Recommendations while tearing down for valve job?

Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.

TX87R10

Full Access Member
Joined
Jun 25, 2020
Posts
1,073
Reaction score
2,235
Location
Texas
First Name
Txr10
Truck Year
1987
Truck Model
R10
Engine Size
305
Hello -

We are heading out of town for a couple of days and renting a car so I figured what better time to pull the heads on the square and drop them off at the machine shop for a valve job.

I was thinking to go ahead and do the following -

1. Remove valve covers, clean, paint
2. Remove both heads with engine still in truck
3. Purchase and replace head gaskets and valve gaskets

While the heads are at the shop should I just go ahead and replace the valve springs? Is there anything else I should have them do at the machine shop or anything I should do while getting that deep in to the motor?

I've got a Haynes manual and I'll watch a bunch of videos ahead of time to prepare but if there is anything I can do while in there to maximize the time and effort of removing the heads I'm all for it.
 

Truck82

Member
Joined
Nov 2, 2024
Posts
68
Reaction score
129
Location
Alderton
First Name
Christopher
Truck Year
1982
Truck Model
c20
Engine Size
350
Hello -

We are heading out of town for a couple of days and renting a car so I figured what better time to pull the heads on the square and drop them off at the machine shop for a valve job.

I was thinking to go ahead and do the following -

1. Remove valve covers, clean, paint
2. Remove both heads with engine still in truck
3. Purchase and replace head gaskets and valve gaskets

While the heads are at the shop should I just go ahead and replace the valve springs? Is there anything else I should have them do at the machine shop or anything I should do while getting that deep in to the motor?

I've got a Haynes manual and I'll watch a bunch of videos ahead of time to prepare but if there is anything I can do while in there to maximize the time and effort of removing the heads I'm all for it.
I would replace the springs while you’re in there. How much is the shop doing? I would suggest having the valve guides and seats replaced also (unless you have the 882 heads that have everything integrated like I do than that could cost a lot to get them all drilled out and fit with replaceable ones )
Just give it a good cleaning and it’ll work like a top!
Good luck with your build!
 

TX87R10

Full Access Member
Joined
Jun 25, 2020
Posts
1,073
Reaction score
2,235
Location
Texas
First Name
Txr10
Truck Year
1987
Truck Model
R10
Engine Size
305
I would replace the springs while you’re in there. How much is the shop doing? I would suggest having the valve guides and seats replaced also (unless you have the 882 heads that have everything integrated like I do than that could cost a lot to get them all drilled out and fit with replaceable ones )
Just give it a good cleaning and it’ll work like a top!
Good luck with your build!
They quoted $500 for the valve job which I think is the guides and seats. I didn't check the price but when I rebuilt my '66 mustang I think it was $25 for the springs so seems like a no brainier
 

ali_c20

Full Access Member
Joined
Sep 20, 2016
Posts
1,290
Reaction score
1,840
Location
Austria
First Name
Alexander
Truck Year
1974, 1979
Truck Model
C20, K5
Engine Size
350, 350
Do as much as possible within your $ limit when your in there. Check lifters, pushrods and all the parts that are accessible without heads and intake. If something fails or wears and you have to pull the heads again...no bueno. Ask me how I know.
 

Ricko1966

Full Access Member
Joined
Apr 11, 2017
Posts
5,390
Reaction score
8,600
Location
kansas
First Name
Rick
Truck Year
1975
Truck Model
c20
Engine Size
350
They quoted $500 for the valve job which I think is the guides and seats. I didn't check the price but when I rebuilt my '66 mustang I think it was $25 for the springs so seems like a no brainier
Seats are very rarely replaced in a valve job,and cost prohibitive,your old seats are cut or ground,depending on the machine shop,you're old valves are cut or ground and the stems are shortened to correct installed height. If you need 16 seats installed,spend the money on new better heads.If you are going to a reputable machine shop, leave what is necessary to their discretion,they have way more experience than 99% of people on this forum. I've never see a problem with factory GM springs,but you might with the quality of replacement parts these days. If you were going with more cam I'd recommend springs,a valve job only,I wouldn't. I guarantee you,the shop I worked at we did thousands and thousands of heads,in the time I was there, we reused factory springs on 90 percent if not more .Have your machine shop get you a headset, they will use the valve seals,you will use all the other gaskets. A lot of times if I'm doing a valve job,I'll do rings, rod bearings and a timing set at the same time,kind of a budget rebuild,these engines will go a long,long time trouble free.
 
