Engine rebuild with no former experience........

...na sowas !

Hi Jim,

I hope the whole thing will still appear as a workshop article in compressed form. Great job description. Keep it up!

I hope my english is not too funny

Hi,

i had a look for another dip-stick tube which would fit maybe....
Really shocking nearly 165 € and not available.

Hi Richard, thanks for trying anyway, I will zinc plate the old one.

Someone suggested to use oven cleaner to tidy up the lower intake manifold, it didn't really work very well.

Potassium Hydroxide + pitted Aluminium => Hydrogen + "soot that is not easy to remove"

Perhaps they were thinking about a different recipe for oven cleaner or smooth aluminium.



After wire brushing and power washing, marginally better than what I started with.



I needed a wire brush for cleaning/polishing parts so .....















The used CAM bearings from ebay also arrived, they are in perfect condition.

Taking a closer look at the valve guides. The intake guides have plenty metal to drive them safely into the head from the top end, however the exhaust valves look very delicate at the top edge which will take the driving load.

Here is a pc of both intake and exhaust guides from the top and below, plenty meat on the bottom of both.



I'm thinking about removing the snap rings and driving the exhaust guides in from below. Either way I will heat the heads to 80degC and buy some dry ice to cool the guides and drive in tools down to -80degC.

The original MB "drive in" tool (110589011500) looks like this. Looking at it's shape it would seem to me that the drive in pressure must be applied to the top edge rather than some lower part of the guide. Hence the need to ream the guides after use.

Has anyone ever seen or used one of these? I've also seen it listed as 910589011500.

I worked out that the CSA of the top edge is about 30sqmm and that the snap ring shoulder is 50sqmm so I'll make a tool to push down on the snap ring shoulder from the top then replace the snap ring..

This morning I made up two new tools to push in the inlet and exhaust valve guides.



The tool pushes on the shoulder of the intake guide and one the snap ring locator on the exhaust guide.







Chased out the spark plug threads.



Then cleaned up the starter motor.....





....and got them primed.

I paid for 1 hour of vapour blasting on these parts. Not perfect but more than good enough.

Moin Jim,

great job

I painted the solenoid and starter motor today.





Then on to fix this rusted and sheared off bolt.



I drilled it out before getting the manifold cleaned but managed to damage the thread.



So drilled it out and taped it for a helicoil.





Installed with thread lock a bit below the surface so as to be fitted in good threads.

I stripped the paint and rust off the harmonic balancer and main pulley today....



....but spraying primer at 1 degC didn't work out too well. I will need to sand out the runs.

Hello Jim,

to assemble the pulley: It is easy to overlook the fact that one of the six screws is on a different locking circle, which defines the installation position. I didn't notice and wondered why I couldn't fit the last screw.

Best Regards

Frank

Hi Frank, whoever changed the front seal in the past on this car did not know this, there were only 5 screws in the pulley! They obviously could get the last one in so just didn't bother.

First sleet of the year overnight.



The delivery of dry ice turned up by 10.30. Somewhere below ~-80degC I presume, the digital thermometer only goes down to -50degC.



Head in hot water, heating to 80degC and a couple of heater strips to keep the head hot once on the bench.



Guides into chill.



Head up to temperature.



All the guides pushed in, all went in easily apart from two that took a bit more force.



Next, two expensive reamers, 8.99mm and 10.99mm.



They went through the cooled down guides fairly easily and only one seemed to cut a tiny amount.



Lubricated with wd40.



The next job will be to check the valve to seat seal.

Cool job .....

Hälsningar,
Lutz

Ha ha, I still have 13kg of dry ice slowly evaporating in the garage, I only needed 1kg or so but the minimum order was 15kg.

Today was spent lapping the valves. First engineers blue on the seats....



...and valves.



I used course then fine lapping compound using a conventional hand tool.



It was a slow pita but it showed all valves to be concentric with the seats, all valves showed a very consistent even pattern.



I then gave all the valves a second lap with the fine compound again using Martin's method. Using the hose to connect the drill takes out the risk of canting the valve stem.



Finally I did a leak test, each recess filled with water.



I ended up with a small single drip on about half the valves after 5 minutes. I have no idea if this is good enough or not, I guess with the valve springs fitted this would be much better.

Tomorrow the other head.

Today I put the springs back on the first head to try a leak test with them.



Then filled the runners with brake cleaner.



There was only just the tiniest of weeps from a couple of valves, to be honest, I am almost ready to call that good.

I will take the heads up the the bike engine builder (who did the TIG welding for me) tomorrow to get his opinion if the seal is good enough. There is nothing like getting an experienced pair of hands on the head, so I put both to one side for the rest of the day.

Next I went on to rebuilding the pistons, only lost one of the wrist pin retainers pinging across the garage.



New, bearings fitted.



Tried out the new torque gauge.



Checked the dimensions, all was good.



Then repeated for the other 8 pistons.

Hi Jim,

Chapeau, you are doing a great Job.

Hello,

did you got a brake bleeding vacuum bottle?
Valve test with vacuum shows much better if the seat is sealing or not.
You need just a plug or a flat iron/ alloy piece and plug the related channel.

Then you see which seat are good to go which one need more grinding work.

Nevertheless the valve and seats should seal good after the cutting job even before final grinding.

Kind regards

JP