Please forgive all the questions, but I am a Big Block Mopar guy in a Slant Six world here.
Is there any advantage to using full groove main bearings on a slant? It is common to use them on the big block. At one time, you either had to get two sets or find a set of Marine bearings to do it. Now, they are easy to get. I really haven't seen this with the 225 engine.
-Matt

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-MattMan
LEANED & MEAN

As far as I know you need to buy two sets to get the second half of the bearing.

I have spoken to a couple racers about this. Some have tried it both ways and have seen no difference in wear and failures.

Others swear that you should use full grooves.

When I spoke to Mike last, he recommended it for the two center mains and not the outer two. The two center mains feed two rods each, so they can use a little more oil on those mains.

So it has been done all different ways. I still do not know what I am going to do with my engine.

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2 Mopars come with Spark plug tubes. One is a world class, racing machine. The other is a 426 CI. boat anchor!

12.70 @ 104.6

I have never used them. Oo, good idea about the 2 center ones to give enough oil to 2+3 and 4+5 rods, though.

Lou

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Home of Slant6-powered fun machines since 1988

its easier to just 0.050" X 0.050" groove the mains on the crank and run stock shells.

i have done both with modified lower shells - It gets expensive after a while to always buy 2 sets of bearings.

One Trip to the machine shop and groove is in the crank forever until you break it.

Others just use a lead in groove on the bottom shells.


Greg

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http://www.youtube.com/hyperpack

Wouldn't grooving the crank make it weaker? I figure I could groove the bearing itself with a dremel. What's the worst that could happen?
-Matt

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-MattMan
LEANED & MEAN

I always use full groove mains. Whan I first started running slants I did have some rod bearing problems. Never had a problem when running stock eliminator, but did once I started hopping it up. At first I used two sets of bearings, and cut a new notch in the cap (never liked Mopars sugestion of filling down the tab,as it could crush the bearing if even slightly high). Now being the cheapskate I am, I cut a groove in the lower shell with a cutoff wheel in a die grinder. It is not fancy or neat, but works for me. Have not had a bearing problem since 1978.

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Charrlie_S
65 Valiant 100 2dr post 170 turbo
66 Valiant Signet 170 nitrous
64 Valiant Signet
64 Valiant 4dr 170
64 Valiant 4dr 225

Well, if it is good enough for Charlie, it is good enough for me.
Thanks,
-Matt

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-MattMan
LEANED & MEAN

the groove is minimal only, only 0.050" X 0.050"

People with 10 Second turbo slants have done this without weakining the crank.


Greg

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http://www.youtube.com/hyperpack

Ok, good to know.

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-MattMan
LEANED & MEAN

You could also consider cross drilling the main journals, i've done it many times.

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There's no such thing as too much cam....only not enough engine!

Charlie, do you tape up the bearing to keep it clean? and how do you clean up the edge left by the cut off wheel? I think you already told me but I forget!

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2 Mopars come with Spark plug tubes. One is a world class, racing machine. The other is a 426 CI. boat anchor!

12.70 @ 104.6

I tried to run full grove mains on a cast crank and suffered major bearing failure. To this day I am not sure why. When I reassembled the engine i used the standard bearings and have not had a problem.

The groves in the top half of the bearing and the holes in the crank are set up to send oil to the rod that needs it at that time. The lower bearing slightly cups under torque. In my opinion all that is needed is to champ her crank oil holes. I have not torn up a crank since I stopped messing with the bearings (7000 rpm every gear every pass). That said I have broken every other part of the motor.
Will

[quote]I have not torn up a crank since I stopped messing with the bearings (7000 rpm every gear every pass).[quote]

Very interesting Will!

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2 Mopars come with Spark plug tubes. One is a world class, racing machine. The other is a 426 CI. boat anchor!

12.70 @ 104.6

I chamfer the Crank oil holes quite a bit as well.

That helps a bunch.


Greg

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http://www.youtube.com/hyperpack