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Technical Sucked in a throttle screw - Holley 94

Discussion in 'The Hokey Ass Message Board' started by NewToMeT, Sep 4, 2019.

  1. NewToMeT
    Joined: Dec 6, 2018
    Posts: 62


    Just a tale for fun bathroom reading :)

    was cruising along, close to home when I heard an intermittent clanging noise. Passenger side of the motor it seemed. Limped it in and shut it off. Pulled the valve covers as I was going to adjust anyway, and thought perhaps something with the valves. All looked reasonable in there, but pulled all the rockers, inspected the push rods, etc. Put it back together and adjusted. Started quickly. Still noise.

    Pulled plugs from each cylinder and found a plug bent. crap. Is the cylinder hitting it?
    Put in a new plug. cycled the motor by hand, didn't feel it touch the plug. Hrm...
    Compression tested. 130psi. so thinking not a broken ring , hole in piston whatever
    Put a new plug. started .... clang....
    Left the plug out and started on 7 cylinders. One clang then whoosh whoosh no noise other than compression.....
    Put plug back in. All was good.
    Something in cylinder that blew out. So what was it.
    Searched my driveway and found a possible contender. hrm definitely chewed up, not rounded so thinking not piece of valve, ring, what have you. Must have sucked something in, and def small screw sized.......

    Looked in the carb (easy to locate as with the Offy intake that 1 carb feeds the offending cyclinder. lo and behold see a hole where a screw should be in the throttle plate.

    Went back in a re-peened all 4 carbs while replacing the missing screw. Motor running well. maintaining compression on that cylinder. Perhaps dodged a bullet.

    ran without the plug to blow out any metal. Stuck a magnet in as well.

    Any other thoughts?

    20190902_101546.jpg 20190902_132523.jpg
  2. Mr48chev
    Joined: Dec 28, 2007
    Posts: 30,840


    There are probably some matching marks on top of the piston. As long as it didn't beat it up close to the edge and crush the top ring land you are probably safe. If you can get your hands on one of those scopes that that you can look down a cylinder with to look at the top of the piston it might tell you if there is real damage on the piston.
  3. Casey Riley
    Joined: Jun 27, 2018
    Posts: 540

    Casey Riley
    from Minnesota

    My buddy had a motor that sucked a big chunk of a golf tee into a vacuum line on the intake port.

    That's all I got...
    Boneyard51 likes this.
  4. borderboy1971
    Joined: Oct 20, 2008
    Posts: 759

    from Canada

    I can't believe you found the screw that blew out in the driveway.

  5. Been there done that.Those little things make a racket all out of proportion to there size.20 years later im still running the engine.
    3340, Boneyard51 and NewToMeT like this.
  6. '51 Norm
    Joined: Dec 6, 2010
    Posts: 760

    '51 Norm
    from colorado

    I had that happen several decades ago. When the screw went through the engine it blocked the exhaust valve open for a little while making a hard miss. After a few seconds the screw blew out the engine ran fine.

    I discovered the problem when I pumped the gas to start the engine the next morning. With one throttle blade screw missing and the other loose when the throttle blade got far enough open it dropped sideways and jammed the throttle open. At that point the engine was idling at around 5,000 rpm. I'm sure glad that it didn't happen while I was driving!

    After pulling the head I found that the brass screw had peened the top of the piston and cleaned all of the carbon out of the combustion chamber. I buttoned it up and ran it for several years with no issue.

    Of course after that excitement I am much more careful with pinning throttle screws!
  7. I had a similar event...except it was a lockwasher (the one under the jam nut that held the air cleaner stud to the center of the carb). We were 1200 miles from home and I removed the air cleaner for some reason. The carb stud came off when I spun the wingnut and I never thought about the washer. The engine began knock like crazy after I kicked off the choke at next start up. After the panic set in, a bit off hotel parking lot diagnosis, then off came the head to find pieces of the shattered washer in a couple of cylinders (the bouncing around that the washer must have done in the short time the engine ran with it loose in there must have been almost unbelievable). Anyway, cleaned out the shrapnel, checked the valves (none were bent fortunately), looked for cylinder scores (again lucky), deburred the new dents in the head and pistons, pulled the pan to inspect the bearings of the affected pistons and put new bearingd in just in case (they had taken a heck of a pounding). 2 days later, we were back on the road. Engine ran great. I don't use lock washers on carb studs anymore.
    alanp561 and '51 Norm like this.
  8. You did all that in a hotel parking lot?
    clem and kidcampbell71 like this.
  9. upspirate
    Joined: Apr 15, 2012
    Posts: 2,294


    Engine had been running fine, shut it off and wouldn't re-start later. I had an air cleaner stud come loose and was sucked in down through the carb, 90 degree turn through the intake, and lodged holding an intake valve open on a 2.3 Ford 4 cylinder. Thought It just vibrated loose til I pulled valve cover off and found a cam follower (OHC motor) off to the side. Pulled the head and found the stud. never hit the piston. Removed it, lapped the valves, and re-installed with no problems.I couldn't believe it!
  10. blazedogs
    Joined: Sep 22, 2014
    Posts: 488


