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Oil pressure issue / motor rebuild

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Chris400F:
This stuff was mentioned in a previous thread, says it is based on Methylene Chloride.
http://www.ebay.co.uk/itm/Paint-Stripper-1-litre-Restorations-Car-Bodywork-Metal-Remover-Wood-Furniture-HD-/291808738692?

royhall:
The shell carriers should not be painted. They should be clean smooth aluminium. The inside of the cases are painted to stop the ally being porous. Maybe after blasting they repainted over the lot? That would for sure lock the crank, but didnt you just Plastigage the shells and they came out good? Weird things happening here?

AshimotoK0:
Be careful with anything with caustic soda in it as it will attack the alloy. If you need locally go to an automotive paint supplier.

Agree with Roy though .. IIRC you Plastigaged it statically and it was OK > Something not right there.

MrDavo:
Thanks for the link Chris.

I did plastigauge, Roy, but at an angle of about 45 degrees from the top, as it was before I got the barrels off and I was performing keyhole surgery. I'll have a proper go on Sunday, the next chance I'll get, doing it across the top, also I have ordered a loan of an internal micrometer from Eddie's works.

Maybe I've been barking up the wrong end of the stick, as my dippy missus would say. What I assumed was a vapour blasted finish turns out to be paint, powdercoat, I don't really know yet. They must have used some sort of blasting to get all the chromate finish off the inside of the cases, as its all rough, but the rest maybe they just painted, or blasted then painted, IDK. Maybe they resurfaced the crank joint, as that's smooth, maybe not, we might know when we measure the journal bores. Certainly you can see here the smooth but painted, not bare alloy, journals:



The moment of truth came when I noticed the small patch where it has been rubbed off on the carrier on the left - a lightbulb moment.

The previous photos were all taken with my crappy mobile camera, however I do have decent cameras and lenses, so I dug one out. Here is a closeup of where I have chipped the paint while trying to lever the barrels off (dog rough, I know, but I was getting frustrated by then).



I should have put something there as scale, but the photo is of the leading edge of the upper case, you can make out 2 of the reinforcing ribs.

Anyhow, you can see the thickness where it has chipped, and for a circular bearing housing we are looking at twice that. It only needs to be a thou thick to steal my 2 thou clearance, though the positive plastiguage result is still a mystery, as it would be uniform around the bearing.

Maybe its a combination of two cockups, we may know more after Sunday when I will be mostly measuring. If it were a paint problem though, that could be good news, as it can be removed from the gearbox bearing housings as well as the crank journals. We'll see.

ETA: Bought the paint stripper, got a mask and safety specs (not before time!) while I was at it. :)

MrDavo:
Right, news from the front, which means theres at least a good chance we can save the cases by getting this &%#*@ silver paint out of the journals.

Ed the engineer turned up with his works' digital bore guage, accurate to 0.001mm, a lovely bit of kit, about £1,400 a pop. We could only get at the two outermost journals though. I had taken the crank and shells back out, cleaned everything, and torqued the cases together back up to 18 ft lbs.

Basically, the holes are circular  :D but measure only 38.955, they should be 39.000 minimum, all the Honda shell options are for this (A, as originally stamped on the cases, is 39.000 to 39.008mm) and above.

The difference, near enough .05mm, is 2 thousanth of an inch, he thinks its quite feasible that this is the 2 layers of 1 thou thick paint either side of the journal. I showed him the patch where it had chipped, in the above photo, and he could catch his nail on it.

When I get the paint stripper I'll get the silver out of all the bearing housings, and he will return next week with the same guage. I showed him the photo I took of my plastiguage attempt, he pointed out that it was squashed almost to the max for that colour (red), the proof of the pudding will be when we try again without the paint. Most people say green is the one to use, though I'm a bit confused as to why, I have both.

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