hey guys,need the help of the experts.Rebuilding a 235 from a 54 power glide to put in my 50 Belair.Got it torn down,cyl walls look good,pistons good .However, main bearings&rod bearings and rings are showing some wear.Previous owner said engine was supposedly redone 30k ago .Question,How do u guys suggest I go about getting correct ring and bearing size,not knowing true history of engine?Also should I go ahead and replace oil pump while it is down.Like many,working on a budget .Thanks in advance&any other suggestions are appreciated.
Well there is a thread that I posted last eyar that is called teardown and inspection that gives a few tips for the novice. Otherwise if you look at the bearings on the back side the undersize will be stamped on there. You can also look at the crank if it has been tuned it will normally have the undersize stamped on it, often it will be dated and or signed bu the machinsist. The pistons will have the over sice stamped on the top as a rule, something like .020 or .030 and etc. Now if you want to do it right and not just a scab it together job, get yourself a manual or find the specs on the engine. Get some micrometers and snap gauges or inside mics and start measuring. I have run my piston to wall clearance as much as .0030 but idealy you are going to want something in the .0015-.0008 range with a cast piston. Your ring gap is going to want to be somewhere in the .0070 range as a rule. If you are setiting up and engine that is on the loose side you are best off to get file to fint rings and file them to th correct ring gap. If you lowere end is on the outer end of spec or loose you want a new pump and preferable a high volumn pump. Donot take the specs that I have given you as gospel they are just standard rule of thumb specs. Find the proper specs either on line or in a manual.
Thanks Porknbeaner.Main bearings have stamped 76w4 on back side and gmma 8541 under that.no Simpson piston just casting # on inside=3835996.Rod bearings stamp fm1950 cp 74.Havent checked crank for marking yet.Headcasting is B29 918 241 670.what do u think?
Except for the Federal Mogul rod bearings (apparently standard size), main brgs. and pistons appear to be factory parts. Also standard size, I would guess. Like porknbeaner said, get everything measured and post your findings and we can give you a better idea of what you need to do. Of course, if you go to a reputable machine shop to have stuff checked out, they will steer you in the right direction.
I would do what 54nomore said in his last sentence. box everything up and haul it to a good automotive machine shop, one that's got a gray beard or two milling about, and have them "mic" everything out, including cylinder wear and taper. They can make recommendations from there and even supply all the parts you'll need if you want.
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