long as you can get a sealing line around the
cup. I have removed them and machined the step/groove on the OD to increase flow to the rear main. Should be
a lot going on back there. A lot of engines carry a wider rear main.

Once everything is clean just press it back in place same way around. Be careful not to damage the taper. Steve (CTR)

[mk1]

While I am sure that people have had excellent results removing this seat to clean their blocks. I have never done so & have managed to build engines that have done thousands & thousands of miles without issue.

Personally, I feel that removing this seat is as likely to cause as many problems as it is to cure them. But as I always say, each to their own.

[bwaminispeed]

Same here, never touched one, never had a problem with one, on dozens of rebuilds.....