2400 Coupe engine rebuild

[doublegarage]

I asked some questions a while back about how best to remove a Coupe engine (upwards? downwards? etc.). I've made some progress, so I thought I should document some of it here.

The consensus on FDF was definitely "remove the crossmember and drop engine-gearbox out the bottom". Sounds good! Someone suggested watching the excellent Mark Devaney YouTube channel which I did - this video in particular, where he's doing just that, removing the engine downwards.
https://www.youtube.com/watch?v=WErUFFZ ... lianGarage
Especially the part around 14:00 where he's dealing with snapped-off captive INside the chassis rail.
I even asked him a question in the YT comments and Mark was kind enough to reply "if you're only doing engine work then take the engine out the top and leave the crossmember well alone"

Well I have gearbox concerns and a couple other reasons so i decided to remove the crossmember and choose the downwards method.

I tested each crossmember bolt for seizing (undo 2 turns, no problem, re-tighten) and they were all good.

Then came the day to actually drop the engine...

[doublegarage]

To cut a long story short - one of the crossmember bolts began to seize as the (probably rusted after 50 years) stump of the bolt was drawn into the captive nut and it sheared off - so I had to cut the head off.

Not good "should have listened to Mark!". I went to the end of the garden and had a little word with myself.

Then came back and finished dropping the engine/gearbox .

[doublegarage]

and finally

.

Then began stripping everything down. I'd read about stuck cylinder heads being a big problem, so I was ready for that - but the Right cylinder head (cyl 1,2,3) came off immediately - in fact it almost fell off when I rotated the engine stand.

Note that...main reason for removing the engine is coolant seen in the oil when draining it (chocolate milkshake look), water vapour in the oil fillers when hot, oil analysis finding antifreeze components in the oil. And I had seen coolant in the #6 cylinder sparkplug well, so I had reason to believe the Left cylinder head (4,5,6) was the problem.

So, over to the 4.5.6 cylinder head - and it is REALLY stuck. Nothing worked - I believed I tried everything, for example:
- hammering with wooden drifts
- prying at rear of head (I know that's bad)
- every penetrating oil known to humans - Kroil, PB Blaster, Freeze-Off, WD-40, Evapo-Rust etc - for 6 weeks.
- the rope trick. Feed rope into the cylinder and turn the crank - nothing..
- heating then freezing the tops of the head studs
- modified Alfa Cylinder head puller, pulls up on the spark plug hole. Didn't work, I now have 3 stripped spark plug threads and head has not moved.

[doublegarage]

Reading various forums it was clear that the only method that "always works" is the big plate method. Bolt it to the head with the cam-cover and cam-cap studs, then screw bolts down onto the tops of the head studs and lift the head with those.

It's tricky to measure up and fix the location of various studs, all at different heights, etc, but I did eventually get there.

I drew up a model of the tool needed in my 3D printing CAD tool (DesignSpark) and went to see the local CNC guy. It's a 0.5" (or 12mm) piece of mild steel plate, 368 x 212 mm. He needed it in a different format so I had to re-draw it in AutoDesk Fusion 360 so that his machine would accept it.

I picked it up today. I suppose I could have tried to do it at home on the drill press - but needing to tap out the 10mm threaded holes made me decide to have it done this way.

[doublegarage]

Here's a pic of the top of the head - 29x M6 studs for cam covers and cam caps.

and the tool sitting on top

bolt that down with 29x M6 nuts (minus a few missing studs) - torque to 90in-lbs (10Nm)

insert 12 M10 bolts

then wind them down like so

Note: the nuts on the head studs were an attempt to protect the threads in case of misalignment, but they were a problem - later removed and started again.

[doublegarage]

and...it actually works! (after 6 weeks I had my doubts)

after some playing I got it up about 30mm. It's still very stuck, but now I can get to the underside of the head it should be easy enough. Tomorrow!

[doublegarage]

I'll post the drawing file for the tool on the download section.

One bonus is... the other head (1,2,3) is a mirror image of the 4,5,6 head around the studs (not the distributor drive but irrelevant) - so the tool should work for either head by flipping it over.

-Richard

[Fanalone]

WOW, greate job Richard.
Please keep us updated on the progress.

BR
Erik

[ThomasK]

Hi Richard,
Thanks a lot for sharing this and documenting it so well! Excellent. I feel Lucky that I have not faced yet such problems - but if in the future I know how to proceed, thanks to you!

KR Thomas

[doublegarage]

I put the files and drill list here
viewtopic.php?p=7630

or links to the files anyway - can only attach picture files on the forum. If someone could click and download one to check I did it right, that would be great.

-Richard