Replacing valves - need machining?

GoSlowGetStuck · 09-23-2009, 11:55 AM

89 Sidekick 8V, has one chipped valve and another burned one, so I ordered a set of all 8 intake/exhaust valves. If I use a valve spring compressor and replace the valves myself, and then use lapping compound and a lapping tool, will that provide a sufficient seal? I would like to avoid paying a machine shop to do a valve regrind, but I know in some instances it's far cheaper in the long run to have the machine work done. Thoughts?

billsmartis · 09-23-2009, 01:26 PM

Dump a little gas down the ports and if the gas don't leak out the valve it's sealed or lapped properly.

Bill S.

GoSlowGetStuck · 09-23-2009, 03:26 PM

Quote:

Originally Posted by billsmartis

Dump a little gas down the ports and if the gas don't leak out the valve it's sealed or lapped properly.

Bill S.

Good idea, I'll give that a shot after lapping the valves and hopefully I can avoid the machining!

aquanaut20 · 09-23-2009, 08:15 PM

Check that your seats are not recessed too far before you spend time lapping. The angles may not be consistent with the new valves.

kick-fix · 09-24-2009, 02:14 PM

a home valve job, ok, we will watch

take it to a machine shop?

they will do all the steps,skipping none,

skipping steps ,is bad. ( every time i try i get egg in face, 40years of mistakes)

1: pressure testing.
2:warpage.
3: cam bearing checks.
4: guides.
5: cut valves to match seats, to spec or to you spec (3 angle?)
6: new seals.

I have no hope for your seats. not after burning the valve.s
just my gut feeling.

$300 exhange or less if you get yours done and wait.

GoSlowGetStuck · 09-24-2009, 02:27 PM

Quote:

Originally Posted by kick-fix

a home valve job, ok, we will watch

take it to a machine shop?

they will do all the steps,skipping none,

skipping steps ,is bad. ( every time i try i get egg in face, 40years of mistakes)

1: pressure testing.
2:warpage.
3: cam bearing checks.
4: guides.
5: cut valves to match seats, to spec or to you spec (3 angle?)
6: new seals.

I have no hope for your seats. not after burning the valve.s
just my gut feeling.

$300 exhange or less if you get yours done and wait.

It's hard for me to spend $300 on a head for a $400 vehicle. Of course if I had money to throw at it then I would have no problem doing it right and taking it to a machine shop. Basically I was just wondering if there is a chance I can do it at home. I see the worst case being that it burns another valve in 1000 miles and then I'm out $60 for valves and a day or so of my time.

For what it's worth though, I'll call the machine shop and see what it would cost to rebuild it, if I supply the valves...

aquanaut20 · 09-24-2009, 02:31 PM

Quote:

Originally Posted by kick-fix

a home valve job, ok, we will watch

take it to a machine shop?

they will do all the steps,skipping none,

skipping steps ,is bad. ( every time i try i get egg in face, 40years of mistakes)

I have no hope for your seats. not after burning the valve.s
just my gut feeling.

LOL, I have been in the same boat, even cut my own seats in the early 60's.

Road rally with Volvo's, 544 and 122 (Canadian,4dr) and P1800, lots of fun.

http://volvo1800pictures.com/bros/oc...0-221-1800.pdf

as the saying goes, "Bin der dun dat!"

aquanaut20 · 09-24-2009, 02:41 PM

Quote:

Originally Posted by GoSlowGetStuck

It's hard for me to spend $300 on a head for a $400 vehicle.

Your other option is this tool,

32-1741 - Neway Valve Seat Cutter Kit

and if it doesn't work at least you have the equipment. This is similar to what I used 55yrs ago. I could not afford a mechanic when I started and could not get factory support.

I was the first to set a GM alternator on a Volvo to replace the generator set, it was unheard of in those days but I needed the power to run my Ham Radio set(it had valves as well, LOL).

GoSlowGetStuck · 09-24-2009, 02:43 PM

Quote:

Originally Posted by aquanaut20

Your other option is this tool,

32-1741 - Neway Valve Seat Cutter Kit

and if it doesn't work at least you have the equipment. This is similar to what I used 55yrs ago. I could not afford a mechanic when I started and could not get factory support.

I was the first to set a GM alternator on a Volvo to replace the generator set, it was unheard of in those days but I needed the power to run my Ham Radio set(it had valves as well, LOL).

Hey, and it's only $421.65

So much for taking the cheap way out of this!

Richard Craneum · 09-24-2009, 07:41 PM

When comes to cylinder heads and machining I shop around. Sometimes and I have seen, is cheaper to buy a reconditioned head with all the fixing for less, or outsource the job to a machine shop. This kind of work a Do-It-Yourself usually cost more, no because of the labor, is the tooling that does not makes it cost effective if you want to do the job right.

I bought 2 Cylinder Heads for a 3.4L V6 GM engine for around $500 at Auto Zone. So far is doing great and have a 1 year warranty. If I bought the pullers, valve seat, press and any other tools, to have the decent one it would cost me more than double. Beside, how often I will do the work to warrant the extra expense?

Anyway, good luck with your vehicle