I dropped the head in for overhaul to the workshop owner, and explained that I had 4 more spare guides if there was any problem. I did not speak to the bloke who did the work as he was having a day off.
When I got the Cast Iron Head back from overhaul, the bloke who did the work wasn't there, so I rang him next day.
He told me that I had given him 3 Inlet and 1 Exhaust guide. "No worries he said - I modified one of the inlets to suit".
He explained that the exhaust guides have a recess machined from the underside of the combustion chamber. He machined one of the inlet guides to suit. This was bit of a mystery to me, as all 8 guides were in there original plastic envelopes and all had identical part numbers. Without opening the packets, it was not possible to see the difference.
I then opened my 4 spares and discovered I had (not surprisingly) 3 exhaust and 1 inlet guides. ( Photo attached).
The externals of the guides are also dimensionally slightly different.
I was unaware that inlet and exhaust guides are different.
I cannot understand what the recess in the exhaust guides are for. Maybe clearance to allow for a small buildup of carbon behind the valve head?? Anyone know.??
Second lesson is always talk directly to the bloke doing the work. He had been unaware that I had spare guides.
I now need to obtain an inlet guide to have a full set of spare guides.
On the whole though, I am confident in the quality of their work and knowledge.
Cheers Colin
