valve guides/seals questions
 

Can a guide or valve seal be changed with the heads still installed? Exhuast valve on #8.

Cloud,
The seal can be changed but not the guide. What type of problem are you having ?

Bill Koustenis
Advanced Automotive Machine
Waldorf Md

The engine builder I used installed some crappy pc seals, last year. I also had a guide come loose last year. Anyways, I pulled exhaust and found one exhuast port that had signs of burning more oil than i'd like, i figured the seal is probably junk. I did pull the valve cover and check the seal, it's still where it should be, but leaking more than it should. Didn't know if i could just replace that seal or not.

Is there a tool made to compress the spring when the head is still on the block? Didn't know that was possible...

Looks like a guy could do it with pressurizing the cylinder and a spring compresser. Learn something every day.

I read somewhere that you can use some small diameter nylon rope (the real flexible stuff) and feed it into the combustion chamber on the compression cycle through the spark plug hole, then with a socket on the nose of the crank, bring the piston up and it will hold the valves closed while you work on them.

Fixx
 

liske makes a on the vehicle valve sprong compressor.http://www.buy.com/prod/lisle-lis595...212938012.html

as you mentioned fill the cylinder with air @ tdc but leave the spark plugs in the rest of the holes,this will keep the engine from turning over when you put air in the cylinder you working with..once you replace the vg seal and you installed the spring and keepers, with the air removed from the cylinder take a plastic dead blow hammer and tap the top of the valve stem to seat the valve keepers..

cool tool

Cloud,
I wont say that the seal is definitely not your problem, but .... I have yet to see a seal really cause an oil problem. You have to remember that all early Chevy engines did not even have valve seals, yet they ran fine and really did not use any oil. I dont think any Mercruiser engines, except maybe some of the real late model ones, use anything other than an umbrella seal. If yours has a PC seal on it and it is still in place, I doubt that it is causing a problem, especially on an exhaust valve.

Just my opinion,

Bill Koustenis
Advanced Automotive Machine
Waldorf Md

it could be that they made the vale guides to big when they did the heads???