No compression on 1 - burnt valve? Topic is solved

[songzunhuang]

Well, after 272,000+ miles of service my car finally has a major issue. I got a P0301 error and after trying the easy stuff (plugs, wires, rotor, cap) I decided to do a compression test. Here is what I saw.

cylinder 1 is dead.

Compression Test.png (1.92 MiB) Viewed 1654 times

Nothing at all on cylinder 1. All others are between 165 and 180. This really looks like a burn valve.

I am trying to figure out my options here. Having a shop rebuild the head or swap a motor is prohibitively expensive. So, my question are:

1. Is it worth rebuilding myself?
2. Should I just get a used head from a dismantler? How do I know that head is good!?
3. Will a remanufactured head just push my issues to the piston rings, etc?

I am trying to figure out what to do with our beloved car. Appreciate any sage advice as I try and figure this out.

[volvolugnut]

Did you try a little oil in the # 1 cylinder to see if rings are leaking?
Did you try to view the valves with a borescope? There are some cheap ones that use a smart phone.
If you have time and moderate mechanical skill, with MVS help you may be able to rebuild your head. First consider the state of the rest of the engine/transmission/car to decide if it is worthy of a head rebuild.
volvolugnut

[xanthefin]

1st cylinder i got lower compression but not so low for sure.

Oil is good question did you try with it.

[erikv11]

Scope will make you certain but I agree 99% with the diagnosis.

1. Is it worth rebuilding myself?
2. Should I just get a used head from a dismantler? How do I know that head is good!?
3. Will a remanufactured head just push my issues to the piston rings, etc?

I am trying to figure out what to do with our beloved car. Appreciate any sage advice as I try and figure this out.

1. Up to you. All in It's going to be about $800+ out of pocket for DIY if you get the head machined as described below, replace timing parts and seals while you have it apart. Maybe it's $1000+ given bay area machine shop prices. This figure is almost always economically viable for a car as well kept as yours but only you can factor in the cost/availability of your time. Could you buy that car, working, or an equivalent, for $1000?

2. I would either (a.) take the used head on your car to a machine shop and have them rebuild it with a valve you got from a dismantler (or from MVS!) and with brand new Volvo branded valve stem seals, or (b.) buy a reman'ed head. Trouble with (b.) is most reman'ed heads will have aftermarket valves stem seals in them. I would not go with (c.) a used head because it likely has old, cracked valve stem seals. The burnt valve is most likely due to leaky valve stem seals in the first place.

3. No. Bottom end is super, super hardy. Your compression numbers attest to that.

I'd fix it. A 98 in CA still has a bright future. With a "new" head it will have renewed zip.

Oh, and if you unplug the #1 injector you can run it as is for a while without much trouble other than chugginess and poor fuel economy.

[songzunhuang]

Did you try a little oil in the # 1 cylinder to see if rings are leaking?
Did you try to view the valves with a borescope? There are some cheap ones that use a smart phone.
If you have time and moderate mechanical skill, with MVS help you may be able to rebuild your head. First consider the state of the rest of the engine/transmission/car to decide if it is worthy of a head rebuild.
volvolugnut

I didn't try the oil thing because with '0' compression, what's a slightly improved ring seal going to give me? 10-20? Still would be toast. You have given me a good exercise to try. I have a boroscope, but it's camera points straight head and and I'm trying to imagine how I would see the valves if I went in through the spark plug home. I guess I could go in through the intake (easy with a little disassembly work) or the exhaust (a lot more pain).

In any case, it's something to check out. If nothing else, I'll see if my pistons and the cylinder walls look ok.

[songzunhuang]

1st cylinder i got lower compression but not so low for sure.

Oil is good question did you try with it.

I did not. See my reply to a similar question above.

[songzunhuang]

Scope will make you certain but I agree 99% with the diagnosis.

1. Is it worth rebuilding myself?
2. Should I just get a used head from a dismantler? How do I know that head is good!?
3. Will a remanufactured head just push my issues to the piston rings, etc?

I am trying to figure out what to do with our beloved car. Appreciate any sage advice as I try and figure this out.

1. Up to you. All in It's going to be about $800+ out of pocket for DIY if you get the head machined as described below, replace timing parts and seals while you have it apart. Maybe it's $1000+ given bay area machine shop prices. This figure is almost always economically viable for a car as well kept as yours but only you can factor in the cost/availability of your time. Could you buy that car, working, or an equivalent, for $1000?

2. I would either (a.) take the used head on your car to a machine shop and have them rebuild it with a valve you got from a dismantler (or from MVS!) and with brand new Volvo branded valve stem seals, or (b.) buy a reman'ed head. Trouble with (b.) is most reman'ed heads will have aftermarket valves stem seals in them. I would not go with (c.) a used head because it likely has old, cracked valve stem seals. The burnt valve is most likely due to leaky valve stem seals in the first place.

3. No. Bottom end is super, super hardy. Your compression numbers attest to that.

I'd fix it. A 98 in CA still has a bright future. With a "new" head it will have renewed zip.

Oh, and if you unplug the #1 injector you can run it as is for a while without much trouble other than chugginess and poor fuel economy.

Well, I called a lot of places today and boy is this going to be pricey. I got quotes from $4,000 for a head rebuild to $7,000 for an engine swap! These prices made me reconsider a DYI route.

I did finally track down a machine shop that says they can check the head for me for $200 if I bring it to them out of the car. If they have to rebuild, then we are looking at another $300. That sounds like the most workable solution.

I'l going to start pricing out a head rebuild gasket set and some replacement valves. Everyone is warning me about aftermarket valve seals. I noticed valve seals are included in rebuild kits from FCP Euro. Are the seals with the Victor Reinz or Elwis sets also suspect?

Finally the machine shop I spoke with told me to check my hydraulic lifters. What are the observation on the service life of those?
It looks like I am about to embark on a DYI head swap with a rebuild from a local machine shop.

[abscate]

You can source the sodium filled valves on the T5 at Skandix, along with the set of Volvo stem seals

I think they were $50 each at FCP and $10 from Skandix. I needed all 10 from a timing belt break so that added up

[FireFox31]

Your car is too beautiful to scrap. Hopefully you have alternative transportation during a rebuild.

have them rebuild it with a valve you got from a dismantler (or from MVS!)

Are new valves so hard to obtain that used and Skandix are our only options?

What does a machine shop do during a head rebuild? Could valves be installed at home as a DIY project (with special tools)?

[abscate]

Price guidance on head reworking here, 2022

http://www.huntsmachine.com/labor.htm