Buick 350 Shortblock build

Discussion in 'Small Block Tech' started by DauntlessSB92, Jul 20, 2014.

  1. DauntlessSB92

    DauntlessSB92 Addicted to Buick

    I appreciate the thought though Derek. I've enjoyed building the engine and learning all about it. I just wish I had a more supportive machine shop whose work i didnt have to double check throughout the process.

    Believe it or not my stock motor before I took it out was around 260hp to the wheels and that was a low compression 72 motor. So as long as there are no major hiccups with this build I am hopeful for a decent amount of power. It has the single plane intake, it will have efi, full roller valve train and oversize valves. Not to mention it's at zero deck and a true 8.5:1 compression. I don't think I'll chassis dyno the car but I think some sort of mid to hi 13 second quarter mile time would be enough evidence of success for me.
     
  2. Gary Farmer

    Gary Farmer "The Paradigm Shifter"


    I believe you. People way underestimate the stock engine because it's worn out/out of tune, etc. Get one running good and it will surprise you! Even the low comp ones. Hell even the low comp factory engines ran mid-high 14's in an A body car. Hit it with a 150 shot of nitrous and it's in the 12's. This is fact.

    Gary
     
  3. DauntlessSB92

    DauntlessSB92 Addicted to Buick

    Surprised everyone that was in the car. I consistently ran low 14s and I was probably new valvesprings and a good ignition system away from 13s. It was a very low mile motor for its age so that helped too
     
  4. Gary Farmer

    Gary Farmer "The Paradigm Shifter"

    My '68 Lesabre ran low 15's all day long @90 MPH with the ST300 and 2.93 gears! It didn't even shift out of low until the 1/4 was almost over lol.

    Quarter mile runs were not its strongsuit. It was a top end car, cruising at 120 on Qjet primaries with little effort.

    If it had better gearing for 1/4 mile runs, I have no doubt it would have been in the low-mid 14's and it was a B body Lesabre outweighing the Skylark by about 500-700 or so lbs. The power that stock Buick 350-4 had was surreal. Many people thought it was a big block.

    It certainly left a lasting impression on me and my friends back then, and even to this day. Quiet memorable.

    There was another guy in town who had a '69 Skylark with the ST300 (last year they used them, I believe. Optional TH350 (which was just coming out) or the ST300). He said that car was so fast it scared him. Same drivetrain as my Lesabre only in a lighter car.

    Not saying ~300 hp is ooh ahh vs all the 500+ hp machines, but hey back in the day it was very impressive for a stocker. There's more to it than raw HP, as anyone who's owned a good running Buick 350 can attest.


    Gary
     
  5. DauntlessSB92

    DauntlessSB92 Addicted to Buick

    Dealt with more problems over the past month. Found a piston that was chipped as I was installing the rings. So I ended up ordering a new piston and having the weight matched to the damaged piston. Turns out the previous made the same mistake I did and installed the rods the wrong direction so the felt they needed to add clearance into the piston so the balance pad wouldn't contact it. The JE pistons unmodified are perfectly symmetrical and can be installed any direction. I sure am learning what not to do while building an engine.

    Bottom end is finally all together now though and I've temporarily installed the heads so I can begin to check pushrod length. I installed the rockers with the Arp studs and made sure the heads were correctly milled for clearance. Lifters are in and feel to move freely in the lifter bore without sticking or binding. With the timing set installed at 0* there is no interference between the cam and crank but its definitely fairly close. I feel a few degrees from there and I'll definitely have interference. Obviously I'll have to degree the cam still but definitely wanted to make sure there are no obvious issues first being that I am using a roller cam.

    I also ordered the fuel injection kit today. 8 coils, 8 66lb injectors and the required harnesses. I can begin to make that work once the longblock is done. The challenge with the fuel injection will certainly be figuring out how to mount a crank sensor and allow adjustment to it if needed and I'll have to figure out a way to mount the coil packs. I've thought to make a bracket that mounts over top of the valve covers using the valve cover bolts.

