ST-300 Hop Up!

Discussion in ''Da Nailhead' started by Bigpig455, Nov 17, 2012.

  1. 66gsconv

    66gsconv nailhead apprentice

    Thank god you fixed it:gp: By the way what was the beer count for that little month and a half fix:laugh:
  2. Bigpig455

    Bigpig455 Fastest of the slow....

    If you count various people brought in to consult, gawk or see what the inside of a transmission looks like, the count exceeded our ability to keep count. Turns out the best way not to get frustrated about your car being out of commision is to forget your car is out of commision.
  3. 66gsconv

    66gsconv nailhead apprentice

    Wow I thought I was the only one useing them methods:beers2:
  4. telriv

    telriv Well-Known Member

    So I was correct in that the valve was installed upside down???
  5. bhambulldog

    bhambulldog 1955 76-RoadmasterRiviera

  6. Bigpig455

    Bigpig455 Fastest of the slow....

    Bulldog thanks, I didnt see that post.

    Toim - Yeah, ultimately you were right. I told you I had it in the right way because I had it just like the manual showed...Ha! If you had seen it you probably would have known right away.

    Whats the lesson here? Never take my word for it! Or never trust the manual. One of those, anyway.

    Hey, since you're on today - I'm trying to button this thing up this afternoon and need some advice on re-assembly- I put this question out on the juice box section, but they dont feel like talking...

    The car came apart and the current sequence was Case/plate/gasket/valve body - car shifted great in this configuration

    The service manual calls for case/gasket/plate/valve body

    Personally, if it didnt hurt anything I would put it together case/gasket/plate/gasket/valve body - I have two gaskets, so thats a possibility

    What do you think?

  7. telriv

    telriv Well-Known Member

    The plate & valve body need to be perfectly FLAT. A big piece of fine sand paper on a KNOWN flat surface would do the trick. You need to get the whole thing on a big, flat surface & use even pressure. Look at the gaskets, put them together to make sure ALL holes etc. are the same. Also there should be a "C" gasket for the case & a "V or VB" gasket for the valve body. This "C" or "V" will be on the gasket, normally punched out at one end of the gasket.

    Tom T.
  8. Bigpig455

    Bigpig455 Fastest of the slow....

    Thanks Tom - Naturally, I have two gaskets with nothing punched in them - both exactly the same. I got these from Fatsco I think... who do you use?
  9. Bigpig455

    Bigpig455 Fastest of the slow....

    Well, it's all back together. In the end, I put it together case/plate/gasket/valve body. Even though the manual calls for the gasket to go on the case side and Fatscos books show the gasket as "case to plate", I didnt do it because:
    • It came apart in that order and shifted well
    • There were open port areas on the case side where the gasket would form an unsupported area where fluid could lift/tear it.
    When I compared the gasket to both the case and valve body, it more closely matched the valve body ports and channels, especially in places where it bridged and directed fluid. Wouldnt be the first time the manual was wrong, and even the illustrations on stator wiring routng were different from my transmission.

    So time will tell if I'm right or not....

    In the meantime I'm going to go get fluid - Are there any cons to using "type F" fluid in this transmission? We started talking about it but never really finished.

    Thanks -
  10. Bigpig455

    Bigpig455 Fastest of the slow....

    Well, It runs and drives....!!!

    Couldnt find enough type F locally, so I went with Dexron. Put in the fluid and drove it around the block, but roads too wet (and salty) to really take and test shift points and pressures.

    Had some intial issues where the transmission would cycle in and out of gear while in drive (felt like you kept putting the car in nuetral) , there might have been some passages that were airbound and the fluid level had dropped. I've been running it, letting it sit for a day and re-checking fluid. Seems to be at the right level now but will still kind of "engage" from idle to part throttle, like you just put it in gear.

    The other issue is my switch pitch no longer works...I can hear the solonoid clicking but no change in RPM...strange, as the valvebody itself was never really touched and went back together with the gasket in the same position as it came apart.

    I'm gonna drive it for a day or two when the weather is better, but I think the pan is gonna have to come back down to try the gasket between the case and plate, check the actuator in the valve body and check the screen o-ring for good suction at the neck...

    Not worried about it, this will all sort out.
  11. Bigpig455

    Bigpig455 Fastest of the slow....

