I haven't been able to remove this as of yet , hoping maybe a loose rocker not allowing a cylinder to function correctly.
There is a chuff chuff noise coming from carburetor
![eek :eek:](./images/smilies/eek.gif)
Thanks again from uk
![helpsos :helpsos:](./images/smilies/helpsos.gif)
The aluminum cylinder head material could not withstand the stress that must be endured by a valve seat. The steel valve seats are a press fit into the head and are normally not removed, unless severely damaged or if they loosen up over time. Dropping valve seats has become an increasingly common problem with Corvairs over time as they age — particularly in the 140 hp big valve heads. A qualified machine shop can replace a dropped valve seat, and special deep seats can be obtained and fitted to help prevent the problem from recurring.Datsolow wrote: » Wed Aug 10, 2016 11:29 am
I didn't realise the valve seats were removable
Bob Helt wrote:Well the suggestions are all over the map. My opinion is to have the one chamber welded up and then install a new seat. Then put it back together and go.......
Sure you could drop another seat sometime...or maybe never. It's an unknown.
I'd say that the crank is undamaged and that the piston is OK to use as is.
FYI, in MO, staking will not help at all and could cause hot spots.
My shop used to use a small hammer and tap all around each seat. From the sounds then, it was possible to determine how well the seat was being retained. Maybe that would work for you too.
Healthy cylinders should read 130 psi each, with a maximum variation of 20 psi between cylinders. Zero is a complete failure (hole in the piston, stuck valve, etc.) If the rest of your readings are accurately measured (following the procedures in the attached shop manual section) at cranking speed with the throttle wide open, etc., then you are looking at worn cylinders and rings, blown head gaskets, worn out or damaged valves, etc. A cylinder leak down test using an air compressor to pressurize each cylinder can help to determine the cause without disassembly, but an engine with such poor readings would certainly require disassembly and overhaul... or replacement with a serviceable engine.Paul wrote:Hi , I've done a compression check and 1=zero2=75psi 3=45psi 4=75psi 5=45psi 6=50psi.
Doesn't look so great how the hell was it running and still runs.
What is a healthy engine meant to read also , where do I go from here?