head

[twincamman]

welllll took 26r s2 33 out for a final blast before winter storage missed a shift and blew the head gasket ----I must be getting old ---so its heads up and a new one [ gaskets kept in stock] I will reset #3 shims In and EX while Im at it as they are a liittle close so it will be ready for spring ----oh brown stuff -- --ed

[denicholls2]

If this were your Europa I'd get it; I understand the gaskets were prone to blowing above 8,000 RPM because the aluminum block wasn't stiff enough to deal with more.

But I haven't heard other allusions to stiffness issues in the Twink block. Most RPM-related failures are rods or the crank itself. So you've got me curious. How do the two relate?

[twincamman]

welll the head gasket must have been weak when I got the motor and it checked out ok as far as oil pressure and compression[ when tested #3 was slightly down ]-last summers trip home from Bronty just off the boil didnt help things im sure but it ran faily well -so the head wasnt removed --I have had problems balancing the carbs for a while -changing carbs and rebuilding the distributor ---but after the 'spirited 'run' the rough Idle really started. Blowing compressed air into #3 atdc resulted in air out the #2 intake ---IM in the prossess of removing the head now and hope its the gasket and not a crack in the head or a bit of block melted away or warped head ----the temperature in the garage is only condusive to an hour a day on these old bones so tomorrow it will be known --the cams and head bolts remain to be removed --but all indications are a leaky gasket ----we will see -------btw the thing is a rocket the way it was I assume it will be sparkling when all the pistons are up to snuff --ed

[twincamman]

twood appear something at one time dwelt briefly in #3 cylinder for about 50 revolutions ---there was evidence of gas exchange on the head gasket between 2 an3 and possibly a tad in4----all intake valves are tight but #1 AND#2 intake leak quite readily---the head is flat so it wont need a skim ---I see its a big valve head -- pistons are sound #3 has a slight area when whatever it was passed through left its evidence nothing to worry about ----a little file I keep just for this purpose smoothed things out nicely in the head ---if the weather holds for a week it will be back together --I will do the aluminum spray paint on both sides of the head gasket ---they never leak that way -----[oh dear here we go again ] -happy happy joy joy ---- ed

[ppnelan]

twood appear something at one time dwelt briefly in #3 cylinder for about 50 revolutions...

Just prior to this, did you keep the tea strainers on the carb trumpets or did you replace them with something 'foamy'?

Matthew

[twincamman]

nope ---these were in the 'factory' air cleaner --all sealed up ---suspect it happened prior too my getting the engine --or perhaps before the carbs were on --my fault ---- and there you go --ed

[triumphelan]

What`s the idea behind "spraying ally paint "on to the gasket ,I have never heard of this

[twincamman]

spraying aluminum paint [ the cheap stuff with large bits in it ] adds to the strength and seal of the gasket -------- spray both sides and apply tacky [HERE WE GO AGAIN --MORE OPINIONS INCOMING NO DOUBT--] ---its an old hot rodder trick ---I use it and have never had a head gasket leak or fail yet ----this motor was a 'bargain' but I paid far less than the head was worth ----there were mixed pistons and now I see the reason for the cost -----but a new set of pistons will fix ever thing up -- -ed

[rgh0]

Ed

From the head photos it appears that the gasket flame ring has left an indentation in the head. The head may be soft causing the bolts to loose tension and this may be the cause of the gasket failure. You may want to get the head hardness tested. have the head bolts sunk into the head ?

cheers
Rohan

[twincamman]

Rohan----there is a .004 thou depression where the washers go under the head bolts -- uniformly --both mateing surfaces are level ---the marks in the block was just residue and cleaned up readily--seeing as there was a set of mis matched pistons I would not be surprised if a used head gasket was also part of the deal --BTW my rockwell hardness tester is out for repair -- -ed

[elansprint71]

nope ---these were in the 'factory' air cleaner --all sealed up ---suspect it happened prior too my getting the engine --or perhaps before the carbs were on --my fault ---- and there you go --ed

26R "factory air cleaner"? i.e. nothing at all.

[twincamman]

one I purchased for street use -a little late I think ---I ran the 7 with teas baggers and have had no nasties --have since built a little more complex system I may convert for the 26R -------believe it or not at Mosport many cars have an cleaner system on them to protect against the sand that blows off turn 2 and dust and dirt from spinning cars -----the snow and ice started today so Ill have to locate a head gasket set on Monday and 4 pistons from the California manufacturer so by the time they arrive and Christmas hits Ill be prepared for the January thaw assembly when it warms up to around freezing ---
---ed

[rgh0]

Hi Ed
Your head is hard enough given the small indentation of head bolts and that the marks from the gasket fire ring cleaned off.

Given the cheap rebuild your probably right about a used head gasket as the cause!!

cheers
Rohan

[steveww]

The engine in my S4 runs a slightly hight compression ratio than normal and the head gasket blew this summer on a track day. I was using the regular copper type. When I replaced it I went for a composite one from QED and this has proved to be much more robust and survived the rest of the track days through the summer.

[twincamman]

hi Rohan --your not the first to suggest the hardness of my head ----my wife is on about it constantly----I cant order anything for the car until Monday as the U.S. is closed up for Thanksgiving and there are no suppliers in Canada that can find a head gasket set--or pistons -- --- but did find some cheery hearing to fill in the time ----ed --