Too much oil in rocker covers!

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Markus
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Too much oil in rocker covers!

Post by Markus » Mon Jul 10, 2017 1:03 am

I know this topic has been around for a long time but I need advice.
My 4.6 is great for the club level circuit racing I'm doing but the faster I go the more oil is collecting in the rocker covers.
I've seen and heard of a number of "fixes".

Grub screws in the cylinder head oil passages - what diameter do I drill in the centre of the grub screw?
Pedestal shims with smaller holes?
End pedestals with the shaft end supported which have smaller feed passages - what brand?
Drains from the heads to the sump?
Ignore the problem and it'll go away?

What is the collective wisdom on here?


Mark
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unstable load
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Post by unstable load » Mon Jul 10, 2017 5:59 am

What is the maximum limit for oil in the rocker covers?

Can the 4 holes for the pushrods not drain it fast enough?
Cheers,
John

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Post by garrycol » Mon Jul 10, 2017 6:43 am

Yes - having just had my manifold, rocker covers and valley cover gasket off I cannot see how oil can stay up in the rockers - each head has two large elongated L shaped holes that are about 2" long and about 1" wide - in addition to the 1cm dia holes at either end of the head. The L shaped holes drain into the valley then over the cam shaft and back into the sump.

However with fast cornering I can accept the oil can be held by the cornering forces to the outside of the rocker cover but when it has built up it will still flow out.

How do you know the oil is building up in the rocker covers - leakage, or overflow out the breather? If the later, maybe you don't actually have oil build up in the rocker as such but just between the "windage" tray in the top of the rocker cover and the cover - there is a space about 1 cm there and the drain holes are small - maybe that is filling up and coming out the breather on cornering.

However as far as the area where the valve gear is, I cannot see how excessive oil can build up because of the size of the drain holes.

Garry

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Post by Markus » Mon Jul 10, 2017 11:00 pm

You're right when you say there are two L shaped drain holes but they're on the upper edge of the heads and so do not come into play when g force builds up and the oil pools along the lower edge.
I'm getting oil leaks along the outer edge of the rocker cover gaskets which then drip onto the headers.
Common problem among racers and there have been quite a few methods to fix but I'm looking for the best ideas out there.
Thanks for your input.
Mark
Triumph TR7/V8 race car
Triumph TR6 road car

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Post by garrycol » Tue Jul 11, 2017 3:39 am

Thought so - now I don't think having an increased volume of oil up there is in an issue in itself but as you said when it leaks that is the issue.

In theory of course the rocket cover gaskets should not leak so you would not have an issue - however every standard RV8 I have had has always leaked from the rocker cover gaskets. So solve the gasket leakage then problem solved 8-) . Certainly the newest rubber gaskets from the 4.0 and 4.6 engines are far better than the old 3.5 gaskets.

Garry

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Post by ChrisJC » Tue Jul 11, 2017 5:57 pm

Are you sure that the underlying cause is not excessive crankcase pressure?

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Re: Too much oil in rocker covers!

Post by mgbv8 » Tue Jul 11, 2017 8:43 pm

Markus wrote:I know this topic has been around for a long time but I need advice.
My 4.6 is great for the club level circuit racing I'm doing but the faster I go the more oil is collecting in the rocker covers.
I've seen and heard of a number of "fixes".

Grub screws in the cylinder head oil passages - what diameter do I drill in the centre of the grub screw?
Pedestal shims with smaller holes?
End pedestals with the shaft end supported which have smaller feed passages - what brand?
Drains from the heads to the sump?
Ignore the problem and it'll go away?

What is the collective wisdom on here?
Your rocker gear is too loose. !

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Post by mgbv8 » Tue Jul 11, 2017 8:44 pm

unstable load wrote:What is the maximum limit for oil in the rocker covers?

Can the 4 holes for the pushrods not drain it fast enough?
The limit is when the oil level floods enough to reach the valve stem seals. This is when blue smoke often happens on deceleration.

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Post by mgbv8 » Tue Jul 11, 2017 8:47 pm

garrycol wrote:Yes - having just had my manifold, rocker covers and valley cover gasket off I cannot see how oil can stay up in the rockers - each head has two large elongated L shaped holes that are about 2" long and about 1" wide - in addition to the 1cm dia holes at either end of the head. The L shaped holes drain into the valley then over the cam shaft and back into the sump.

However with fast cornering I can accept the oil can be held by the cornering forces to the outside of the rocker cover but when it has built up it will still flow out.

