head resurfacing and timing, techs wanted

[BAlbertiX]

I’d like to share some diagnostic work in the hopes you all can point me in the right direction before I start tearing this thing apart.

I’m stuck between a Failed head gasket, Failed piston rings or (now) Poor valve seat on cylinder 2.

Here are the facts:

The block is a factory rebuild M20 with 100k now, purchased with 50k 3 years ago and the 885 head was rebuilt by Markert Motor Works, also 3 years ago. The engine was assembled and timed by a German specialty shop here in CT, and I finished up the install. Oil changed religiously every 3k with Castrol synthetic 5W-30, and the head has had a valve adjustment within the last year to .010”.

The engine started misfiring out of nowhere just over a month ago while I was driving home after work. The only difference between this day the ones previous, was that it was an unseasonably warm day at the tail end of winter. See video below for more details.

Replaced with new parts during the rebuild include;

All 3 temperature sensors
Crank Position Sensor
02 Sensor
Distributor Cap & Coil
Plugs & Wires
MAF
FPR
Fuel Filter
All Vacuum Lines
Head gasket & Bolts

Parts I have not replaced that other threads have commonly pointed too related to loss of power / hesitation / misfire, etc.

ECU
Fuel Rail
Fuel Injectors
Fuel Pump

More FACTS:

I have noticed a reasonable loss of oil between each 3k change.
I have noticed a gradual loss of power over the last year.
I have noticed longer turn over times to get the engine running over the last year.
I do not see coolant in the oil.
I have not noticed blue exhaust gases.
I have not noticed white exhaust gases.

Compression Test Results: 160 75 150 115 130 150

Engine sounds: http://youtu.be/CSBOCokF9XY
clip 1 engine running, doesn't sound too bad at idle, yet the whole car is shaking
clip 2 engine turning over, no plug wires, note the hesitation every 6th spark
clip 3 engine turning over, no plugs or wires, note the hesitation no longer present – aka not crank or timing related

Spark plugs: Back of engine to front, left to right.


Coolant Reservoir: Coolant is dirty, with oil...not sure.


Dipstick: Oil looks clean of coolant and thick.




Any and all help will be appreciated. Thanks for your time.
Brandon

[spdracrm3]

well you have serious issue per your compression test, normal should be in the 160-170psi range (is that warm? cold ?,when was last valve adjust? ) you only want to see about 10% difference across all cylinders. try add some oil into each cyl (use a small oil can with some small tubing inserted into sparkplug hole and give each a couple squirts ) crank over a few times with plugs out and then redo your compression test if numbers improve on low cylinders you have ring/piston issues if not most likey valve sealing issues, and a leakdown test is needed next .

get rid of those autocrap sparkplugs to ,known to cause misfire issue themselves

[TobyB]

A leakdown test will explain if it's rings, headgasket or valves.

t

[jlevie]

+, the compression test points to the cause. A leak down test will tell if it is the rings or the head.

[BAlbertiX]

well you have serious issue per your compression test, normal should be in the 160-170psi range (is that warm? cold ?,when was last valve adjust? ) you only want to see about 10% difference across all cylinders. try add some oil into each cyl (use a small oil can with some small tubing inserted into sparkplug hole and give each a couple squirts ) crank over a few times with plugs out and then redo your compression test if numbers improve on low cylinders you have ring/piston issues if not most likey valve sealing issues, and a leakdown test is needed next .

get rid of those autocrap sparkplugs to ,known to cause misfire issue themselves

It was a cold test. I ran the engine for a minute or two, but the engine was definitely not at temp.

Last valve adjustment was last summer, gapped to .010".

I will redo the compression test this week with your suggestions. If that does not prove anything, I will find an air compressor for the leakdown test.

For what it's worth, and I will add this above, the engine started doing this out of nowhere just over a month ago while I was driving home after work. The only difference between this day the ones previous, was that it was an unseasonably warm day at the tail end of winter.

[Cabriolet]

you have a blown head or headgasket. just pull the head. if you have the money rebuild the engine. ($2500). rebuilding an m20 makes it a lot of fun again. otherwise, if you dont have the money, just get the head checked and rebuilt. Then slap it back on. (<$1000). if you dont have the tools ask a fellow r3v'er to help you.

[BAlbertiX]

you have a blown head or headgasket. just pull the head. if you have the money rebuild the engine. ($2500). rebuilding an m20 makes it a lot of fun again. otherwise, if you dont have the money, just get the head checked and rebuilt. Then slap it back on. (<$1000). if you dont have the tools ask a fellow r3v'er to help you.

I'm crossing my fingers it's head related. The block was 50k new when I bought it 3 years ago. I know the rockers wear over time and the eccentrics need tightening, but any chance it's common for the set screws to let go?

It might be worth inspecting every rocker arm and shaft retainers for cracks?

[BAlbertiX]

Winner winner chicken dinner Cabriolet. The break would explain the hesitation sound on start and lack of oil in coolant and vice versa. Looks like a overheat, time to deck the head.

[dnguyen1963]

Glad you found the problem. BTW, 5W30 is way too thin for this engine.

[BAlbertiX]

Glad you found the problem. BTW, 5W30 is way too thin for this engine.

Thanks dnguyen, 10W-40 it is.

[Cabriolet]

Thanks dnguyen, 10W-40 it is.

10-40 winter, 20-50 summer

[TobyB]

I have this thing about flow- testing injectors.

If one or 2 are restricted, those cylinders will run lean,
the others will run rich, and things like this can happen.

Not saying it's your problem, just that it's good to test for...

fwiw
t

[mpowerful]

^true

[BAlbertiX]

I have this thing about flow- testing injectors.

If one or 2 are restricted, those cylinders will run lean,
the others will run rich, and things like this can happen.

Not saying it's your problem, just that it's good to test for...

fwiw
t

The engine did overheat and stall out on the highway due to a fast coolant leak approximately a year and a half ago. Once it cooled, I replaced the hose, filled the reservoir and went on with my life. However, I think this was the start of it's slow death. Given the burn marks were on the front end of the gasket, and the front of the head was out of flat by .003, leads me to believe overheating caused this.

On the other hand, I DO want to be sure my fuel system is strong. My budget is tight, and would rather stay away from the sea-foam / injector cleaner, over the counter stuff. While I've got the manifold off, how would you suggest I test and clean? Eeuroparts sells rebuilt injectors for $40ea... Side note: Fuel rail, fpr, and filter are new.

[Northern]

I'd start by replacing your fuel flex hoses between the tank/hard lines, and in the engine bay. While you're there, replace the fuel filter.

There are numerous people on r3v who will clean/flowmatch injectors for much less than $40ea.

I bought a set Here for ~$10/ea, and I'm very happy with them.