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Technical New Engine lacks power SBC in the Studebaker-RESOLVED

Discussion in 'The Hokey Ass Message Board' started by vtx1800, May 20, 2020.

  1. gimpyshotrods
    Joined: May 20, 2009
    Posts: 17,658

    gimpyshotrods
    ALLIANCE MEMBER

    I am sorry to hear that.
     
    brigrat likes this.
  2. If my eye's could see the small things it'll be like purple is grape to a child until corrected. ;)
     
    57 Fargo and loudbang like this.
  3. 1946caddy
    Joined: Dec 18, 2013
    Posts: 1,705

    1946caddy
    Member
    from washington

    The correct manifold is pretty cheap.
    [​IMG]
    Intake Manifold Fit Chevrolet 1987-1995 350 For TBI Stock Heads 52001
    Item price USD 123.58
    Quantity 1
    Item number 143537242428
    Shipping service UPS Ground
     
    loudbang likes this.
  4. karl share
    Joined: Nov 5, 2015
    Posts: 103

    karl share
    Member

    have you checked what your total timing is at 3000 rpm ??
     
  5. How about a distributor dropped in a tooth off? Pretty easy to check and drop back in. I had one on a 327 that was like that, ran better with the old flat lobed cam before I took it apart.
     
  6. Pat
    Joined: Jan 6, 2002
    Posts: 166

    Pat
    Member

    Not sure if this has already been mentioned. Are the rockers adjusted properly? I installed a customer supplied 302 once that ran horrible. Ticking sound under the valve covers. He told me it’s a nasty solid lifter cam and he adjusted the lash. Turned out it was a hydraulic cam! But it ran like you described.
     
  7. canning
    Joined: Jan 22, 2012
    Posts: 70

    canning
    Member

    Don't laugh. I had a 305 performing similar stunts. Timing changes tried forward and backward. Got a tank of non-ethanol fuel...you would have thought it was a different engine. I also believe your Petronix ignitions have a rev-limiter built in, yes?
     
  8. Rickybop
    Joined: May 23, 2008
    Posts: 6,619

    Rickybop
    Member
    from Michigan

    V, sorry to see you going through so much to diagnose your problem.

    Couple of things...

    If your any of your cam lobes were worn very much at all, you would have been popping and spitting through the carburetor on acceleration, probably right from take off.
    31V mentioned that your dial indicator didn't look exactly in line with the lifters and pushrods. If that's the case, your readings will be short... as yours were.

    And I see now that you've found no metal shavings. Good deal.

    Actually, if I had pulled the valve covers and hadn't detected any loose rocker arms, I might have moved on to other possible issues. But I understand the concern with a newly assembled engine.

    The intake manifold...
    I've heard about the wedges to adapt an intake manifold. But I would never feel good about using them.
    I kind of doubt this is the problem, but have you checked for intake leaks? Spray around any questionable areas with carb cleaner or starting fluid... take note of any rpm change. Does your idle speed tend to hover when you goose the throttle before it finally settles down to the correct idle speed? That's another good indicator of an intake leak.

    Okay, the problem itself...
    You said the carburetor is full when you check. Okay, let's say it's ignition then. But you've been round and round with that too. Could still be ignition. I have a hunch that it is. Maybe something simple like the spark plugs.
    Was your carburetor running rich at some point? If it was, you may have partly fouled your spark plugs which would affect good spark at higher rpms. If spark plugs get fouled even more, it would of course be worse or not run at all.
    Check your spark plugs. Just a little bit black? Doesn't take much. Maybe replace them just to be sure. And remember, if any of them are white, you're of course running too lean.

    Good luck.
    Let us know.
     
  9. landseaandair
    Joined: Feb 23, 2009
    Posts: 4,408

    landseaandair
    Member
    from phoenix

    Guess I'm way late to this party and someone may have already mentioned this but have you tried running it till it misfires and cutting off the fuel pump just before you shut it down? Then checking the bowls for fuel. Possible clogged vent or pinhole in pickup tube?
     
    canning likes this.
  10. canning
    Joined: Jan 22, 2012
    Posts: 70

    canning
    Member

    Small hole made by a rodent sounds feasible...has suction but not enough under load.
     