    What method do you guys use for pushrod length checking? I have a TA checking tool but was told it could be too long for my application. Will I need to install lighter weight checking valve springs? 12310568_10205218400048860_2349197805767394335_n.jpg 12342518_10205226553412689_27233419220848366_n.jpg 12299110_10205219533877205_2587151715855528729_n.jpg 5658_10205377487785954_3633123076176197800_n.jpg 534115_10205377486825930_3948238669234703798_n.jpg 1456530_10205377487305942_8713667668654281027_n.jpg
     
  6. 8ad-f85

    8ad-f85 Well-Known Member

    Sorry about the problems you are experiencing! Sounds like that shop is going through the same learning curve you are.
    Not that it matters now, but do you suspect that chip was caused by it slipping from their piston vise when they milled more clearance?
    It would be really hard NOT to notice that happening.
    If so, you think they thought it would be OK to slide that by you?
    I can see the logic of an impending discussion to suggest that the rings affected are still supported, but only after showing you the chip and offering solutions.
    If I'm mistaken on which build this is...it's hard to keep some threads straight from others :)

    It's very easy to change a spring pair out using compressed air (at TDC) vs risking the damage.
    I'm not familiar with their tool though.
    Be sure to have it at true TDC and don't leave a bar on the crank, ask me how I know lol.

    Are you using minimum sweep and contact pattern placement or mid-lift geometry?
     
  7. DauntlessSB92

    DauntlessSB92 Addicted to Buick

    It's hard to place blame on who damaged the piston. It's been moved around so much and been to two different machine shops. I know the piston was technically okay to use based on that damage but it still bothered me. $150 for a new piston is cheap insurance compared to how much I've spent on this motor.

    I know very well about making sure you have a bar on the crank haha when I was in A&P school we got a demonstration of checking leakdown on an aircraft piston engine. The instructor let go of the prop and we watched it make a good 2 or 3 revolutions. Definitely would have hurt to be in the way of that.

    So I know nothing about how to get correct geometry. All I know is that ideally you want the adjustment screw to be flush with the rocker and for the pattern to be centered on the valve tip throughout its travel.

    As far as springs, I can just use 2" springs with .875 diameter? That's what it seems all the cam companies like crane and crower sell so I can just pick that up at a hardware store.

    Also as an additional note, the valve job done on these heads is certainly sub par. So I almost guarantee I'll be using a few different length Pushrods to get the geometry correct unfortunately
     
  8. 8ad-f85

    8ad-f85 Well-Known Member

    Your geometry shouldn't be too far off from the seat depths varying a bit. Might as well use the adjusters to take up the slack, if not too far.
    Keep in mind on a 20tpi thread 1 full turn is .050". Your VJ and seat depth shouldn't vary THAT much.
    You could check the deepest vs the shallowest one's geometry.

    Your particular build will let you know which method is feasible.
    The mid-lift way is rotating the crank until the lifter is 1/2 way up it's lobe, setting the valve at 1/2 lift (with some type of fixture) and attempting to use the pushrod length to position the rocker contact points 90* to the valve stem. In theory, you are centering the arc around the 90*.
    It's much tougher to do than playing with the contact pattern placement and sweep.
    You're not running 9000 rpms, so...you should be fine with contact pattern.

    I wouldn't use the piston either.
    I'd be more worried how distorted the set could have become if pins were pressed out a few times. Tough to measure though.
    Damage still looks like from slipping out of a piston vise or being dropped onto a corner or something.
     
  9. DauntlessSB92

    DauntlessSB92 Addicted to Buick

    So I think I have a better grasp on this but let me run my thought process through and see if it makes sense.

    First being that these rockers are shaft mounted and not stud mounted it seems to me that geometry should not vary too much and that since I'm starting from scratch my main concern is getting the correct length pushrod that will limit over adjustment on the roller rocker.

    To further explain this point: TA states that to adjust the rockers you find 0 lash and then add in 1/2 to 1 and 1/2 turns (roughly .030 to .060" of preload) and that should be the correct adjustment. In addition to this you should be able to have your preload without having more than 1 thread from the adjuster screw protruding below the rocker.

    Now I am not sure what the importance is of having only one thread below the rocker (ideally it states the adjustment should be flush) but again since I am starting from scratch the adjustment should not be an issue.

    So what I assume I have to do is get all the rocker adjusters to the same point, ideally maybe 1 turn from flush. Then put my pushrod checking tool in and extend until I reach 0 lash. That should be my correct pushrod length. Because then at that point I would use the rockers to get my preload adjustment.

