Help me design a 350

Discussion in 'Small Block Tech' started by vonhef, Jun 24, 2018.

  1. Jim Blackwood

    Jim Blackwood Well-Known Member

    I'd like to add, grind your main seal journal to the proper size and smoothness for the new neoprene seal. The existing journal is too big, has hash marks, and WILL LEAK if you don't. A Redi-sleeve on the damper may work, but check the specs for the seal, as turning the journal down may be the better option there too.

    On my 340 with all the oiling mods and the stock factory oil pump I get better than 30 psi @ 1500 rpm thoroughly warmed up using 5w20 Mobil-1 oil. You can't expect to do any better than that. The suction galley is at 9/16", all corners are radiused and the pump cover is lightly ported and smoothed.

    Jim
     
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  2. 300sbb_overkill

    300sbb_overkill Well-Known Member

    Do you remember what you set your engine's oil clearances at?
     
  3. Jim Blackwood

    Jim Blackwood Well-Known Member

    My target was .001 to .0015" I think it came in midrange. No special treatment of lifters or rockers (shaft oiled). TA booster plate (ported), TA front cam bearing, cam bearings oiled at 3 o'clock, V6 pickup. Relief spring gives ~50psi. I think that's everything... I did lightly break the corners on the oil pump gears, just enough to see.

    Jim
     
  4. vonhef

    vonhef Member

    413 Cam? Nope... not a good idle and I don't want a stall converter. I went with new rods because the price to purchase isn't much higher than reconditioning the originals and adding new bolts.
     
  5. Jim Blackwood

    Jim Blackwood Well-Known Member

    Is there a forged crank available? (I'm asking for a customer who has a bug about it.)

    Jim
     
  6. alec296

    alec296 i need another buick

    You will need new valve springs for the new cam.
     
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  7. vonhef

    vonhef Member

    Good point! I hope the new heads are available by the time I am ready for heads
     
  8. sean Buick 76

    sean Buick 76 Buick Nut Staff Member

    No forged crack available but King makes a billet crank for us.
     

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  9. vonhef

    vonhef Member

    what is the max clearance I should see on the main bearings & rod bearings? The salesman at TA said they recommend .0022” on both...
     
  10. OddfireV6

    OddfireV6 Member

    The "official" Buick specifications depend on where you look. Buick (and GM in general) were not very consistent about their published clearance or torque specifications. However, most GM sources say 0.0005" to 0.0015" of main and rod bearing clearance is recommended with 0.002" being the maximum. So....tight. It's hard to build an engine that tight because most machine shops to not grind and polish the crankshaft journals precisely enough to allow for really tight clearances. They allow too much taper and oval in the journals to run them tighter than about 0.0015". Half a thousandth of taper or oval is no big deal when you are running 0.0020" clearance, but it is a huge deal when you are trying to run 0.0010" clearance! The tighter the clearance, the more precise they must be.

    I can tell you from experience that running a Buick at 0.0015"-0.0020" on all bearings will give you 10 PSI @ 600 RPM and 35 PSI @2500 RPM or higher fully warmed up with 10W30 with no oiling mods.
     
  11. 300sbb_overkill

    300sbb_overkill Well-Known Member

    You need to find a different crank grinder, it sounds like "they" are hacks! Even a mediocre crank grinder shop should be able to hold .0002" roundness and the same taper! A good shop will be even closer.
     
  12. GSJim

    GSJim Founders Club Member

    I built a 350 for my Convert back when Poston was still alive. I bought 8- V6 Hyper pistons for it. They were advertised at 10:1 comp. I put in a 118 cam. Ported the heads and exhaust manifolds. I port matched the exhaust ports to the manifolds. Opened up the end of the manifold as much as I could. I couldn't find any headers to fit my project. So I bought the TA 350- 2 1/2 " down pipes. They worked very well. I used the stock intake manifold and ported it out. I also used a re-jetted 800 QJ. Electric fans and a bunch of other little stuff that really added up. 200-4R trans and a 3:55 posi rear. That car would really move. I suprized a lot of Chebbys with it. If you take your time with your engine and do it right you will be very happy with the results. The Buick 350 has a lot going for it and will respond for you if you take care of all the little things that make it GO.

    Jim (Ponch)
     
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  13. GSJim

    GSJim Founders Club Member

    I still have a new Crower cam for my 350 that I never used. The part number is 50259 and another part number on the cam card is 68405. Grind number 284HDP. I dont know which One to use.The spacs are Int duration: 284* at 512 lift. Exhaust: 290* at 522 lift. These are with a 1.6 Rocker Ratio on the card. The R.R on a 350 being 1.55 brings the specs down to 496 intake lift and 505 Exhaust lift with a 6* overlap which is the kind of overlap I like. No shaking the emblems off the car.

    I'd like to get 50 bux for it plus shipping if you're interested. I live in Linden, MI. 48451.
     
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  14. vonhef

    vonhef Member

    Thank you for this precise and thoughtful response. Just a few questions about your build:
    - Is your engine stock or something a bit more performance oriented?
    - If non stock, what horespower would you say it is?

    The reason I ask, is the machine shop I am using... while I believe a very good machine shop, has no experience with Buick performance builds and he expressed concern about running tight main bearing clearances.
     
  15. OddfireV6

    OddfireV6 Member

    It's a stock 231 odd fire making all of 105 net horsepower that pushes my 3600 pound badge-engineered Nova 0-60 in 17 seconds....15 if I preload the torque converter.
     
  16. vonhef

    vonhef Member

    My block is still in the machine shop having some work done on it.
    The Roller cam & Lifters have come in from TA! I noticed that for the big blocks use a "button" for the roller cams, is there any prep work or add-on items I will need to use for this roller cam in my 350?
     

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  17. Mart

    Mart '71 350 GS, almost stock

    Check your crank throw to roller cam lobe clearance, possibly cam to rods if you have aftermarkets. You will need a cam button of sorts. TA can set you up.
     
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