740 2.0 engine problem: Low compression - Volvo Forums - Volvo Enthusiasts Forum


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Old 11-10-2017, 08:04 AM
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Unhappy 740 2.0 engine problem: Low compression

The engine is failing and has a lack of power. I just checked the compression and cylinder #2 has no compression...

I'm going to start to take the head off and lets hope it's just a valve problem.
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Old 11-11-2017, 06:31 AM
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Removing the head...
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740 2.0 engine problem: Low compression-img1629-.jpg  
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Old 11-13-2017, 06:44 AM
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I found this photo online of a special tool to hold down the cam when removing/instaling.
I don't have one, so I guess I will just loosen each bolt slightly...


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Old 11-13-2017, 07:14 AM
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With the cams out try a leak down test on the cyl with 0 compression. I also note it is the GLE twin cam so I would suspect maybe a bent valve unless there wasn't a valve adjustment and you burned an exhaust valve.
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Old 11-14-2017, 08:30 AM
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Thanks for the sugestion, I did try a leak down test and got blow out of the exhaust.
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Old 11-14-2017, 08:32 AM
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The end result is a broken exhaust valve.
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Old 11-24-2017, 12:20 PM
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Here is the broken exhaust valve:

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Old 11-24-2017, 12:23 PM
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I also noticed that 3 of the cylinder heads had marks on them from valves breaking sometime in the past...

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Old 11-24-2017, 12:44 PM
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By the way, the exhaust valves are TRW 47128, which are the more expensive ones with hardened valve stem tips.

I replaced all 8 valves with IVAM 062V052N31, made in Italy. +30 each valve wasn't cheap...

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Old 11-24-2017, 12:54 PM
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Question

I sent the head off to a machine shop to have it professionally skimmed and the valves seated. They did a great job for only 85.

Now that I'm puting it back together I find out that the the gasket kit doesn't have a gasket for the top half of the head...

... and after some googling I find out that I have to use a special VOLVO ANAEROBIC CHEMICAL GASKET SEALER that's crazy expensive

Some people say they have used Locetite 510 or 518, does anyone know of a compatible sealer?


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Old 11-24-2017, 01:51 PM
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Taking a look at the piston damage it makes me suspect someone did not do a proper belt change and some of the valves hit the pistons. The GLE twin cam is an interference type engine where the valves can hit the pistons if the timing belt breaks or is put on incorrectly.
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Old 11-24-2017, 02:44 PM
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that anaerobic sealer is for the whiteblock motors, I thought? they use no gaskets other than the head gasket, just sealer for the 'valve cover', and oil pan. whiteblocks are built like a sandwich, the valve cover is in fact the uppers for the cam bearings, and the lower block piece is the lower half of the crankshaft bearings.
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Old 11-29-2017, 07:09 AM
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Default Hydraulic lifters



So I opened up the hydraulic lifters, as you can see in the photo the piston is very dirty. Most of them were really hard or stuck, others moved freely.
I'm cleaning them the best I can, without opening up the valve check because there seems to be a clip holding the plunger and I dont want to damage it trying to remove it.

Some people say to soak them/fill them with oil, others say leave them dry and let them fill in when the engine starts running. Opinions?


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