Copper head gasket spray

ratwing · Post by **ratwing** » Sat Jul 16, 2016 8:49 am

I've got oil leaks on both head gaskets on a rebuilt Rover 4.6 (new top-hat block and skimmed heads).
I was just going to re-torque the head nuts (its got nuts & studs instead of stretch bolts) but I think I'll renew the head gaskets instead (I'll probably use Elrings again) and I was wondering about using a copper spray too - maybe it's going a bit over the top but if it stops me having to strip it down again it's worth it.
I haven't bought or used it before, I assume this is the stuff or is there a better one

http://www.ebay.co.uk/itm/Copper-Spray- ... Swu4BVr3Se

Any tips on getting the best results from it?

sidecar · Post by **sidecar** » Sat Jul 16, 2016 9:22 am

I run comp head gaskets in my 4.6, I also run a 100 BHP NOS shot. Ages ago I blew both head gaskets and I reckon that it was due to the huge chamfer that Rover machine into the tops of the liners which leaves the half of the fire rings uncompressed. The combustion gases where getting past the fire rings and blew away the rest of the gasket.

Anyway I rebuilt the top end with new gaskets which I sprayed with copper spray, so far the gaskets have not leaked!

I made up a jig to hold the gaskets so that I could spray one side then let the coating set, I then flipped the gasket over and sprayed the other side and let that set.

You need to be careful when fitting the gaskets not to scratch the coating off, I cleaned the gaskets with meths before spraying them. Oh I use Arp studs too!

sidecar · Post by **sidecar** » Sat Jul 16, 2016 9:34 am

As you only have oil leaks and not blown gaskets you could just smear silicon around the oil holes on both sides of each gasket. Let the silicon set before fitting the gaskets. I am of course assuming that your heads and deck are not warped! Some gaskets come with a sort of o-ring built into the gasket.

stevieturbo · Post by **stevieturbo** » Sat Jul 16, 2016 3:35 pm

blue hylomar might be better as a non setting option.

Although really the gaskets shouldnt be leaking as long as head/block face etc is flat, the yanks seem to love copper spray though.

unstable load · Post by **unstable load** » Sun Jul 17, 2016 6:09 am

I used the copper spray back when I was an apprentice for a Mercedes Dealer, but an Old Timer gave me a tip that has served me better than the copper spray.
After an old banger I had had yet another head gasket failure, he told me to paint the gasket with Indian Head shellac and fit it before it dried off. That old banger went for a few years before it was retired due to tinworm.
I did the same when I replaced my Disco Td5 head gasket and coming up on a year later, it's maybe had 2 litres of water added since then.

ged · Post by **ged** » Sun Jul 17, 2016 8:09 am

Same here. I used Indian Head shellac on copper m/cycle head gaskets in the 70s & 80s after being advised by an old mechanic. I used the same gasket for years on that Triumph & that engine went through a few rebuilds & I was using 11-1 pistons.

ChrisJC · Post by **ChrisJC** » Sun Jul 17, 2016 9:56 am

I suspect that the oil is leaking from the valley across the block deck and out of the side of the engine.

My engine does it very slightly with standard composite gaskets.

You could run a smear of instant gasket along both block and head along the valley side.

Chris.

ratwing · Post by **ratwing** » Sun Jul 17, 2016 10:14 am

ChrisJC wrote:I suspect that the oil is leaking from the valley across the block deck and out of the side of the engine.

My engine does it very slightly with standard composite gaskets.

You could run a smear of instant gasket along both block and head along the valley side.

Chris.

If only that was the case - I had another look a few minutes ago and the valley gasket and rubbers are still completely dry and oil tight.

sidecar · Post by **sidecar** » Sun Jul 17, 2016 10:30 am

The other thing to check is the rocker cover gaskets. The cork ones are all that great in my humble!

ratwing · Post by **ratwing** » Sun Jul 17, 2016 2:47 pm

I'm using rubber gaskets, stuck both sides to the heads and rocker covers with the same Wynns black sealer, I don't know how easily they'll come apart but there aren't any oil leaks so far.
Definately seems like its the head/block joint because I can't see any oil coming from anywhere else and there's no bodywork so I can get a good close look pretty much all round the engine.
When the new bits arrive and I take it apart I'll be really careful to keep an eye out for anything at all that looks unusual.
Watch this space...

kokkolanpoika · Post by **kokkolanpoika** » Sun Jul 17, 2016 8:18 pm

ChrisJC wrote:I suspect that the oil is leaking from the valley across the block deck and out of the side of the engine.

My engine does it very slightly with standard composite gaskets.

You could run a smear of instant gasket along both block and head along the valley side.

Chris.

I think this is not true..

Oil has got too long travel to outside that way..
In my mind your compression gas is escaping in your cylinder.. Very small leakage..

My 5.2l has got similar issue when i use those crap custom gasket´s. When i last time dissemble my engine, i notice that fire ring has got ultra small leakage.. I see it on my head face below fire ring, some very small carbon line´s..

As i understand fuel might look like engine oil if not burned properly.

ChrisJC · Post by **ChrisJC** » Mon Jul 18, 2016 5:49 pm

ratwing wrote:
ChrisJC wrote:I suspect that the oil is leaking from the valley across the block deck and out of the side of the engine.

My engine does it very slightly with standard composite gaskets.

You could run a smear of instant gasket along both block and head along the valley side.

Chris.
If only that was the case - I had another look a few minutes ago and the valley gasket and rubbers are still completely dry and oil tight.

Ah, but it leaks from inside the valley area and down the block deck. You will see that the head gasket seals the bores, and possibly the water jacket and oil feed gallery. But they don't specifically seal this, so unless the gasket is very well compressed, it can leak that way.

I still put my money on it.

Chris.

ratwing · Post by **ratwing** » Tue Jul 19, 2016 2:50 pm

ChrisJC wrote:
Ah, but it leaks from inside the valley area and down the block deck. You will see that the head gasket seals the bores, and possibly the water jacket and oil feed gallery. But they don't specifically seal this, so unless the gasket is very well compressed, it can leak that way.

I still put my money on it.

Chris.

I misunderstood but see what you mean now - its leaking down from the valley, past the headgasket between the heads & block and comes out at the bottom of the joint.
That would explain why there's no oil anywhere else on the outside of the engine.
Because its quite a big leak with oil running down the sides of the block after a 20 mile trip I'm going for a belt and braces fix, replacing the gaskets, using copper spray and your idea of using sealer across the top looks worth doing too.

ratwing · Post by **ratwing** » Tue Aug 09, 2016 10:28 pm

Chris, you were right - I undid the first head nut and it didn't seem very tight so I tried a torque wrench on the rest and they were all loose, some took nearly a full turn to tighten up

Both heads were the same so I re-torqued the nuts in order, went for a run just to see if it made a difference and it looks like the leaks have gone

The joint is still slightly damp with oil but I suspect that's just residue squeezing out because it isn't getting worse so fingers crossed, the problem is fixed.