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Premium Member
1983 380 SL
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3,093 Posts
Discussion Starter #661
Rule of thumb years ago (like 40 years ago) was 33% out the crank, 33% out the exhaust and 33% elsewhere (friction, radiator heat and block heat losses). It was actually more like 40, 30, 30. But I forgot which got the 40. I'm betting its a lot better now.
You're probably right.
 

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Premium Member
1983 380 SL
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3,093 Posts
Discussion Starter #662
One thing that bugs me about this engine... the timing pointer is on the water pump and the water pump can't go on before the front plate so you need to install the front plate and the water pump so you can see where the cam timing is by reference to the pointer on the water pump and the balance. It's one of those you can't get there from here problems.

So without the pointer reference on the water-pump you must guess where the actual TDC is. Sure, you can stick a screwdriver in the #1 spark plug hole and see when the screwdriver gets to it's farthest point out, but then there are several more degrees of rotation before the pistons starts back down again.

A bit of a PITA.
 

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Premium Member
1983 380 SL
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3,093 Posts
Discussion Starter #663
Is there a trick to putting the front cover on? I tried for 1/2 hour but it just won't go.
 

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Premium Member
1986 560SL with M120 V12 Engine, 1988 560SL Stock
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10,504 Posts
Is there a trick to putting the front cover on? I tried for 1/2 hour but it just won't go.
It should go but it will be a pia and you might compromise the head gasket in that area. But its not under any pressure in that area so just use sealer. That why I put the heads on last.
 

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Premium Member
1986 560SL with M120 V12 Engine, 1988 560SL Stock
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10,504 Posts
Is there a trick to putting the front cover on? I tried for 1/2 hour but it just won't go.
I just thought of this. If you pull the alignment pins. You should be able to install the cover loose with the bolts. Then camphor the ends of the alignment pins and drive them in from the front.
 

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Premium Member
1983 380 SL
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3,093 Posts
Discussion Starter #666
I got the front cover to go on by turning the engine over on the stand. Even though I thought I was being careful I managed to bend the head gasket 90 degrees but like you said, there's no pressure at that point so I just bent it back and I'll use sealer.

I removed the cover once I found what I wanted to find... true TDC. You can only do that with the water pump installed because the pointer is on the water pump. My experiment was a success in that I found that the cam sprockets were off by 1 tooth each.

And in keeping with me never being satisfied... I ordered a new tensioner guide and now I'm looking for a new crank sprocket.

What is it that they say in the home built aircraft industry... "perfection is the enemy of progress". I've had this engine sitting on the engine stand for months and I don't even have the front cover on yet.

Hopefully once I get this front cover permanently installed progress will improve... but I have my doubts.

.
 

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Premium Member
1983 380 SL
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3,093 Posts
Discussion Starter #667
I tried to move the chain one link on both cam sprockets but in the process I must have jumped a tooth (maybe 2) on the crank sprocket. Result... locked engine again. Here we go again... I'll remove all the followers and start over. I'm starting to get pretty good at this but... damn!
 

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Premium Member
1983 380 SL
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3,093 Posts
Discussion Starter #668
A question for all you guys who know a great deal more about these engines then I do...

With everything in place, all the followers installed, the chain tensioner installed, and the cam timing set as close as I can get it; as I rotate the crank and the passenger side cam approaches about 30 degrees before the timing mark... the passenger side cam snaps forward and the chain becomes slack between the passenger side and the drivers side.

The slack quickly disappears as I continue to rotate the crank but it is unsettling to see that slack appear and then tighten again. I can't see that as being a positive thing to happen.
Perhaps once the engine is running, the natural rotation of the cam sprocket at idle will be faster than the snap forward and it won't be an issue... I just don't know and I'm hoping one of you do.

bTw... the reason it happens at that spot in the rotation is because two valves on the passenger side are closing almost simultaneously and the combined valve spring pressure is causing the cam to rotate rather than the sprocket rotation causing the cam to rotate. The valves that are closing when the snap forward occurs are the #1 intake and the #4 exhaust.
 

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Premium Member
1986 560SL with M120 V12 Engine, 1988 560SL Stock
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10,504 Posts
A question for all you guys who know a great deal more about these engines then I do...

With everything in place, all the followers installed, the chain tensioner installed, and the cam timing set as close as I can get it; as I rotate the crank and the passenger side cam approaches about 30 degrees before the timing mark... the passenger side cam snaps forward and the chain becomes slack between the passenger side and the drivers side.

