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Dressing top of cylinder block

Posted: Fri Dec 17, 2010 8:09 am
by helen&tony
Hi
I see that some folk have had cylinder head problems, and after a replacement head, the next one fails.
This failure of new heads is sometimes put down to the fact that the block surface was not dressed. I am querying this, as unless the head gasket has failed between cylinders, and caused burning across the top of the block, surely a new head gasket is all that is necessary, and new bolts with the new head.
I presume that the block is dressed with a stone and carborundum paste, so this means removing the whole engine, or carborundum will get into the oilways...if this is the case, is it not better to machine the surface until trued?
The reason for my asking, is that I have had some silicon hoses failing, and , hopefully, changing the hoses will cure the problem....if it is the head, getting the block dressed over here would be about as easy as catching wind in a butterfly net!...there are very limited skills here, and it would be daft to get a new head fitted if dressing is a must!....it would mean that the Bongo would have an appointment with a disc cutter!, and sold as scrap metal...
Thanks in anticipation of any pointers!
Cheers
Helen

Re: Dressing top of cylinder block

Posted: Fri Dec 17, 2010 12:19 pm
by francophile1947
Never tried it on a Bongo, but I just blocked the oilways with cotton wool before starting. It may not be the approved way, but it kept the oilways clear when I pulled it out :lol:

Re: Dressing top of cylinder block

Posted: Fri Dec 17, 2010 1:08 pm
by helen&tony
Hi
John...
What did you use..and what paste?....is it REALLY necessary on the Bongo, or would it only be needed in the event of inter-cylinder burning?...and what type of block were you using?
Cheers
Helen

Re: Dressing top of cylinder block

Posted: Fri Dec 17, 2010 2:21 pm
by francophile1947
Really necessary? Don't know, but several members have said that it is 8)
I did it on an old Ford Anglia and used a sheet of plate glass as the rubbing tool - can't remember the name of the paste, but it was just valve grinding paste - coarse followed by fine (the tin had the different grades at each end). To be honest, the only irregularities I found were very slight "lumps" around the head bolt holes - the new gasket might well have sealed them anyway.

Re: Dressing top of cylinder block

Posted: Fri Dec 17, 2010 3:06 pm
by helen&tony
Hi
That makes sense, John...I must admit that whenever I have changed a gasket or done a decoke in the old days, I just used a gasket, except when building engines, I would send the parts off for machining! I don't expect any attention to detail here, though, as most workers are totally inept :lol: :lol: :lol: :lol:
Cheers
Helen