98 V70R Sudden Loss of Power & Now Barely Runs

[northernlights]

Despite the improbability, I think they must have burned within about 15 minutes of each other.

I was thinking maybe one killed the other, or similar, as they share the same runner in the exhaust manifold.

And, look at this old topic for a 1997 850 NA that burned up #2 and #3.

https://www.matthewsvolvosite.com/forums ... =1&t=26864

If you look at the entire thread, he alluded to the fact that he ran 87.

It's why I'm also curious about plugs in your case, i.e. anything that can cause detonation.

[erikv11]

There are two turbo coolant hoses to pay attention to, see here https://www.matthewsvolvosite.com/forums ... =1&t=55306. Lower rad hose while you have it apart? I know, parts cost adds up quickly ...

If you are looking to save money I would do a whole bunch of maintenance before the NA cams, unless they are super cheap. Your car is already pretty fast, a 98 R can benefit far more from a tune and a bit of timing advance (to move the power band) than from NA cams. But it is a fun and easy modification to try, I will grant you that.

That SAS connection to the exhaust is a hassle to get to but the two I removed, the fastener actually turned easily once I could get a wrench on it (soaked it though, for sure). I didn't have a big enough metric wrench but a 7/8 box wrench fit well enough. After removal I plugged the hole in the exhaust with an oil drain plug of the proper size, I don't remember which. If you just want to remove the SAS valve you can just put a plate on there, take the SAS to a machine shop and ask for a blanking plate but they may charge you like $20 for it. That's what I paid now it its in my tool box because I later just removed the whole pipe. And you will also have to dremel the SAS mount surface flat to use a plate; better to just wrestle around and remove that whole SAS valve mounting tube. Removing it will simplify any future work relating to the turbo, too.

[BigRed]

...If you look at the entire thread, he alluded to the fact that he ran 87.

It's why I'm also curious about plugs in your case, i.e. anything that can cause detonation.

I always run 91, or 93 when 91 is not available, and 9 times out of 10 it's Sunoco. But, I've only had the car for 20K miles or so of it's life.

Is that build-up that looks like chunky mold the result of poor gasoline, too low octane, or otherwise? It's real bad on #1.

The plugs were all cripsy black, at the ground starp and electrode. They were quite hard to get a good picture of.

There are two turbo coolant hoses to pay attention to, see here https://www.matthewsvolvosite.com/forums ... =1&t=55306. Lower rad hose while you have it apart? I know, parts cost adds up quickly ...

That helps clear it up! I will ceratinly do the turbo inlet. The lower hose appears to have been replaced, I will check the records I received when I purchased the vehicle. I don't remember it being too difficult to do when I did it in my wife's 850.

After removal I plugged the hole in the exhaust with an oil drain plug of the proper size, I don't remember which. If you just want to remove the SAS valve you can just put a plate on there, take the SAS to a machine shop and ask for a blanking plate but they may charge you like $20 for it. That's what I paid now it its in my tool box because I later just removed the whole pipe. And you will also have to dremel the SAS mount surface flat to use a plate; better to just wrestle around and remove that whole SAS valve mounting tube. Removing it will simplify any future work relating to the turbo, too.

That's not really making sense to me. I will need to take a closer look at it when I'm at the car again. If you removed the whole thing, how did you seal it? Oil drain plug again? And when you used drain plug to seal hole in down pipe, did you just JB Weld it in? As is, the SAS valve appears to be interferring with the wastegate arm on my car.

If you are looking to save money I would do a whole bunch of maintenance before the NA cams, unless they are super cheap. Your car is already pretty fast, a 98 R can benefit far more from a tune and a bit of timing advance (to move the power band) than from NA cams. But it is a fun and easy modification to try, I will grant you that.

I've been putting off the tune because I would like to do it after having custom downpipe fabricated so that could be accounted for in the tune. But as both of those are far more more wants than needs, it hasn't happened, and I don't foresee it happening in the near future. Unless of course running with those burnt exhaust valves cooked the cat...