The slack quickly disappears as I continue to rotate the crank but it is unsettling to see that slack appear and then tighten again. I can't see that as being a positive thing to happen.
Perhaps once the engine is running, the natural rotation of the cam sprocket at idle will be faster than the snap forward and it won't be an issue... I just don't know and I'm hoping one of you do.

bTw... the reason it happens at that spot in the rotation is because two valves on the passenger side are closing almost simultaneously and the combined valve spring pressure is causing the cam to rotate rather than the sprocket rotation causing the cam to rotate. The valves that are closing when the snap forward occurs are the #1 intake and the #4 exhaust.
When checking this you need to hold clockwise pressure (looking from the front of the engine) on the crank and counter clockwise pressure on the passenger side (for LHD vehicals) cam. You need to hold enough pressure so that the chain is tight on the driver side (LHD) of each cam. The chain can only be slack near the tensioner.
 

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Premium Member
1983 380 SL
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3,093 Posts
Discussion Starter #670
When checking this you need to hold clockwise pressure (looking from the front of the engine) on the crank and counter clockwise pressure on the passenger side (for LHD vehicals) cam. You need to hold enough pressure so that the chain is tight on the driver side (LHD) of each cam. The chain can only be slack near the tensioner.
When the snap forward occurs the tensioner yields to the demand of the rotating left side cam and causes the slack to appear between the RH cam sprocket and the intermediate gear that is located between the heads. I'll try to get a video of it when I get home.
 

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1986 560SL with M120 V12 Engine, 1988 560SL Stock
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10,504 Posts
When the snap forward occurs the tensioner yields to the demand of the rotating left side cam and causes the slack to appear between the RH cam sprocket and the intermediate gear that is located between the heads. I'll try to get a video of it when I get home.
That's why you need to hold the right side cam back. That will keep everything in tension from the right hand side cam to the crank. Its OK to have slack between the crank and right side cam, at least when its not running.
 

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Premium Member
1983 380 SL
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3,093 Posts
Discussion Starter #672
I've pretty much given up on trying to get the &^%^$^@# chain cover to go back on when the heads are already installed and torqued down.

I tried everything, including putting .030 shims under the gaskets trying to hold them up while I slide the cover under the gasket, while trying to align the various shafts with their bushings. This just ain't gonna happen.

So with great sorry, and a whole bunch of cursing the gods... I'm pulling the heads... again. This is not something I'm looking forward to... all the rockers have already been installed and I went to a great deal of trouble getting the TDC and cam timing just right and I'm about to undo it all just because I can't get the front cover on. Damn!

I'm probably going to order new head gaskets too, in fact I'm certain I'm going to order new head gaskets as soon as I'm done with this post. Generally your not supposed to reuse head gaskets once they've been torqued and had I not bent the shit out of them trying to get that damn front cover on I might have reused them but like with wearing masks when out in public... better safe than sorry.

I'll pull the heads, install the front cover and clean more parts while I wait for the new gaskets to get here.

bTw... here's what she looks like with the front cover 80% home. I painted the cover black to match the one black valve cover I have. Hehehe.
Just kidding. I originally wanted to leave it bare aluminum but after sand blasting, it looked like flat grey, so I painted it with high temp barbecue black spray paint.

Front Cover1.jpg


Here's picture of just how close I could get... but it may as well have been a mile. The heads come off tomorrow.

FrontCover2.jpg
 

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Outstanding Contributor , Bob's Your Uncle!
-----'83 280 SL----- 5 speed....The PIG
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29,604 Posts
Pretty sure that's why I bought a good used engine as a spare.
So I can keep my thread to a 2-3 week duration.
LOL.
I love you, man.
 

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Premium Member
1983 380 SL
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3,093 Posts
Discussion Starter #674
Pretty sure that's why I bought a good used engine as a spare.
So I can keep my thread to a 2-3 week duration.
LOL.
I love you, man.
I started this process last September with the mission of finding that damn tic, tic, tic that drove me nuts. It snowballed into a complete rebuild (something I never intended to do) and here we are almost a year later and I don't even have the front cover back on yet. Now that's German engineering for you. Why make something simple when you can over engineer it and make it complicated as shit?

I really do feel as if this front cover is the last major hurdle to overcome but just when you think it's safe to go back in the drivers seat.... wham!!.

bTw... Head gaskets are ordered.
 

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Outstanding Contributor
450slc5.0cab 280sl5sp 280se4.5 500se+500slAMG +250seStkW108 350sl4spdX3 500secEuro
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22,664 Posts
What was I asking along with Jason for a decent 380 motor? Like $500 or was it $1500? There’s a 380sl with a motor and no fuel system that was said to be a good running car with no title, just sitting, waiting to be scrapped out, but the body is darned near rust free too. Then I think there’s a block that’s a core too. I think those are the only 380 motors that Jason and I have access to besides a low compression euro 380slc driving car. Oh. Rick Angeley has one too. All those are dual-row TC motors. 380 motors seem to be in more demand than others because they seem to have issues more often. So although they are less desirable than a 5.0 OT 5.6, I think they are harder to find.

