• Welcome to the new NAXJA Forum! If your password does not work, please use "Forgot your password?" link on the log-in page. Please feel free to reach out to [email protected] if we can provide any assistance.

Valve Job Cost?

S

stephenspann27

NAXJA Forum User
Location
College Station, Tx
I have the head off my 4.0 and I poured water into the ports to see if the valves were sealing, several of them leaked. I was hoping that maybe lapping them would be good enough, I went the extra mile and spent a lot of time laping the valves for cylinders #1 and #2, installed new seals.. and they failed the water test again. I put black marker on the valve seats, and kept lapping them until it would wear all the marker off evenly. Anyways.. I give up.. I'm going to have to shell out the $$ for a valve job.. all I need is the seats cut, and valves cut.. I already have the seals.. Any ideas on the cost?
 
Varies between machine shop. Best bet is to call a local machine shop and get a price. I paid $380 for 3 angle valve job, back cut valves 32*, mill head, install seals, and machine valve seats.
 
It all depends on where you go. But keep in mind that you get what you pay for.

Do you have any friends that work as mechanics or who are into racing? If so, ask them what machine shop they recommend.

Lapping only takes off a very small amount and if you were to do it long enough to get the valves to hold water the seats would be very wide and you would loose flow at low lift and loose power along with that.
 
I do have access to shop where I could get the valve job done for next to nothing but it's 4 hours away.. and I won't be going that direction until the end of the month.. and I was hoping to be driving my XJ by then.. instead of driving my head there to be worked on.. I'm hoping I can find a place to do it for under $100..
 
I would probably run away from someone offering to do it for $100. The $380 noted above is about right. I think that's what I paid about 3 years ago, and that involved moving all the valves over to a new casting, since mine had a crack (did NOT include cost of casting, I lucked into that for $20). $100 is only an hour of labor, and there is no way someone can do a valve job anywhere close to correct for that.
 
oldradiostuff said:
The $380 noted above is about right.
Click to expand...

For a basic valve job I would expect to pay a little bit less. I had some stuff done that he would not need.
 
Talyn said:
For a basic valve job I would expect to pay a little bit less. I had some stuff done that he would not need.
Click to expand...

Not much, though. Shop has to tear the head down, tank and magnaflux the casting, mill the surface to get it flat. Grind/reface the valves, grind the seats, install new guides or drill out and put guide inserts in (don't ever let anyone knurl your old guides - I speak from experience on this one). Reinstall everything and then trim the valve stems to the correct height.

Even if you don't need any new valves (usually exhaust), that's a lot of labor. I would say if someone is quoting you under $250 - 300 they are leaving important work out. I'm in California and regular auto shop labor normally bills out at $80 - 100 an hour, and machine shop will be quite a bit more than that.

After going to all the trouble to pull a head, I would not go cheap on a valve job. Have it done right and it will last you another 250K miles.
 
yea I don't want all that extra work... I did notice a crack.. but it looks like a casting flaw.. it's up in the water jacket, then comes across the valve seat. It's not wide enough that you can catch you finger nail on though. I basically just want the seats cut and that's it. I'll even take the head to them with the valves all the way out, and put the valves back in myself.
 
I think that a 3 angle valve job, mag and quick clean would cost 240 and 300 where I work. I don't work in the office or pay much attention to prices but that sounds about right.
The shop labor rate is $84/hr.
 
oldradiostuff said:
Not much, though. Shop has to tear the head down, tank and magnaflux the casting, mill the surface to get it flat. Grind/reface the valves, grind the seats, install new guides or drill out and put guide inserts in (don't ever let anyone knurl your old guides - I speak from experience on this one). Reinstall everything and then trim the valve stems to the correct height.
Click to expand...

He most likely doesn't need the valve guides replaced, nor the valves replaced so that will reduce the cost.
 
If you have what looks like a crack across the valve seat, it probably is a crack. This can be verified with a magnaflux or a dye-check test. My own experience with having a seat installed was not encouraging. When they bored to install a seat, a crack formed in the corner of the bore. I think if they had bored leaving a fillet around the bottom corner (most seat inserts have a chamfer) they could have saved the head. Instead, two shops spoiled two heads. Their advice was to only use a head that doesn't need a seat insert.

Hope you have better luck than I did!
 
if I could fine a used head that would be great, but its a Renix jeep.. and most used Renix head are going to have high mileage.. mine has 260k...


yes my valves guides are perfect. My seals didn't have any wear either, I'm replacing them anyways. I can also tell the head has been off.. so it may have had a valve job before.
 
Here are the pics of what appears to be a casting flow, that turns into a crack across the valve seat. It stops abruptly after the seat. Keep in mind that up inside of the intake port where the crack is more pronounced, the water jacket is on the other side of that wall of steel.. I have had no signs of a coolant leak. Level stays exactly the same all the time.

castingflaw.jpg


seatcrack.jpg
 
I'd call that a crack.
Super duper usually accurate test, shoot it with carb clean or brake clean, use a blow gun to dry the area, then put the tip right up to the suspected crack and see if any more comes out of the void.
 
i've had good luck w/ this place for other cars http://www.aluminumcylinderhead.com easy people to deal with, they pay shipping for the old head, you just got to return it within 30 days. and they had the cheapest fully reman'd cylinder heads. for a car i was working on, most others cost $100 or so more and did not include the cam and hydrolic lifters. this place included a reground cam, and brand new lifters, and was still a good deal cheaper! plus factor in that you are getting new valve stem seals, assured the head is flat/true, ect ect ect. well worth it. IMO
 
You must log in or register to reply here.

Similar threads

M
1992 XJ A/C Air Conditioning Replacement - Parts List
Replies
7
Views
2K
Rob Mayercik
R
D
Chasing misfire and running out of variables.
2
Replies
21
Views
3K
deloxx
D
B
Dash brake light on after replacing rear brakes
Replies
1
Views
1K
RCP Phx
R
F
Curious MAP sensor failing - symptoms
Replies
0
Views
2K
fenns7
F
Anak
How to Slot the CPS
Replies
2
Views
90
Rob Mayercik
R
Back
Top