Oil leak from head gasket

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Misterb_57
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Oil leak from head gasket

Post by Misterb_57 »

I'm getting a thin film of oil running down the outside of both sides of my 3.5 block, from beneath the heads between 3-5 & 4-6 cylinders. I'm using composite gaskets, with 10 x ARP studs only, holding down SD1 heads .
The heads were skimmed & gaskets were coated with copper gasket sealant (as this has happened before) and torqued to 75 ft/lbs in stages. They were retorqued after a few thousand miles.

http://www.v8forum.co.uk/forum/viewtopi ... highlight=

This post suggests that the oil can seap out from the valley, which would mean the firing ring has not compressed to the point where the composite element seals to the block.

So my questions are:

Is this still likely to ocurr even after using copper sealant?

If this the case, could I use some Hylomar on the joint in the valley area, to eliminate it?

Could it be leaking from the rocker oilway - seems to be the wrong area, as no sign of oil at front of block.

Will mls gaskets cure the problem?

As this is the second set of gaskets that have developed this problem in around 6k miles, it's starting to bug

So look forward to your help and advise.

Chris.

:(



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Re: Oil leak from head gasket

Post by JP. »

Misterb_57 wrote: and torqued to 75 ft/lbs in stages. They were retorqued after a few thousand miles.
:(
When was your, or the one you used, torque wrench last calibrated ??

Should be very year.

There could be the cause of your issue.

The L cheapo ones comes without a calibration report and are worth nothing. Have seen them 50ft out, both sides.
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Seight-V8
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Post by Seight-V8 »

I've had this happen to me as well.....and under 475 road miles.

I'm just about to put my 4.6 engine back together, and planning to use cometic head gaskets this time, instead of elring.

I too use ARP head studs, and again torqued correctly, or I thought I did.

On the torque wrench issue, I've spoken at length to a torque wrench supplier who also calibrates wrenches.....and he has explained that I should not use even a good ratchet type wrench for the head bolts, but a breakback torque wrench.

I've chosen a torqueleader BDS160, you can get them cheapish of ebay, then get them calibrated at £35, worth it my book.

The reason for this is a ratchet wrench, is just that a ratchet and prone to incorrect torques, the breakback wrench works on a cam system instead, and does not over torque.

I've had my heads & block measured on the works CMM for flatness, and the values are no more than 0.038mm each....so good to go in my book.

But this problem still worries me, and i'm not sure of the cause either.

Also be aware that most torque wrenches are calibrated to +/-3% to +/-6% of the reading depending on wrench type.....

If you get yours calibrated though you can take this error in to account when you tighten your head bolts.

Lets hope someone can shed some light on this issue, as it cant just be down to bolt torque.

regards

scott

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Post by ChrisJC »

I run a bead of sealant along the valley side of the head gasket on both sides. Keeps the oil out for sure.

A very thin bead.

Chris.
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Misterb_57
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Post by Misterb_57 »

Thanks for the replies - good points!

The torque wrench was brand new (this time) but was the issue last time.

It is a Clarkes ratchet type but didn't come with a calibration certificate.

I think I'm going to try some sealant in the valley and change the wrench, then get it calibrated.

If this doesn't work it's Cometic mls gaskets.

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Post by unstable load »

Instead of the copper sealant I'd suggest you use Indian Head shellac on both surfaces of the gasket. Don't use it directly on the fire rings, but the rest of the gasket is fine.
https://www.permatex.com/products/gaske ... -compound/
Cheers,
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Post by Seight-V8 »

just as a matter of interest.....


who other than cometic make a 96mm bore head gasket?

as I have a 94.5mm rebore in my top hats.....looking for a slightly bigger bore head gasket than standard.

cheers

scott

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Post by DaveEFI »

I'm a bit confused by this discussion. How is the wrong torque setting likely to show by the oil gallery leaking - rather than a cylinder?
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Post by ratwing »

I've also had this on a freshly top-hatted 4.6 with newly skimmed heads and Elring composite gaskets - I'm not convinced it's because of an inaccurate torque wrench because the fire rings have sealed (no water in the oil or oil/combustion gasses in the water in my case).
Also, its the same torque wrench I've used at similar settings on other engines with no problems.
It's been suggested the block decking/head skimming might result in the head locating dowels now being too long and bottoming out (although I haven't yet got around to measuring my engine) but it then it doesn't seem likely all 8 fire rings would still seal?
I wonder if the soft bit of the gasket is thinner than it should be or the fire rings are thicker than they should be so the soft bit isn't being compressed enough to seal properly?
When I get around to looking at my engine, I'm going for belt and braces - file down the dowels if they're too long then copper spray and silicone along the valley edge of the head gaskets.

