98 V70 AWD LPT Generic Burnt Valve Question

[mtd240]

This thread has a good bit of relevant information..

[mecheng]

I agree with the mechanical engineer...

- Weekend "Italian Tuneup" on the highway...(watch for cops lol).
- Octane 91+ gasoline.
- Pray like crazy I don't have to pull the head.

Why bother, they won't be able to catch you in the POS Crown Vics.

If you are NA - yes watch for Cops, they will be able to catch up with you

[j-dawg]

would an AFR sensor be a useful diagnostic tool? i suppose most of us MVS users don't belong to the gauge-pod-high-boost crowd, but if anyone had experienced a burnt valve with such a setup maybe he would have noticed the engine running lean in the days before the catastrophe.

i also burn oil, but Things Came Up, as is their wont, before i could take on the seal replacement job, and i won't have space to do it in the future. i'll keep crossing my fingers, pumping that 93, and crawling from a stop to burn off the oil at lower temps. i dunno if all that makes a difference but it's the best i can do for now.

btw, those crown vics aren't quick off the line, but they put out similar HP to a T5 from twice the displacement. they could probably run at 100+ all day without breaking a sweat.

[mecheng]

would an AFR sensor be a useful diagnostic tool? i suppose most of us MVS users don't belong to the gauge-pod-high-boost crowd, but if anyone had experienced a burnt valve with such a setup maybe he would have noticed the engine running lean in the days before the catastrophe.

i also burn oil, but Things Came Up, as is their wont, before i could take on the seal replacement job, and i won't have space to do it in the future. i'll keep crossing my fingers, pumping that 93, and crawling from a stop to burn off the oil at lower temps. i dunno if all that makes a difference but it's the best i can do for now.

btw, those crown vics aren't quick off the line, but they put out similar HP to a T5 from twice the displacement. they could probably run at 100+ all day without breaking a sweat.

Burning oil at start up or all the time? What viscosity are you using?

The crown Vic's were the pride of St Thomas ontario , they are near bulletproof engine wise and body. Because they were body on frame they were quite easy to bend the frames back after a hit. It's time to replace them, they are terrible on gas and if you figure how many police cars are driven and idling it adds up to a lot of waste fuel and pollution, it is time for them to be retired: they are obsolete.

[rspi]

Well, I'm still scratching my head on this one. The car I just sold had a burnt valve at 105,800. It had all the signs of being babied, garage kept and sold into preventive maintenance. Had mostly Volvo parts, timing belt done at 48,000 @ 7 years, newer coolant hoses, changed PCV, etc. But man those darn valves had plenty of carbon build up. While preparing the head for install, I found another bad valve ready to burn.

This is what I think:
1. Driven to passively. These cars will shift before 3k if you let them. The valves start to spin in the head at about 3k from what I have been told. Spinning valves cleans the seats.

2. Low quality fuel. To many mechanics tell people that "it's run just fine on 87". Not good.

3. Not running synthetic oil. Leaking valve stem seals do build up carbon on the valve stems, but I doubt full synthetic would build up as much. Many, many of these cars have leaking valve stem seals and NO burnt valves.

4. Fuel injector cleaner every 2,500 miles or 90 days would help.

5. Plugged up or busted PCV systems. Running rich or lean can cause valves to go outside of their temperature range.

Robert