67-1496 Oil pressure relief valve spring

[KeithJ]

Hello, I'd appreciate some guidance please. 

I'm just rebuilding my engine and have three different springs and not sure what the correct one should be. The one in the middle was fitted in the engine and the other two are spares I have purchsed over the years.

The one in the middle is the same lenght as the one on the left but it is thicker.

Also, what is the correct thickness of the large diameter fibre washer to ensure the vavle is positioned correctly?

Thanks

[Greybeard]

Was the engine completely dismantled? There is a spring loaded anti wetsump ball valve in the crankcase behind the pump. The spring used in that is quite light, like the one on the right.

I put a new complete PRV in mine when I restored it.

[KeithJ]

Good point.  Yes, I have taken out that spring and ball as well.  I've just checked that spring and it looks like the one on the left. 

So the thicker spring in the middle looks correct for the Pressure release valve

How can I confirm which is correct for the anti sumping valve as it looks like I had a shorter one fitted, the one on the left and you favour the one on the right?  They both are of similar gauge and the only difference looks to be the length.

Curious?

ATB

[Greybeard]

Could you somehow have an old tired spring and a new one?

[KeithJ]

It is possible but more likely if the lengths were similar.  The thinner ones are so different in length I doubt one is "tired"? 

[JulianS]

The PRV spring 67 1496 is the same part as the pre 1969 A65 - the A65 workshop manual gives length as 0.609 inches (just over 15mm).

The ball is 5/16 inch diameter.

The non return valve ball is 1/4 inch diameter. I think that the spring is about 20mm length and logically somewhat weaker than the one above. Presume it is smaller diameter to suit the smaller ball

[KeithJ]

The PRV spring 67 1496 is the same part as the pre 1969 A65 - the A65 workshop manual gives length as 0.609 inches (just over 15mm).

The ball is 5/16 inch diameter.

The non return valve ball is 1/4 inch diameter. I think that the spring is about 20mm length and logically somewhat weaker than the one above. Presume it is smaller diameter to suit the smaller ball

Opps!  Reply gone adrift.  Meant to say aim to do the ant syphon bits tomorrow, fingers crossed.

[muskrat]

G'day Keith.
The one on the left is the non return valve spring from inside the motor. The center one is the PRV spring. The one on the right should not be used as the ends are not closed (round) as the others, a ball would not sit square.
Cheers

[KeithJ]

G'day Keith.
The one on the left is the non return valve spring from inside the motor. The center one is the PRV spring. The one on the right should not be used as the ends are not closed (round) as the others, a ball would not sit square.
Cheers

Thanks, really appreciate the replies.
Keith

[Greybeard]

The one on the right should not be used as the ends are not closed (round) as the others, a ball would not sit square.
Cheers

Ah, but what about the PRV's with a bucket type plunger?

[muskrat]

G'day GB.
Keith's PRV is not that type.
Cheers

[RichardL]

It seems to me that just validating the appearance of the spring does not address the question of pressure required to move the ball and, therefore, relieve the pressure. Though it looks unmolested, even if it is the original spring, it could be out of spec for F=kX.

Richard L.

[KeithJ]

It seems to me that just validating the appearance of the spring does not address the question of pressure required to move the ball and, therefore, relieve the pressure. Though it looks unmolested, even if it is the original spring, it could be out of spec for F=kX.

Richard L.

Aye, that is the question.  Would be ideal to know he spec of the original springs.

[JulianS]

Other than spring length etc as above the only other information I have seen is that the valve should blow at 50/60 PSI.

If in doubt fit one of the SRM piston type valves.

[Greybeard]

If in doubt fit one of the SRM piston type valves.

Yup, agreed, that is what I did.