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RE: Big End Advise Please - Mark McKibbin - 02-09-2017
(01-09-2017, 04:02 PM)Ruairidh Dunford Wrote: Tod knows the set up well - he gave it to me! Prior to that I scraped and blued as he describes.
The height is set up using cones and an adjuster underneath, everything is then locked in place. Cones shown below:
The cones make lots of sense, I was wondering how. Setup time would be minimal. I suppose you could do the same thing with one cone on a mill to centralise it.
(01-09-2017, 01:39 PM)Tod Wrote: Mark,
Mark,
Over the years I have overhauled a fair number of Engines mainly small to medium Diesels (1 to 8 cyl). I have only come across a "shimmed" big end once it was on a medium sized Ruston Engine. It did not seem a "Bodge" repair as the shims were fitted correctly and shaped accordingly. I know it was common practice to shim plain bearings on many other applications.
What thickness is the shim ? If it is only a few thou. it may be worth considering discarding the shim and scraping the bearing to fit the shaft.
When I fitted a Pheonix C/Shaft to my engine I made a mandril crankshaft size less 0.0005" and had it hardened & ground. I scraped all the rods to this and then finally scraped them to the New Crankshaft so the rod just fell under it's own weight when tightened. For what it is worth, my preference is to use a small 3square (triangular) scraper to do this. Always keep it sharp, giving it a wee rub up on a fine oil stone now and again, and don't try and use it blunt.
Tod,
I was hoping to avoid removing the crank if possible so would it be possible to install the rods so they stuck out of the sump with the engine on its side then check how they fall that way?
RE: Big End Advise Please - Tod - 02-09-2017
Mark, Yes that could be done I think, although I have not tried it. It might be a bit difficult to tighten up the bolts and you could not rotate the rod through 180 degrees. An interesting question though!
RE: Big End Advise Please - Dave Wortley - 02-09-2017
R,
Little end bolt locking using spring washers is supposed to be not good practice according to the website boltscience.com. I wrote about rebuilding an engine and installing a Phoenix crank recently in the PWA7C newsletter and one reader pointed out afterwards that spring washers promote loosening of the little end bolt and referred to the above website. I have been using springwashers and loctite for the little ends for a long time but perhaps I had better just use loctite from now on.
Cheers,
Dave.
RE: Big End Advise Please - Ruairidh Dunford - 02-09-2017
I have been using the same combination as you Dave.
It works fine in my experience so I think I shall stick with it, not keen to change and discover somebody else was wrong!
RE: Big End Advise Please - Dave Wortley - 02-09-2017
R,
The next time I rebuild an engine and get round to little end screw locking I will re-read the bolt science article carefully and then make the decision to use or not use spring washers with
loctite.
Dave.
RE: Big End Advise Please - Ruairidh Dunford - 02-09-2017
Cool.
RE: Big End Advise Please - Ian Williams - 02-09-2017
Just to add weight to the Dave and Ruairidh Loctite spring washer argument I have also used this method on numerous engines over the years and I am not aware of any failures. However we may be retaining the bolts through the Loctite rather than the spring washer, I use Loctite alone to retain Flywheel and Camshaft nuts with complete success.
The above said I don't personally believe that the spring washers are a bad idea, in my experience they appear to reduce loose fixings elsewhere on my cars
RE: Big End Advise Please - Ruairidh Dunford - 02-09-2017
I also ditched tab washers years ago in favour of loctite Ian, seems to work for me too.
RE: Big End Advise Please - Ian Sly - 03-09-2017
(02-09-2017, 10:13 PM)Ruairidh Dunford Wrote: I also ditched tab washers years ago in favour of loctite Ian, seems to work for me too.
I have used shakeproof washers on the little ends of an engine that has been regularly "thrashed". No loctite, just crossed fingers!
RE: Big End Advise Please - Ruairidh Dunford - 03-09-2017
Cool.