1.850" rod bearings

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donclark
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1.850" rod bearings

Post by donclark »

Looking at rod bearings for a new build, 1.850" journals. Mahle lists two bearings, the differences I can see is the 1664 is 0.100" narrower @ 0.655" and 0.032" larger OD than the 1798. Both are available with 0.001" extra clearance if required. Anyone have experience with either of these bearings? Application is drag racing, aluminum rods. I'm leaning towards the 1664 as it is narrow and thus lighter with less drag.
clshore
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Re: 1.850" rod bearings

Post by clshore »

#1 What rods are you using?
The 1664 fits a housing bore of 2.008"
The 1798 fits a housing bore of 1.976"
Which do you have?
Or are you going to rework the rods?

#2 Exactly how wide is the flat portion of your rod crank journal.
Not side to side, I'm talking about the flat portion between the fillets on each side?
If you have the room, the wider bearing will support a higher load than the narrow one.

The weight difference is really, really slight.
The load bearing difference is at least 10% more for the 1798.

Carter
donclark
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Re: 1.850" rod bearings

Post by donclark »

clshore wrote: Tue Apr 24, 2018 10:04 am #1 What rods are you using?
The 1664 fits a housing bore of 2.008"
The 1798 fits a housing bore of 1.976"
Which do you have?
Or are you going to rework the rods?

#2 Exactly how wide is the flat portion of your rod crank journal.
Not side to side, I'm talking about the flat portion between the fillets on each side?
If you have the room, the wider bearing will support a higher load than the narrow one.

The weight difference is really, really slight.
The load bearing difference is at least 10% more for the 1798.

Carter
Rods have not yet been ordered, journal width is 1.625", plenty of room for the 1798 bearing. This is a normally aspirated deal, max power around 900, engine rpm 10k, just because it's fun.
clshore
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Re: 1.850" rod bearings

Post by clshore »

Then ignore whatever minuscule weight difference there may be, and choose the bearing that's compatible with the best rod choice.
B Original
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Re: 1.850" rod bearings

Post by B Original »

This subject is just On The Fringe of my comfort zone of knowledge so I am interested. From my limited understanding in this area on a small block Chevrolet shouldn't narrow bearing and connecting rod be for a piston pin guided Rod instead of a crankshaft thrust design rod
Warp Speed
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Re: 1.850" rod bearings

Post by Warp Speed »

You can run a narrow bearing in a standard width rod and lose a little friction. As long as you are not overpowering the bearing area or uncovering a feed hole.
user-30257

Re: 1.850" rod bearings

Post by user-30257 »

donclark wrote: Tue Apr 24, 2018 10:34 am
clshore wrote: Tue Apr 24, 2018 10:04 am #1 What rods are you using?
The 1664 fits a housing bore of 2.008"
The 1798 fits a housing bore of 1.976"
Which do you have?
Or are you going to rework the rods?

#2 Exactly how wide is the flat portion of your rod crank journal.
Not side to side, I'm talking about the flat portion between the fillets on each side?
If you have the room, the wider bearing will support a higher load than the narrow one.

The weight difference is really, really slight.
The load bearing difference is at least 10% more for the 1798.

Carter
Rods have not yet been ordered, journal width is 1.625", plenty of room for the 1798 bearing. This is a normally aspirated deal, max power around 900, engine rpm 10k, just because it's fun.
How about the oiling system?
donclark
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Re: 1.850" rod bearings

Post by donclark »

Headguy wrote: Tue Apr 24, 2018 1:55 pm
donclark wrote: Tue Apr 24, 2018 10:34 am
clshore wrote: Tue Apr 24, 2018 10:04 am #1 What rods are you using?
The 1664 fits a housing bore of 2.008"
The 1798 fits a housing bore of 1.976"
Which do you have?
Or are you going to rework the rods?

#2 Exactly how wide is the flat portion of your rod crank journal.
Not side to side, I'm talking about the flat portion between the fillets on each side?
If you have the room, the wider bearing will support a higher load than the narrow one.

The weight difference is really, really slight.
The load bearing difference is at least 10% more for the 1798.

Carter
Rods have not yet been ordered, journal width is 1.625", plenty of room for the 1798 bearing. This is a normally aspirated deal, max power around 900, engine rpm 10k, just because it's fun.
How about the oiling system?
Six stage dry sump.
user-17438

Re: 1.850" rod bearings

Post by user-17438 »

donclark wrote: Tue Apr 24, 2018 10:34 am
clshore wrote: Tue Apr 24, 2018 10:04 am #1 What rods are you using?
The 1664 fits a housing bore of 2.008"
The 1798 fits a housing bore of 1.976"
Which do you have?
Or are you going to rework the rods?

#2 Exactly how wide is the flat portion of your rod crank journal.
Not side to side, I'm talking about the flat portion between the fillets on each side?
If you have the room, the wider bearing will support a higher load than the narrow one.

The weight difference is really, really slight.
The load bearing difference is at least 10% more for the 1798.

Carter
Rods have not yet been ordered, journal width is 1.625", plenty of room for the 1798 bearing. This is a normally aspirated deal, max power around 900, engine rpm 10k, just because it's fun.
If you have a set width. Just call up Pankl, Lentz whoever you choose, give them the width, included radii, journal and purpose. No sense in over thinking this. Are you using guided pistons etc.

Don't run huge bearing clearances please.
donclark
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Re: 1.850" rod bearings

Post by donclark »

MTENGINES wrote: Tue Apr 24, 2018 2:43 pm
donclark wrote: Tue Apr 24, 2018 10:34 am
clshore wrote: Tue Apr 24, 2018 10:04 am #1 What rods are you using?
The 1664 fits a housing bore of 2.008"
The 1798 fits a housing bore of 1.976"
Which do you have?
Or are you going to rework the rods?

#2 Exactly how wide is the flat portion of your rod crank journal.
Not side to side, I'm talking about the flat portion between the fillets on each side?
If you have the room, the wider bearing will support a higher load than the narrow one.

The weight difference is really, really slight.
The load bearing difference is at least 10% more for the 1798.

Carter
Rods have not yet been ordered, journal width is 1.625", plenty of room for the 1798 bearing. This is a normally aspirated deal, max power around 900, engine rpm 10k, just because it's fun.
If you have a set width. Just call up Pankl, Lentz whoever you choose, give them the width, included radii, journal and purpose. No sense in over thinking this. Are you using guided pistons etc.

Don't run huge bearing clearances please.
GRP did not have a preference.
Not using guided pistons.
With that size journal, I'm thinking 0.002-0.0023"
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