    My main concern has been that I do not want to order a set of pushrods and then find that I cannot safely adjust my preload with the rockers. Its been very confusing for me to get this all straight since everyone has a different way of doing this. I've always been a manual guy but obviously our motors never had valve train adjustment so I can't use that as a starting point. I just have TAs instructions to make sure there is no more than 1 thread below the rocker.

    By the way I did check my contact pattern after setting my pushrod length with the tool and it was dead center on the valve tip.

    Having done only one intake and exhaust valve so far it seems I need a 9.000 pushrod for the exhaust and a 8.975 intake. I don't even know if TA stocks pushrods in those lengths. Closest I saw for 455 (they don't show lengths they stock for 350) is 8.900 and 9.175 which is much too far off I would imagine.

    I have checking springs installed where I was checking pushrod length but it seems that too isn't necessary if I don't need to check contact pattern on each valve. Of course i could be totally wrong about pushrods not having a large effect on valve train geometry on shaft rockers.
     
  10. 8ad-f85

    8ad-f85 Well-Known Member

    Check the valves in which the stems protrude the most vs. the least.
    You mentioned inconsistent valve job.

    I like to start off knowing the decks are parallel and the rocker mounting surfaces are the same heights from the head surface.
    They can be off a long ways on other makes but a quick check saves a surprise.
     
  11. Thumper (aka greatscat)

    Thumper (aka greatscat) Well-Known Member

    I can get .080"wall pushrods at 9.00" and 8.975" for you within a week .
    gary
     
  12. DauntlessSB92

    DauntlessSB92 Addicted to Buick

    So here is the final verdict on pushrods. The right cylinder head (2,4,6,8) all measured at 8.950" adding in .050 preload that puts me at 9.000" for pushrods. The left head (1,3,5,7) had all the intake pushrods at 9.000 with preload added and the exhaust pushrods measured at 9.025 except for cylinder 7 which measured at 9.0375 for the exhaust.

    These measurements were taken with the rocker adjusters flush with the base of the rocker and the checking tool was adjusted to 0 lash.

    If my newly found knowledge of pushrod and valve train geometry serves me right, I technically could just add a half turn of adjustment on the exhaust valves to make up for the shorter than necessary pushrod. This would still be less than the 1 thread protrusion that TA reccommends is the limit of safe adjustment before affecting geometry.

    Or should I split hairs and order the 5 longer 9.025 pushrods and then 11 9.000 pushrods. I guess my decision depends on availability.

    TA already said when I called a couple weeks ago that they will not sell a mixed set of pushrods unless they have a set that's already broken up.

    Gary if you aren't able to do the 5 longer pushrods I'm still interested in a full set of 9.000" 5/16 .080" wall hardened pushrods.


    More progress pictures and some pics of my efi kit[​IMG][​IMG][​IMG][​IMG][​IMG][​IMG]
     
  13. DauntlessSB92

    DauntlessSB92 Addicted to Buick

    I'm also starting to get really curious what this motor will make power wise. I want to be overly optimistic and say 350 crank horsepower but I'm sure I won't get that far. Anyone good with a desktop dyno?

    8.5:1 compression, stock port heads with stage one valves. Full roller valve train. Cam is 270/270 (advertised) .545 lift on 113 lsa. Multiport sequential fire fuel injection. Single plane intake. 1 5/8" headers. This was built as a turbo motor so I keep worrying it will be a dog without boost. It seems I'll be spending this season turboless until I can scrape together some turbo money
     
  14. 300sbb_overkill

    300sbb_overkill WWG1WGA. MAGA


    What is the duration @ .050", that would be more helpful than the advertised duration and you'll get closer guesses. If Gary jumped in with his dyno program he would need more cam specs to run a simulation.

    Anyway you should be close to 300 HP because with the advertised duration being 270 the duration at .050" shouldn't be that radical unless that is a solid roller cam? With the duration @ .050" on the mild side that will allow the cylinders to fill up more with a power band more on the down low side which should feel good for the street.






    Derek
     
  15. 8ad-f85

    8ad-f85 Well-Known Member

    Is it possible to order all of them a smidge long and put the adjuster screws IN 1 turn further w/o interference?
    What does it do if you adjust your pushrod long and cycle it?
     
