47 replies to this topic

[Northernpower]

"If I run too much it has a tendency to force the oil into the layers of the head gasket."

Out of interest, how do you know oil is being forced into the head gasket layers?

I've just changed the head gasket because of oil leaking out of the joint. When I took the old gasket off I looked at where the oil transferred from the machined gallery in the head to the head bolt. I split the gasket at that point and saw the oil in the layers.

[imack]

"If I run too much it has a tendency to force the oil into the layers of the head gasket."
Out of interest, how do you know oil is being forced into the head gasket layers?

I've just changed the head gasket because of oil leaking out of the joint. When I took the old gasket off I looked at where the oil transferred from the machined gallery in the head to the head bolt. I split the gasket at that point and saw the oil in the layers.

Ah, ok, didn't realise you'd had the head off. I've not seen one of these gaskets, I presume there are rings in the gasket at the water ways that are preventing oil getting into the coolant.

[Northernpower]

"If I run too much it has a tendency to force the oil into the layers of the head gasket."
Out of interest, how do you know oil is being forced into the head gasket layers?

I've just changed the head gasket because of oil leaking out of the joint. When I took the old gasket off I looked at where the oil transferred from the machined gallery in the head to the head bolt. I split the gasket at that point and saw the oil in the layers.

Ah, ok, didn't realise you'd had the head off. I've not seen one of these gaskets, I presume there are rings in the gasket at the water ways that are preventing oil getting into the coolant.

Yes, never had a problem with oil in the water but it did come up through one of the head bolts.

[Chris.Williams]

I rebuilt mine 2000kms ago, I do have a turbo oil pump, and cold I'm at 75psi, once warm it sits on 60-65psi.
All seems fine, and I'm assuming, from reading this, that it's quite normal.
Chris

[Northernpower]

I rebuilt mine 2000kms ago, I do have a turbo oil pump, and cold I'm at 75psi, once warm it sits on 60-65psi.
All seems fine, and I'm assuming, from reading this, that it's quite normal.
Chris

Yes, I'm thinking that's where mine's going to end up. Which gasket did you use?

[Cooperman]

I reckon that so long as there is over 20 psi at 1000 rpm when fully hot it is OK.
A further check point would be not less than 50 psi at over 3000 rpm with 60 at 5000 rpm.

[Ethel]

Playing devil's aardvark, do you need to see more pressure on the gauge with higher rpm? Sure the bearings will be centrifuging their way through more oil, but the pump will be pumping faster too.

[Northernpower]

Playing devil's aardvark, do you need to see more pressure on the gauge with higher rpm? Sure the bearings will be centrifuging their way through more oil, but the pump will be pumping faster too.

I'm just going to work on the basis of reducing it in stages while looking to see how consistent it is over the rev range (other than tickover).

[mini13]

somthing thats not been mentioned yet is that the head sees a different amount oof opil flow/ pressure to the rest of the engine. what happens is there is a groove in the largest cam braring that transfers oil to the rockers once every 2 engine revolutions, this is done so that the rocker box dosent over fill with oil to the point it gets down the guides.

[nicklouse]

somthing thats not been mentioned yet is that the head sees a different amount oof opil flow/ pressure to the rest of the engine. what happens is there is a groove in the largest cam braring that transfers oil to the rockers once every 2 engine revolutions, this is done so that the rocker box dosent over fill with oil to the point it gets down the guides.

interesting is that really how it works?

 

so how about the guys that dry deck the engines (both oil and water) and they take the oil for the rockers from the pressure switch area to the head drilling direct?

[Northernpower]

somthing thats not been mentioned yet is that the head sees a different amount oof opil flow/ pressure to the rest of the engine. what happens is there is a groove in the largest cam braring that transfers oil to the rockers once every 2 engine revolutions, this is done so that the rocker box dosent over fill with oil to the point it gets down the guides.

Don't quite understand the point you're making. How does the oil get back to the crankcase if it doesn't go down the guides? Hot oil, being very thin will soon drain back down. Its only when you do an oil change with cold oil does it take time.

[nicklouse]

 

somthing thats not been mentioned yet is that the head sees a different amount oof opil flow/ pressure to the rest of the engine. what happens is there is a groove in the largest cam braring that transfers oil to the rockers once every 2 engine revolutions, this is done so that the rocker box dosent over fill with oil to the point it gets down the guides.

Don't quite understand the point you're making. How does the oil get back to the crankcase if it doesn't go down the guides? Hot oil, being very thin will soon drain back down. Its only when you do an oil change with cold oil does it take time.

 

it goes down the pushrod holes and also lubes the cam followers.

[Northernpower]

 

 

somthing thats not been mentioned yet is that the head sees a different amount oof opil flow/ pressure to the rest of the engine. what happens is there is a groove in the largest cam braring that transfers oil to the rockers once every 2 engine revolutions, this is done so that the rocker box dosent over fill with oil to the point it gets down the guides.

Don't quite understand the point you're making. How does the oil get back to the crankcase if it doesn't go down the guides? Hot oil, being very thin will soon drain back down. Its only when you do an oil change with cold oil does it take time.

 

it goes down the pushrod holes and also lubes the cam followers.

 

Absolute brain fade, when I read guides I was thinking pushrod holes. Doh 

 

EDIT: I also understand the point about being too high a level in the head so it's higher than the guides but given the viscosity of hot oil I'd never thought this would be a problem.

Edited by Northernpower, 21 September 2017 - 03:30 PM.

[Ethel]

My guess is the rockers need actual pressure the most - not the amount of pressure, but enough to ensure all the rockers are fed, even if they're furthest from the oilway in to the rocker shaft. 

[Northernpower]

My guess is the rockers need actual pressure the most - not the amount of pressure, but enough to ensure all the rockers are fed, even if they're furthest from the oilway in to the rocker shaft. 

And the difficulty is when the pressure is reduced measuring that it's still getting to the end of the shaft.