I have an interested buyer for my 280e euro motor. Foolishly I removed the engine from the car without doing a compression test. The buyer wants me to run a compressoin test. I want to do so and I want to be fair to him and to me.

The engine was run for about a half hour a couple of weeks ago before removing it from the car.

I can crank it over with a battery and jumper cables to do the compression test.

My question is should I do anything with the bores before running the compression test? Put in any liquid before testing or just go with whatever is in the bores at the moment?

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

usually to get a good comp test you need a little oil in the cyl's first.especially if it's been sitting.

NO, do a dry compression test first. If you find a low cylinder THEN put a LITTLE oil in the dead cylinder and spin it a few times without the gauge to make sure there is not so much oil that it will lock. Then test that cylinder again. If the oil brought up the compression, the problem is piston/cylinder/ring related. If not it is valve related.

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2001 SLK 320 six speed manual
2014 Porsche Cayenne six speed manual

Annoy a Liberal, Read the Constitution

It has only been a couple weeks since it has run. I am sure it is a sound engine having ran it but have never run a compression test on it.

OK then I will do it dry but make sure I have oil in the sump.

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

Yes, you should at least have enough oil in the sump to keep the pick up covered.

What kind of engine is it?

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2001 SLK 320 six speed manual
2014 Porsche Cayenne six speed manual

Annoy a Liberal, Read the Constitution

It must be an M110.

Tom- I would be curious to know what readings you get. I bought one of these M110s when Upullit had a 50% off sale, just because I like these engines and I have a lot of cars I could put it in (if and ) when I retire. After all that hassle when I got it home and did a dry compression test on it it had numbers that were pretty bad like 110, 130, 140, 110, 130 , 120 or something like that. I happened to find the POs business card in the junk car , so I called him, and he told me the engine ran great, but that it had probably been off the road for 5 years. So, I have been tripping over it in my garage now for a year, after filling it with MMO.

Sigh.

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80 300SD (129k mi) 82 240D stick (193k mi)77 240D auto - stick to be (153k mi) 85 380SL (145k mi) 89 BMW 535i 82 Diesel Rabbit Pickup (374k mi) 91 Jetta IDI Diesel (155k mi) 81 VW Rabbit Convertible Diesel 70 Triumph Spitfire Mk III (63kmi)66 Triumph TR4a IRS (90k mi)67 Ford F-100 (??)

No matter. If that engine is properly oil primed before lighting it off, it will most likely run as good as ever after an hour or less.

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2001 SLK 320 six speed manual
2014 Porsche Cayenne six speed manual

Annoy a Liberal, Read the Constitution

Still, the devil in me wants to pull it apart and at least re-ring it.

It's gonna sit a long time if this economy doesn't improve before I have time and motive to mess with it. I should at least repeat the test now and see if the MMO freed up the rings.

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80 300SD (129k mi) 82 240D stick (193k mi)77 240D auto - stick to be (153k mi) 85 380SL (145k mi) 89 BMW 535i 82 Diesel Rabbit Pickup (374k mi) 91 Jetta IDI Diesel (155k mi) 81 VW Rabbit Convertible Diesel 70 Triumph Spitfire Mk III (63kmi)66 Triumph TR4a IRS (90k mi)67 Ford F-100 (??)

Have you learnt nothing from me!

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1992 W201 190E 1.8 171,000 km - Daily driver
1981 W123 300D ~ 100,000 miles / 160,000 km - project car stripped to the bone
1965 Land Rover Series 2a Station Wagon CIS recovery therapy!
1961 Volvo PV544 Bare metal rat rod-ish thing

I'm here to chat about cars and to help others - I'm not here "to always be right" like an internet warrior



Don't leave that there - I'll take it to bits!

What readings did you expect? That does not sound all that bad to me. US spec engine?

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

Why, yes I have- that's why it's still more or less in one piece.


Tom- no euro. I think it needs to be more like 160-170 , IIRC. And I think there was more variation, maybe the low was 105ish

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80 300SD (129k mi) 82 240D stick (193k mi)77 240D auto - stick to be (153k mi) 85 380SL (145k mi) 89 BMW 535i 82 Diesel Rabbit Pickup (374k mi) 91 Jetta IDI Diesel (155k mi) 81 VW Rabbit Convertible Diesel 70 Triumph Spitfire Mk III (63kmi)66 Triumph TR4a IRS (90k mi)67 Ford F-100 (??)

If it ain't broke, don't fix it.

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2001 SLK 320 six speed manual
2014 Porsche Cayenne six speed manual

Annoy a Liberal, Read the Constitution

It's dry and hasn't been run in awhile. Even if it had, those are not necessarily low numbers. I bet they'll even out and rise after it is run awhile.

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2001 SLK 320 six speed manual
2014 Porsche Cayenne six speed manual

Annoy a Liberal, Read the Constitution

It will run, but depending on a lot of factors (like what kind of car it is going in, the price of premium fuel , the size of my 401K) may influence how much attention it gets.

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80 300SD (129k mi) 82 240D stick (193k mi)77 240D auto - stick to be (153k mi) 85 380SL (145k mi) 89 BMW 535i 82 Diesel Rabbit Pickup (374k mi) 91 Jetta IDI Diesel (155k mi) 81 VW Rabbit Convertible Diesel 70 Triumph Spitfire Mk III (63kmi)66 Triumph TR4a IRS (90k mi)67 Ford F-100 (??)

Instead of a compression test, do a leakdown test.