Cylinder Head Rebuild
05-23-2011, 06:24 PM
#1
Registered User
Thread Starter
Join Date: Mar 2005
Location: Bethesda
Posts: 400
Likes: 0
Received 0 Likes
on
0 Posts
Cylinder Head Rebuild
It has been a while since I posted, but this should be pretty interesting.
My engine was burning a huge amount of oil. It progressively got worse over the last couple of years and then suddenly it was burning more than half a quart a week. I was trying to diagnose the problem, at the very least determine if it was the top or the bottom. I had pretty decent and consistent compression readings all at 220+-15 (done 6 months ago), the motor has about 138k miles on it. After some deliberation I determined/assumed the problem was in the head (oil in the pistons didnt really raise compression much, the pcv was not being heavily used to vent, other such things that made me think that blow by was not a significant contributor to my problems).
So I took the head off and sent it to an engine machine shop that I have had some unrelated business with in the past. They said I needed new valve guides and stem seals all around, and are in the process of looking at the valves. In addition to installing the guides and seals they will check for stress, grind the valve seats if needed, face the valves, check the springs, and clean the head. This will cost about $450. The major factor in deciding to get the head rebuilt was because I dont have the money to rebuild the whole long block.
I have attached some pics of the cylinder walls and pistons, as well as the combustion chambers.
the head, trying to show the cams
4
3
2
1
4
3
2
1
So my questions are:
What are your opinions on the cylinder walls? I dont see any issue apart from lack of crosshatch, but im unsure if I should be able to see it at this stage.
Why does it look like only the intake valve seats have copper inserts? (or are the exhaust ones obscured by the gunk deposits?
Do you see any other issues, or can you suggest something that I might also get done.
I should add that I had misfire codes from all cylinders. And obviously a lot of dark smoke out the back, this primarily occurred on acceleration after running at constant rpm for a while.
My engine was burning a huge amount of oil. It progressively got worse over the last couple of years and then suddenly it was burning more than half a quart a week. I was trying to diagnose the problem, at the very least determine if it was the top or the bottom. I had pretty decent and consistent compression readings all at 220+-15 (done 6 months ago), the motor has about 138k miles on it. After some deliberation I determined/assumed the problem was in the head (oil in the pistons didnt really raise compression much, the pcv was not being heavily used to vent, other such things that made me think that blow by was not a significant contributor to my problems).
So I took the head off and sent it to an engine machine shop that I have had some unrelated business with in the past. They said I needed new valve guides and stem seals all around, and are in the process of looking at the valves. In addition to installing the guides and seals they will check for stress, grind the valve seats if needed, face the valves, check the springs, and clean the head. This will cost about $450. The major factor in deciding to get the head rebuilt was because I dont have the money to rebuild the whole long block.
I have attached some pics of the cylinder walls and pistons, as well as the combustion chambers.
the head, trying to show the cams
4
3
2
1
4
3
2
1
So my questions are:
What are your opinions on the cylinder walls? I dont see any issue apart from lack of crosshatch, but im unsure if I should be able to see it at this stage.
Why does it look like only the intake valve seats have copper inserts? (or are the exhaust ones obscured by the gunk deposits?
Do you see any other issues, or can you suggest something that I might also get done.
I should add that I had misfire codes from all cylinders. And obviously a lot of dark smoke out the back, this primarily occurred on acceleration after running at constant rpm for a while.
05-24-2011, 12:53 PM
#4
It has been a while since I posted, but this should be pretty interesting.
My engine was burning a huge amount of oil. It progressively got worse over the last couple of years and then suddenly it was burning more than half a quart a week. I was trying to diagnose the problem, at the very least determine if it was the top or the bottom. I had pretty decent and consistent compression readings all at 220+-15 (done 6 months ago), the motor has about 138k miles on it. After some deliberation I determined/assumed the problem was in the head (oil in the pistons didnt really raise compression much, the pcv was not being heavily used to vent, other such things that made me think that blow by was not a significant contributor to my problems).
So I took the head off and sent it to an engine machine shop that I have had some unrelated business with in the past. They said I needed new valve guides and stem seals all around, and are in the process of looking at the valves. In addition to installing the guides and seals they will check for stress, grind the valve seats if needed, face the valves, check the springs, and clean the head. This will cost about $450. The major factor in deciding to get the head rebuilt was because I dont have the money to rebuild the whole long block.
I have attached some pics of the cylinder walls and pistons, as well as the combustion chambers.
So my questions are:
What are your opinions on the cylinder walls? I dont see any issue apart from lack of crosshatch, but im unsure if I should be able to see it at this stage.
Why does it look like only the intake valve seats have copper inserts? (or are the exhaust ones obscured by the gunk deposits?
Do you see any other issues, or can you suggest something that I might also get done.
I should add that I had misfire codes from all cylinders. And obviously a lot of dark smoke out the back, this primarily occurred on acceleration after running at constant rpm for a while.
My engine was burning a huge amount of oil. It progressively got worse over the last couple of years and then suddenly it was burning more than half a quart a week. I was trying to diagnose the problem, at the very least determine if it was the top or the bottom. I had pretty decent and consistent compression readings all at 220+-15 (done 6 months ago), the motor has about 138k miles on it. After some deliberation I determined/assumed the problem was in the head (oil in the pistons didnt really raise compression much, the pcv was not being heavily used to vent, other such things that made me think that blow by was not a significant contributor to my problems).
So I took the head off and sent it to an engine machine shop that I have had some unrelated business with in the past. They said I needed new valve guides and stem seals all around, and are in the process of looking at the valves. In addition to installing the guides and seals they will check for stress, grind the valve seats if needed, face the valves, check the springs, and clean the head. This will cost about $450. The major factor in deciding to get the head rebuilt was because I dont have the money to rebuild the whole long block.
I have attached some pics of the cylinder walls and pistons, as well as the combustion chambers.
So my questions are:
What are your opinions on the cylinder walls? I dont see any issue apart from lack of crosshatch, but im unsure if I should be able to see it at this stage.
Why does it look like only the intake valve seats have copper inserts? (or are the exhaust ones obscured by the gunk deposits?
Do you see any other issues, or can you suggest something that I might also get done.
I should add that I had misfire codes from all cylinders. And obviously a lot of dark smoke out the back, this primarily occurred on acceleration after running at constant rpm for a while.
05-24-2011, 03:37 PM
#5
Registered User
Thread Starter
Join Date: Mar 2005
Location: Bethesda
Posts: 400
Likes: 0
Received 0 Likes
on
0 Posts
I just went to go check out the valves, after being resurfaced the seating surfaces did not have enough clearance on either end. The machine shop guys thought that this head had been worked on before and the the valves specifically had been resurfaced, thus not leaving much room for more work afterwards. There were a few valves which were ok, but I decided to replace all of them, i got them at a decent price, about 30% below list.
Trending Topics
09-26-2014, 12:18 PM
#9
They don't sell valve seats OEM, you'll have to get them aftermarket.
Thread
Thread Starter
Forum
Replies
Last Post