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Post by Misterb_57 »

Thanks ratwing, I think you are right.

Like you I'm pretty convinced that the fire rings are sealed as there is no coolant in the oil and vice versa.

Mine being an 14 bolt 3.5, I've come to the conclusion that the extra 4 bolts on the outer edge did in fact seal the gasket on the outer edge (but of course put an unequal load there as well, causing the fire ring to fail and blow into the valley). I'm only now using 10 bolts (studs) and feel the fire ring does not compress enough to seal the composite element. This means oil draining back from the rockers can seap between the fire rings and out, then down the block.

I'd coated all surfaces with copper gasket spray but surprisingly this has not sealed. I have a suspicion that the copper spray is not oil resistant.

I have the valley gasket off now and will run a bead of sealant along the joints (once I've degreased) but will use Hylomar as I'm more confident in that, than silicone in that area.

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Post by ChrisJC »

You have to remember that in most engines, the edges of the head-gasket are effectively 'outside', so as long as the holes through the gasket seal, you won't get any oil.
But on the RV8, the valley side has oil being sprayed at it by the camshaft, so it will eventually run across the deck unless the non fire-ring part is also compressed.

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Post by SimpleSimon »

Had the same problem with a freshly decked block and true heads using Elring HG's and ARP studs, initially I thought it was from the front valley area block to intake I was wrong 8) when I cleaned off the area I found the real reason a re-torque of the heads sorted things out there was still residual ARP lube round the nuts and studs, this leak satred after about 1500 miles after a fresh build no issues since done around 7k miles since, oh I indexed the fasteners 1st and found on re-torque I was around 35/50 degrees on the fasteners so those Elring HG's had compressed a tad :( obviously not a problem with the stock LR yield/stretch bolts constantly pre-loading the gaskets, cant really blame the Elrings for this though seeing as I deviated from the stretch bolts ....... oh OK I will 8-)
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Post by jimbob »

I had the same issue on some 10 bolt heads, drove me nuts, started with oil, then water.

I ended up stripping it down again, cleaned all the surfaces with thinners, new gaskets, all the outer water ways covered with RTV, same time valley gasket was fitted with blue hylomar, The two rubber gaskets were coated with RTV, that the valley gasket joins too. Four bolts in each corner of the inlet manifold, pulled the heads down slowly over a period of a couple of hours. to a final torque setting of 75ft/Lb's, then the valley gasket was neatly in place.

Rocker cover gaskets also had a coating of hylomar to stop any oil seeping.

So far 3,000km's no water or oil loss. i really hope its sorted. Couldn't face another strip down.

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Post by jimbob »

I had the same issue on some 10 bolt heads, drove me nuts, started with oil, then water.

I ended up stripping it down again, cleaned all the surfaces with thinners, new gaskets, all the outer water ways covered with RTV, same time valley gasket was fitted with blue hylomar, The two rubber gaskets were coated with RTV, that the valley gasket joins too. Four bolts in each corner of the inlet manifold, pulled the heads down slowly over a period of a couple of hours. to a final torque setting of 75ft/Lb's, then the valley gasket was neatly in place.

Rocker cover gaskets also had a coating of hylomar to stop any oil seeping.

So far 3,000km's no water or oil loss. i really hope its sorted. Couldn't face another strip down.

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Post by jimbob »

I had the same issue on some 10 bolt heads, drove me nuts, started with oil, then water.

I ended up stripping it down again, cleaned all the surfaces with thinners, new gaskets, all the outer water ways covered with RTV, same time valley gasket was fitted with blue hylomar, The two rubber gaskets were coated with RTV, that the valley gasket joins too. Four bolts in each corner of the inlet manifold, pulled the heads down slowly over a period of a couple of hours. to a final torque setting of 75ft/Lb's, then the valley gasket was neatly in place.

Rocker cover gaskets also had a coating of hylomar to stop any oil seeping.

So far 3,000km's no water or oil loss. i really hope its sorted. Couldn't face another strip down.

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