Author Topic: A7 head grease plate --- remove pistons that are seized  (Read 1161 times)

Offline Bsa Nut

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I 've heard of using grease as a hydraulic enema to free seized pistons, so I had the opportunity to give it a try on the new A7 purchase.
Found a half inch steel plate and drilled it to match the head pattern, added two zerks, and bolted it up tight with old head bolts, and used sockets as spacers.

This is a safe and affective way of driving out the rusty bits without damage. I did have to nudge it a bit at the very end with some wooden wedges and a hammer.
All apart and NO damage!


https://fbcdn-sphotos-d-a.akamaihd.net/hphotos-ak-ash4/1403396_246788725474152_448067072_o.jpg

Offline Bsa Nut

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https://fbcdn-sphotos-b-a.akamaihd.net/hphotos-ak-frc3/1398474_246788128807545_1533894081_o.jpg

Another shot before bolting it on the head...

Did I mention this is a MESSY operation? Very messy. Three tubes of grease, squished everywhere.

;)

Offline Stephen Foster

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Its a good idea which I doubt can harm the seized pistons ?
I own a 1955/56 B.S.A Swinging Arm "Golden Flash" , had it since 1976 .

Offline Bsa Nut

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Its a good idea which I doubt can harm the seized pistons ?

I've been warned that a solidly stuck set of pistons that refuse to budge could cause the barrel to crack.
It would have to be an EXTREME case. And in retrospect, if it was seized that badly, then the barrel was most likely junk anyway.

No hammer and drift marks all over the piston tops!
No rod damage or bushing damage.
Just one big mess...wish I had a parts washer at home.
;)

Offline Briz

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Well done!
That sounds like a great method. Well worth a try.
Its amazing how seized pistons can be; last year I bought an old Daimler V8 short block for parts. 2 of the pistons were rusted in there good.
I dismantled everything else and left them to soak in a mixture of diesel & ATF overnight and then set it in my 50-ton hydraulic press to shove them out (which had to be done from the underside)
It took every bit of the power of that press to move them, and made a noise like a car crash when they did! The pistons & rods did not survive the ordeal *lol*

Offline wilko

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Love those Triumph V8's!

Offline BSA_54A10

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Use vasoline rather than grease.
A lot cleaner as it washes off in boiling water.
Convincing 'er indoors what you are doin g with all tht vasso down in the garage might be a little more difficult
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Online RichardL

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Might add to check that pistons are neither at TDC or BDC. Well, really BDC, because you would know right off if they were at TDC.
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Offline kiwipom

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hi guys, Briz says( last year I bought an old Daimler V8 short block for parts) as a matter of interest a mate of mine has (Daimler V8)pistons in his Bsa A65,cheers
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Offline Briz

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Yeah, that'd work, Daimlers are 3" bore (76.2mm) so a 1.2mm overbore  would get it. Same size gudgeon pins too.