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1984 380SL
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7 Posts
Discussion Starter · #1 ·
I am a retired police officer and I live in Plano Texas. I recently bought a 1984 380SL that has been parked in a garage since 2012. Unfortunately it wasn’t properly prepared for storage, just parked in the garage one day and never driven again. So far I have discovered damage to a few piston heads and I think the gas has somehow turned to crystal meth! I removed the gas cap and found what looked like dried sugar…..so there is my intro to the group…..any thoughts? The body is in excellent shape.

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1987 300SL
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2,338 Posts
G'day Frank, and welcome
Sounds like a complete fuel system rebuild, and an engine rebuild as well
Ouch!
$$$$
Do you plan on doing the wrenching yourself, or relying on an experienced mechanic?
 

· Registered
1984 380SL
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7 Posts
Discussion Starter · #3 ·
Right now I’m doing research to determine how big a project this will be. How many things (and how major are they) need to be addressed in order to get this on the road. I don’t have the skills to replace the valves or do extensive engine repairs and I’m on a limited budget for mechanic expenses. I did a ground up restoration on a 59 Impala and ended up investing more than it would sell for. Love the 59 but told myself I wouldn’t get upside down on a car again.
 

· Outstanding Contributor , Bob's Your Uncle!
83 280 SL- 5 speed-The PIG
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35,281 Posts
but told myself I wouldn’t get upside down on a car again.
Welcome to the forum. I hope your stay is not short lived. :)

I wouldn't waste time on the fuel system until you figure out the piston / valve issue.
 
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'99 Range Rover ~ '01 Land Rover ~ '06 Mercedes e350 ~ '76 Mercedes 280C
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449 Posts
Looks like Euro lights..... How did you determine piston head and valve issues? I'd clean the fuel system and run it....
 

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'99 Range Rover ~ '01 Land Rover ~ '06 Mercedes e350 ~ '76 Mercedes 280C
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449 Posts
......and most importantly.... THANK YOU for your Service! RPO too
 

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1985 380 SL
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616 Posts
Right now I’m doing research to determine how big a project this will be. How many things (and how major are they) need to be addressed in order to get this on the road. I don’t have the skills to replace the valves or do extensive engine repairs and I’m on a limited budget for mechanic expenses. I did a ground up restoration on a 59 Impala and ended up investing more than it would sell for. Love the 59 but told myself I wouldn’t get upside down on a car again.
I suspect most of us are well upside down with our cars, and have been so for a while. These are not investment cars, especially the 380.
 

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1973 MB 350 SL Euro 116 engine
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380 Posts
I've seen valves stick from bad (rotten) gas, someone could have fired it up while it was still somewhat liquid and bent a bunch of valves. Dings in the pistons (minor ones) aren't the end of the world, but it sounds like the heads will have to come off at the very least.
 

· Registered
1983 380SL (us), Former owner: 1965 190Dc
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1,452 Posts
Welcome to the forum.

As far as fuel system work is concerned here is how my almost complete fuel system rebuild panned out.

1) $855 to have CIS Flowtech rebuild the fuel distributor and warm-up regulator, including shipping.
2) Around $25 each for 8 new injectors.
3) Pulled the fuel tank and complete flushed and de-rusted the inside of the fuel tank.
4) Blew out all the fuel lines with compressed air. I poured fresh gas in. Connected the fuel supply hose under the hood to the return line. Then connected the fuel pump directly to the battery (in the trunk) with a temporary wire and let it cycle for a couple of hours.
5) Replaced all the fuel hoses, reusing the original fuel line fittings, using Gates fuel injector hose that is rated at 225 PSI. I also replaced the 14mm fuel line off the bottom of the gas tank with hose I bought from Autohausaz, reusing the original fitting.
6) Replaced the non-Bosch fuel pump, and replaced the the accumulator.

All in all that racks up to around $1200. The car runs fantastic though.

I later had a knocking noise in the #8 cylinder that turned out to be carboned up heads caused by a clogged catalytic converter. Seafoam works great.
 

· Registered
1984 380SL
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7 Posts
Discussion Starter · #12 ·
I've seen valves stick from bad (rotten) gas, someone could have fired it up while it was still somewhat liquid and bent a bunch of valves. Dings in the pistons (minor ones) aren't the end of the world, but it sounds like the heads will have to come off at the very least.
Pretty sure it’s not gas anymore
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95 SL600
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1,314 Posts

· Registered
1985 380 SL
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616 Posts
3 out of 4 I checked. Wouldn’t they look similar if it was valve relief? I scope the rest of them and try and figure it out. Thanks, I hope you’re right!
From the internet...380SL piston crown
3 out of 4 I checked. Wouldn’t they look similar if it was valve relief? I scope the rest of them and try and figure it out. Thanks, I hope you’re right!
From the internet, 380SL piston...

Why do you suspect a problem with the piston(s)? Have you made a compression or cylinder leakdown test?
 

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· Outstanding Contributor , Bob's Your Uncle!
83 280 SL- 5 speed-The PIG
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35,281 Posts
Question: WHY did you even decide to scope the cylinders / piston heads? What made you do that? Gut feeling or something else?
 

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95 SL600
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1,314 Posts
There ya go. Time to clean the fuel system out and fog the cylinders and start it. I would clean all the fuel lines before attempting to pump fuel into the injector plenum. The tank strainer will stop most if not all of that nonsense I see. The fuel filter will stop the rest, but from the filter to the injection it has no filter. This is what I would attempt to clean before trying to start. This is ethanol goo and with e85 it gets real bad. Clogs up everything. I
 

· Registered
1988 560sl, 1988 M6, 1985 500sel Euro
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636 Posts
Open up the valve cover gaskets and check the timing chain and guides.
The 380 motor is notorious for its single timing chain if not converted to dual.
The motor is very fuel efficient about 25mpg has a sweet spot from 70mph-90mph.
 
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