Club Cobra - Phosphor Bronze lifter bores

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Phosphor Bronze lifter bores

While this is not strictly an FE question... If one had the option between plain lifter bores & those that have phosphor bronze inserts, what would be the advantages or disadvantages? (Less friction? Shorter life?) Are the bushings a press fit? Is there any trick to replacing these? Are there standard sizes or are they custom made to the application?

Any info would be greatly appreciated.:)
Bill

I have heard of phosphor/bronze valve stem inserts, because this is a dry lube environment, but never heard of phosphor/bronze lifter bore inserts. Are you shure you got this right ????

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I have run the sleeves you speak of

I have run the sleeves you describe in my 427 BBC that is being replaced right now for other reasons.

The reason I installed them was to correct the lifter bore alignment errors intrinsic in factory block machining. It allowed me to square the lifter to the cam as well as locate the bores correctly for proper indexing. I felt this accuracy improvement was needed in order to run the high RPMs I needed from the "little" 427 motor (shift point was 7400 RPM).

The sleeves are pressed and require the overbore to correctly compliment the sleeve OD. There should be no disadvantage in life. If your oiling system is working correctly, there should be only minor (not detectible) reduction in friction. They can be more forgiving if you get a piece of trash in the bore.

Whether they are an advantage to you is more likely a function of your engine's intended operating regime associated with the requirement for correct valvetrain geometry - unless FEs have inherent oiling problems in the lifter area, then the sleeves may reduce the tendency to gall during operation. Someone else can speak to any specific FE issues.

That is all.

I found this little article on the "Hot Rod" web site:

Lifter Bores

Lifter-bore problems are rare because most engine designs provide plenty of pressurized oil to prevent excessive wear. When a used block has seen service in a racing application, some engine builders enlarge the lifter bores and install bronze bushings to restrict the flow of oil to the valvetrain so that more of it gets to the crankshaft. This practice is viable in certain racing applications, but on the street it often causes rapid valvetrain wear. If you spot bronze bushings in the lifter bores of a used block, move to the next candidate.

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CobraED,

It is much, much more common to use a screw-in oiling restrictor (they are much cheaper to achieve the same goal) to restrict top-end oiling.

Lifter bore sleeves are most commonly used to repair bores damaged during lifter failure. Second most common use is to produce correct valvetrain geometry as I described above.

If you look in the sleeve, you can determine the size of the cross-drilled oil hole. Easy way to tell if the sleeves were installed for restriction purposes.

I think you are right. I did a google search and found that article. It seems not to be the norm though.

My Pond block came equipped with the prettiest set of bronze bushed lifter bores that I ever saw.. I consider them a big plus-up from the machined aluminum lifter bores.

My Genesis block was equipped with them and I got to thinking about what this meant to performance, life, repare, replacement, etc. Thanks for all the info!
Bill

Bill,

Cast or alloy?