    Fired up the heat in the garage yesterday and went to work....Happy to report everything finally works!
    • Cycling in and out of gear - I was losing pressure from between the valve bodies and case when the fluid got warm/thin. Everythign was pretty flat, but I took Toms suggestion anbd used gaskets between both the case and plate, and the plate and valve bodies. Works great.
    • No Switch Pitch - I had matched the new plate up to my old one to make sure all the holes were there and the same size, but what I didnt see is the holes that werent on the original- I held it up with the original facing me, didnt see there were additional holes in the replacement over the SP valve body that the original didnt have....I dont know what the application was, but I'm getting the sense that there were alot of differences between year/year, SP/Non-SP, Buick/Olds applications. For instance, the parts that Nekkidhillbolly sent me are clearly from an ST300, but entirely different than mine....Anyways, those holes must have been bleeding off application pressure. I guess the 65 GS plate is a rare bird! I put my old back in and works great
    • Lazy Shift - Was probably due to low pressure. I didnt want to (I generally keep the stock parts handy...just in case) , but I modified my original plate High Clutch Feed orafice from .090 to .125. before I re-installed. Looking at it, you wouldnt think it would make a diffence. Finally took it for a full throttle blast and WOW! I cant describe it but the shift is RIGHT THERE...1st lets go and 2nd is right there, the nose doesnt even dip. Not at all harsh, just quick. In stock form, that transition took a full tenth, and it was painful to sit through..If you're running a ST300 -DO THIS.
    • Shift Pressure - At Tom's advice, I stretched the pressure valve spring a 1/4 inch to increase the line pressure. During my valve issue, I did fully compress the spring a few times and it seemed to take the additional length back out of it,or just looked that way anyway. The car has no noticable bad traits now engaging gears or shifting, but maybe it is partially responsible for the speed of the 1-2 shift. If I had to do it again, I would use a TH400 shim to increase the pressure. NOTE: I'm glad this turned out this way, I didnt know what I was messing with... I've since learned that if you get this wrong, you can balloon the converter, put thrust presure on the crank and wipe out your motor....You need a guage to measure line pressure and a more scientific approach..
    • Governor Mods - More room here, from one blast it still shifts just below 5k. I had drilled 5/16 holes in the outer weights and left all springs in. The formula is 2 1/4 holes each weight and remove one spring gives you 5300 - 5500 rpm, I'm just starting slow and would like to end up around 5200....
    • Quadrajet ICR replacement - When I had low voltage to the coil, I was hogging out the idle channel restrictions to cover the off idle stumble (which kinda worked for a while) -the result was the car had enough idle fuel for a 600 hp motor...taking a leap of faith, I got new ICR's from Cliff Ruggles, and did the surgery, which with Cliff's advice went just like he said it would! But when I put the carb back on the car it ran terrible, loading up (with less fuel?) and hard starting, etc.. I had to start form scratch, recalibarating the mixtures and choke application..Happy to say it was all worth it, the car idles beatifully and is MUCH crisper off idle into the primaries.
      As a pleasant surprise, I was torquing up the car in gear and found that all the suspension mods really do what I meant them too - the car now does the infamous "Gessler Rise": (the video is about 3/4 down the page.)
      I had never really torqued it past 1700 rpm, it wouldnt launch that way.. but when you bring it up to 2K, it's like it on hydraulics! I dont mind telling you, THATS pretty cool! If anyone can PM me on how to get a video embedded here, I'll take one when the snow goes away...

      So time will tell what all this work nets me on the track. I'll go on record that the shift alone is worth a half a tenth or more..

      Thanks to everybody who chimed in along the way
  12. nekkidhillbilly

    nekkidhillbilly post whore

    i know little about those trans but my car was a 66 340 st300 car oem. idk i hope you can use some of it though. i guess they may be different in a 401 vs 340 i wouldnt think there that different. that or 65-66.
  13. Bigpig455

    Bigpig455 Fastest of the slow....

    Yeah - it's funny how different they are.. The high pressure valve is entirely different, some differences in the valve body and the pan too..If you still have the sheetmetal plate from between the valvebody and case I'd love to see that too...not that I think I could use it. Also, did you send the governor? I looked quick through everythign but didnt spot it..

