How to increase BBB engine longevity!

Discussion in 'Race 400/430/455' started by Staged70Lark, Aug 31, 2005.

  1. Staged70Lark

    Staged70Lark Well-Known Member

    Guys and Gals,

    I would like to start a thread that talks about some modifications that can be done to increase the life expectancy of our engines.

    Please give any and all ideas..... The most important areas of concern for me are the rod and main bearings and how we feed oil to those areas. Some of this information has been covered in other threads but maybe more can be added.

    Lets start with the engine block itself. Stopping the main caps from moving around is the first and most important part of building our engines. As you can see in the picture I have used chrome moly tubing to pin my main caps to the block. As the crank forces the center of the caps downward they have a tendency to pinch inward at the parting line. This can reduce the amount of oil moving through the main bearings and into the rods. The cost of this modification is maybe $150. I would do this on any engine that is going to be line honed. That is with or without an engine girdle.

    Attached Files:

  2. Staged70Lark

    Staged70Lark Well-Known Member

    As you can see in the above picture, there are two additional oil holes in the bearings!!

    If you compare the BBB main bearing to just about any other main bearing out there, you will find the BBB has a very small oil groove. This is bad since our oil comes down from the passenger side lifter galley, through the main bearing, into the crankshaft and then into the rod journal. As we increase the RPM of these engines its important to increase the volume of oil to the rod bearings.

    In the picture below you will see a machine oil groove in the block that lines up with the two additional oil holes in the main bearings. This modification will increase the volume of oil to the main and rod bearings. I dont know what a machine shop would charge to do this modification but I wouldn't build a 500 hp engine without it. Its very cheap insurance.

    Attached Files:

  3. jmccart

    jmccart John McCarthy

    Totally awesome. Please share more of these great ideas. I was recently reading the tech for oil mods (at Buick Performance Group). It says you should drill from the sender to the #1 cam journal, but stop before going all the way through. I also remember reading this may no longer be considered the best way to do it. Keep good tech coming, I am going to print it out for my next project.
  4. Davis

    Davis Moderator

    This is exactly the kind of how to I am looking for. The pics help a bunch also.
  5. Staged70Lark

    Staged70Lark Well-Known Member

    I hope this information helps everyone!!!! I want to start this thread by saying.... These mods should be done by a skilled machinist!!!!

    Since we are still on the subject of rod and main bearing oiling I want to discuss clearances.

    This is an area where you will find many different opinions. I dont build to many street engines so I cant say that the following information applies to street cars. But.... if you have oil volume and a race engine spins to 6500+ rpms then it should work on the street. :Do No:

    Bearing manufacturers suggest clearances be run at .001 for every inch of journal diameter...

    Example.... 2.250 rod journal equals .00225 rod journal bearing clearance.
    Example.....3.250 main journal should have .00325 bearing clearance.
    The above rod clearancesare for a steel connecting rod.

    Below are the clearances for aluminum rods.
    A minimum of .003"-.0035" bearing clearance for Import and Small Block motors. Rod journals of 1.888 to 2.100
    A minimum of .0035"-.004" bearing clearance for Big Block motors. Rod journals of 2.100 to 2.250.

    When rods are being used in a supercharged or heavy nitrous motor, increase clearance by at least .001"

    Some will say these clearances are to large for a BB Buick. I say they are correct if there have been no oil modifications. If the oil mods have made then there should be NO issues running these clearnances.

    After you have the block and rods completed then its time to send the crankshaft out to have it ground. Insist upon this happening!!!! Have your machinist assemble the mains with bearings and the rods with bearings. Then have him measure the actual bore of EVERY main journal and EVERY rod journal. After this information is obtained then minus your disired clearances and have the crank ground to those EXACT specs. ANY GOOD crank grinder and put it right on the money.

    I am not a writer guys and gals so I hope you can follow message I am trying to convey.

  6. jmccart

    jmccart John McCarthy

    Are you installing the maincaps w/bearings, giving them proper torque, and them measuring the I.D?


