Grinding Valve seats?

[russ1302]

I have my head off of my A4 and the exhaust valve seats need to be reground. Is it possible to do it in the boat? Is there a seat dressing tool available? I'm trying to decide if it is worth saving this thing. Any advise would be appreciated.

Thanks
Russ

[67c&ccorv]

There is probably somewhere out there a "tool" for everything, but in this case I will bet there is not.

[sandspur]

If you have the room above the block for the machine it can be done, Just got done doing mine, Finding some one with the machine might be the hard part If your in N. E Fla I could help

[Don Moyer]

Russ,

We have a small hand tool that does a very good job of resurfacing valve seats that takes up very little room above the top of the block that we've been renting to folks. If you can give me a call at (410) 810-8920 I'll describe it to you in more detail to see if it's something you could use.

Don

[67c&ccorv]

Looks like I lost that bet Don!

[keithems]

i just finished removing & replacing the head [and lots of other things].

unfortunately, my a4 has developed a new, intermittent rattling/clicking sound. [she had always had a "tick" but i was told that was normal -- probably from the cam on the mechanical fuel pump] -- but this noise is new, plus she has to be fully warmed up to go into gear without stalling.

so...to correct this, i decided to start by making sure the valve clearances were all correct. in doing that, i found 2 valves that were almost impossible to get right -- one has the keepers below the retaining washer; the other has the valve stem completely flattened. [pix will be posted when available.]

so, i assume both will have to come out, and i'll be starting on head removal to do it.

thus, my next question:

does anyone know...

if i put in a new valve, must i also grind the seat or replace it? if so, can this be done with the engine in the boat? or must the engine block be removed and taken to a machine shop?

thx for your help...

[Dave Neptune]

Kissing the seats

kieyhems, when I bought my boat the engine was siezed and needed a valve job as the #1&2 exhaust seats were badly pitted from rust. I borrowed a "seat cutter" and did the job in the boat. It took about an hour to do all of the seats and then I took the valves to work and ground them on one of my grinders (tool and cutter grinder) that is suited for the task. The toughest part of the job was replacing the keepers on the valves.
AND YES IT WAS WORTH IT as she has been ticking away for another 25+ years since. One exhaust valve is the only non-stock part inside the engine. That's 41+years on my A-4. The A-4 is extremely tough and with a'little care they go a long way.

Dave Neptune

[keithems]

i've had my a4 for 3 1/2 seasons now -- got it for $800 & put another $600 into it [mostly in mmi things], and it usually ran like a top, which is why i assumed the ticking was "normal" -- so i know, it doesn't owe me a thing, and i'm hoping to keep it -- just don't want to have to pull the motor during our short delicious summer up here....

luckily, in my boat there's good access, so servicing the valves does not scare me. but the one stem looks pretty crushed, and ken at mmi thinks it's going to be hard to get out. therefore, i'm wondering --

if i have to cut or otherwise destroy it to remove it and / or have to replace it with new from mmi, will the seat have to be replaced also or at least machined to match the new valve? and if so, can a non mechanic [me] do that without removing the motor?

also -- since you mentioned that replacing the keepers is difficult -- will a non mechanic [me] be able to do that with the motor in the boat?

one other comment to other neophytes -- there are lots of threads on this topic -- DON'T ASSUME THAT A TICKING NOISE IS NORMAL -- IT COULD BE A VALVE STEM GETTING BEATEN TO DEATH!!

[ps -- if u read all my posts since i got this motor, you'll see that i'm not totally a non mechanic any more -- just an occasionally stupid one ;-} ]

[hanleyclifford]

If you have a crushed valve stem head it is going to be challenging to get that valve out. Resist the temptation to just pry it out because you could damage the guide. If you can spin the valve once you get the spring out it should be possible to file or grind the stem enough to get it back out. The success of a valve seat regrind will depend on the condition of the guides. It is pointless to grind the seats with sloppy guides. Check their ID before proceeding. BTW, there are no stupid mechanics on this forum; they are the ones who don't come to the forum.

[hanleyclifford]

Putting in a new valve does not automatically require grinding a valve seat. In fact whenever I have to replace a valve it is usually because the stem has gotten smaller than spec. I avoid taking material off a block as much as possible. Often a light lapping with pumice will suffice. Most would be surprised how much damage it takes to make a valve leak that is sound and straight itself and is running in a guide that is up to spec.

[keithems]

here are the pix

first pix shows keeper below spring on 4th valve from right -- look for 2 shiny tabs below the spring.....

http://www.moyermarine.com/forums/attachment.php?attachmentid=4220&d=1310355155

2nd pix shows pancaked valve stem on 2nd valve from right...

http://www.moyermarine.com/forums/attachment.php?attachmentid=4221&stc=1&d=1310355517

amazing to me that the motor operates at all....

can i remove the pancaked valve by cutting off the stem and pulling it out from above?

thx...

k

[keithems]

pix are way to large -- but i think if you all hit "control -", you can reduce their size

[lat 64]

Keithems,
It looks like your keepers fell out. That's rare. I think they were not installed right. A sharper photo would really help. I can't see any "mushrooming" because of the blurred image, but I think it may actually be the retainer you are referring to.
Definitely something wrong though. Yes you can saw off the valve stem, but it takes a good saw or file, and some strong coffee. This is probably not necessary; it just might need the top dressed with a file to allow it to be pulled up through the guide.
Hold a file to the edge and then rotate the valve by grabbing the head. This all happens after you get the springs out.

Good luck,
Russ

[sastanley]

keith, also, if your camera has a "macro" setting, like for taking pictures of flowers & bees and stuff, that works great for getting sharper, close up engine pics.

Good luck...I don't know anything about valves (except how to adjust them), so I am learning along with you.

[keithems]

valve keeper remover and installer tool

from all i've read in the mmi manual and elsewhere, installing / reinstalling the valve keepers is the most difficult part of a valve job.

apparently lisle makes a number of valve keeper removal and installer tools. has anyone tried any of them? did they help? which one would they recommend, if any?