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Technical SBC question

Discussion in 'Traditional Customs' started by jwrig43, Sep 8, 2019.

  1. jwrig43
    Joined: Sep 8, 2019
    Posts: 1


    Hello, I stumbled across your site while researching SBC questions. I am not sure if this would be qualified to post on this type of forum, but it is a SBC 350 that I am dealing with. This engine I am trying to get running is in an older boat. We have installed 2 reman long block 350s, one is standard rotation and the other is reverse. We had both engines running out of the boat. We dropped them in the boat and now one will not start. It tries, stumbles and nothing. I figured a 350 is a 350 no matter what it is installed into so hence why I am here and hoping someone can help me. I am out of the US so there is no one here that can help, just the internet :). We have new reman Rochester 4 barrel carbs installed, new distributor, plug wires, plugs, coil, and fresh fuel. I am just at a lose with this thing. It seems so simple, but what am I overlooking. I have verifed my timing by bring #1 up to TDC and my timing mark on my damper matches the front cover mark at 0. Also had a nice puff of air on 1 and set my distributor/cap dead on 1. I got it fire and start just for a second or two twice with new plugs, but this makes no sense. If I am fouling plugs why? This is a reman long block. I know they recommended special oil, but we can not get the oil the rebuilder suggested here. I called and told the only oils we can get, a synthetic 10w/30 blend oil. The builder said he did not think it was the best, but better than nothing. We ran this engine for about 25 minutes to set cam bearings and it seemed fine. Good oil pressure, temp was good, sounded good. (Actually have video of it with gauge readings). I did set the timing just before shutting her off to 10 BTDC. I have tired to turn distributor CW just a little to help it start easier, but makes no difference, will not start and stay running. The other engine I could get to run in boat. So I switched the carb from this one to the non runner, nothing. I can give a pump of fuel in carb, so I know its getting fuel, I can see it. I am going to try to make some videos of my timing procedure, spark quality etc. Maybe I can share a link here, not so sure it will work. Really could use some help with this SBC. Thanks for any and all input.
  2. Casey Riley
    Joined: Jun 27, 2018
    Posts: 388

    Casey Riley

    I hope someone helps.
  3. Fuel under compression and spark all at the correct time and it will run. Are you certain you have the correct starter to turn the reversed engine backwards?
    upspirate likes this.
  4. The problem may be in your wiring for the ignition. You may only be getting spark when the starter solenoid is engaged. Some circuits will bypass the resistor for starting and then through the resistor for running.
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  5. irishsteve
    Joined: Jan 10, 2017
    Posts: 350


    Check for spark at the plugs.Have someone crank it while you hold the wire 1/8 inch from a plug.If you dont hear it snapping,or see a arch you have electrical trouble.If it has spark shoot some starting fluid down the carb.It should fire right up at least for a second.If it wont then the timing is way off.If it does start on starting fluid,but dies its not picking up fuel.Check the lines for cracks where air can get sucked in.That will kill the fuel pumps vaccunm so it cant pull fuel.
  6. 2OLD2FAST
    Joined: Feb 3, 2010
    Posts: 1,619

    from illinois

    What's different than when the engine was on the stand , fuel , fuel source , electrical connections ?? , If you flattened a cam you should be able to see it, pull a valve cover. You spent all that money and couldn't import some ZDDP additive ??? C'mon really ??
  7. oldtom69
    Joined: Dec 6, 2009
    Posts: 389

    from grandin nd

    is it the reverse-rotation engine that won't start?
    upspirate likes this.
  8. sunbeam
    Joined: Oct 22, 2010
    Posts: 4,211


    Question for boat engine builders on a reverse engine do you use standard pistons installed backwards.
    Montana1 likes this.
  9. Desoto291Hemi
    Joined: Apr 21, 2009
    Posts: 634


    I’m with oldtom ,,,, is it reverse rotation engine giving the trouble?

    upspirate likes this.
  10. Country Joe likes this.
  11. sunbeam
    Joined: Oct 22, 2010
    Posts: 4,211


  12. Flathead Dave
    Joined: Mar 21, 2014
    Posts: 2,210

    Flathead Dave
    from So. Cal.

    Is this a "traditional" boat build?
    Deuce Bigalow and Desoto291Hemi like this.
  13. upspirate
    Joined: Apr 15, 2012
    Posts: 1,980


    54vicky, Old wolf and Johnny Gee like this.
  14. Sorry guy's. My eye's read points. :oops:
  15. upspirate and sunbeam like this.
  16. Try the link I provided on my mistaken reply.
  17. DDDenny
    Joined: Feb 6, 2015
    Posts: 12,035

    from oregon

    U.S. or Down Under.
  18. buffaloracer
    Joined: Aug 22, 2004
    Posts: 773

    from kansas

    Another care where I would be checking for a good ground.
  19. No the helix on the cam gear must be different and also the dist and the oil pump modified. Its impossible for the cam to rotate in a different direction than the crank. unless you used a gear drive without a idler gear. on a small block chevy the gears would need to be so large of diameter they would not fit under the timing cover. I messed with reverse rotation detroit diesels.( Know it all's )claimed you turned the crankshaft around to reverse them. I never even tried to educate them. What you did was swap the dead cam with the live cam and rotate the cyl head 1/2 turn. For a reverse engine the field coils on the starter are wound in a different direction so it spins backward. and a reverse spiral is also necessary on the starter drive.
    53 ford likes this.
  20. Montana1 likes this.
  21. upspirate
    Joined: Apr 15, 2012
    Posts: 1,980


    The ones I heard of for reverse rotation have different grind cams. Thanks, I learned something new!
  22. ^^^^^ Still needs proper grind regardless which way cam turns.
  23. Correct. SBC requires a reverse ground cam and peripherals...
    Old wolf likes this.
  24. 6sally6
    Joined: Feb 16, 2014
    Posts: 673


    Who cares (not me) the OP never came back!
  25. Being that it was his first post, he probably went to fix his motor with all this information that he didn't ask for... :rolleyes::D
    Old wolf likes this.
  26. brigrat
    Joined: Nov 9, 2007
    Posts: 4,779

    from Wa.St.

    Had a V-Drive I bought on the cheap with a 460 Ford, owner could not get it to start. Turned out he had bought a brand new starter for the 460 BUT forgot to mention to the parts guy that the starter was installed from the rear, nother words it was turning engine over backwards. Took a minute to figure out but it was fun for a few summers!
  27. Mr48chev
    Joined: Dec 28, 2007
    Posts: 25,382


    As usual the normal bull shit artists have chimed in with their nonsense that has nothing to do with the question.
    You didn't say which engine doesn't want to run but most are assuming that it is the reverse rotation one.

    What is different on the engine from when you test ran it?

    If it is getting fuel to the carb that should mean that you don't have a restriction in the line.
    That leads to something not being correct in the ignition system for that engine. Every twin gas engine boat I have seen has two totally separate ignition systems from switch on the control panel out. I'd make sure I had power to the coil with switch on and power to the coil when it is cranking.
    You could have wiped out the cam during the start up but normally that only takes out a lobe or two and it still runs but doesn't run good.
    upspirate and Desoto291Hemi like this.

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