    Also been there done that . 1962 chev 283 Had the carb off dropped a washer down the intake,wasn,t sure till I started the engine and sure enough a knock... Wouldn,t do this anymore but back then , raced the motor and it apparently came out a exhaust valve and was just fine,no ill effects. gene
  11. NewToMeT
    Joined: Dec 6, 2018
    Posts: 62


    Yeah. Def low odds given how dirty my driveway is. though I didn't hear any noise so figured if something had come out it came out in a straight line and didn't hit anything on the way out so had my search area. Found it about 10 feet away.
  12. Hdonlybob
    Joined: Feb 1, 2005
    Posts: 4,013


    Scary stuff here..fortunately the only time I dropped something down the carb we new it and were able to retrieve it..
  13. jaw22w
    Joined: Mar 2, 2013
    Posts: 1,451

    from Indiana

    A couple years ago a washer got dropped down an injector tube on our 410 c.i. Sprint car motor. We were lucky enough to know it went in there. It doesn't take long to get a sprint car motor out. So we pulled it, and six of us picked it up, turned it over and shook it. The washer came tinkling out on the ground. Cool. Crisis averted. Those sprint engines are $EXPENSIVE$.
    clem, Jet96 and alchemy like this.
  14. town sedan
    Joined: Aug 18, 2011
    Posts: 1,290

    town sedan

    Pulled a Y-Block apart a few years back. On the edge of one of the combustion chambers it looked like threads had been rolled into the head. Figured the engine had swallowed a bolt, or something, in the past.
  15. Binkman
    Joined: Nov 4, 2017
    Posts: 281


    I had a small wheel weight in the engine on my cabriolet.
    I have no idea how it got in there but I have my suspicions.
    One day I started the car and the throttle seemed to stick open.
    I goosed it to get it to close. About a month later I started it in the garage and it started knocking loudly.
    I pulled the head and found the 1/2 ounce weight.
    Evidently it went past the carb and got stuck in the exhaust valve and bounced around the valve chamber for a while, it was all rounded off.
    Eventually the steel retainer on the weight came loose allowing the weight to enter the combustion chamber.The piston had some dome divets and there was some scoring on the cylinder wall.
    I pulled the 302 and put in a crate stroker. That motor had bad mojo and I wanted a guaranteed engine.
    All has been well for a few thousand miles.
    The carb was a "new" Edelbrock carb from a private seller on EBAY that was out of the box. I suspect the weight was in the carb when I installed it.
  16. 56sedandelivery
    Joined: Nov 21, 2006
    Posts: 6,695

    Member Emeritus

    Both of my dragsters, the FED and the RED, had Hooker, adjustable, up-swept headers; the collectors stopped right at and above the slicks. Race tracts are't known for being really clean, there's dirt and gravel everywhere. I knew of one guy who had a pebble come off a slick, bounce into and down the header, into an open exhaust valve; the engine was't running as the dragster was being towed back after a pass. Next fire-up he had a noise that lead to him pulling the heads; he found a beat up piston and chamber, and the small, chewed up pebble, still in the cylinder. Put the engine back together, finished the race, and rebuilt it after getting back home. I did't need that happening to me, so the first thing I did after buying the headers, was to attach some flapper valves, that are usually used to keep rain water/snow out of tractor, generator, gas powered welders, and such, exhausts. Other guy did the same thing. An ounce of prevention sort of thing. I am Butch/56sedandelivery.
    alanp561 likes this.
  17. I/t but Mazda has an issue with the 4 bangers the intake runners had long n short runs and the screws would work out of the mechanism and go through the engine never had on with damage
    Mostly like you just a damaged plug

    Had a guy at jaguar do some major work on a v12 and one of the wire clips that hold the fuel injector harness on fell in the plug hole
    Major damage valve, head , piston not nice at all from a wee bit of wire
  18. sevenhills1952
    Joined: Mar 14, 2018
    Posts: 956


    In mid 70s I worked at a large appliance store where they had a variety of vehicles. One was a Datsun pickup we used to get supplies, etc. It started running rough...not old or many miles, but local dealer had replaced carburetor under warranty. One fellow Glenn who worked there was a good mechanic and like OP found spark plugs hammered. So Glenn pulled the head and showed me what happened. The dealer dropped a carb nut in and left it, just replaced nut. That nut jumped cylinder to cylinder...all four pistons looked like someone dented tops with a ball peen hammer.

    Sent from my SM-S320VL using Tapatalk
  19. BJR
    Joined: Mar 11, 2005
    Posts: 7,468


    It blew out, you dodged a bullet, now go buy a lottery ticket and report back in a week.
    anothercarguy likes this.
  20. AVater
    Joined: Dec 9, 2008
    Posts: 2,767

    1. Connecticut HAMB'ers

    A while back, I took the carburetor off my avatar and in an effort to keep something falling into the intake, I put a clean paper towel over it. Later, I wanted to turn the motor a bit so touched the starter. Much to my surprise, there must have been enough fuel in the intake because the engine coughed and sucked the towel into the engine. I could not retrieve it. Thought about it a while and took a chance and decided to leave as is when I reinstalled the Carburetor.

