Big DIY project 1984 MB 380SL Head Replacement.

[Axi005]

Hello everyone I want to say thank you for all your help, advice and suggestions in advance. This is my first MB project and First post her. I look forward to this project and becoming a part of this community. Ive searched multiple forums and spent time browsing but I couldnt really find anything specific to this car, possibly since it is an 84.

Here is the story, I purchased a 1984 Mercedes 380sl 3.8 107body 116 motor with 102k.

The previous owner had a timing belt go out on him (From research I can see this is a common problem with these cars). He had a mechanic replace the chains, they upgraded them with the 560 chains, replaced the guides, Tensioners ect. They went to spin the motor and realized there was no compression in the drivers side head. (The mechanic told me the exhaust valves were bent.) So the previous owner decided not to continue repairs and sell it and that is where I came in.

I purchased a Left and Right head assembly already from a gentleman locally. Here is the history behind them, They were removed from a 1983 380 SEL. The owner had a piston seize so when he was rebuilding the bottom end he had the heads rebuilt, He had a machine shop plane them, put new guides in ect. He assembled the motor ran it for 5 min and had another piston seize. At that point he scrapped the bottom end and posted the heads for sale.

Im mechanically able, I've done multiple motor and transmission replacements, clutch jobs, motorcycle work etc. But ive never went internal so this is my first time taking a motor apart or working with heads.
Step 1 How can I check the heads before I install them, what should I be looking for.
Step 2 I basically know how to tear the motor down to the block, ive assisted in a head gasket replacement before and im assuming this job will be similar.
Step 3 Can you guys give me any advice on reassembly, I downladed AllData so i have all the torque specs, I have the new head gaskets and I have the complete heads with cams, should I tune adjust the cams/ valves. Do I have to do anything with the shims. Like I said this is my first time so please bare with me. While I have the motor apart what should I do.
I will be replacing the water pump while im there, any other recommendations.? Also i know the 380 motor is weaker than the rest. Has anyone ever ported/polished these heads, Im debating if this is something I should do while I have the heads off of the motor to get better airflow and maybe a few extra ponies. As mentioned previously the chains, guides, tensioners are new and were just replaced.

If anyone can offer any positive input. I know this is not for the faint of heart and that is exactly why I purchased this project (before anyone comments on that) also I have looked at and browsed through other alternatives like engine swaps, from the 560sl, to american v8 swaps. I want to keep the car mostly original since it is in pristine condition.

Any DIY links or advice on head replacement are welcome.

I want to hear your opinion on the porting/polishing.

How to tune the cam/valves whiles off (shims, etc) is any of that necessary if the heads were just rebuilt and how would I check them.

What other components to replace while im taking the apart. Like the water pump.

I want to gather as much information and knowledge about this project before starting it. So thanks in advance guys and once again I look forward to working with you guys. I havent filled out my profile yet but im located in Jacksonville Fl 32216. Thanks

[Simpler=Better]

First things first I would take the heads to a local shop and have them checked for cracks/leaks/flatness, etc. This should be no more than $80/head worst case scenario. For a little bit more they can check the valve guide wear and see if new guides are needed.

Once you KNOW you have a good set of heads then focus on the repair.

I would definitely port match the heads, and smooth out/cc the combustion chambers. It's a small gain but then you know they're the best that they can be. Don't go hog wild-just get smooth flow that matches from the intake->head->exhaust. Often the gaskets are oversized, so match your ports to the manifolds-use your judgement. There are plenty of websites that give in-depth porting tips.

edit:
CC means to get all combustion chambers to the exact same fluid volume, it helps balance the power output. Also, polish the combustion chamber face for heat reflection. Don't bother polishing the intake/exhaust tracks, just get them smooth.

[Frank Reiner]

Axi:

If you will examine the camshafts in the heads which you acquired, you will find code numbers stamped in the back of the rear journal. They may be 62/63, 68/69, 70/71, or 08/09, left & right respectively.

Also examine the heads for the casting nos.:
116 016 30 01 & 116 016 31 01 (L&R) or,
116 016 34 01 & 116 016 33 01 (L&R)

With this info we can advise you as to improving performance.

Another area you may wish to address, as permitted by your perception of the emissions control requirements in your state (which is?), is the exhaust system from the manifolds on back. Put quite simply, the 380SL system in the US is dreadful. If you can eliminate the two small cats at the manifolds, do so, and then incorporate a smoother crossover pipe for starters.

With this said, you may unfortunately be faced with the prospect of damaged pistons resulting from the aforementioned timing chain failure.

[Axi005]

Thank you for the help guys I appreciate it, sorry for the delayed response this is a side project that I want to tackle this upcoming week. Ive done some extensive research on porting/polishing, Ill look more into the exhaust system as well, thank you for the tip.

The heads were rebuilt by the previous owner and were used for only 5min
He had new chain guides installed, new valve guides, it was machined and received a full rebuild as the PO told me. The valves were numbered with a permanent marker when the heads were put together and didnt even burn off. "this shows that the heads were barely used"

My main question is when i bolt the heads back on, do I need to adjust the valves, camshaft, shims in any way? I know about TDC and all those markings on the front. The heads i got some of the valves are slightly open is this due to the cam shaft rotating?

When I get a chance to look at the heads ill post the parts numbers. thanks for the help guys.

Are there any DIYs on head replacement or head gasket replacement DIY, would these be similiar to the 560sl procedure?

[Frank Reiner]

Axi:

Originally Posted by Axi005

My main question is when i bolt the heads back on, do I need to adjust the valves, camshaft, shims in any way? I know about TDC and all those markings on the front. The heads i got some of the valves are slightly open is this due to the cam shaft rotating?

If you will look under the tips of the cam followers (rockers) at the valves, you will see a thrust piece seated in the top of the valve spring retainer. That thrust piece is available in different thicknesses for the purpose of adjusting the initial, preload position of the hydraulic compensator (ball stud) upon which the cam follower pivots. Mother Benz, in her Service Manuals, shows a special gauge tool for measuring and setting the preload. If the folks who did the repair work on the heads which you bought did not have that tool, then there is a good possibility that the preload is incorrect.

The reason for asking about the camshaft codes is to help you in setting the camshaft-to-crankshaft timing.

Are there any DIYs on head replacement or head gasket replacement DIY, would these be similiar to the 560sl procedure?

The procedures are the same.

[Axi005]

Sorry for the delay, I had to focus my attention on my daily driver since I ran into some problems with that, but now im back on my project.



I examined the heads and the casting numbers are-
116 016 34 01
&
116 016 31 01

Also where could I purchase a set of head gaskets
I called the dealer and the price was +/- 150 per side.
Should I purchase them through the dealer, ebay or are there any other websites you guys would recommend. Thank you.

[Frank Reiner]

Originally Posted by Frank Reiner

Axi:

If you will examine the camshafts in the heads which you acquired, you will find code numbers stamped in the back of the rear journal. They may be 62/63, 68/69, 70/71, or 08/09, left & right respectively.

Axi:

Let us know what the cam codes are. The head casting #s are OK.

Get gasket set on Ebay. Elring is good.

[Walrus]

Model 107

This may help...