  16. DauntlessSB92

    DauntlessSB92 Addicted to Buick

    Duration at .050 is 212 I think Mike at TA figured that the smaller cam would make more power down low off boost. After doing my own research months later I realized I probably could have gone a decent amount bigger on the cam and still been fine once I went forced induction
     
  17. DauntlessSB92

    DauntlessSB92 Addicted to Buick

    TAs instructions state that the adjuster should not be more than 1 thread from flush in either direction. So that doesn't give too much room for adjustment but it's enough to make up for .025 I'm sure. I checked the pattern with different length pushrods and noticed no real difference. Being that the fulcrum is at the same place no matter what length the pushrod is I think that's why the geometry is relatively fixed
     
  18. 8ad-f85

    8ad-f85 Well-Known Member

    I wasn't referring to the geometry at this point, just if you dialed in a longer p-rod would it hit stuff as it rotated through the lift cycle?
    Seems like you could get away with slightly longer p-rods and have it safely covered, with the dimensions you listed.

    Or would it be possible to shim up the short side to match the long side?
    How about take down the long side with a ball end mill, assuming the dimensions observed from the other head support the logic?
     
  19. DauntlessSB92

    DauntlessSB92 Addicted to Buick

    I don't think a longer pushrod would hit anything but in the same thought the 9.000 pushrod would also safely cover everything

    The real issue is that it's just the exhaust valves that require the longer pushrods because the seats have slightly sunk. The original machine shop took it upon themselves to decide this is acceptable instead of asking me what I wanted to do about it.

    Im comfortable going with the complete set of 9.000 pushrods. It will only take a half turn of the adjuster to keep the 5 affected lifters at the right preload. If I was spinning 7000 rpm or had a crazy cam with high lift and high spring pressure I would definitely do what I could to correct the issue instead of saying it's good enough. I think this will be fine as is though. I hope to have the new aluminum heads next winter too so any small wear patterns that may develop on the 5 valves with the rockers that have the adjusters turned in a little more wouldn't be too bad.

    I could be totally wrong thinking this way. That's why I try to think out loud in this thread so guys with way way more experience can offer their advice. I really do appreciate all the help
     
  20. 8ad-f85

    8ad-f85 Well-Known Member

    Just a couple of comments,
    Unless specs, tolerances, and corrective machining are discussed beforehand, they generally aren't going to get partway through cutting a head on a seat machine and then call for permission or customer's preferred spec limits when something doesn't clean up.
    If it's on the machine...it's getting cut.
    You can tell before it goes on the machine if a seat is trashed beyond the range of the lifter's preload. It's visually obvious and the questions would come up early, such as the costs of new seats or any other concerns they had.
    It wouldn't be normal for them to do otherwise. They typically go by AERA or similar specs, and I'm guessing what they did would be considered quite normal.
    This has little to do with being "Buick knowledgeable" or "performance oriented".
    I'm not defending them, BTW. I expect better also. Those concerns need to be communicated up front.

    Valves aren't very consistent regarding margin thickness. It would be an easy solution to move the thick and thinner ones around some to even things out.
    Then you wouldn't have to take a risky amount off the tips of the valves, if that was in the cards.
    I can tell you that it's very time consuming to try to measure all the valves off of one seat and mark them, then do the same for all the seats using one valve, then plan a layout that works.
    One couldn't possibly expect this to be done for the price of a basic VJ ($150??)
    I typically order more than 8 ea. for this reason.

    Wouldn't the valve needing a longer pushrod suggest the seat being cut shallower, if comparing on the same head?
    I say that because the height of the rocker mounting could be different between heads, for various reasons.
    They may not have sunk your seats (or 3 required a deeper cut on that head). They could be (for the most part) "the same depth" from the seat cutting machine's perspective to the other head.
    Cutting the one a bit deeper would even out that head.
    Example: I've seen 2 heads from the same engine (date codes 1 day apart) have the combustion chamber roof, and therefore the valve seats, differ by nearly .100" in distance from the valve face to the decks. This was an issue for piston/valve depth clearance as well as not having to heavily shim the spring pads one head.
    The solution there was larger diameter valves to allow more material to play with, giving an easier target to hit for a dimension.
    (One head looks like a 3 angle seat and the other looks like a 2 angle seat with a .010" edge-break on the top cut. Both measured the same from the deck to the port floor at the short turn radius.)

    I apologize if this is the thread I left similar comments in.
    This isn't aimed directly at you sb92, just for the sake of general information sharing.
     

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