    Thanks, RT
  14. nekkidhillbilly

    nekkidhillbilly post whore

    i couldnt get the govenor out of it. i thought the plate was in there i must have layed it down up dads ill get it this week.
  15. Bigpig455

    Bigpig455 Fastest of the slow....

    Thanks! If it helps, you've got to spin the governor out, I think counterclockwise like the teeth of a speedo gear...if not, oh well.

  16. nekkidhillbilly

    nekkidhillbilly post whore

    the speedo gear part had some damage and i couldnt get it out. i think dad got to close to it with something. where is the govenor in these things?
  17. Bigpig455

    Bigpig455 Fastest of the slow....

    Driver's side, round 3 bolt cover right behind the sector shaft where the linkage bolts up..

  18. nekkidhillbilly

    nekkidhillbilly post whore

    ok ill see if i can get it out while im at it
  19. Bigpig455

    Bigpig455 Fastest of the slow....

    Well, the weather has finally broke and the salt is washed away, so it's time to turn wrenches for real!

    I took the 65 out yesterday with the recalibrated governor and the shift mods, and I put the G-Tech meter on it to start data logging what was happening and where, pretty much focused on shift points. I had some interesting results. I dont know if you'll be able to really see the attached graph, but it represents RPM over time. The red line is yesterday's results, the black is on the AFB in 2011 and the green and blue lines are on the Q-Jet in 2012. Yesterday's run was made with 2 people and a full trunk, the others were made with just me and an empty trunk. The RPMS for 2011 and 2012 are about 200 RPM low, they were calibrated to the console tach, yesterday I calibrated to a snap-on timing light to be more precise.
    • 1 5/16 hole and 1 1/4 inch hole in each weight, and removing 1 spring from the governor got me a shift point of 5100 rpm. This is probably because the 5/16th holes were more in the middle of the weight where the spring pocket was, as opposed to out on the end where they would have more effect. With the stock governor, I had been shifting at a little over 4600 rpm
    • The first time I took the car out shift points at 5100, I thought it pulled well all the way through. As I made more runs yesterday, I realized it wasnt making power and nosing over about a full second before the shift. If you look at the chart, that puts the optimal shift point at about 4900 rpm. I put the spring back in this morning and will test again this afternoon. I think it will put me back at 4800-4900 RPM. If not, I'll leave the spring out and weld the 5/16 holes shut for weight and see where that puts me.
    • The weights in the B&M calibration kit arent worth a damn
    • I thought shifting at higher RPM would bring me into second gear at a much higher rpm. Not really so, 2nd gear really seems to follow vehicle speed, and I wasnt any MPH faster from 7 to 9 seconds at the higher rpm. (remember prior runs were 200 rpm low) Because the shift is so quick now, I really only come into 2nd about 100 RPM higher, and have to hold the shift about 300-400 rpm higher to do it (and not making power at 200 of them) It boils down to this": There was a 1400 rpm drop between gears shifting at 4600, there was a 1900 rpm drop between gears shifting at 5100 rpm.
    • For whatever reason, I was 1 mph faster than usual at the end of the quarter.(I think this was due to better carb calibraton)
    • The most beautiful part - the shift is .3 tenths quicker by opening up the high clutch feed hole in the valve body plate. Look at the lazy shift of the green, black and bue lines, and look at the sheer drop of the red line. I dont think I'll gain all those 10ths back in my ET (because the car was still moving pretty good even during the lazy shift) But I do this I'll gain .1 or .2 because the the car is back under full power that much quicker.
    • Tommy's trick of stretching the front pump pressure spring seems to have worked better than I thought. The shift really gives you a shove between the shoulders, but isnt harsh or bangs on the drivetrain. Some of that could be attributed to higher pump pressure from the RPMs, but I noticed it at lower RPMS too!
    Net result: shift and pressure mods GOOD! RPM mods (on a 75k original nailhead) not as effective.

    Attached Files:

  20. gsgtx

    gsgtx Silver Level contributor

    Rhett, very good testing, always found 4800 was the best shift point for a stock nailhead with just a bigger carb. if you get a chance, keep it on high stall till after the shift would like to see the rpm drop after the shift. thanks Joe

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