    Keep the great info & photos coming.
  7. 72GSX

    72GSX Well-Known Member

    I used to work in a engine machine shop and I would see alot of the higher performance 4 cylinder engines would have the same oiling setup on the main bearings. I have wondered many times if this setup would work in a big Buick motor so I guess that answer is yes :beer I also have seen alot of motors with the pinned mains.

    With these mods and a little looser bearing clearance will the standard size oil pump keep up or does it take the high volume pump? John, what are your feelings on oil weight? Do you like the thinner stuff like 10-30 or the thicker like 20-50. I have been running the 10-30 mobile1 but my bearings are on the tighter side with a stock size pump with a booster plate and white spring. This is a great tread coming from someone with John's know how on the BBB. :TU: Tom
  8. texas ranger

    texas ranger One riot one ranger

    John thanks for this info on block mods well over due. :TU:
    I have 3 questions for you. 1) Is it mandatory that you internaly balance the engine to survive shifting it at 7000 rpm. 2) Would eagle H beams be too heavy for this or aluminum the way to go. 3) With these mods and a good extra capacity oil pan and TA timing cover. would all the extra lines running to the back of the motor to balance oil pressure be needed or external pumps? I'm told the new line of though is to restrict the amount of oil that goes to the top of the engine to keep more going to the mains.

    I hope you dont mind me posting these but these are some closer pic of this mod that you do. I took on my trip to TA to get my heads.

    Attached Files:

  9. texas ranger

    texas ranger One riot one ranger

    One more.

    Attached Files:


    JEFF STRUBE Well-Known Member

    First the Main bearing bores need to be checked.If the block doesn't need to be line honed. Install bearing with no Crank and torque to spec. Then take a dial bore Gauge measure all the bearing bores record the reading'sThen take your crank to the Crank grinder with the main bearing spec's that you got when you Measure the mains with the bearings. He can grind the crank for the proper clearances. I can see a street motor living with bearing clearances that loose for very long. My be a Race Motor with a Dry Sump or a Big External Pump with lot's of oil Pressure and thick oil.
  11. jadebird

    jadebird Well-Known Member

    I could be wrong, but I think the idea is to get the volume up to the rods in conjunction with opening up the clearances. If you didn't have the extra oiling holes in the main bearing, then it might starve the rods for oil (bleed off pressure). With the volume increased and oiling the rods at 3 locations instead of one, that problem is eliminated. This mod makes a lot of sense to me since we see so many motors that have come apart as a result of rod bearing failure due to lack of oiling. My question is, do you have to use a deeper oil pan to keep oil on the pickup when moving so much more volume?
    The idea of so much pressure is a bad work-around for the problem at hand. It only increases cavitation and makes the oil that gets to the bearings less effective. The best solution is the one that gets the most volume to the right places with the least pressure, which seems to be what John is doing. This is only my opinion, of course.
    All I know is that John and Stan make a lot of power, and have very few motor problems. I'm listening to what they say!
    Last edited: Apr 26, 2011
  12. Staged70Lark

    Staged70Lark Well-Known Member


    Some questions I will answer... others I may not get to because I will try to talk about it later.


    Yes... install the bearings... torque to proper specs then measure the housing bores. THIS IS THE ONLY WAY to make sure your bearing clearance are exactly what you want.


    The stock pump gears are more then enough to supply the volume for our engines. I will try to discuss what modifications are needed to get the oil from the gears to the rod and main bearings as we move forward.

    I am still a 25/50 Pennzoil High Performance racing oil guy. But I will say there are MANY people running the lighter weight oils. I just dont have the courage to change yet.


    Thanks for posting those pictures. I was given this idea by Mike at T/A. So I give him the credit for this idea. I believe.... Mike can correct me if I am wrong.... this idea was given to Mike from Dennis Manner. Dennis was the designer and engineer of your 455s. He said this mod alone should double the volume of oil to the rods. I am sure he is able to figure this out mathematically.
    This picture you posted is a much nicer job than I can do with my hand made tools. I would like for everyone to notice how Mike has made a radius where the main oil feed hole to the oil groove. When working on your oiling system its a GOOD idea to do this to EVERY AREA WHERE OIL HAS TO TURN. Get in there somehow and get rid of sharp edges. This will cost very little to do and has great benefits.


