Just bought an incredible '97 850R with under 100K miles. The car has been sitting a long time...the guy I bought it from bought it with a bad miss from the original owner. The rear cam seal was leaking BADLY and the dist cap was completely corroded inside... I put a new seal and new cap/rotor/wires on. Car still ran terrible. Did a compression check as I know there is a lot of gas in the oil. Cylinders 1,4 and 5 have 160+ and cylinders 2 and 3 have 0...not even a HINT. My mechanic in Dallas (5 hours away of course) says do a combination of trans fluid, Marvel Mystery and a touch of good motor oil...about 1/8 cup in each cylinder and let it sit three or four days, then do a good oil change. I've been around cars with bad head gaskets, and they at least had SOME kind of compression register.
Any advise? I really don't want to put a used engine in it but will as I got it for a steal...the interior is near flawless, the exterior is nice, and I have a great set of chrome directional 960 16inch wheels to go on it. It is white with a black interior.
Thanks ahead of time!!!

Just thinking. Your mechanic suggested soaking the rings with oil. That works with engines that have stuck rings because they have sat too long. In your case, it sounds like there is no gasket between #2 and #3 which results in zero compression. Lets hope the rings aren't buggered, that would mean a new block.

These Volvo blocks are pretty robust and should show no wear in the cylinder sleeves.

My fingers are crossed,

Klaus
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Common sense trumps a PhD

First of all, the 960 wheels have a different offset which will not work well with the FWD 850, sorry.

As to a bad headgasket, your mechanic was almost correct. You don't need a blend of oils, just basic motor oil. Pull the bad cylinder spark plugs and using a turkey baster, pour a table spoon of oil in. That will help coat the rings and should give you enough compression to "start" the engine. You only need to wait 5 or 10 minutes before restarting. Remember, the compression readings on a cold engine will be very low because of the lack of oil on the rings. You should have close to 180psi each for a new engine.

Don't worry too much about gasoline in the oil just yet, it will thin out the oil and lower the oil pressure.

Headgasket failures between 2 & 3 are common and usually due to overheating or over boosting in your case. I would opt for a rebuilt head rather than an entire engine because it is an R. About the same price if the valves are inspected and new seals and guides are installed.

Klaus
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Common sense trumps a PhD

on the issue of the wheels : I used a set of 15" wheels off my 1986 760 all winter on my 1998 V70... were the 900s different somehow? Are the wheels I have weird in some way?

on to the other issues...

If the car was sitting a long time is it not possible your hydraulic valve lifters are not pressurized as well. I don't know what the fix for repressurizing them is, but I've heard of this effect before. There should be posts on the board about it. Again, I don't know if this could lead to 0 pressure in a compression test...

Definitely soaking the rings will be required though.

If the head is toast I would look at rebuilding it unless you know where you can get one off a junker R. Come to think of it I am not sure the heads are different from a regular head... maybe different cam? I don't know. I thought the main difference between the R engine and the others was in the bottom end and in the turbo...

Still rebuilding is still a pretty solid option unless it's completely destroyed. Some would argue you're better off with a rebuilt head than a used one anyway due to all the nice cleaning and polishing and bearing/sleeve replacement they can do in there. Depends on what condition the cams are in maybe?


I'm just thinking out loud, but I can't help but weigh in - the idea of getting an R for a song is so cool!
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1998 V70 AWD Turbo 190k+

While the wheels will bolt on nicely, the offset is different and can adversely effect handling and turning radius. I have seen 850s with 700/900 wheels mounted and wondered why.

As to the possibility of lawn mower syndrome, it would happen to all of the lifters at the same time. He did have the engine running for a while.

Klaus
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Common sense trumps a PhD

Interesting stuff Klaus.

I didn't know the offset was different.

BTW which way are they different? New wheels positive, old wheels negative? I guess if you don't know offhand I'll measure the next time I have one of my new wheels off.

Do you suppose wearing the wrong offset wheels all winter contributed to my bevel gear failure?
http://www.brickboard.com/AWD/volvo/1356271/V70/front_end_whine.html
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1998 V70 AWD Turbo 190k+

Because all 4 wheels were the same size, it shouldn't have made a difference to the bevel gear. The offset could contribute to more stress on the bearings and will effecct the handling.

