Replacing Valve Seats / Seals?

[RobertK]

One or more of the valve seats around cylinder 3 are getting pretty bad.

Anyone know if the valve seats can be replaced without removing the head? Details?

[der affe]

do you mean valve seals? you either regrind valve seats or to r& i them you have to heat up the head in an industrial oven drive them out then drive the new ones in and let the head shrink around them as it cools. the latter being some what expensive to do.
greg

[nando]

have them ground, that's what a shop would do when they rebuild it anyway.

[arsevader]

do you mean valve seals? you either regrind valve seats or to r& i them you have to heat up the head in an industrial oven drive them out then drive the new ones in and let the head shrink around them as it cools. the latter being some what expensive to do.
greg

You are confusing valve seats, valve seals and valve guides.

Seats are ground and are what the valve head sits in. Seals are the rubber collars attached to the top of the guides that the valve stems go through and guides are the brass tubes that the stems are pushed through.

The seals can be replaced without removing the head. The guides need to be pressed in like you are refering to.

[RobertK]

Ok.. whichever is allowing oil to get burned in the combustion chamber. The compression on Cylinder 3 is 160psi which is consistant with all the other cylinders so I was told a vlave seal was bad letting oil into the intake? Does that sound right?

How easy is it to replace the Valve seals and could that be my problem?

[arsevader]

Ok.. whichever is allowing oil to get burned in the combustion chamber. The compression on Cylinder 3 is 160psi which is consistant with all the other cylinders so I was told a vlave seal was bad letting oil into the intake? Does that sound right?

How easy is it to replace the Valve seals and could that be my problem?

Do you get any blue smoke when deccelerating? If so then it's usually valve seals. Seats usually wouldn't cause a leak unless the seals were bad too.

The seals are a pain but are doable without removing the head. You just need to find a valve spring compressor that is designed for working on an installed head. You also need to pressurise the cylinder to ensure the valve doesn't fall into the cylinder when you remove the spring.

[RobertK]

That's exactly the problem.. it's getting worse and it's fouling the plug in that cylinder.

How do you recommend pressurizing the cylinder?

[FredK]

Use Lisle tool #19700. It's a hose for a 14mm spark plug and has a 1/4" NPT female end so you can hook up an air fitting of your choice. It's around $10.

Usually a compression tester will have the right hose for your purposes. The added benefit is that you can check the compression later.

[rs4pro3]

A compression tester hose may or may not work, the style I have has a check valve in it so air can't go back into the cylinder. When I built my Leak down tester, I took the hose and drilled out the check valve so that air could flow both ways. Compresion testers are only about $20 so that should work. Also some rope shoved down in the cylinder will work also

[RobertK]

A compression tester hose may or may not work, the style I have has a check valve in it so air can't go back into the cylinder. When I built my Leak down tester, I took the hose and drilled out the check valve so that air could flow both ways. Compresion testers are only about $20 so that should work. Also some rope shoved down in the cylinder will work also

Rope in the cylinder? WTF?

How bout I just pay you to do it Ely?

[rs4pro3]

hum, that's tempting. Is it on the Intake or Exhuast side?
As for the rope just get that cylinder near topdead centerm pull the plug and start shoving some rope down in the cylinder, But make sure to leave some hanging out so you can remove it, then turn the engine to compress the rope and it will hold the valve in place.

[RobertK]

hum, that's tempting. Is it on the Intake or Exhuast side?
As for the rope just get that cylinder near topdead centerm pull the plug and start shoving some rope down in the cylinder, But make sure to leave some hanging out so you can remove it, then turn the engine to compress the rope and it will hold the valve in place.

Not sure you tell me.. I would just assume replace them all while we're in there.. but I would seriously pay for you time and help.

The thing I hate the most is when I declerate to a stop and then my exhaust lets out a puff of blue smoke that comes in my window.. it's driving me crazy.

[der affe]

i like the rope idea! good for those w/o compressed air:D

[rs4pro3]

Well if replacing them all it would be easier to just yank the head, Since my summer class is coming to an end next week, I could probally help out some weekend. Only problem is I've yet found a good spring compressor that would work with the head on the car, I've got one that works perfect with the head off, but the other one I have won't compress the spring enough with the head in place.

[RobertK]

Hmm.. if you think we can get it done in one weekend.. I may just take a 4 day weekend sometime this summer pull the head and have it reworked, ported, and polished by the tuner shop down the road.

How much am I looking at to do all this? Maybe I should have you bring over your homemade leakdown tester to make sure my rings are for sure in good shape before I do all this.