Grooved bearings

Discussion in 'Street/strip 400/430/455' started by ohioscott, Mar 5, 2020.

  1. ohioscott

    ohioscott Well-Known Member

    I have an engine that was built in the 90s. Had all the best at that time. Heads are ported. Oil upgrade.lifter galley epoxies. HEMIkiller cam. Engine runs great. Where grooved bearings available then ??. If not should I take a good running engine apart to install grooved bearings???
     
  2. 1973gs

    1973gs Well-Known Member

  3. Bens99gtp

    Bens99gtp Well-Known Member

    I wouldn't
     
  4. Mark Demko

    Mark Demko Well-Known Member

    In the 80's I remember Kenne Bell touting grooved main bearings in their catalog saying it saves the expense of cross drilling the crank (it does) and provides additional oiling to the rods (maybe)
    BUT, it does reduce the lower bearing half's load carrying ability due to the groove, you now have two narrow surfaces instead of one wider one.
    That reason is exactly why for years, I've had the groove on the #1 cam journal spray welded closed, and either groove the block or use TA's grooved #1 cam bearing.
    If your engine runs good, leave it be:D
     
  5. ohioscott

    ohioscott Well-Known Member

    Thanks guys
     
  6. Rodney Byrd

    Rodney Byrd Torque

    I ran the Kenne Bell fully grooved bearings back in the day and used my last set (.010" u/s) in our nostalgia front engine dragster 462". I was a believer in HV oil pumps with bronze distributor gear and full groove bearings but upon teardown of the rail engine to upgrade (flat top pistons better connecting rods, bigger camshaft and ported heads), I was a little dismayed at front cam bearing wear. The mains (and rods) looked PERFECT though and I was planning on reusing them. I think I'm going to go with a new timing cover and regular gears this time, as some of my logic for using a HV pump and thrust plate, etc. was to crutch gear pocket wear. With the standard volume gears I think I'm going to go with Federal Mogul 3/4 groove mains, but I'm still not scared of the KBs.
     
  7. Tom Righter

    Tom Righter Well-Known Member

    I believe you would be better off grooving the saddles and then adding two extra oil holes in the bearings. Doing This modification there’s a lot less oil Bleed off
     

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  8. No Lift

    No Lift Platinum Level Contributor

    I'm still wondering which grooved bearings the OP was talking about. No matter which ones I would agree that if the engine is running good with good oil pressure there is no reason to pull an engine apart.

    I ran the KB fully grooved bearings back in the '80's and they were done on some kind of cutting machine to groove the lower half so it wasn't as big as the top groove. They are meant to supply oil to the rod bearings for 360* of rotation. I found that although my oil pressure dropped slightly at idle the main and rod bearings looked great after use. IMO the only way you stress the load bearing capacity of the lower bearing(with groove) is by making BIG power which will actually stress the main webbing right out of the block before the bearing goes(requiring a girdle).

    Rodney, I would think the biggest problem with the dragster running a HV pump is almost every start is a cold start. I would continue to run the thrust plate which just increases the oil pump's efficiency. I'd also run a distributer gear oiler. I've run cam/distributer gears that got worn with an oiler and had no more wear develop in the gears.
     
    Rodney Byrd likes this.
  9. Tom Righter

    Tom Righter Well-Known Member

    Also make sure the front cam bearing is driven in .125 past flush the front of the block, this is a overlooked install of the cam bearing that causes distributor gear wearing because the oil doesn’t get to the gear. Of course also running the proper viscosity oil and making sure it is up to temp I’ve never had issues with distributor gear wear, and when I take the distributor out there’s always oil dripping off of it.
     
    Rodney Byrd likes this.
  10. Rodney Byrd

    Rodney Byrd Torque

    I have the gear oiler (copper tube aimed at the gears off the t/c cover pressure passage), and the bronze gear looked fairly good. I only ran 10w-30 oil and had the adjustable regulator set for 60lb above 3000rpm hot, I can't remember where it was cold, but it wasn't 100 like my big block MoPar wedges are-LOL. We had a Poston GS105A cam in it (cackle-cackle!), so it idled over 1000rpm.
     
  11. 87GN_70GS

    87GN_70GS Well-Known Member

    Mid 90s is about when Federal Mogul started their 3/4 grooved mains. Clevites were 1/2 grooved
     
  12. Rob Ross

    Rob Ross Well-Known Member

    I switched to fully grooved mains (1-4) on my current engine and oil pressure is more stable that it was without them. PM if you want to know how to get a set.
     
    71GS455N25 and kenny t like this.

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