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Cylinder head gasket BJ8

robolab

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High Austin Healey friends,

My dismantled BJ8 engine is back with new parts from the engine builder.

Crankshaft balanced with new bearings,
Camshaft with new bearings,
New pistons fitted with oversize,
The contact surfaces of the head and body are remilled,
New Valves,
Side cover cut out for split shaft seal on rear end of the crankshaft,
All welch plugs renewed. Now will start to put the engine back together. I have a question about this:
The manual says that the head gasket is to be installed dry, i.e. without sealants such as Hylomar.
With my Triumph TR3a, however, it was stated that the head gasket should be installed with Hylomar or something similar.
What is better now? Are there any experiences? My triumph has been tight for 10 years.

Thanks Gerd
 
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Norman Nock used to recommend Wellseal for 100 head gaskets which, of course, are notorious for leaking between #2 & #3 cylinders. In general, though, if both surfaces are properly prepared a quality gasket can be fitted dry; the question is, what are the quality gaskets these days? When I had my rebuilt BJ8 my builder used a Payen gasket that I bought years ago but, last I heard Payen is no longer manufactured in England. I've seen some solid copper gaskets available on a custom-build basis.
 

Healey Nut

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I have no idea where the is adding sealant to gasket thing came from .
The definition of a gasket is a mechanical device to seal between two surfaces and fill imperfections .
Now yes there are certain types of gaskets that require you to use additional sealant such as O rings . I use Loctite 515 on many of the Orings of the equipment I rebuild but its specified by the manufacturer . They are also specific about the amount of extra sealant to use . Using 3 tubes instead of one is not going to make it “seal better”
If the manufacturer of the gasket or rebuild guide says install it dry then install it dry .
I never use additional sealants on head , exhaust , intake gaskets . Use good quality know manufacturer gaskets and follow their instructions they are the ones who have done the research and testing of their products .
 
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I have no idea where the is adding sealant to gasket thing came from .

"Norman Nock used to recommend Wellseal for 100 head gaskets ..."

That's one specific example for a known (problematic) installation. Note many/most new cars don't use gaskets in many 'traditional' locations anymore, such as pan gaskets, they use sealant only. I was never able to get a good seal with contemporary, dry exhaust downpipe gaskets; high-temp RTV and double-nutted studs finally fixed that problem for me.

ps. Norman was a factory-trained BMC mechanic.

Edit: Sometimes, you do what you have to do. I got a repop gas tank for my BN2 and couldn't get a good seal on a sub-par sender flange--even tried the newfangled rubber gaskets with 'ribs' ;)--none of which did the job. Finally put a thin smear of fuel-resistant silicone on a couple cork gaskets and, with longer screws, the leak--and smell--finally stopped.
 

Patrick67BJ8

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"Norman Nock used to recommend Wellseal for 100 head gaskets ..."

That's one specific example for a known (problematic) installation. Note many/most new cars don't use gaskets in many 'traditional' locations anymore, such as pan gaskets, they use sealant only. I was never able to get a good seal with contemporary, dry exhaust downpipe gaskets; high-temp RTV and double-nutted studs finally fixed that problem for me.

ps. Norman was a factory-trained BMC mechanic.

Edit: Sometimes, you do what you have to do. I got a repop gas tank for my BN2 and couldn't get a good seal on a sub-par sender flange--even tried the newfangled rubber gaskets with 'ribs' ;)--none of which did the job. Finally put a thin smear of fuel-resistant silicone on a couple cork gaskets and, with longer screws, the leak--and smell--finally stopped.
Can you post what brands of sealers you used? Part numbers? Thanks
 
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For the sender (cork) sender gaskets, I put a thin smear on both (you don't want any globs that can fall into the tank):

https://www.tanksinc.com/index.cfm/...Kx5wHl9uIpFTr5dfBbwzcEy1WMzXZy8MaArCpEALw_wcB

For the BN2's head gasket, Noman's recommendation:

https://www.pegasusautoracing.com/productselection.asp?Product=3304

When I rebuilt my gearbox and OK for my BJ8 I put Permatex Aviation Form-A-Gasket on all the paper gaskets:

https://shop.advanceautoparts.com/p...hmpEbz3oHdt3Mvc7RRAaAl5iEALw_wcB&gclsrc=aw.ds

And a silicone sealer/adhesive on the ungasketed body/tailcone joint:

https://www.walmart.com/ip/Permatex...xvZt4H-YlaAczm_CVCjb2Y_OUZfgvPdEaAswZEALw_wcB

So far, except for some oozing around the operating shaft O-rings the box/OD are-oil tight.
 

dancrim

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I always painted them with silver spray paint. Never had a problem. The idea is that the aluminum in
the paint flakes and makes a good seal. I have used this method on head gaskets for 50 years with not
one blown gasket. Of course you do have to be sure the head surface is FLAT.
 

HealeyPassion

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FWIW, I used a recommended copper spray with the high quality copper gasket (yes, there is a difference in copper gaskets). I got these from British Parts Northwest (I have no affiliation with them).

Steve
 

HealeyPassion

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ROBOLAB .... Gerd ... looks like you got plenty of advice/input but don't think there is a clear path forward! Good luck! And, since I'm guessing that all that provided input didn't have leaks (mine doesn't), there probably are a few solutions that will provide a leak free result.

I will add one other thought. It is important that the head bolts are not already over stretched... i.e. how many times has the head been on and off the engine?... each re-torquing stretches the rod bolts and at some point (after maybe 2 or 3 or ?) re-torquings they will not stretch consistently which can cause a leak. I had this on one head... I put on new ARP head bolts, new solid copper gasket (again with copper spray)... and then it was fine. Keep in mind if the head gasket does leak it may leak externally (so you can see the seepage) or it could leak into the oil/piston area... that may take a bit longer to diagnose.

Cheers,
Steve
 
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robolab

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Thank you for the many answers, which are very different. After careful consideration and the positive experience with my Triumph TR3, I will use the head gasket with Hylomar. Since I don't know how many times the head has been up and down, I'll be using new head bolts, washers, and nuts.

Thanks
 

Healey Nut

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Here’s why Hylomar is NOT a good idea IMHO .
 

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robolab

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The temperature range of Hylomar M is -50 to +250 C

Gerd
 

Keoke

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Healey Nut

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150C is 302F. Do cylinder heads on Healeys ever reach such a temp?

I don’t have documentation but I’m sure around the exhaust valve area they get very hot , how hot does your exhaust manifold get ?
I would rather just install it dry as is suggested in the manuals such as Haynes etc .
 

John Turney

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The cylinder temperature can easily reach 1,300F, but by the time it gets to the water jacket, it will be no higher than 230F.
 

Joe Schlosser

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IMHO putting anything other than a coat of Copper spray on a head gasket is a bad idea. The copper spray is specifically made for head gaskets (NAPA and others).
Remember the gasket needs to seal against the every high temperature and pressure of the the cylinder head and the relatively low pressure and temperature of the water jacket and oil passages.
The even torque of the head bolts is what provides the sealing. Anything on the gasket will upset the torque/pressure between the block and the head.
 
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I agree. Wellseal was only recommended for 100 heads, to hopefully prevent the common leak between #2 & #3 cylinders (the head needed another stud or two).

I've read the copper 'paint' doesn't so much act as a sealant as it does a lubricant, since there may be some movement between the surfaces when being torqued-down, and the sealing rings around the pistons could be repositioned a tiny bit when they get squashed.
 
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