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Registered
1979 450SL UK spec
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1,759 Posts
Discussion Starter #1
The time has come, I plan to rebuild my engine as I need to take it out of the car to paint the engine bay. It has a few issues, leaking rear main seal and head gaskets etc, so while it is out of the car I will take the opportunity to carry out a full rebuild. I have also had an issue with a loose valve guide so I will be able to fix this at the same time, on top of this I am sure I am down on power since I installed this engine ten years ago.

My garage space is very limited so I decided to put my XK8 into storage over the winter to free us space to work on the engine. I drove it to the storage location on Wednesday, it was a large grain store on a remote farm and was dry and extremely warm inside.



Yesterday I moved the car lift out of the way and retrieved the engine crane from the shed and had a freak accident!



I was using this pry bar to lever up one end of the car lift to fit its castor wheels to move it, I levered it up to put a block of wood under the frame and left bar down where I had used it.



Next the lift slipped off the block of wood, fell about 5cm and landed on the pry bar and propelled it through the air, into my head!

Ouch!



Back to it today, I jacked up the car and the supported under the chassis rails.





Then drained the fluids and removed the radiator.





Since there have been a few scare stories about car stands I decided to put another two stands under the sills without any weight on them as a backup, that will give me more confidence when working underneath.



To get some knowledge about engine building, I bought this US book, its not ideal for the MB engine but does cover all of the basics.



The weather is bad tomorrow so will make some more progress.
 

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Premium Member
1983 380SL, 2000 S430, 1991 420SEL (retired) - RHD
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5,890 Posts
The time has come, I plan to rebuild my engine as I need to take it out of the car to paint the engine bay. It has a few issues, leaking rear main seal and head gaskets etc, so while it is out of the car I will take the opportunity to carry out a full rebuild. I have also had an issue with a loose valve guide so I will be able to fix this at the same time, on top of this I am sure I am down on power since I installed this engine ten years ago.

My garage space is very limited so I decided to put my XK8 into storage over the winter to free us space to work on the engine. I drove it to the storage location on Wednesday, it was a large grain store on a remote farm and was dry and extremely warm inside.



Yesterday I moved the car lift out of the way and retrieved the engine crane from the shed and had a freak accident!



I was using this pry bar to lever up one end of the car lift to fit its castor wheels to move it, I levered it up to put a block of wood under the frame and left bar down where I had used it.



Next the lift slipped off the block of wood, fell about 5cm and landed on the pry bar and propelled it through the air, into my head!

Ouch!



Back to it today, I jacked up the car and the supported under the chassis rails.





Then drained the fluids and removed the radiator.





Since there have been a few scare stories about car stands I decided to put another two stands under the sills without any weight on them as a backup, that will give me more confidence when working underneath.



To get some knowledge about engine building, I bought this US book, its not ideal for the MB engine but does cover all of the basics.



The weather is bad tomorrow so will make some more progress.
Well RD, everything else you've done on this car has been great so I'm sure you'll do a great job(y)
 

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Premium Member
'72 350SL, '85 300D, '98 E320, '19 Subaru Outback (sold '14 GLK250)
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11,081 Posts
Good luck with it RD. Sounds like a big job depending on how far you will go. Can you farm some of it out - like the heads for example?
 

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Registered
1981 380SL
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528 Posts
I hope you will be documenting! Your "journey" with this vehicle has been one of my favorite things to read and follow around these parts.
 

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R/C107 Moderator
1986 560SL: '84 500SL: '84 280SL 5 speed: other 107s
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32,693 Posts
Think carefully on a total rebuild. A head job is one thing but the short block will get real expensive if you do it by the book. The rod bolts will most likely not meet the spec. to reuse n there are 16 expensive (if you can find them) bolts. The original compression rings were chrome moly which are very expensive or at least they were in 2008 when I rebuilt my '73. Neither the '72 or 73 4.5s I have dismantled had a ridge at the top of any cylinder showing wear. On the '73 I could see the original honing marks. In the end I regretted that part of the rebuild. There was nothing really wrong with the engine to begin with. I heard the fatal chain slap on start up. Being
Chevy wise and Mercedes ignorant I relied on the toilet paper Haynes Manual for guidance. Big mistake.

Anyway I would not delve into the short block unless you can see something really obvious. It is pretty much bullet proof.
 

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1987 300SL
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518 Posts
I'm with rowdie on this RD. Unless your short has a definite problem leave it alone. Your power comes from your heads, generally speaking, and that is where you will get all your gains from in terms of back to original output. Do seals that need to be done, but I would suggest concentrating on the heads. I recently had to look at my M103, spoke to my indie and he said lets pull the head off and look at the bores. He said they looked like new, couple of pistons had some build up from leaking valve guides and seals, but he suggested just a head rebuild which is all we did. Thing goes like a rocket again. And I bet you're going to plate everything? 😨😂
 

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Registered
'79 450SL, '04 CLK200 convertible; former A124, W210, A209.
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2,438 Posts
Following with interest Jim, best of luck amigo and please be careful - that crowbar incident could have been nastier!
 

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Premium Member
1999 500SL, 1988 SEC
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1,523 Posts
Couple of comments. First I am not sure if you have the aluminum block but if you do the bores are impregnated with silicone. To hone them it takes a special process and its hard to find a shop for that. Second wnen you have the valves done make sure they measure the valve stem length before they take it apart and make surethe make them the same length. If not adjustment is a pain. Ihave a m117 560 so some things might be a little different
 

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Premium Member
'72 350SL, '85 300D, '98 E320, '19 Subaru Outback (sold '14 GLK250)
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11,081 Posts
Before you take engine apart, have a good listen - May tell you just where likely problems are:



I read that UK now does celebrate Halloween like NA does? No more Nov 5th?
 

