Main Bearings

[dereklola]

Red for Christmas!

My main journals measure 2.4996.
Clevite book lists range as 2.4990/2.5000.
Am I OK with Std size bearings?
Does ACL still make .001 undersize? (couldn't get through to them today)
- or does anyone still have any .001 undersize bearings to sell me?

Engine is an Indy Lights type (non-turb0) used for vintage enduro races (typically 90 minutes)
so engine gets used continuously at 6000-7000 for those 90 minutes.

Do I assume most of you recommend the 'NASCAR' MS960H or MS960V rather than the standard MS960P?

Thx - Derek

 

[Alky V6]

I've had good results with Federal Mogul CH series bearings.

 

[dereklola]

I've had good results with Federal Mogul CH series bearings.

Thx Donnie - I'll bear that in mind.
But I was more concerned about sizes.
Derek

 

[Alky V6]

Where in the range are your main saddle diameters at? I assume an iron block?

 

[Squid4life]

I've had good results with Federal Mogul CH series bearings.

Bringing this back up as I collect small stuff for my build. Donnie, are you talking about the 7118 CH? I am looking for these in .001, as that is what I pulled from the block. You have a line on someone who sells them? Quick internet search turned up nada, including Summit...

 

[Alky V6]

Bringing this back up as I collect small stuff for my build. Donnie, are you talking about the 7118 CH? I am looking for these in .001, as that is what I pulled from the block. You have a line on someone who sells them? Quick internet search turned up nada, including Summit...

I sourced mine from TA Performance. The last set I got from them, they were talking like the .001 were going to be discontinued.

 

[Squid4life]

I sourced mine from TA Performance. The last set I got from them, they were talking like the .001 were going to be discontinued.

Donnie, are they in fact the 7118CH you run?

 

[Alky V6]

Donnie, are they in fact the 7118CH you run?

I will try to remember to check that for you tomorrow.

 

[Alky V6]

Checked and they're 7116 CH and 7117 CH and 7118 CH.

 

[turbodave231]

The FM 107 set is in fact the Std size "CH" bearing set. They are one of the only Tri-metal main sets still available in .001 US. Summit sells both Std and .001 size. I just bought several sets. The Summit part number is SLP-107M for the Std and SLP-107M1 for the .001 US. Mike at TA sells the 107M bearings for around $100 a set. Summit gets $81 and change.

Derek, first I would measure the main bores to be sure they are within the 2.6870-2.6880 tolerance. Try to keep the main bores closer to the 2.687. It gives better bearing crush and will translate into slightly tighter bearing clearances. I would start with a Standard set of bearings. If the clearance is more than you expect, you can use one half of a .001 shell to take .0005" clearance out. If needed you can use both halves in combo with STD bearings in other positions to get exactly the clearances you want. I have several broken sets of 107M1 .001 US. bearings if you need some help.

Try to stay away from turning the crank .010 unless there is no other way to fix the crank. If the journals look good and are not out of round or tapered, Use them as is and fit the bearings to the crank.

Worst case.......you can have the crank journals hard chromed and reground back to any STD dimension you want. I can help you with a local supplier who can do this for you. In fact, I have a crank out for hard chroming right now.
Hard chrome is a common process for aircraft crankshafts. The new surface is very durable.

 

[Alky V6]

Glad to hear they're still available.

 

[dereklola]

Derek, first I would measure the main bores to be sure they are within the 2.6870-2.6880 tolerance. Try to keep the main bores closer to the 2.687. It gives better bearing crush and will translate into slightly tighter bearing clearances. I would start with a Standard set of bearings. If the clearance is more than you expect, you can use one half of a .001 shell to take .0005" clearance out. If needed you can use both halves in combo with STD bearings in other positions to get exactly the clearances you want. I have several broken sets of 107M1 .001 US. bearings if you need some help.

Try to stay away from turning the crank .010 unless there is no other way to fix the crank. If the journals look good and are not out of round or tapered, Use them as is and fit the bearings to the crank.

Worst case.......you can have the crank journals hard chromed and reground back to any STD dimension you want. I can help you with a local supplier who can do this for you. In fact, I have a crank out for hard chroming right now. Hard chrome is a common process for aircraft crankshafts. The new surface is very durable.

First an apology - I started the subject and then disappeared - I thought I was getting emails for any replies - apparently not - however here I am now.

David - mucho appreciato - I'm more or less on that track. I ended up with Clevite bearings. Used MS-960P mains (that's their Passenger car standard since MS-960H Heavy Duty is no longer made and apparently not needed) and CB-1398H for rods (where the H is recommended and available). In both cases I needed and used Std size and had them coated by Calico. Thx also for the 'hard chrome not .010 under' recommendation.

Thx everyone else also for your information - how did we ever live without the internet? Derek