Babbitt vs Inserts

[hardtimes]

Originally Posted by 1929

what has the better advantage? is it true that with babbitts the head should be no more then a 5.5. If you are going to rebuild your motor, why not go with inserts even if it costs more.

Hey 1929,
Excellent question, to which there is a lot to consider when making choice. For example, I have a B block that was machined for inserted mains. Then new high end inserted rods were added. I did it this way, for what I considered...the loong run idea. That is, I envisioned running across the USA, to Alaska, etc..and wanted an engine that would give no trouble doing that. Now , you do not have to run full oil pressure to run inserts or badditted rods/mains, but for durability (look to modern engines longevity) , I decided to go to full pressure WITH full oil filtration ! Clean oil is the key, IMO, either way you go. I'm now building another B block with poured battitt both mains/rods, but again with full oil filtration system. I'm expecting the babbitted mains/rods to perform perfectly , if perfectly done ! That's a mouthful these days, that is , getting perfectly done Babbitt job, for reasons already stated-vs- buying modern inserts which are factory made and where the best machining/assembling IS the key. As you go along this information trail, you will see that the more perfection that you want (either way) will cost you more money. Someone said, put the money in your pocket, where the heck was he many years ago ! When the 'bug' to go farther, smoother, faster hits you...this quest can be a bottomless $ pit, eh !
I say done correctly BOTH can and have been used successfully, even at higher RPM. Do either wrong, and you will end up wishing that you had done the other 'correctly'...maybe.

BTW you can use full pressure with babbitted rods. You just have to block of stock oil holes in rods, and get crank shaft that is drilled for full pressure AND do a number of other 'things' to accomplish the job.
I recommend that you obtain/study a book by a member here (Jim B), as it will help explain a lot of how to and why/why not questions/answers.

I do not think that on a 'good engine', that high compression ratio of head has detrimental effect. Just more power to be gained if tuned right and run with complimentary equipment, i.e.- cam/carb/exhaust, etc. I've run 8:1 on a sturdy B with positive results.