Oil pressure issue / motor rebuild

[Trigger]

Have you got the head and barrels to part company ?

[MrDavo]

The head and barrels are apart, yes, but the barrels are still very much part of the upper crankcase.

I was getting perilously close to doing real damage, and I don't see why it won't go back together the way it came apart. It makes it more difficult, but not impossible, in  race paddocks (and cars) bottom end issues are often dealt with like this to save time.

BTW your engine stand is turning out to be an essential. I noticed the first pages of the Honda manual shows a sandcast motor in something very similar.

[Trigger]

sorry, I meant the barrels to the crank case

[Trigger]

A busy day Sunday. I polished the cam cover at last, stripped the carbs for an ultrasonic bath and the choke linkage for a replate.

I also removed and stripped the oil pump. The rotors and their fit together are like new, with slight scuffing, but the endplates are badly marked up. Some scratches in the body but not much. Trigger, are these toast or useable?

I was building up some pumps today and have a chance to show you what a good pump looks like.

[MrDavo]

Well the hiatus in this thread was due to me testing my engine building skills touring the north coast of Scotland on my Sportster, with its brand new crank, rods, cams and bushes. 1700 miles later, and no more noises than it started with. Here she is on Skye:

In the meantime, Trigger has sorted me with an oil pump rebuild kit, and Ashely has kindly sold me his spare crank which turned up via courier this morning, in enough packaging to wrap an oven:



To my great surprise, as per the instructions on the Honda crank bulletin, when I tilted it to the light, I can see the scrawlings on the crank, AAAA a squiggle in a circle, then 4444. I need to check the rods for markings, and at the weekend we will use a calibrated mike from Ed's works to check all the measurements, but as the cases are BBBB it looks like I will need a set of green shells for the mains.

My 2 assistants who helped me pull the motor and I all wrote dates on the garage wall to predict the refitting date, Ed the engineer picked the earliest date and is quietly optimistic. Last night I dropped the carbs off with him for a go in his ultrasonic bath, and the choke linkages to get zinc plated. We were intrigued by the little sprung trapdoors on the chokes, I'm  guessing this is to stop a backfire blowing the carbs off. Nothing that fancy on an Amal!

[Trigger]

Make sure the con rods have not ovaled, as you will be wasting new shells.

[AshimotoK0]

Make sure the con rods have not ovaled, as you will be wasting new shells.

May  still have rods off that crank if they are ! Isn't it wonderful packing cranks so courier doesn't trash them !

[MrDavo]

I don't really understand why, but although the main bearings were all toast (shells and journals), the conrod bearings were all fine.

I will be using new shells, of course, to fit this crank, I'll try checking the rod big ends for roundness with my vernier calipers, though.

[Trigger]

I did not realise that the con rod shells were all fine. To that extent of wear to the crank case shells, I would of thought it would of picked up on the rod shells.

[MrDavo]

On careful measurement the crankpins and shells had slightly ovalled, but the roads were still perfectly circular inside.

Ash, your crank measured up perfectly, all 'A's as you said, and as marked. Please pm me as to where to Paypal the money to, or whatever other way of payment you want, again a thousand (or 736) thankyous.

Now this is interesting- with a full set of A crank journals, and all As on the cases, (not Bs as I thought), you'd fit yellows. We checked the old crank and although the journals were too FUBAR to measure, this crank was also marked. AAAAA. However, a set of greens had been fitted. As we understand the crank bulletin, this would mean you have the maximum size journal, the minimum size hole in the cases, and a full set of greens fitted, which is wrong, and tightens things up by .005 or so - would this lead to a too tight fit that semi seized on startup?

[AshimotoK0]

Glad it worked out for you mate. As I said my old mate Big Al had measured it up and he was apprentice of the year at the National Engineering Laboratory for 2 or 3 years running (used to go on the back of Midge Ure's BSA C15 to work) !! but I could only find the bit of paper with his measurements on for the one I am keeping. Bryan, Trigger & Oddjob are the sages on this, not myself, but I gather the old pro's just bang in GREENS anyway BUT tell the customer to run in very carefully. Maybe someone fitted GREENS and then thrashed it.

[Bryanj]

It would not have seized, partial or otherwise, with those shells mate. I would just about guarantee bad oil/changes

[MrDavo]

Ok, thanks for that info. A set of NOS yellow shells for the mains and greens for the big ends have been ordered from Yamiya750 in Japan, along with the oil seal for the crank, timing side. Last time I ordered anything from Japan (a JIS screwdriver) it took a month to come, in a ridiculously big box. Lets see how long this takes, in the meantime I shall continue to whittle away at scraping off the head gasket, delaminated but solidly baked onto the barrel, and I'll also do a valve regrind, and fit new valve seals.

The Athena gasket kit and plastiguage I bought off eBay arrived today. I have also polished the cam cover, which is why I wanted to take the engine out in the first place, before I realised there were crank issues.

[AshimotoK0]

Yamiya is very quick delivery I think. They are very efficient to deal with.  But I get mine in Japan and get someone in Japan to ship it for me as you get stung big time on import duty.

[MrDavo]

B*gger, I hadn't thought of that, the parts were dear enough as it is. Also, if my new K1 seat, from Florida, was anything to go by, ParcelFarce bill you another £12 or so for the privilege of collecting the duty from you.