On the performance side I've been considering the Snabb Performance Fresh Air Pipe and Poly Intake Manifold Spacer

The oil return line is a metal tube that runs from the turbo down to the oil pan. The gasket I mentioned is down at the oil pan, it is a thick rubber o-ring. Actually there is a paper gasket too, up at the turbo end of the tube, but that can be any brand the paper gaskets don't leak.

I have contacted FCP about getting an OE O-ring for that, as they don't list it on there site. I planned on getting everything else from them, so it's just for convenience.

[erikv11]

Option one is remove it all and plug the exhaust by screwing in a drain plug. I can put up a pic or two if you want, let me know.

Option two is remove just the SAS valve, and plug up the pipe there at the SAS mount using a fab'ed metal plate. No other plugging needed on the exhaust end.

[northernlights]

...It's why I'm also curious about plugs in your case, i.e. anything that can cause detonation.

Is that build-up that looks like chunky mold the result of poor gasoline, too low octane, or otherwise? It's real bad on #1.

The plugs were all cripsy black, at the ground starp and electrode. They were quite hard to get a good picture of.

Do you mean on the plugs or exhaust valves? You said you used Bosch coppers - do you remember the part number?

Carbon buildup is usually from plugs being too cold for whatever driving is typical for the car.

I just replaced a set of NGK Iridiums after 25k miles, and this is what they looked like on my 94 Turbo.

https://www.matthewsvolvosite.com/forums ... =5&t=62504

To me they don't look cooked, but the deposits are heavier than I would expect. I only run 93 down here in Florida.

[BigRed]

Bosch FR7DC 7555. They were replaced 4K ago along with Bougicord wires. I did those after having a random stumble, usually after slowing down, or stopped at idle. Though, sometimes under acceleration, too. The stumble felt like the engine was about to stall, loss of power, RPM dropped, but only lasted a second. No code was ever set as a result. Records showed it was due for plugs and wires, so did that. The random stumble continued. A Short while later I did experience stalling, always in the same spot at a STOP sign at top of a fairly steep, long hill. When it happened, random misfires were recorded, and the engine would run rough for several minutes after restarting. I found that was result of rear intake cam seal failure. I replaced the seal, but did not replace the distributor cap and rotor. The stalling ceased, but the random stumble continued. Awhile later I replaced the cap & rotor with Bosh units. The stumble continued.

Point of that story is that the plugs did spend most if their life wired up to an oil burnt cap & rotor. As a result, they were probably not receiving the power they should have.

The plugs looked nothing like yours. They were entirely dry fouled, with the slightest bit of deposits. I have them in the back of car, and labelled with position. I will try to get better pictures of them.

[rspi]

I'm in the middle of the head job on a '96 R. Head gasket, timing, PCV and a few other parts have run the parts and supply cost over $1,000. The darn hydraulic tensioner leaked like a stuck pig.

I'm shocked to see 2 burnt valves. My guess would be that one burnt before the other. If you were having idle and stumbling issues, one may have been burnt a while.

If you are planning mods, I really would try to get some NA cams. Not trying to push mine, get a set from anywhere. The change in the torque curve, putting your power lower on the RPM scale will help all of your mods pay off.

Back to those burnt valves, I suggest you get your injectors checked. Also, that hacked up PCV may have contributed to your valve situation if it caused the car to run rich or lean.

[rspi]

Usually clean pistons are from coolant steam cleaning them. Maybe a small head gasket leak.

Here is a view of the block from our S70 that I believe had about 170,000 miles on it when the head was pulled (for the 2nd time).

[cn90]

Just curious where you guys buy your exhaust valves these days?

1. Volvo valve is about $50 each.

2. Osvat ~ $15-$20/each.

3. Intervalve ~ $15-$20/each.

[rspi]

I thought those Volvo exhaust valves were about $80 each.

The head I have at the shop is toast, maybe warped beyond repair.