Head Gasket

Post by **Tweedy** » Thu Jan 01, 2009 8:44 pm

Hi everyone, hope you all had a good new year. I took the head gasket of my moggy 1098 engine because of an oil leak from the front left behind and down from the thermostat housing , put a new copper gasket on and tightened down to 40 and then started her up and she was going first time but noticed the oil leak was still there so I took the head of again to find some water just under the copper gasket at the front, could anyone please tell me what I have done wrong

Post by **mike.perry** » Thu Jan 01, 2009 8:55 pm

Is there any sign of corrosion to the head or block in that area?
Is the face of the head true in the corner?
Is there any debris around the base of the head stud?
Did the gasket lower smoothly onto the block?
Is the water definately coming from between the block and head and not from the thermostat?
Did you drain the water completely before lifting the head? Water still in the block will spread over the surface.

Post by **Tweedy** » Thu Jan 01, 2009 9:05 pm

There was some water come out of the thermostat housing when I lifted it. there is no corrosion at all and it all went on smoothly but the nuts were realy hard to get off and they went on ok all the studs are in firmly, do you think they might have been put on tight before as the old gasket was very thin

Post by **stag36587** » Thu Jan 01, 2009 9:12 pm

how accurate is your torque wrench - mine was not very accurate, hence made a complete hash of putting a new head gasket on the stag some time ago.

What do people here think about gasket sealants?

Post by **Tweedy** » Thu Jan 01, 2009 9:17 pm

Only had moggy a few month, bought a new torque wrench to do the car with so I dont know if its accurate or not, they advise not to use sealants on Cylinder head gasket

Post by **rayofleamington** » Thu Jan 01, 2009 9:31 pm

What do people here think about gasket sealants?

useful on some joints but NOT headgaskets.

In this case I'd suspect a warped head - as the head is off again it's really worth to get it checked before re-assembling.

Post by **Tweedy** » Thu Jan 01, 2009 9:35 pm

Thanks Ray will do
Bob

Post by **IslipMinor** » Fri Jan 02, 2009 8:42 am

Do you have some pictures of the head and block - especially where the leak is coming from.

Definitely no sealants on Minor head gaskets, but a good smear of ordinary grease on both sides of a copper type head gasket, and all up the studs, will make sure that everything will come apart more easily at some time in the future - same applies to the thermostat housing.

Post by **bmcecosse** » Fri Jan 02, 2009 12:00 pm

Definitely NO sealant of any kind - just smear of grease. Look carefully at the cylinder head - the oil way drilling across the face of the head is sealed off at the front end of the head and it's possible the little plug has come loose ? It's VERY unusual to have an oil leak from the joint between block and head - the head would need to be very badly warped for that to happen.

Post by **fsk658** » Fri Jan 02, 2009 8:29 pm

Head gasket sealant or not ? I have always fitted without sealant. If the mating surface is true and clean it shoudn't be neccesary. But after seeing head gaskets being replaced at an overseas rally by two different professional mechanics, they both used hymalar sealant. I asked if this was okay. They both said they have used it for years with great success. I have since used it when fitting a head to one of my engines over two and a half years ago and thats bean down to the south of france since. PS I still prefer not to use anything. Just make sure its very clean

Post by **rayofleamington** » Fri Jan 02, 2009 10:54 pm

no sealant, no grease IMHO

Post by **Cam** » Sat Jan 03, 2009 12:12 pm

Same here, no sealant and no grease, but I do take the point about the grease aiding future removal.

Post by **Longdog** » Sat Jan 03, 2009 1:25 pm

I use no sealant or grease,down to 40lb/ft and no more.Torque wrenches at the cheaper end of the market can be way off.
Quality of head gaskets varies also, I have had numerous problems, switched to Payen gaskets and none since (touch wood

)

Post by **bmcecosse** » Sat Jan 03, 2009 6:16 pm

Gaskets from local Autoparts are fine - the 'Payen' thing is grossly over-stated, certainly for standard engines. Safe to take the standard head nuts/studs to 44 ft lbf - but do make sure the studs are well anchored in the block and the threads are oiled.

Post by **Longdog** » Mon Jan 05, 2009 7:19 pm

Not in my experience.Payen yer money and take yer choice.If you like doing jobs over and over save £5 by all means.Never had a gasket stick though.So no grease.Winding nuts up beyond the torque setting can split reinforcing between bores on the gasket.Nuts were wound up at the factory dry.Motor manufacturers spend Years and many thousands on research and development to find ideal torque settings therefore I go with those.

Post by **bmcecosse** » Mon Jan 05, 2009 9:22 pm

Threads should always be oiled when setting torque. Later engines using the very same studs/nuts are specified at 44 ft lbf. Even later engines had better quality studs (dimple end, then Y marked end) - and are specified for 50 ft lbf - and obviously the gaskets didn't 'split' ! But not wise to go to that torque on original studs. I have never had any problems with normal Autoparts gaskets !

Post by **Longdog** » Tue Jan 06, 2009 12:50 pm

Why oil the studs though, they never bothered at the factory.If you are changing the friction characteristics of the thread you will essentially be over torquing the nut.

Post by **bmcecosse** » Tue Jan 06, 2009 11:21 pm

Lots of things the 'factory' didn't do correctly - good engineering says oil the threads to get the correct torque - otherwise you are winding it against the unknown 'stiction' rather than measuring the applied torque to the stud.

Post by **Kevin** » Wed Jan 07, 2009 10:18 am

good engineering says oil the threads to get the correct torque

But what is the correct oil as they all have different characteristics so in theory would give different torque settings.

Post by **bmcecosse** » Wed Jan 07, 2009 11:27 am

Indeed -but anything is better than dry threads. Engine oil is fine ! They don't need to be dripping in oil - just a wipe will do.