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Head Gasket fitting

Warsash 2
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Head Gasket fitting

Post by Warsash 2 » Wed Dec 19, 2018 2:50 pm

The engine rebuild is going a pace. We are now ready to fit the heads. I have 2 questions.
1) The head gaskets have a ridge on one side does that go to the block or the head, there is no this way up instructions?
2) The heads have been lightly skimmed do it need a sealant if so what is recommended?
Thanks in advance


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Vortex O'Plinth
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Re: Head Gasket fitting

Post by Vortex O'Plinth » Wed Dec 19, 2018 4:49 pm

The cylinder heads are identical but asymmetric, as are the gaskets. I think you'll find with all the water passages lined up, the gaskets will only fit one way up.

Original gaskets were varnished and Daimler recommended no sealant.

Pas d'elle yeux Rhône que nous.

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Re: Head Gasket fitting

Post by silverdart » Wed Dec 19, 2018 7:11 pm

Hi Colin, I have just rebuilt the top end of my engine. As the waterways on my cylinder heads were not perfect, I used Hylomar 2000 gasket sealer on the head side and a smear of grease on the block side.
I am happy to report that, having run the engine it seems that everything is o.k.
I hope you have a similar outcome.
AS Nick says the gaskets will only fit one way round.


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Re: Head Gasket fitting

Post by Jez » Thu Dec 20, 2018 11:27 am

I was recommended to use Wellseal when I did mine. Not sure whether it was strictly necessary, but is certainly doing the job.

Cheers - Jez
Jez Stow
1960 Daimler Dart
and a few other toys

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Re: Head Gasket fitting

Post by JT7196 » Thu Dec 20, 2018 8:48 pm

I used Hylomar ,on my previous engine rebuild, on subsquently stripping because of an unrelated problem , I was alarmed to see that the Hylomar has intruded into the waterway ports etc, and I thought that I had used it very sparingly !
I have now rebuilt using a thin coat of Wellseal !

Cheers Al :D

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Re: Head Gasket fitting

Post by tjt77 » Sun Dec 23, 2018 4:34 pm

head gaskets fit only one way.. as Vortex O'Plinth states above.. As regards any sealant.. factory reccomendataion is fit dry.. practical experience says a high quality sealer does help.. BUT.. its critical not to overdo it. and there are other important things to assure a troubler free installation :-
(1)head bolts and washers .. there is chamfer on the washer that should be at the top ..this is in place to avoid any binding twixt washer and bolt head.. make sure it all spins freely..if not take action to rectify..(use a counterskink bit to slightly increase chamfer..with a fine file remove the 2 ridges under bolt head ..until washer spins under both head with zero binding)
(2) make sure all threads are clean.. run a thread chaser into every threaded hole in block face ( 7/16' NC ) and blow out any debris with compressed air....and clean all the bolt threads with a rotary wire brush.. run each bolt into block to check for smooth resistance free operation full length .. a small amount of anti seize compound on the threads is recommended..
IF you do use gasket sealer..use a very thin but even coat on either side of gasket ..I personally use K&W 'copperseal' in an aerosol can ..hang the gaskets by wire.. and spray both sides and allow to dry for about 15 mins before assembly.
With Hylomar, standard practice (as rcommeneded by rolls royce who originally used this brand on their aero engines) is to stipple the sealer on with a short bristle brush to get and thin but even coat on both sides..
the thing to avoid with gasket sealing compounds is to have excess that can come adrift and cause restrictions in water ways /radiator core etc.. or worse, can get into the oil and cause a restriction of oil flow somewhere..

Warsash 2
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Re: Head Gasket fitting

Post by Warsash 2 » Mon Jan 07, 2019 9:53 pm

Thanks for this Colin has now fitted the heads. He used Grease on the face towards block and Hylomar diluted with thinners towards the head. The car will be returned to Colin's on Thursday and hope to have it fitted in a couple of weeks. We will then know if the heads are sealed. Thanks to all who contributed.
Regards Colin

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Re: Head Gasket fitting

Post by heh101353 » Mon Jan 21, 2019 6:02 pm


Most of my questions are already answered in this thread.
But still being a rookie when it comes to gaskets and materials and so on I have a question.
What is the recommended cylinder head gasket?
What was the original material?
DM sells two variants, a "normal" gasket and a composite gasket (price is tenfold)
Any experience, advise or suggestions?
Any comments much appreciated!


Big Col
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Re: Head Gasket fitting

Post by Big Col » Mon Jan 21, 2019 8:45 pm

Original was/is aluminium plate stamped with bubbled rings around the holes to make a seal.
I think the composite ones are thicker to allow for heads that have been skimmed.
I may be slow but I’m rough as well !

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Re: Head Gasket fitting

Post by tjt77 » Tue Jan 22, 2019 6:48 pm

The Original stamped steel gaskets are approx .010" thick.. the after market 'composite' gaskets are approx .040" thick... they were produced in order to compensate for heads skimmed below acceptable margins set by factory. If you fit the composite gaskets on unskimmed heads, you will lose power to to lower compression ratio..
The standard workshop manual does not give maximum amount that can be skimmed from head faces , but in practice -.025" is the 'safe' limit when using the standard head gasket and up to -.060" per head with the composite gaskets is workable. I believe the depth of head from top to bottom when new is 3.0"

The main issue when one skims too much off the head face is it upsets the geometry of the valve train.. this can lead to push rods binding in the head and the rockers having metal to metal contact with end of push rods at full opening.. this can be compensated for by shimming the bases for rocker gear.

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