Last edited:

TX87R10

Full Access Member
Joined
Jun 25, 2020
Posts
1,073
Reaction score
2,235
Location
Texas
First Name
Txr10
Truck Year
1987
Truck Model
R10
Engine Size
305
Seats are very rarely replaced in a valve job,and cost prohibitive,your old seats are cut or ground,depending on the machine shop,you're old valves are cut or ground and the stems are shortened to correct installed height. If you need 16 seats installed,spend the money on new better heads.If you are going to a reputable machine shop, leave what is necessary to their discretion,they have way more experience than 99% of people on this forum. I've never see a problem with factory GM springs,but you might with the quality of replacement parts these days. If you were going with more cam I'd recommend springs,a valve job only,I wouldn't. I guarantee you,the shop I worked at we did thousands and thousands of heads,in the time I was there, we reused factory springs on 90 percent if not more .Have your machine shop get you a headset, they will use the valve seals,you will use all the other gaskets. A lot of times if I'm doing a valve job,I'll do rings, rod bearings and a timing set at the same time,kind of a budget rebuild,these engines will go a long,long time trouble free.
That's the other thing I was thinking lol I've worked in a plant where we assembled torque wrenches and modern springs are **** quality...

Thanks for the advice
 

DoubleDingo

Full Access Member
Joined
Jul 3, 2012
Posts
11,235
Reaction score
17,099
Location
Right where I am
First Name
Bagoomba
Truck Year
1981
Truck Model
81-C20 Silverado Camper Special-TH400-4.10s
Engine Size
Carb'ed Vortec 350
All excellent advice, I can't add anything worth while, except maybe reseal the engine while it's torn down that far and replace the timing set. It's not needed, but it can't hurt. With it that far down, you only have three sets of seals left to do, pan gasket set, timing cover set, rear main.
 

Craig Nedrow

NADAR UNDER THE RADAR
Supporting Member
Joined
Sep 1, 2018
Posts
1,035
Reaction score
2,175
Location
Washington State
First Name
Craig
Truck Year
1973 (have two), 1985
Truck Model
K10, K20, C20
Engine Size
350, 454, 6.2 Detroit
Like ^^^^^ those guys said. If you are in doute find the specs for the cam and have the shop check the PSI at the installed height of the springs. I always do, but I have access to a spring tester. Do pretty much what Ricko suggests. The head man has all the tools to measure and test the heads. If they are a reputable shop, you will get a nice clean shiny head set up for your cam, probably with the stock springs.
 

77Dmax

Junior Member
Joined
Nov 10, 2024
Posts
26
Reaction score
41
Location
vt
First Name
Joe
Truck Year
1977
Truck Model
c20
Engine Size
6.6
Having done this job several times before, I recommend pulling the motor. It's only a few more bolts, and working bent over the fenders/cowl is such a PITA.
 

DoubleDingo

Full Access Member
Joined
Jul 3, 2012
Posts
11,235
Reaction score
17,099
Location
Right where I am
First Name
Bagoomba
Truck Year
1981
Truck Model
81-C20 Silverado Camper Special-TH400-4.10s
Engine Size
Carb'ed Vortec 350
Having done this job several times before, I recommend pulling the motor. It's only a few more bolts, and working bent over the fenders/cowl is such a PITA.
I agree. And torquing the head bolts is much easier standing on the ground than straddling the engine under the hood.
 
Top