[Healeys] FW: no compression 100

[Dave Porter]

Guys,
 I've posted a picture of this at http://porterbikes.com/
As to John's discussion (below) let me say this.. Before the introduction of
unleaded fuel, I could pretty much be assured that on any given week I'd be
doing at least one valve job. It was any shops best bread and butter repair.
Ah, since unleaded, I might do a valve job once or twice a year! And they
are usually unrelated to the fuel issue. So, while valve seat recession is
still possible, it hasn't proven to be the fault that was predicted. The
symptoms stated in the e-mail do not reflect a cracked head either. Most of
those problems are seen as very slight seepage through the head to the
rocker deck and I've never seen one that causes dramatic compression losses.
 As a helpful hint to all. Any time your engine falls on its nose, save a
rod through the block, duh, check the compression first! It's so basic it's
often overlooked. You can see what is the state of combustion in each
cylinder instantly and quickly deduce all sorts of possibilities..IMHO
Dave

frogeye at porterscustom.com

Porter Customs   2909 Arno NE
Albuquerque, NM USA 87107
505-352-1378
1954 BN2  1959 AN5
Porter Custom Bicycles

cars:
 www.britishcarforum.com/portercustoms.html
gallery:
http://picasaweb.google.com/porterscustombicycles/PorterCustomBicyclesStuff

blog: http://porterbikes.com/



100s that I know are still running around without 
changing valve seats without problems 20 years later.

Now to this I can add another point. As we know the 100 head is very 
prone to cracking across valve seats. One owner I know added seats to a 
perfectly good head but soon found the a fatal crack had appeared beyond 
the valve insert. The conclusion was that as the seat has to fitted by 
interference fit, the extra pressure had caused the crack.

My final point is that if one does get seat recession then all that is 
happening is that the part of the head that is being ground away would 
have to be cut away later when fitting a seat; so why bother.

Regards