    When installing a girdle or just adding the locating dowl pins the engine should be line honed. Thanks for adding that to the thread. If the block is line honed then the housing bores should all be the same but YES... they should be checked anyway.


    Long time no talk to!!!
    I was running the larger clearances without the extra oil holes. But I did increase oil volume in other areas. And there is a delicate balance between Hi Volume and low pressure and Hi volume and Hi pressure. If your going to run high volume hi pressure then you had better make sure you have a pan that holds a great deal of extra oil. But there are issues with too much oil in the pan and creating foam. We will try to hit on that later.

    Thanks guys for adding to this thread. Lets keep this engines running and kicking some brand X @$$.


    JEFF STRUBE Well-Known Member

    I just put that up because so you can have the crankshaft ground for the Right clearances. Because we can not get one over or under bearing. Like all the other Race engine's out there that have +or- bearing you can get. So you can get your clearances where you want them. Also a nother thing to look at is if we had a Cast iron oil pump housing like the Mopar's have are oiling wouldn't be as big as a problem. Aluminum oil pump housing was not a very good idea. Question for Buick Racing Family how many oil pump housing have you been threw. We have had many. What happens to Aluminum when it's hot it expands. They are almost always getting tore up in the Pump housing bore by the steel oil pump gear's. A few mark's in the oil pump housing and we are changing cover's
  14. john hixon

    john hixon Well-Known Member

    grooves or no grooves...

    Looks like a new debate in regards to block integrity for the oil groove mod.

    What's the Weise, Burek, Earick, Evans, Guadagno, and Ketchum opnions here?

    It's a shame this thread isn't seeing more action/activity.

    --Not a way to attract new potential recruits for the racing scene.

  15. armyguy298

    armyguy298 Well-Known Member

    Jeff- you can get a .001 over bearing. I picked mine up from TA Perf. I dont think a lot of folks ask for them though.
  16. 69GSCAL

    69GSCAL Well-Known Member

    How do these mods (extra holes and groove) affect oil pressure and volume received by lifters/ rockers?
    I would assume you'd absolutely have to have a booster plate in place to keep from starving you valvetrain of oil with these mods?
  17. Staged70Lark

    Staged70Lark Well-Known Member


    Thanks for posting the link to that thread. Its very interesting to say the least. The machine shop that I use had given me the idea to put the oil groove in the bearing itself. He said the top bearing doesn't see any loads therefore it wouldn't be a problem, but I wasn't to sold on the idea.


    Typically I like to reduce the amount of oil going to lifters and up. Unfortunately we Buick guys feed our crank from the passanger side oil galley that is directly connected to the passanger side lifters, therefore you cannot limit the oil to the passanger side oil galley. But I do put an oil restrictor on the drivers side oil galley. I remove the plug in the front of the oil galley on the passanger side. There is a step (or counter bore) that tapers down and is the correct size for a 1/4 or 3/8 pipe thread. I dont remember the exact size. I tap and insert a pipe plug that has a 1/8 to 3/16 hole drilled in the center of the plug. This will allow enough volume of oil to the lifters, pushrods and rocker arms. The restrictions eliminates massive oil hemmoraging at the lifter bores and pushes that oil downward to the crank where its needed.

  18. jmccart

    jmccart John McCarthy

    Wow. That thing you said about restricting the galley is very interesting. How far in is this tapered down part of the galley that you tap & insert the plug w/a hole in it?
    Great info, thank you.
  19. Staged70Lark

    Staged70Lark Well-Known Member

    Attached is a picture of how the Oldsmobile guys feed there lifters, pushrods and rocker arms.

    Attached Files:

  20. 69GSCAL

    69GSCAL Well-Known Member

    Restricting the oil to the lifters doesn't make a whole lot of sense to me if you were using hydraulic lifters. But I suspect most of you guys with the sub 9 sec cars are running solid lifters in which case I could see it.

    That Olds block is pretty trick. :TU:


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