  11. landseaandair
    Joined: Feb 23, 2009
    Posts: 4,408

    landseaandair
    Member
    from phoenix

    Dealt with the air in the line deal on my buddies Chevy powered F100. Cracked hose at top of tank pulled air and basically vapor locked at speed.
     
    canning likes this.
  12. vtx1800
    Joined: Oct 4, 2009
    Posts: 1,089

    vtx1800
    ALLIANCE MEMBER

    Today my neighbor came over and we did a check to see how the cam timing was. It appears to be OK. The best guess now is weak valve springs. I cheaped out and used the original valve springs that came on the heads when I built the motor.

    I have new valve springs on order.

    @karl share & @bobss396 I've set timing multiple times with two distributors with 34 degrees at about 3000 RPM or so. I am getting pretty good at swapping distributors:) As well as distributor wires:) What a PITA!!
     
    Last edited: Jun 6, 2020
    bobss396 likes this.
  13. vtx1800
    Joined: Oct 4, 2009
    Posts: 1,089

    vtx1800
    ALLIANCE MEMBER

    Note fuel bowls have always been full. two fuel pumps have been used both electric. all new line/rubber etc.
     
    Last edited: Jun 4, 2020
  14. vtx1800
    Joined: Oct 4, 2009
    Posts: 1,089

    vtx1800
    ALLIANCE MEMBER

    @1946caddy The manifold was just gathering dust, now it is one less item my wife has to take care of after I go to room temperature:)
     
    bchctybob likes this.
  15. 1946caddy
    Joined: Dec 18, 2013
    Posts: 1,705

    1946caddy
    Member
    from washington

    I still think your problem is that you have the wrong camshaft for your TBI heads. Your mild cam at .450 lift is not Mild for your TBI heads which were the worst head design from Chevy. Your stock TBI valve spring are good for 4500 rpm.
    This kit uses a camshaft specifically for a TBI to carburetor modification.
    Also noted that the camshaft in this kit has a warning ;
    Do not use late model timing sets. They are machined in a retarded position and are not recommended for this camshaft installation.
    What timing timing set is recommended for the cam you're using.
    https://www.jegs.com/i/Edelbrock/350/2104PK/10002/-1

    Your cheapest route is to get a TBI rated camshaft or follow the recommendations in this article.
    https://harristuning.com/Tbi/recommended-350-tbi-mods/
     
    Last edited: Jun 5, 2020

  16. Save them old ones for cam break in springs!:D
     
    winduptoy likes this.
  17. Blues4U
    Joined: Oct 1, 2015
    Posts: 4,880

    Blues4U
    Member
    from So Cal

    Weak valve springs are not going to give a low power condition, but they will allow valve float at high rpm's, which doesn't sound like what you are experiencing. You've also not mentioned any kind of a mis-fire, rough running or stumbling, surging which would be expected if it was a fuel delivery issue. What you've described sounds like an air or exhaust flow restriction, cam timing or ignition timing. Did you try setting the ignition timing by vacuum gauge yet?
     
    loudbang, olscrounger and big duece like this.
  18. I have to put my 3.5 cents in to the Pot.
    Most Chevy like the Timing set at 38 even my BBC ran at 38 Total
    Did you ever think that the Problem was your Rear end Ratio!

    Just my 3.5 cents

    Live Learn & Die a Fool
     
  19. dirty old man
    Joined: Feb 2, 2008
    Posts: 8,686

    dirty old man
    ALLIANCE MEMBER

    I'm starting to think the main problem is too many cooks in the soup.
     
    Last edited: Jun 5, 2020
  20. Dave............I think your right

    I was thinking that the Rear Muffler bearing's are not Teflon..!
    which would cause a Problem..??

