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Piston soak for rings.

Help, Advice, Owners' Discussion and DIY Tutorials on S40 and V40. In this forum you'll find S40/V40-specific owners asking and answering questions on maintenance, ownership, repairs, tutorials and almost every do-it-yourself thing you can do to save money owning these Volvos.

1996 - 2004 S40
1996 - 2004 V40

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jakeb123
Posts: 10
Joined: 10 June 2019
Year and Model: S40 2002
Location: EU

Piston soak for rings.

Post by jakeb123 »

I have the B4164S2 engine, compression in all cylinders is equally low, at 60PSI cold and 120 hot, test was done with WOT. All the cylinders measure the SAME compression. The symptoms are a general lack of power. The engine is rated at 109hp, but it's probably half that.

Squirting oil(two full tablespoons or more, not teaspoons) brings it up to about 150 PSI, again it's absolutely the same for all cylinders.

It's either valves, worn rings or stuck rings. So I will try a piston soak as a last resort for stuck rings with Kerosene-based solvents and Acetone-based solvents mixed together, cause in Eastern Europe we don't have Seafoam,Marvel Mystery Oil, Kreen or B-12 Chemtool. It will either work or it will not. If it doesn't, it's likely not stuck stuck rings, but either worn or bad exhaust valves and/or worn piston rings. Recently replaced the belt, had 2 skipped teeth on exhaust cam, but after fixing this the compression did not move at all.
Car has 155+k miles on it, though it could be more as odometer rewinding is extremely common over here.
Before anyone mentions PCV, yeah mine was clogged and had a broken diaphragm for nearly 2 years, so we replaced it with an open-tube system, the blowby gets out.

If this doesn't work, I've prepared thicker 10w50 oil to try.

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RickHaleParker
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Post by RickHaleParker »

jakeb123 wrote: 02 Oct 2020, 10:24 cause in Eastern Europe we don't have Seafoam,Marvel Mystery Oil, Kreen or B-12 Chemtool.
Homebrew Sea Foam (SeaFoam) Motor Treatment Recipe.
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1998 C70, B5234T3, 16T, AW50-42, Bosch Motronic 4.4, Special Edition package.
2003 S40, B4204T3, 14T twin scroll AW55-50/51SN, Siemens EMS 2000.
2004 S60R, B8444S TF80 AWD. Yamaha V8 conversion
2005 XC90 T6 Executive, B6294T, 4T65 AWD, Bosch Motronic 7.0.

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volvolugnut
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Post by volvolugnut »

It is interesting that all cylinders are the same for all compression tests. You would expect some variation in condition.
volvolugnut
The Fleet:
Volvo: 2001 V70 T5, 1986 244DL, 1983 245DL, 1975 245DL, 1959 PV544, multiple Volvo parts cars.
Mercedes: 2001 E320, 1973 280, 1974 280C, 1989 300E, 1988 300TE, 1979 300TD, parts cars.
2009 Smart Passion
Ford: 1977 F350, 1964 F150 (2), 1938 Tudor Sedan
Farmall tractors: 1956 400 Diesel, 1946 A
And others.

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RickHaleParker
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Post by RickHaleParker »

volvolugnut wrote: 02 Oct 2020, 17:50 It is interesting that all cylinders are the same for all compression tests. You would expect some variation in condition.
volvolugnut
Makes one wonder if he is at a high altitude.
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1998 C70, B5234T3, 16T, AW50-42, Bosch Motronic 4.4, Special Edition package.
2003 S40, B4204T3, 14T twin scroll AW55-50/51SN, Siemens EMS 2000.
2004 S60R, B8444S TF80 AWD. Yamaha V8 conversion
2005 XC90 T6 Executive, B6294T, 4T65 AWD, Bosch Motronic 7.0.

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alschnertz
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Post by alschnertz »

What's your oil consumption?
Does the engine miss at idle? Will it even idle?
'60 PV544, '68 220, '70 145S, '86 745T, '95 854T, '01 S40
'84 Prelude
'06 MPV
'13 Ford Focus SE

jakeb123
Posts: 10
Joined: 10 June 2019
Year and Model: S40 2002
Location: EU

Post by jakeb123 »

It idles just fine. It has always started consistently without any issues. I have not measured oil consumption but I have added numerous additives to thicken the oil, so it has subsided, before if I fill it to the max on the dipstick, it would go to the half within 1000km, where it would stop or drop very very slowly.

I did the soak for 12 hours and noticed it had all drained. I added some more and left it there and noticed it had drained within less than 2 hours. I measured compression, nothing. No change I think.

Another thing I must mention, when I rev the engine and let go of the gas, as the engine decelerates there is some muffled pop-back occurring. If I add a piece of cloth, my god does it get sucked in. I've heard that an exhaust leak can cause this, as I have a broken flex pipe, but if it isn't the culprit, then it's valves.

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