Driving with a burned exhaust valve

[abscate]

Total of 40000 miles on a total $5000 outlay for cap and maintenance?

Not bad, 10 cpm all in. Even counting labor, you would be at about 15 cpm.

You can attract Robert if you have some pets that need to be buried...

[mecheng]

Sorry to hear this happened to you; I know you've put in a lot of hard work into the car. How many km/miles on the car? That can determine whether or not it is worth to fix. Good thing, is that you have a helping community here and I believe you are competent enough to do the work, but I agree time is precious.

Please fill out the info on the burnt valve log so we can determine trends. I will update the Pareto chart.
viewtopic.php?f=1&t=74239&hilit=burnt+valve&start=50

The data is working, it shows that it is most common on: 98s , cylinder 3, Prestone coolant use which is your situation. Jury is out on Octane, but I never use less than 91 in summer and 89 in the winter.

[cn90]

Hi guys,

- My 1998 S70 GLT VIN = YV1LS5642W1437526


EXHAUST Valves Questions:
- Is "Engine Number" same as last 7 digits of the VIN?
- I assume that I need 7-mm Valve (and NOT 6-mm)?
- Brand as we discussed in the past:
* Volvo OEM (expensive at $65/each)
* TRW
* Intervalves
* Osvat

Any further advice on this topic of Exhaust Valve?

MACHINE Shop Questions:
- Why do people send the head to machine shop when this is not a bent valves (from broken timing belt) or overheated when the head can be warped?
- I am talking about simple burned valves, so the head should be straight?

- For burned valves job, I assume one can safely:
* Keep the Valve Guides (which rarely go wrong)
* Replace burned valves
* Lap all valves
* Change all Valve Seals (Volvo OEM only).
Then re-install the head.

So I am just curious why people send their head to the machine shop?

Valves.jpg (115.71 KiB) Viewed 1812 times

[erikv11]

RE: machine shop

I sent mine to the shop to have them:
- freshen up lower head surface (you are correct, it should be straight, but the shop knows/decides this in the process anyway)
- freshen up upper head (cam side) surface
- freshen up cam cover lower surface
- install all new valve stem seals
- valve job on all valves, install the one replacement (you are correct, guides are all fine and are re-used, the shop knows/decides this too)

The head work is not rocket science, but I didn't want to DIY it. If you want to do all that yourself then go for it, just how I managed the time demands of the job. I view all of the resurfacing as a huge benefit of sending it to the machine shop.

[cn90]

UPDATE driving with burned exhaust valve #3.

1. So, for the last 2 months and 1000 miles, I drove around with injector #3 electrical connector disconnected. As others have said:
* The idle is rough when COLD in the morning and at STOP light. Other than that when the car is above 20 mph, it seems fine.
* On highway, I drive alone and can get up to 70-80 mph without issues.
* It drives like a 4-banger Honda Accord with 4 cylinders.
* Fuel mileage seems the same, i.e., not better or worse.

2. The cyl head job: I have asked a few seasoned mechanics re machine shop. They say that although this is a burned valve and not an overheated engine (which usually causes warped head), the fact that when you undo the head bolts, this can cause the head to warp a tiny tiny bit, enough to be a problem during installation, thus the recommendation of machine shop to check the flatness of the head surface: if it is flat, then they do not need to resurface it. If not, the resurface it.
* The valve: anyone can do it: the owners can replace the valves (and lap them in place) or the shop can do that as well.

For now, I do not have the time to fix it, so this is my "grocery getter".

PS: If those who replaced the exhaust valves, please chime in re machine shop: did you have to send the head to the machine shop? Did you get away with no machine shop?

[cn90]

Should one resurface the cylinder head or not?
See the debate below from different car forums:

https://ls1tech.com/forums/generation-i ... e-off.html

https://www.ericthecarguy.com/kunena/8- ... gine-heads

[tryingbe]

No overheat, no resurface.

Overheated, measure the the flatness.

[cn90]

I have been driving the car for 6 months with burned exhaust valve #3 (fuel injector connector disconnected).
- Vibration at idle but on highway it is smooth.
- Now I have a coolant leak at upper radiator outlet (photo later), just underneath the upper outlet. Th rad is Volvo genuine OEM, about 7y/60K miles, a bit early for the minor crack (never say never lol).

Q: anyone here driving around with burned valve develops anything unusual from the vibration (such as cracked radiator or other issues)? Right now I don't have time to fix the burned valve, thus this question.

[shadetree_v70]

There was a guy on here that drove on a burnt valve for about 8 months before he finally checked compression. Was driving me nuts. Lol

HA! That might have been me. My wife’s car lost #5 but it was intermittent for a long time until it just let go.

+1 on unplugging the injector

[rspi]

There was a guy on here that drove on a burnt valve for about 8 months before he finally checked compression. Was driving me nuts. Lol

HA! That might have been me. My wife’s car lost #5 but it was intermittent for a long time until it just let go.

+1 on unplugging the injector

No, I think it was a guy in Illinois, but a lot of people do it. A guy from NYC has driven his 960 about 2 years. Crosses state line and anywhere he feels the need. I just wouldn't want to be far from home when the 2nd one burns.