    Just my 3.5 cents


    Live Learn & Die a Fool
     
    vtx1800 and '49 Ford Coupe like this.
  21. 173
    Joined: Feb 12, 2017
    Posts: 15

    173

    Had a chevy pickup with a 700r4, truck was a dog, one day the torque converter bolts loosened up and wrecked the pads on the converter. Put in a new converter and flywheel and it really woke up, could peel out and pass on the highway. If the engine looks good maybe the trans is holding it back
     
    Kevin Ardinger and loudbang like this.
  22. Gman0046
    Joined: Jul 24, 2005
    Posts: 6,253

    Gman0046
    Member

    Back in the day, my 56 Chevy BelAir had a ragged out 265. The block was bored and stock Chevy 283 pistons and parts were used for a rebuild. It had 3 Rochester 2 barrels. I have no idea what cam was used but this car could not get out of its own way. It had to be the slowest SBC powered Chevy ever. It was a complete embarassment. The cam was replaced with an 097 and solids and it woke the engine right up. It then ran just the way it should have.
     
  23. Kevin Ardinger
    Joined: Aug 31, 2019
    Posts: 231

    Kevin Ardinger

    Don’t mean to beat a dead horse but have you tried to stall test the converter yet? I’m telling you a broken or inop one way clutch in the converter will definitely cause this. Will run like you threw an anchor out when in gear. Run fine in neutral. I really doubt the engine is that much of a dog unless the cam timing is way off and you said you checked that.


    Sent from my iPhone using The H.A.M.B. mobile app
     
    jaracer likes this.
  24. wuga
    Joined: Sep 21, 2008
    Posts: 362

    wuga
    ALLIANCE MEMBER

    He stated that the engine will hardly run over 2000 RPM. How can this be a torque converter, transmission or rear end problem?

    Warren
     
    loudbang likes this.
  25. Blues4U
    Joined: Oct 1, 2015
    Posts: 4,880

    Blues4U
    Member
    from So Cal

    I believe he meant "in gear" when he said that, not in neutral.
     
    loudbang likes this.
  26. big duece
    Joined: Jul 28, 2008
    Posts: 6,022

    big duece
    Member
    from kansas

    OP stated it revs to 4500rpm then cuts out, wet rag when driving...
     
    loudbang likes this.
  27. wuga
    Joined: Sep 21, 2008
    Posts: 362

    wuga
    ALLIANCE MEMBER

    I think we are talking load or no load. Still has nothing to do with trany etc.
    Warren
     
    loudbang likes this.
  28. indyjps
    Joined: Feb 21, 2007
    Posts: 3,935

    indyjps
    Member

    Following along, interested in the outcome, offering moral support...."go get em tiger":D

    You have about 53 action items already, I wont add to that list. Looks like spring swap is next on the agenda.
     
    loudbang likes this.
  29. Kevin Ardinger
    Joined: Aug 31, 2019
    Posts: 231

    Kevin Ardinger

    As I read it it revs up fine in neutral. Driving it it won’t go ove 2000 rpm


    Sent from my iPhone using The H.A.M.B. mobile app
     
    Blues4U and loudbang like this.
  30. vtx1800
    Joined: Oct 4, 2009
    Posts: 1,089

    vtx1800
    ALLIANCE MEMBER

    @Blues4U Yes I have tried setting the timing by vacuum gauge, no real improvement. I've endoscoped the intake manifold and could find no obstruction as well as the exhaust headers. The rest of the pipes are straight pipes to glass packs. All New.
    @a50merc 3.31 gears with a 700 R 4, don't think that is an issue.
    @31Vicky with a hemi when I built the motor I wondered about using lighter springs:) Guess I will have them for any future builds (highly unlikely at this stage of my life)
    @1946caddy These are not TBI heads, they came off of an OMC boat motor with a four barrel manifold. This from the Mortec Site
    14096217...55-86...350..........Crate motor, 285hp/300hp, 64cc chambers,
    72' or 90' center intake manifold bolt angles
     

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