    When I started the engine, “confetti” blew out the tailpipe. Apparently more a fire hazard than an engine damage issue.

    Car still running fine.
  21. Maybe they have borescopes at Harbour Freight or some other discount outlet. I got an inexpensive borescope from Canadian Tire, which sells a lot of low grade, inexpensive tools. My camera cost $100 on sale. I also have one with a USB attachment for a smart phone that cost me approximately $15.00, and it also worked well.
    If you have a smart phone, there is a fibre optic video cable that you can buy for some phones. I have one, and although I don't use it that often, when I have needed it, it was a lifesaver.
    Here is a link to the search result page.
  22. BamaMav
    Joined: Jun 19, 2011
    Posts: 5,473

    from Berry, AL

    I lost the plastic reinforcement piece out of a Ford carb spacer down into a 460, never knew it until I cranked it after a carb change. Sounded like a young war! Pulled and replaced the engine, later on pulled the head on the side that was making the noise. Two pistons were beat to hell with all kinds of dents. Never did find that plastic piece, only way I figured out what it was was it was missing off the spacer. Never would have thought a piece of plastic would do that.

    Dropped a valve in a 350 Chevy when the keeper popped off. Left a few witness marks on the piston and valve, but didn’t even bend the stem! Figure it must have just jumped up and down on the piston since it never came out of the guide. Had a new guide and valve put in the head anyway, just to be safe.
  23. s55mercury66
    Joined: Jul 6, 2009
    Posts: 3,980

    from SW Wyoming

    I found a 1/4-20 panhead screw that was used to attach the air filter base to the carb, laying on the intake valve of my friend's Sportster years ago. Installed longer screws with nylock jam nuts after that.
  24. LM14
    Joined: Dec 18, 2009
    Posts: 1,937

    Member Emeritus
    from Iowa

    A few years ago at a national dirt late model race had a friend put in a brand new engine to start the 3 day show ($40,000 engine). In hot laps he was wide open down the back straight (big half mile) and when he got to the corner he drove straight into the wall at full speed. When he got back to the pits he said the throttle stuck but he couldn't get it to pull back. Acted like it was back but still wide open. On closer examination, they found both the primary throttle plates fell out. It was also a new carb that was dyno tuned to the engine. Engine builder handed him a new engine and carb to put in for the next night. Not sure who paid for all the body and frame/suspension damage it caused.

  25. pirate
    Joined: Jun 29, 2006
    Posts: 712

    from Alabama

    Peening the thread end of the butterfly screws will prevent them from backing out all the way if they loosen but still allow them to be removed if disassembly is required. A dab of blue Loctite is also a good precaution.
  26. David Chandler
    Joined: Jan 27, 2007
    Posts: 1,101

    David Chandler

    I dropped a bolt down through the distributor hole once, on an SBC. I didn't realize it at the time, but was suddenly short one bolt. It ended up on the counterweight and hung the crank up, when I tried to turn it over. Educational to say the least. My first flathead I found a hardened screw nail and a spring, probably from an oil pump, stuck in the sludge in the valley area. No idea how they got there or when. But they had been there for some time by the looks of them. Thankfully they didn't end up inside a cylinder.
  27. borderboy1971
    Joined: Oct 20, 2008
    Posts: 759

    from Canada

    Sort of related... when I went to automotive mechanic school many years ago, one of the guys was changing the camshaft in his camaro. When he tried to remove the lifters, a bunch wouldn't come out of their bores. He lifted them up as far as he could and slid the camshaft out. Several of the lifters then fell down and out of their bores. He wasn't going to be bothered by it and just threw some new lifters in it. He started it up after it was all back together and the crank decided to push the lifters out of the oil pan. We sure had a good laugh at that guy.
  28. seb fontana
    Joined: Sep 1, 2005
    Posts: 7,441

    seb fontana
    from ct

    I was putting an engine together and was short one piston pin snap ring..Could not find one the right size in my "collection" so spent an afternoon running all over hell; finally found one..Got the engine together walked out the back door to check the weather..There was the snap ring on the side walk; no clue [just suspicion] how it got there...
  29. deadbeat
    Joined: May 3, 2006
    Posts: 543


    Yes same with me on one of my Fe's. Was driving along and car started to develop a miss. Hauled into my daughters workshop and pulled the plugs. Sure enough, bent electrode. New plug and she fired up nice. Took it for a drive and the same again only this time it was a different plug, other side etc. Pulled the head off and there was a spring washer, or a smashed up one, that had fallen off when I was changing carb base gasket., No damage to the piston or valve but couldn't understand how it got over to the other side,, cheers
  30. Elcohaulic
    Joined: Dec 27, 2017
    Posts: 2,598


    There usually brass..

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