The real stress on the AWD comes when the wheels are slipping and then come into contact with dry pavement. Or, one of the tires is worn too much causing the the AWD system to send excess power to the rear wheels all of the time - like driving with the spare.

Klaus
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Common sense trumps a PhD

Yeah that all makes sense.

I was very careful with my tires and rotations, and never wore the spare so I guess I'll just have to assume that the bevel gear was either worn out by someone else or it's just old. I've only had the car for 10 months.

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1998 V70 AWD Turbo 190k+

I drove the car home...ran rough but even with the 2 cylinders missing, just the least bit on the highway makes the turbo KICK. I have read that the only major thing with the R is the high pressure Turbo and the electronics. I could be wrong though... There is no oil in the water and no water in the oil. There is a pungent smell of gasoline and oil from the leak(s).
I did put oil in the cylinder and tried the comp test again...with no success. I don't REALLY want to have to rebuild the head on the car, but it's a LOT less than finding a motor.

I got this car for $1300. I think it was a pretty good deal. Even if I have to rebuild the head...

The 960 wheels I have are off of a 95+ model. The offset is the same as the 850 wheels...I've seen a number of late 960's with the 850 wheel and the opposite.

The late 960 wheels will NOT fit an earlier car.

When I took the spark plugs out...cylinders 1,4, and 5 looked ok. The 2 and 3 were totally black... I assume that they got soaked with gasoline when they stopped firing. When I got the car, 2 and 3 spark plug wires weren't getting spark. I just can't imagine what is giving 0 compression.

Thanks guys...you're giving me hope!

There is nothing wrong with the HPTs, they last well over 250K. Unless someone screws around with the blow off valve to get more boost.
The electronics are the same as any other 850.

Who knows, you might have a blown valve or two. If the plugs are iridium multi point instead of copper, check the points on the plugs, the iridium cannot stand the high heat and break off. Regardless, a good head rebuild will solve those problems. Around $850-1200 depending on where in the USA you are at.

Don't worry a lot about the oil leaks. Gasoline dilluted oil will seap through everything. They go away as soon as you change the oil and heat up the block.

While the head is out, change the oil separator and it's tubes. Send the injectors off to be cleaned: http://www.cruzinperformance.com/

Klaus


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Common sense trumps a PhD

Wow...this is news... I just put platinum plugs in it. I ran platinum plugs in the 740 Turbo and never had an issue and never read a concern about it. Do I need to replace with Copper plugs? I have never read this before.

I'm HOPING that with some soaking of those two cylinders that I get the compression back. The more I read about the procedure of taking that head off and reinstalling the more I want to hide under a rock...

RT

Get yourself a Haynes manual for the 850. Head removal and reinstallation is fairly straight forward. The valve cover has a liquid gasket put on with a foam roller, very thin, using only an ounce or so.

When you take off the head, label the cams for intake and exhaust and up/down. Take pics of each step to help you at reassembly. Use PB Blaster like it is free! Use new exhaust header bolts from the dealer, the old ones get pretty rusty.

Try to have the crankshaft at #1 TDC, it will help at installation.

And buy new plugs, cap, and rotor from FCP but only OEM.

Head R&R is not for the faint of heart, but considering what mechanics charge these days...

Klaus
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Common sense trumps a PhD

Did an initial oil change and put some oil in the cylinders...slight change but no cookie. Put enough Lucas/Marvel combination in the two cylinders to see it puddle. After a couple of hours it was still visible, so at least that's a good sign that the rings are good (correct me if I'm wrong...)

SO...if this doesn't change anything, I guess it's on to a head rebuild. I am going to get hold of a couple of import shops here and see who does their work. I've found rebuilt heads for it online from $350-650.

Are there any specialty tools that are absolutely necessary to perform this act of love? Can it be done in one day for tear down and one day for reassembly?

I've restored the dash/interior and part of the suspension of a Rolls-Royce Silver Spur, so I do have patience with complicated design.