1985 400i 5 spd / Long overdue / 12k Service

Extremely helpful. Thank you @Steve Magnusson!

 

It's been a busy few weeks. The car is back together. The 'sport' exhaust took a number of fixes to cap all of the exhaust leaks but once capped, we went for a full shakedown run, about 800 miles roundtrip from So. Cal to Central California.

We spent about one hour going back and forth on Hwy 229, It is here where the 400i chassis and torque curve completely blew me away, tight twisties, gobbs of torque and a chassis that was planted, flat and predictable in the tightest of the decreasing radius turns. What a chassis, and what a pleasure, complete with good feedback in the ZF power steering. I really pushed it hard and it kept responding. Unbelievable for its size and girth. It’s on new Michelin TRX’s.

Here is a quick clip of the new exhaust note getting back on the 101 Freeway near Santa Barbara.

It drank a little oil, the self leveling pump fill hose is still dripping (odd, its new) and the rest of the engine service performed flawlessly, both at speed and back in traffic.
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12k Service -Phase II - Valve Adjustment
I am deep into the pass. side valve clearance checking and shim adjustment. A pleasant surprise while lifting the cam covers was the pristine condition of the internal cavities. Clearly this motor at 12k got a lot oil changes. The peaks on each lobe look pristine with no visible wear. 5 of the 6 exhaust valve clearances were way too loose. Here are the details. New shims are on the way.
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@Theruse Happy to share. Format is MS Powerpoint. Here is a sterilized version. Also included is the MS Excel shim calculator.
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I just realized FChat does no allow Microsoft .ppt format. I have that for you, just email me and I'll send it. To anyone.

to: [email protected]

 

Before I go any further. A brief but important acknowledgement to Phil Auldridge from the GTC / C4 forum for the spectacular write up on doing this valve adjustment. See attached. Really well done and a great baseline before you grab your 10mm socket to remove the cam covers.

 

Woops. I just found an error in the MS Excel file. Please use this one as the final -Rev. 2.

Plus, I bumped my target clearance from 0.300 mm to 0.325mm as it is on the hotter, exhaust side.

Pass. side valve adjustment is finished. Time to button it up with some detailing. Then on to the drivers side.
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@raemin Good question. There is one benefit: my piece of mind.

The 'before' clearances were very loose and the valve train remained very quiet. I take any valve clearance adjustments, particularly further tightening, on the 'hot side' (exhaust) very seriously and always set them at the right end of the distribution. It gives me more confidence that in the extremes of thermal expansion, I will never burn an exhaust valve. Its theoretical, but I sleep better at night knowing I am not overlifting my valves by 13/1000's of a millimeter.

 

@Al Campbell my comment was in jest -in that we are splicing hairs with these small increments.

Impressive photo of your rebuild. I gotta ask, what is the 'trick' with cutting the O rings on the mating surface to the front of the cylinder head?

 

Ok, it does not take a concours judge to see what's wrong with the below photo. Cylinder head on the pass. side all buttoned up, new acorn bolts, etc. It's those headers. And the surface rust.

At the moment I have the entire center section mufflers and resonators out of the car. It open collectors x 4 downstairs, I think you see where I am going with this.

I am considering removing the headers, media blasting and ceramic coating them. I've cracked about half of the exhaust flange bolts to the head and no issues so far with stripping, studs extracting, etc. It *appears* that these two header sections would simply slide out. This is obviously the easy side, duping you to dive in deeper. Only to discover major issues on the LHD steering box side.

Before I do: A question for the FChat forum: How hard is it to remove and replace the drivers side headers on this model? Is the steering shaft a major issue?

Any input from those with the scabs on their knuckles would be greatly appreciated.......
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@raemin Thanks for the reply. Removing the Fuel distributor/air box is easy. So, do I lift the headers out from the top side (around the steering shaft) or do they drop out the bottom?
Thank you.

 

@raemin / Others,

Well, that was easy. All the exhaust studs stayed in place and the header set is now out and ready for blasting. It'll be a few weeks, but I'll be back with some Cerikoted headers.

I've done a lot of searching on this Forum for the correct header color for the 365 / 400i. I may have missed it, but what was the original color?

Thanks


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Back on the project today. Got the Driver's side cam covers off and the valve clearances checked. Only one of the exhaust valves had an issue at 0.38 mm clearance. One shim swap was all it took to get it back in tolerance. All off the intake valves were within tolerance.

Cam lobe peaks are in great condition and there is no wear on the back side of the lobes.

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I can't recall who suggest that I 'service' the starter motor while the headers are out. Holy tamole that was a brilliant. With the heat shield in place, I can't image how anyone could remove the starter. Bendix and armature shaft have been lubed. Time for some new asbestos in the heat shield.
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Hello Theruse,
I did not get any replies as to the question about: "what is the original color of the 400i headers?".

That (not) said, I decided to go with Cerikote "Cobalt'' which is sort of a matte titanium color, as shown below:

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