M103 - Compression Test Readings

[BlackBeauty]

I've have had some problems after installing a used Brabus Cyl Head onto my car. Basically, the engine eats oil, spark plugs foul up after a week or so, which causes misfire. On 3 of the spark plugs, cant see the tips at all... all covered with carbon. Also, I am experiencing loss in power recently.

Today I did a compression test and got these results. Not sure if my technique was correct but I let the engine turn about 7 times. Hopefully someone can let me know what's wrong with my engine.

Dry Test
Cyl 1. 135 psi
Cyl 2. 135 psi
Cyl 3. 85 psi
Cyl 4. 105 psi
Cyl 5. 145 psi
Cyl 6. 90 psi


Wet Test
Cyl 1. 140 psi
Cyl 2. 145 psi
Cyl 3. 95 psi
Cyl 4. 110 psi
Cyl 5. 150 psi
Cyl 6. 95 psi

I believe the Brabus Head increases compression and hence is breaking up a 120000 mile old engine. Your views pls.

Thank you.

A compression test is only halfway to the mechanical diagnosis. Now you need to do either a wet compression test or a leakdown test to determine if the problem is with rings or valves.

120,000 miles, unless the engine has not been maintained with oil and filter changes, should have a very tight bottom so I don't think the added compression would bring the engine to its knees, especially that fast.

If putting a tablespoon of oil in each cylinder doesn't bring the compression up, then it is valves or head gasket. If it does it is rings/pistons/cylinders.

With a leakdown you will need to listen to tell where the leakage is. Through oil filler hole is rings, through intake manifold is intake valve, exhaust is exhaust valve or around head gasket is head gasket.

Good luck,

[cc260E]

[QUOTE]Originally posted by LarryBible
[B

With a leakdown you will need to listen to tell where the leakage is. Through oil filler hole is rings, through intake manifold is intake valve, exhaust is exhaust valve or around head gasket is head gasket.

Larrybible,
your advices are always very helpfull.
On my 260E 1988 Euro, +/- 400 000km, I see very often oil in the intake manifold below the throttle flap and (keeping the Air Mass Flowmeter diphragme wide open).
Does it mean that I have a worn intake valve? even if I do not feel any loss of power nor excess fuel consumption.
just some oil to be refilled(' 2 liters per 10 000 km ( which sounds normal to me).

Thanks for your advice