Is this head dead?

[Rooter]

Hi all - bit of advice please - this head came off a ms660 that had just been out the shop after blowing up once , only to die again instantly from crank bearing disintegration so head was brand new , I’ve cleaned the smudges out to find a single score running from top to transfer port , scratch can be felt with finger but it’s shallow and not down to the metal ,  seems the piston took most of the shrapnel to the top and bashed some into the top dome of the head (note the pock mark above score) will it be alright to reuse or is it junk ?

 

Edited May 24, 2021 by Rooter
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[openspaceman]

It's hard to judge, it doesn't look bad and the standard finger can detect a half thou groove and that is not enough to worry about.

[Stubby]

Light hone and jobs a goodun . 👍

[spudulike]

Looks like it has pushed a smooth groove in to the cylinder. It may kill the compression if deep enough but it may be fine. Only way to tell is to get it back together again, do all the relevant checks and set up and see how it runs. 

Less likely to impact a big engine than a small one.

[spudulike]

I would also say that the first top end probably died after what I assume to be a big end failure and "the shop" just fitted a new top end without recognizing what had failed!

[Stubby]

1 minute ago, spudulike said:

I would also say that the first top end probably died after what I assume to be a big end failure and "the shop" just fitted a new top end without recognizing what had failed!

Wankers ! 😁

[Rooter]

Quite possibly could of been on its way out I’ll post a pic of the crank -when emptied  the fuel in it looked like it had been stained only by the remnants on the last mix to occupy the fuel can , the bloke I got it off s a minimal maintainer to boot so perhaps many factors in play , it got so hot that when I got it the chainbrake /mech spring had bust out where the plastic around the retaining screws  on the chainbrake cover had simply melted . 
I think possibly died of mix and what I call “smega-mortis “ - he used to use a lot of bio and mostly veg oil which turns /baked into some sort plastic evil that only swearing and a scalpel seem to shift often taking paint with it , perhaps he put it into be repaired in its smeggy state and the shop guys just fixed it up and waved it goodbye knowing that he’d be back for a new one cos it would boil itself anyway in that state . 

1 hour ago, spudulike said:

I would also say that the first top end probably died after what I assume to be a big end failure and "the shop" just fitted a new top end without recognizing what had failed!

 

[Rooter]

Thankyou for your advice gents I’ll pop it back on and see if it performs as I’ve no means to hone it . Cheers! 

[Ratman]

Thankyou for your advice gents I’ll pop it back on and see if it performs as I’ve no means to hone it . Cheers! 

Bet you could get a small honing tool for about £5 amazon / ebay

 

0.75 -2.5 Car Brake Honing Cylinder Tool Use B4 fitting repair kit READ 80g 922a

WWW.EBAY.CO.UK

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A Brake or Clutch Cylinder Honing Tool. Flexible shaft for ease of use and self centering. You will need to obtain the correct repair kit for your cylinder to fit after you have honed the existing body.

[Rooter]

Cheers ratty , I always assumed honing would have been a expensive  lathe type kit job , so never really looked into it .  Happy days , as it may mean I can get one of my beloved 056 supers wood hungry again.

knowledge is power ,  many thanks !