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I decided on Durabond 0-6B back-grooved cam bearings while my 350 block was at the shop. I had those installed with the supply hole at the 3 o'clock position when facing the front of the block. I have now noticed that bearing positions 2 and 4 have non-threaded thru-holes above the bearings, which looks like an opportunity to lose oil pressure. I suspect I need to plug these. Any suggestions?
Last edited by 68 D88; February 26th, 2024 at 10:06 AM.
Reason: clarification
The holes were used on the 330s and very early 350s to anchor the splash shield when using the multi-part metal intake gasket. The holes are blocked by the non-grooved bearings. You'll need to tap and plug them for grooved back bearings.
That's what I was thinking Joe. Correct flemming442, an "error in procedure" no doubt. It looks like I have a 1/4" depth to the bearing. Perhaps a couple of taps, regular and bottoming, set screws, and loctite will work out if I'm careful. I'll report back.
While a tapped hole and setscrew would be preferred, you could probably get away with a freeze plug hammered into place in each hole. These are what, 1/4" holes? At 100 psi oil pressure that's five lbs of force pushing the plug out.
Joe, they're 3/16" which I also see listed on your link. Mark, the machine shop. I think know what you're gonna say, and if so I agree. They should've caught this prior to installing the bearing.
Joe, they're 3/16" which I also see listed on your link. Mark, the machine shop. I think know what you're gonna say, and if so I agree. They should've caught this prior to installing the bearing.
How were they supposed to know that you were not going to use the shield with the hammer in rivets ???? Jeeeeeze . . . its always the machine shops fault
Joe, so at 100 psi and 3/16" holes, plugs should see 2.76 lbs. With a smidge of red loctite and the plugs, I should be good.
Green Loctite for plugs.
Personally I would turn it upside down and tap it for whatever size small set screw will fit. Tap it just far enough to get a few threads to hold. Do it dry and a shop vac and some brake clean from the other side will get any residue out.
Mark, the machine shop. I think know what you're gonna say, and if so I agree. They should've caught this prior to installing the bearing.
Yep. I’d tell them to remove the cam bearings so you can tap it. Then they need to reinstall new ones on 2 and 4.
Great attention to detail with that shop. I’d run the other way.
Yep. I’d tell them to remove the cam bearings so you can tap it. Then they need to reinstall new ones on 2 and 4.
Great attention to detail with that shop. I’d run the other way.
Mark,
I dont think that is fair in any way shape or form. Every Ford small block since 1985 or so has had those holes and they get a screw in them. How do you expect anybody to know that about every engine built for the last 50 years ????? Was there a note in with the cam bearings telling them that ? I certainly would not have known it ? Does that make me a shop that people need to "run the other way" from ?
I suppose you know every little detail about every single engine made for the last 75 years or so ???
Mark,
I dont think that is fair in any way shape or form. Every Ford small block since 1985 or so has had those holes and they get a screw in them. How do you expect anybody to know that about every engine built for the last 50 years ????? Was there a note in with the cam bearings telling them that ? I certainly would not have known it ? Does that make me a shop that people need to "run the other way" from ?
I suppose you know every little detail about every single engine made for the last 75 years or so ???
Give me a break.
Nobody picks up on everything, very true. But you don’t think this is really an obvious potential problem? At the very least, could they admit they’ve never seen these before and maybe try to contact someone who has? I think that’s one of the few good things about the internet right?
But case in point, I had never done a diesel build before 8-10 years ago. The front cam bearing is grooved on the inside to flow oil thru another hole to the fuel pump bushings. It took me 2 seconds to realize, that with a pump no longer in there, that it would leak oil thru it in great quantities.
Like my old shop teacher used to say, “look past the end of your nose.”
Just sayin.
Last edited by cutlassefi; February 27th, 2024 at 05:45 AM.
To summarize: the best way is to remove the bearings, tap the holes, and use screw in plugs. It could probably be done assembled, but there's a good chance debris could get into the oil groove, which will exit right into the bearing oil wedge. While the numbers may point to a miniscule pressure load, I don't like the idea of things glued into areas where the item(s) coming loose lead to catastrophic failure. Sure, gluing a plug in might work for a very long time, but if it fails, you lose oil pressure and something is ping-ponging around in the block. I'd start over.
I finally worked up the nerve to do something myself with this. The holes were approximately 0.201" D, and a #7 drill bit fit the holes closely. I ground the point off a new 1/4-20 tap, turned the block slightly more than 90 degrees, and proceeded carefully. Every 3/4 advance of the tap, I backed off and vacuum the hole, watching the thread depth carefully. I stopped cutting perhaps 2-1/2 threads distance from the bearing (third pic shows that well). I finished the thread cut with a bottoming tap, maintaining the 2-1/2 thread distance from the bearings. Vacuumed it, sprayed brake clean from the bottom, and applied compressed air. I think all is good. I never touched the bearing. I then ground the taper from the ends of 1/4-20 set screws so as not to touch the bearing when tightened. I'll finish it with some loctite or JB epoxy as mentioned above. Then I had some beer!
Good job !!! I would not bother with any JB weld etc. I would worry about it coming off in the future. If you put some loctite on the setscrews that's all you need. Even if they leak a little around the threads (it wont) it will be insignificant.
Use JB weld and only install them finger tight. If you tighten them too tight, you could distort the casting enough to pinch the cam bearing. It’s very thin there
February 26th, 2024, 10:04 AM
