Anyone ever changed the main and rod bearings with the motor still in the car without pulling the crank out i have been told people do this but just wanted to see if anyone here has done this? its on a ford 302 that lost oil pressure but only at an idle.
Yep same prob on a 351W . Mains wore ,loosened all the main caps and rolled in a new set of bearings. Do that job on HD diesel truck engines as regular maintance.
im going to get a new motor but i want a temp fix for now i want to drive it the rest of the summer! so i think im just going to swap them out from under the car.
I have done it on a big truck,,, nothing to it... Rods are easy enough, Mains are "rolled" out and then "rolled" in by sticking a small pin or machine screw in the oil hole in the crankshaft and turning the crank to push the insert... Just have to be mindfull of the bearing tang... It is as easy as it sounds...
I've done it on a 59A motor installing a new thrust bearing. It went another 20K after that. Go for it!
Yes. my auto teacher and i have attemted thid on a jeep because they are so easy to change but the right way to do it is to take it all apart and have your crankshaft remachined. Not always but in some cases even though you change the bearings it will still loose pressure due to the improfections. Sometimes you can get away with it though but i suggest doing it the right way the first time and it willl save you a lot of headache in the future.
It's kind of a pain in the neck, literally, compared to having a nice clean engine flipped upside down in front of you. But, it's pretty straight forward and besides, what have you got to lose?
So long as a person has good access to the engine it is not hard, and I am sure it can be done for less than $200 in parts,, gaskets and all. Provided you don't find a journal really f-ed up, it will probably extend the life of the engine some. You will need to loosen all of the mains to get the clearance you need. The tranny holding the crank up was not an issue when I did this. you just need a little room like maybe 1/16th" or less... get a machine screw that will fit the oil hole well and not hit the crank journal. Be mindful of the bearing tang, it wont go around the crank, the tang needs to be "first side out" and "last side in"...
The method listed in the old books has you using a cotter pin inserted into the oil hole and both tangs bent opposite. I'd file any sharp edges off the tangs, too. Cosmo
Absolutely. I "rebuilt" my 327 this way when I was a kid. My Dad watched over me, told me to pull the mains and rods, dunk the new bearings in motor oil, and spin 'em in. Pulled the pistons, put on new rings by hand, walking them around the pistons. Used a hone on an electric dril, and ran all the bores. Bought a new budget gasket kit from the local parts place, and drove that 67 Impala for years. Was my first car that Dad tought me about tools and motors on. No fancy motor hoists or machine shops. Just hand tools and new parts. Things don't always have to be perfect. Good luck, Pete.
Mains and Rod bearings won't solve your oil pressure problem. I did the same thing for a 302 that I bought in a box-replaced the mains and rod bearings and the oil pressure still hovered between 0 and 10 lbs. The problem was (and prolly is for you, too) cam bearings. Having said that, I ran that engine in a '56 F100 for three years with that oil pressure with no problems.
well i got good oil pressure when i first start the car but when the car gets up to temp the oil pressure is dropping out i just went out there to mess with it and found this out!
The real problem may lie in the oil pump. Put in a new one and an oil filter and the problem may be solved.
but if it was the pump why would it work good when its cold and when the oil gets hot and thin i lose pressure?
If your crank is still standard (has never been turned) look into a set of 0.001 or 0.002 undersize bearings (for smaller than stock dia.) this might give even better results than just putting in a standard set. Cranks that have a lot of miles and have been subjected to infrequent oil changes (or non at all) are usually a a couple of thousands undersize just from running in a gritty environment. Just a thought that might make an even more dramatic pressure difference than replacing with standard size. Frank
Pull a main or 2 mike the lower shell and see how much wear is there. More than .002 thiner will lead to low pressure. Funny thing is the uppers wear very little. Ya need to do a bit of looking to get a better handle on what the problem really is.
While you are under there, pull the oil pump and see how badly worn it is. If it's still good enough to get by with, try shimming the pressure relief spring with 2 or 3 washers. Also put in a new pump drive shaft while you are under there. It's a weak point on those engines. I had one twist up like a corkscrew before it broke. Also if things are really sludged up, you may wear out your new bearings quickly, when some of this stuff gets pumped through them. But for the price of the bearings, a pan gasket and a pump drive shaft, I'd give it a shot. Good Luck!
thats a good idea about the washers man thanks i got a new shaft and i was planning on cleaning everything out real good thanks for your help!
"They" make a plastic "T" like piece that fits into the oil holes then just rotate the crank to move the shells out. It's better because it's plastic and won't scratch the crank like a bolt or cotter pin could. A couple of bucks at a parts jobber good piece of mind.
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