How do you know the oil is building up in the rocker covers - leakage, or overflow out the breather? If the later, maybe you don't actually have oil build up in the rocker as such but just between the "windage" tray in the top of the rocker cover and the cover - there is a space about 1 cm there and the drain holes are small - maybe that is filling up and coming out the breather on cornering.

However as far as the area where the valve gear is, I cannot see how excessive oil can build up because of the size of the drain holes.

Garry
Oil can build up in the top of the heads to a point where it often seeps out of the rear lower corners of the rocker covers (due to crap seal of the gaskets) where it drips onto the exhaust pipes... Not uncommon ;)

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Post by mgbv8 » Tue Jul 11, 2017 8:59 pm

ChrisJC wrote:Are you sure that the underlying cause is not excessive crankcase pressure?

Chris.
Excessive crankcase pressure can cause all sorts of unusual problems as you know Chris. (Long time no speak mate. I hope you are well ? )

But what excess crankcase pressure cannot do is prevent build up of oil in the heads due to clapped out rocker gear? The pressure in the crankcase is the same pressure that is in the rocker covers eh? the crankcase + valley area + rocker cover area is all the same space.

The posters comment about fitting grub screws / restrictors in the oil feed to the rocker gear is an old way of avoiding the inevitable job of replacing clapped out rockers and shafts. I have done this loads of times on clapped out RV8's for mates with road cars. Especially the old 3500's with rubber washer stem seals, which have gone to heaven after a few thousand miles anyway ;) But for a race car I would not want to have clapped out rocker gear starving the rest of my engine of oil for a start. And by chucking in some restrictors to the rocker feeds to solve this, you are then starving the rockers of oil at high rpm.
This excess oil CAN build up in the head to a point where it WILL reach the valve stem seals!!

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Post by mgbv8 » Tue Jul 11, 2017 9:01 pm

You need to fit new rockers and shafts mate!!

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Post by mgbv8 » Tue Jul 11, 2017 9:23 pm

Markus wrote:You're right when you say there are two L shaped drain holes but they're on the upper edge of the heads and so do not come into play when g force builds up and the oil pools along the lower edge.
I'm getting oil leaks along the outer edge of the rocker cover gaskets which then drip onto the headers.
Common problem among racers and there have been quite a few methods to fix but I'm looking for the best ideas out there.
Thanks for your input.
#

Markus!
I have answered several questions for this issue as you can now see.
You need to fit new rocker gear as a proper fix, BUT... You also need to know how to properly seal your rocker cover gaskets. I've Been there, Seen it, Done it, and have the T shirt on this over the years mate. If the rocker gaskets are correctly sealed you can fill those rocker galleries up to the oil filler cap and it still wont leak :)
So!
Remove the rocker covers and cork gaskets. Clean the rocker covers with petrol etc to make sure the gasket mating face is bone dry. Also give the Cork gaskets a wipe over with the same cleaner to make sure they are bone dry. You now need two new cork gaskets, a small tin of Evo Stick & a couple of bricks or reasonably heavy weights & a flat surface. I use my kitchen worktop for this.
Ignore the instructions on the Evo Stick re coating the joint and then pulling it apart to dry before you place the two parts back together. Just put a nice even coat of Evo Stick on the rocker cover flange as well as a thin smear on the gasket face. Then Snug the gaskets onto the rocker covers to make sure that you are happy that the glue has spread evenly on the faces of the gasket and the rocker cover gasket face. Then place the rocker covers gasket down onto a flat surface and place a weight on top of each rocker cover so the gaskets can bond to the rocker covers over night.
What you should have the following day is a cork gasket that is bonded rock solid to each rocker cover. The cork gaskets will NOT alter in shape when you tighten the rocker covers now. I then use Blue Hylomar as the seal between the rocker cover gaskets and the heads. You can tighten the screws on the rocker covers as tight as you like now, and the gaskets will NOT deform.
Perry

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Post by DaveEFI » Tue Jul 11, 2017 11:20 pm

The snag with the cork gaskets is they shrink with time. Not sure the rubber ones are perfect, either.
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Post by garrycol » Wed Jul 12, 2017 12:15 am

Why use old cork gaskets - horrid things - use the much newer rubber ones that are slotted sit down on the edge of the head - use a bit of sealant ans the metal col-lets prevent overtightening and the ribber squishing out like cork can do.

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Post by DaveEFI » Wed Jul 12, 2017 7:44 am

As an aside, the mention of EvoStick reminds me the current stuff is nothing like as good as the original. Think they changed the solvent. Is there a better alternative?
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