I respect the decision to fix the original block keeping the car all original. I just probably would have wanted to put a running motor in it for the mean time, so you have something to enjoy that moves under its own power until you get the original motor done. You are getting there though. In the home stretch, right?
 

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Premium Member
1983 380 SL
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3,093 Posts
Discussion Starter #676
What was I asking along with Jason for a decent 380 motor? Like $500 or was it $1500? There’s a 380sl with a motor and no fuel system that was said to be a good running car with no title, just sitting, waiting to be scrapped out, but the body is darned near rust free too. Then I think there’s a block that’s a core too. I think those are the only 380 motors that Jason and I have access to besides a low compression euro 380slc driving car. Oh. Rick Angeley has one too. All those are dual-row TC motors. 380 motors seem to be in more demand than others because they seem to have issues more often. So although they are less desirable than a 5.0 OT 5.6, I think they are harder to find.

I respect the decision to fix the original block keeping the car all original. I just probably would have wanted to put a running motor in it for the mean time, so you have something to enjoy that moves under its own power until you get the original motor done. You are getting there though. In the home stretch, right?
I have 4 cars... 2 are running and on the road and 2 are not. I also have a 1982 Yamaha 650 Maxim (bought it new in '82), runs great is insured but not registered. My wife gets a new car every 3 years... my kids all drive relatively new cars. The newest car I own wasn't even built in this century. What can I say.... I enjoy working on cars.
 

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Premium Member
1986 560SL with M120 V12 Engine, 1988 560SL Stock
Joined
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10,504 Posts
I've pretty much given up on trying to get the &^%^$^@# chain cover to go back on when the heads are already installed and torqued down.

I tried everything, including putting .030 shims under the gaskets trying to hold them up while I slide the cover under the gasket, while trying to align the various shafts with their bushings. This just ain't gonna happen.

So with great sorry, and a whole bunch of cursing the gods... I'm pulling the heads... again. This is not something I'm looking forward to... all the rockers have already been installed and I went to a great deal of trouble getting the TDC and cam timing just right and I'm about to undo it all just because I can't get the front cover on. Damn!

I'm probably going to order new head gaskets too, in fact I'm certain I'm going to order new head gaskets as soon as I'm done with this post. Generally your not supposed to reuse head gaskets once they've been torqued and had I not bent the shit out of them trying to get that damn front cover on I might have reused them but like with wearing masks when out in public... better safe than sorry.

I'll pull the heads, install the front cover and clean more parts while I wait for the new gaskets to get here.

bTw... here's what she looks like with the front cover 80% home. I painted the cover black to match the one black valve cover I have. Hehehe.
Just kidding. I originally wanted to leave it bare aluminum but after sand blasting, it looked like flat grey, so I painted it with high temp barbecue black spray paint.

View attachment 2644290


Here's picture of just how close I could get... but it may as well have been a mile. The heads come off tomorrow.

View attachment 2644291
Have you considered what I suggested in post #665. Iv'e never seen it done but I think its worth looking into.
 

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1985 380 SL
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131 Posts
Was the deck resurfaced after the install of the sleeve? If so, do you know how much material was removed? Perhaps the timing cover needs to be reworked accordingly.
 

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Premium Member
1983 380 SL
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3,093 Posts
Discussion Starter #679
Have you considered what I suggested in post #665. Iv'e never seen it done but I think its worth looking into.
The alignment pins are only part of the problem. The distributor drive sprocket and the chain idler sprocket both need to align with their respective bushings in the front cover before the alignment pins come into play. With the heads on and the gasket less than flat, (in fact destroyed) I just can't manipulate the front cover enough to get everything to line up.

The manual says to use grease on the head gasket where it contacts the front cover and perhaps had I done that I wouldn't have messed up the gasket as much as I did, but I'm past that consideration now. Both head gaskets have been compromised where they contact the front cover so it makes more sense to correct the screwup rather than create another one. My biggest concern is the fact that I'll need to torque 36 head bolts again. Hopefully the TimeSerts (and my nerves) can take it.

However, I am taking the advice you gave me during one of our prior conversations... put the front cover on before the heads. (y)
 

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Premium Member
1983 380 SL
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3,093 Posts
Discussion Starter #680
Was the deck resurfaced after the install of the sleeve? If so, do you know how much material was removed? Perhaps the timing cover needs to be reworked accordingly.
Yes, the deck on the drivers side was resurfaced but I don't know by how much. I can't imagine it being more than 0.010 or so. Putting the front cover on before the head should eliminate any variance created by resurfacing the deck. The head gasket will compress by far more than the skim cut on the deck.

Interesting side note: I have a record of all the thrust washer sizes on both sides. It will be interesting to see if the thrust washer sizes on the drivers side need to be adjusted to bring the drivers side valve clearance alignment to nominal.
 
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