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  #1  
Old 02-26-2006, 02:14 AM
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Location: Phoenix, AZ
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No and Low Compression, et al

Need some help with an 82 380SEL (w/double row timing chain) I just inherited...PO said car was running OK when it SUDDENLY died and didn't want to mess with it anymore. His trash is my $200 treasure (or headache). Anyway, car will idle and start up on first crank, but bogs when given any gas-if I play with the accelerator I can get it up to 20 mph. I can rev it pulling on throttle and pressing down air plate. Reviewed forum (which is great!) and frequency valve checks out (buzzing), fuel pump OK, new fuel filter, OVP and fuse OK, idle control seems to be working properly-pulled off conector and idle jumped up. Replaced coil, good spark on all plugs. First thought: maybe a massive vacuum lead somewhere (car lurches when taken out of Park).

Here is where things go downhill: checked ign timing. It looks like timing is set at 20 deg? I'm guessing someone must have tried compensating with fuel mixture (increasing richness?) to keep it running???
Vacuum readings were way off! Needle vibrates excessively between 5-10" hg at idle--no where near 20". Drops to zero on acceleration and jumps up to 15" on deceleration.
Checked compression: Cyl 1 = 0, Cyl 2 = 0, Cyl 3 = 20, Cyl 4 = 130 first test, 50 second and third test...dropped in a little oil and no effect. Cyl 5 6 7 8 = all were between 140 to 150. Didn't bother to check fuel pressure yet as this needs to be addressed first.

I guess I know where start next. Does anyone have a good link with pictures that walks thru removing the head? (is the passenger side bank considered the left side-like your looking at it, or the right side-looking at it from inside?)

Any and all help is greatly appreciated!

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  #2  
Old 02-26-2006, 08:24 AM
t walgamuth's Avatar
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Join Date: Apr 2005
Location: Lafayette Indiana
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sorry

to hear it isnt simple.

but your method of doing the compression test may be an issue. there is not any reason i can see for it to come out high then low on the same cylinder except tester fault. or testing.

is your compression testor a screw in type?

tom w
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Old 02-26-2006, 11:22 AM
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its the threaded type...I found that odd too.
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Old 02-26-2006, 12:58 PM
Larry Delor's Avatar
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Not that I am an expert, but my gut instinct would have me looking at the cams and their timing (and their condition) next.
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Old 02-26-2006, 02:41 PM
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Your right side camshaft has jumped time and has bent valves in the right cylinder head. I have seen this happen and the engine will still run (barely) on the 4 cylinders on the left side. You have a head job staring you in the face. I wouldn't try to run the engine any further. I have seen valve heads break off and damage pistons which then requires a complete rebuild instead of a head job.
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Old 02-26-2006, 07:51 PM
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since I'm only doing the right side, does the intake manifold need to come off? will it make things "a lot" easier? I read only the bolts need to be removed--how many are there?
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Old 02-26-2006, 08:32 PM
t walgamuth's Avatar
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Location: Lafayette Indiana
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i have never

heard of a v8 that a head could be taken off wo removing the intake. but i have never done a benz.

tom w
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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.
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  #8  
Old 02-27-2006, 08:39 PM
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Even if you could unbolt the head with the intake in place, it wouldn't save you any frustration on that engine. Remove the intake. You should do both heads, better now than when #8 cylinder is buring oil bad through the valve guide.

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