Engine build advice - general

[happy1]

Hi,
I am going to build together an engine that I have dismantled, with new bearings, piston rings etc, and would like to discuss some best practices, and general advice.

The engine I am building now is a JCB 444 Dieselmax, 4.4 litre turbo, with mechanical Delphi injector pump. It has very low hours, but has been under seawater for a little while, and was preserved before I got it.
I have dismantled it successfully, and found that two of the four pistons had seized rings, and a some corrosion on the friction coating on the skirts.

So this engine has no visible or measurable wear, but the bearing shells were not pretty, they seemed to have worked as 'anodes' (discolored and some powder corrosion), so I have ordered all new bearing shells.

First discussion topic; Crank bearing surfaces: Mine are not scored, not deep rusted, mostly shiny but have some slight discoloring from the bearing shells being in contact with them. I was thinking using 800 grit paper and give them a light rub. Is that bad? I have seen a racing engine specialist here in Perth offering polishing of cranks, should I instead send it there, or what is the general advice by guys on the forum for sandpaper grit level if touching the crank surfaces?

Second topic; Cylinder honing: My engine had seized with all pistons about half way down, and after knocking out the pistons with a wooden block and hammer, there are no obvious pitting or scratches in any of the bores. I have already used some 400 grit paper and my hand to rub off some of the loose grub or dirt that was between the piston and wall, (first I knocked the pistons down, cleaned the bores a little before knocking the pistons up and out).
I have bought a cheap cylinder hone tool with 3 spring loaded stones, it says 'Medium', and my plan is to use the battery drill and this hone to do a light hone of the cylinder bores. I intend to keep standard size pistons and rings, and the purpose of the honing is just to clean away any light rust and stains where the pistons were sitting. What is your general advice, should I hone mostly in the lower section and less / none towards the top of the bores, or just a light cross pattern all up and own the bores? Should I ditch the 'medium' and get some 'fine' stones instead?

Third topic: Assembly paste; Before when building motorbike engines, I used 'Suzuki Moly paste' on all the bearing shells and rotating parts.
I have seen some youtube builders only using oil on the bearing shells. Is the general advice to add some moly paste too? Is there a particular brand / type that you use, or any 'installation paste' (for camshafts etc.)

Fourth topic: Bearing clearance: Previously when I was building motorbike engines, the bearing shells were always available in multiple tolerances, and I used the tolerance stamping and a table to find right shells, or measured the diameters before ordering shells, and i used plastic-gauge to measure the shells as part of the assembly process. Since this is a larger diesel engine it comes only with one size 'STD' bearings for the crank main and rod big end bearings. There is no suggestion to check clearance when assembling it, but do you do it anyway as an 'always', just to be sure?

Fifth topic: Clean-up of seal surfaces; i plan to use 320 or 400 grit paper by hand to rub all sealing surfaces in 'along' direction, not across the sealing direction, until squeeky clean steel. Does any of you use a more 'power tool' method, such as rotating brush or even flap disc on a small angle grinder?
I wasn't going to send the head away for surfacing, as it wasn't old, didn't have a gasket problem, and didn't have high running hours before being taken apart. Any comment or recommendations?

Sixth topic: Re-use of certain bolts; When assembling an engine it could be hundreds of dollars in new bolts. For this one I have bought new rod bolts, the were only $38 for 8, but I haven't decided yet if I should get new head bolts as well. This engine isn't for sale, and in worst case it develops a headgasket issue in the future, it wouldn't be a problem for me, versus a spend of approx $300 for 10 new bolts now. The parts dealer recommended bolts, but for now I plan to see it run first, before spending more than needed. I know that some bolts are stretch bolts, but these ones looks just fine. I think i will give them a try.

Seventh topic: Refurbish pistons with new anti-friction coating? Two of my pistons had some corrosion on the graphite sulfide low-friction coating on the piston skirts. It seem to have become 'mush' and scrapes off. The engine coating specialist in Perth that I called earlier in the week offered to refurbish my pistons and re-apply new low-friction ceramic coating on the skirts for $45/ per piston. The alternative is to buy new pistons for $250/each. I will give the coating a go first. Any comments? The guy recommended doing all 4 at once, I can't really see a reason to remove coating from the two that looks like new, just to re-apply it. In this case two of my pistons looks like new, no scratches or wear. Generally, do you apply low-friction coating when building engines?

I saw one of these new JCB 444 engines for sale new for $17k, but I have high hope of 'rescuing' mine from being dipped in seawater, and getting it running 'like new' again. So far I have spent $ 450 on all the crank bearing shells and rod bearing shells, and 4 piston ring kits. It will be another $400 for head gasket, other gaskets, oil filter, diesel filter, etc, and I will need a $400 core for the turbocharger, $400 for a new starter, and $250 for a new alternator. plus a bit for various tools and consumables. The aircon compressor doesn't turn either, and I will drop it off to the local Aircon guru for some new bearings.

Thanks for any advice. Hopefully it can be useful read for others doing DIY engine build as well. Cheers,