Seized 4108 . Crankshaft damaged as well

[pcatterall]

(edit.... there should be a comma after 'as well' in the title
I have 'obtained' a seized complete engine (A) with all the marine bits and gearbox that I need.
I was also given another engine(B) which turns freely and has an ( alleged) recon head. ( it looks good with the rocker box removed)
I want to finish with one good engine which will last (Another 40 years!)
I will obtain one of those £370 comprehensive overhaul kits for the engine.
Present thinking is to remove the head from engine B, check the valves rockers etc, and inspect the general engine condition, if it is anything less than very good
I would get the kit and replace everything.

An alternative could be to check out engine A so as to keep the box and other bits with their original engine but the possibility that the crankshaft is damaged concerns me.

What is the experts advice ( other than don't waste time on old technology!!)

Thanks in advance

 

[reeac]

What it comes down to is the certainty that you need to carry out major work on engine A but with the compensation that the gearbox etc come with that engine versus the probably lesser amount of rebuild required for engine B but with the need to transfer the gearbox plus marinisation bits. Marginally the latter sounds a better bet.

 

[pcatterall]

Thanks reeac. A lot of the marinization bits will come off for refurbing but I take the point that it may be better to refit them to that engine. I probably have enough parts to rebuild engine B as well but only to sell on.
I hope to be able to set up a 'test bed' so as to be sure the engine(s) are working ok before transplanting to the boat or selling on.
Thanks again

 

[DownWest]

Having had a couple of these in non marine applications, along with sorting a couple on boats, my thoughts:
Strip engine A and find out how good the bores and pistons are. Then strip B and do similar. Grinding a crank and fitting new bearings is not too bad. Pistons and rings a bit more expensive and, when I had one damaged bore out of limits, there was no oversize set, so I had the defective cylinder sleeved and machined back to standard. It was actually quite cheap, but not in UK.
So, take the best block and fit the best C/head, then the marinisation with the kit you have. Put what is left on e-bay and probably some canal boat user will be pleased.
If you have trouble with the raw water pump, the bearing is difficult and not supplied by normal agents. But I found it for little money on a French bearing site. Way cheaper than a new pump for circa £350.

Incidently, the engine I worked on in a Swan, came from a Challenger Tank as an APU. They are still available with very low hours..

 

[Deleted member 36384]

Strip both engines down. Using the parts manual and the workshop manual select all the good bits by careful dimension checking and compatibility. Replace every bearing, o ring, gasket, including bushings. Ream all new bushings. Reassemble using old and new parts. Anything less will probably not give the service life you want.