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Should have left the head alone! 3 parts

PostPosted: Tue May 21, 2019 8:41 pm
by Mike Attew
Last year I rebuilt my engine 1256, after about 50 miles I noticed oil coming from the head near the dip stick. I retorqued the head and got about 3/4 turn or more on the bolts, lately I have been using a bit of water so thought it was all relative.

Re: Should have left the head alone! 3 parts

PostPosted: Tue May 21, 2019 8:42 pm
by Mike Attew
Gasket kit from Fred, head off, Wellseal on the block, gasket on then Wellseal. Torqued head up in 5lb stages to 49lb. Started up and as it was warming up oil started coming from the head near the dip stick and also water from near the number stamp area.

Re: Should have left the head alone! 3 parts

PostPosted: Tue May 21, 2019 8:42 pm
by Mike Attew
Head was skimmed last year, bolt holes were clear. Do these newer gaskets need Wellseal? I have never had this with rebuilding engines before but then again I have never used Wellseal before.

Found this was the only way to post this question. Sorry.

Re: Should have left the head alone! 3 parts

PostPosted: Tue May 21, 2019 11:50 pm
by vauxhallbitz
Had exactly the same problem last month, would certainly recommend Wellseal as per the manual.

I ended up getting a friend to refit the head for me with Wellseal and have had no problems since.

Did you put it on both sides of the gasket?

How thick did you put it on?

See my post "Chevette engine v Viva engine" for the full story.

Re: Should have left the head alone! 3 parts

PostPosted: Wed May 22, 2019 7:12 am
by Mike Attew
Put the Wellseal on the block, placed the gasket in place then Wellseal on the gasket.
Possibly put it on too thick?

Re: Should have left the head alone! 3 parts

PostPosted: Wed May 22, 2019 11:03 am
by Fred Dukes
don't know if it has a bearing but I had trouble with head gasket on the Double plus Van and only succeeded with a proper seal by using some 2 temporary dowels in bolt holes at each end of the head so that the head located accurately on the block allowing me to put the other bolts in 1st and then extract the dowels to put the final bolts in prior to torqueing down.

Re: Should have left the head alone! 3 parts

PostPosted: Wed May 22, 2019 6:47 pm
by thomas
Though both of the HB manuals I have handy: Haynes and Autobooks, explicitly say use Wellseal jointing compound on both sides of the head gasket, the last Haynes Chevette manual I have covering from '75 up to '84, (published in 1986, thus presumably representing 'state-of-the-art' practice) says do not use anything at all on the head gasket! There might have been differences in gasket material between early and later types to account for this, (the early ones being steel and asbestos, when not the low compression copper ones) but I fail to see how say a 70s/80s Chevette 1256 differs in procedures from that for an identically-engined Viva 1256.

:catamongstpigeons:

Re: Should have left the head alone! 3 parts

PostPosted: Thu May 23, 2019 12:31 am
by vauxhallbitz
Don't think you can put it on too thick, I put it on with a plastic scraper the first time and it leaked so I asked a friend to put it on for me. He builds Austin Healy racing engines and swears by Wellseal.

He put it on the block quite thick, dabbing it on with his finger then fitted the gasket and did the same with it, finally he put the head on and we torqued it down, no leaks!

I have no idea why it didn't work when I did it but it seems to be fine now.

Re: Should have left the head alone! 3 parts

PostPosted: Thu May 23, 2019 2:08 am
by thomas
There is a Supplement section to the last Chevette manual, which varies from the information given in the main engine section.

Old section:

Image

New section:

Image

In case the second image disappears, the text is:

"Contrary to the instructions given in Chapter 1, Section 34, it is now recommended that a 1 to 2 mm diameter bead of jointing compound (Hylomar PL 32/M) is applied to the upper left-hand face of the cylinder block along the outer push rod rail and also along the outer edge of the cylinder head gasket upper face in the same vicinity [...]".


Whatever works for you, works.

Re: Should have left the head alone! 3 parts

PostPosted: Fri May 24, 2019 12:02 pm
by Mike Attew
It is all an enigma and this will start something else. I spoke to my local engine centre and they seemed to think the problems are to do with torquing the head down. They said do not use Wellseal, Torque the head down and then run the engine till it's hot. As the head bolts expand more than the head retorque the head hot. I did this and I got about a 1/4 turn on each bolt to 55lb.

It seems to have worked in my case.