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Premium Member
1979 450SL
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285 Posts
I've rebuilt Alusil Porsche motors as DIY projects. Attention to detail, lots of research, cleaning endlessly, and an unjustifiable
budget were key, but finding the right machine shop was the single most important thing. If it's not too late, consider a leak down test to see how well the rings are sealing. That may help you decide whether to rebuild the bottom end.
 

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Premium Member
'72 350SL, '85 300D, '98 E320, '19 Subaru Outback (sold '14 GLK250)
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11,081 Posts
No Phineas Gage comments yet? I'm disappointed ;)
Had to look that up! Crowbar affect?

For a moment, I thought you were referring to Fred Gwynne (aka Herman Munster) who appears to have an ear for engines.
 

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Registered
1979 450SL UK spec
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1,759 Posts
Discussion Starter #14 (Edited)
Think carefully on a total rebuild. Anyway I would not delve into the short block unless you can see something really obvious. It is pretty much bullet proof.
Yes, I'll review once the heads are off, but I did buy two sets of rings, one full standard iron set then I saw a full chrome set and bought them too since they were so cheap.



Couple of comments. First I am not sure if you have the aluminum block but if you do the bores are impregnated with silicone.
Luckily it's an iron block.

I read that UK now does celebrate Halloween like NA does? No more Nov 5th?
Well England is going back into lockdown and we are in partial lockdown here in Scotland so Halloween and Guy Fawkes will be very muted this year. Kim keeping up appearances when jogging earlier.

2658694


No Phineas Gage comments yet? I'm disappointed ;)
Well some would say I do have a brain injury, best case this rebuild will cost me £2000 (already spent £1600 on parts and new micrometers etc), and probably closer to £4000 if I have to touch the block.

As for head/machine shop work, there are three places within an hours drive from me, I just need to work out which is best. These guys get good reviews but doubt they have all the high tech CNC kit you see in US engine shops.



Back on it today.

The first job was to drain the PS pump.



Then remove the PS oil cooler, I had to disconnect the lower valance to get it out. I am removing more than would be needed just to remove the engine as I plan to paint the engine bay.



Both removed.



Then battery and tray removed to give access to the top of the exhaust.



This spanner is good for the right manifold.





H pipe and damper removed.



Does anyone know the optimal height to raise the front of the car to make the engine and transmission removal trouble free?
 

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Premium Member
1986 560SL with M120 V12 Engine, 1988 560SL Stock
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11,033 Posts
Before you take engine apart, have a good listen - May tell you just where likely problems are:



I read that UK now does celebrate Halloween like NA does? No more Nov 5th?
Is it me or does that thing have 5 carburetors, maybe 10.
 

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Premium Member
'72 350SL, '85 300D, '98 E320, '19 Subaru Outback (sold '14 GLK250)
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11,081 Posts
Is it me or does that thing have 5 carburetors, maybe 10.
According to Wikipedia, 10 carbs! But then only 8 exhausts?
The engine was a 289 cubic-inch Ford V8 originally configured for installation in a 1964 1/2 Mustang, it was built with Jahns high compression pistons, 10 chrome plated Carter WA-1 carburetors, an Isky cam, and had a set of Bobby Barr racing headers. It had a three-speed toploader manual transmission.
It is apparently on display at George Barrett museum in Hollywood.

 

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Registered
1979 450SL UK spec
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1,759 Posts
Discussion Starter #18
I had been hoping to leave the middle and back exhaust box in place, but realised today that the prop shaft nut is above the middle box and heat shield. I will have to rethink that plan, perhaps with a bit of leverage I may still be able to get to it. Has anyone else managed with the middle box in place?

Anyway today, lots more disassembly.

Steering drag link ball joint removed at one side to help with the clearance for the transmission.



Earth strap disconnected.



Heat shields out and right downpipe, the left downpipe is in a restricted place and does not want to come out yet.



Engine mount bolts next.



Then the engine dampers.



Throttle linkage, oil pressure gauge and coolant hoses disconnected.



Brake booster vac line.



Wiring harness at the front and rear disconnected.



I remember when I put this engine in ten years ago that the crane chains came close to the fuel injector pipes so I decided to remove it first as its only held on by four nuts.





I have a couple of other questions, first, should there be a rubber boot around the throttle lever in the bulkhead here?



And second, can the front pully be removed from the harmonic balancer by removing these smaller bolts? I was surprised to see that one was missing.

 

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Premium Member
1976 450SL
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570 Posts
On the throttle lever there should be an orange rubber boot. But, I think it's almost impossible to replace unless the heater is removed (at least on my LHD 450SL)
-Steve

Sent from my SM-T813 using Tapatalk
 

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1979 450SL UK spec
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1,759 Posts
Discussion Starter #20
Day 4, I moved on to the transmission today. Drained the fluid.



Released the gear linkage.



Removed the front part of the cradle.



Kick-down wire removed.



Remainder of cradle removed.



Speedometer cable and PNDR switch harness released.



Prop-shaft coupling released.



For the prop-shaft spline coupling.



Finally the torque converter was drained.



That's all the prep work now almost complete. A few more things.

Protection for the radiator support.



Make your bets now, will the engine come out with the bonnet on or not?





It's up as far as I dare.

 
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