Looking for a little advice here. I know a guy that has a 51 chevy pickup with a 235 inline 6 in it. He claims that when he had it apart years ago, he noticed a cam bearing that was slightly loose and he was afraid it would spin with the engine running. He put it all back together and hasn't run it since. I bought some parts from the guy and noticed he had a mill/drill/lathe combination machine sitting around not really being used. I expressed some interest in it and he said he really didn't use it that much and would consider selling it. I am thinking about offering to fix the cam bearing issue (loctite 620 and maybe a few center punches around the bearing to hold it tight) in trade for the machine. I really just need to know how difficult it will be to get to it, mostly can it be done with the engine still in the truck? I'm thinking if this is something I can wrap up in a weekend it would be worth it. Thanks in advance for your wisdom.
You got a lot to learn about motors son, but that particular avenue isn't the place to start. Advice; Don't experiment on other people's motors.
Okay, apparently I have alot to learn about motors, so you tell me. How do you hold a round bearing in a slightly larger round hole. And before you have an aneurism, the owner is looking for a very low buck solution, i.e. NOT pulling the motor, reaming it out and installing an oversize bushing. After all, if he wanted to go that route the truck wouldn't have been stored in his garage for the last ten years! This guy is looking to get his truck running so he can use it to haul hay around his few acres, not to be his daily driver. By the way, it's really not experimenting if you've done it before with good success, I just haven't done it on this motor and my question was really all about access. Thanks for the vote of confidence 6, it seems like some folks have forgotten that there's plenty of old tricks out there that may not sound kosher to someone with an engineering degree but they sure did the trick to keep a lot of the precious old iron we covet out of the crusher.....btw dad, didn't know you were a HAMBer, how's mom?
access is a real problem. the timing cover cant come off unless the pan is off - the bolts for the timing cover come from inside the pan. In order to get to it, the engine is going to likely hit the engine stand.
Im 98% sure you gotta pull it.... And even if im wrong, i would think it would be waaaaay easier to do out of the truck. Seems odd the dude would have it out and apart, not like it, yet still put it back in the truck, then not want it pulled to fix it.
Somebody may be able to add more detail, but I think the cam bearings are a light press fit. If one was loose, either the block or bearing is worn from one spinning or the bearing was the wrong size. Apparently he didn't put in new ones.
Thanks alot 6, that's the kind of wisdom I was looking for. And for those that doubt the integrity of that repair, consider this. Loctite 620 is a high temperature , large gap anaerobic adhesive that is good to 450 F, with up to .015" gap. You take the loose bearing out, clean and degrease it thoroughly, rough up the OD with emory cloth, do the same to the ID of the block with a few rags to catch any debris. Wipe both surfaces with a lint free rag with a little acetone on it, apply just enough loctite to coat the OD and ID making sure it doesn't run all over the place. Reinstall the bearing, a pipe cleaner works well to absorb any excess loctite from the oiling hole, and let it cure for 24-48 hours. Loctite 620 yields a shear strength bond of @3800 psi. The surface area of the bond in this instance is probably 2 to 3 square inches, so the bond could be as strong as 7600 lbs, more than enough holding force to overcome the 2-3 inch pounds of rotational force exerted by the cam, probably less with good oil pressure. Any doubters can come hear my '55 Ford 850 tractor run, did that repair to it over ten years ago, and she's still running strong. Thanks again for the advice 6, if I go into it knowing I need to pull it, it'll be that much easier.
yea, didn't ask why he just put it back together, said he was in college at the time, probably no money and didn't know any other way to fix it
Well first off measure the OD of the old bearing, if it is less than it should be try a new one. Me I would just turn up a OS OD replacement on the lathe out of either aluminum or 660 bearing brass. Of course I have the equipment and knowledge to do it. But in any case upside down on the stand.
This is not your standard parts store red or blue Loctite. It is Loctite 620, it is made for securing bearings with a slip fit OD. This is not a repair I would do when rebuilding an engine, but to get an old farm truck running, I mean come on guys!!!Here is a link to the product specs http://www.henkelna.com/cps/rde/xch...tredDotUID=productfinder&redDotUID=0000000M7T
I'm kind of curious how you came up with 2-3 inch pounds torque (not force) exerted by the cam? That means the coefficient of friction of a plain bearing is around .01-.02? Interesting!
While we are on the 235 cam bearing subject, I have a McGurk cam for a 216, and would like to run it in my '55 truck 235 motor, any suggestions on some spacer bearings? or should i just get someone to make them? any takers?...
torque is the tendency of a force to rotate an object around an axis, in this case that object would be the cam bearing and the axis would be the centerline of the cam. So yes, torque...
I think your going to have a tuff time getting around the area you need to to get a sucessful job.. but, ive seen crazier shit work.. and as you said there have been many things done out in the field , where the engineers would fear to tread, let alone get their boots and hands dirty.. give it a shot and report back. im still thinking to even get at it right , its going to have to come out of the truck, than go from there Im not a 235 Guru...but i did stay at a holiday inn....,,once
I'm betting it could be done in a weekend,but it might kick your ass. sounds like you have youth and enthusiasm on your side though... pull the radiator,distributor,and fuel pump. remove the timing cover,side cover,valve cover,and oil pan. loosen the rocker stand bolts enough to pull the pushrods,then remove the lifters. then see if there's enough room to pull the cam out. if there is,you're golden I've repaired numerous things using that particular Loctite and a few well placed centerpunches.
Well this should tell you what needs to be done to get to the cam bearings. Got a bit of work there. Dom
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