350 GM Bongo Drum engine noise - Problem solved.

loadnet · Sep 15, 2003

Removed starboard side valve cover and found 2 rockers off... 1 push tube broken, and one was just laying off to the side.. 2 valves were stuck shut.. We freed up one, and are soaking the other hoping to save this engine in the wind up. Take care and thanks to all that responded. PB customerservice@401hosting.com

CharlesW · Sep 15, 2003

Re: 350 GM Bongo Drum engine noise - Problem solved.

You might want to check the condition of the rocker arm mounting stud. We once had a Chevy V-8 that had a groove in the side of the stud that was not visible unless you looked on the back side of the stud. When you install a new rocker arm, it immediately starts working it's way into that groove and eventaully will turn enough to mess up a push tube. Charles

Wellcraft 89 · Sep 16, 2003

Re: 350 GM Bongo Drum engine noise - Problem solved.

Glad you found your problem,Its difficult to diagnos things through the internet,only give our suggestions.

One thing to think of in the future is not to start a new post with your answer or fix to a problem .it gets confusing and takes up bandwith space

Rich

loadnet · Sep 16, 2003

Re: 350 GM Bongo Drum engine noise - Problem solved.

Sorry about that new post. Won't do that again. One valve freed up but one is being very stubborn. It's stuck in the down position and we can't get it up for NUTTN. Plastered it with PB lube and let it sit overnight and it still didn't pop up. It was stuck up and we tapped it down to make sure it was freed up and it just kept going down down down..as we tapped on it. We turned the engine over by hand to make sure the piston was out of the way. We're hoping it'll free up after a couple of days of squirting it to death with the PB lube... pouring trany fluid on it and so on.. Worse comes to worse we're going to remove the valve spring and seal and try heating it up a little. Anyone know how to free up a stubbord valve stuck in the down (fully open) position?

ufm82 · Sep 16, 2003

Re: 350 GM Bongo Drum engine noise - Problem solved.

You can try this method. Take the spark plug out of the hole and put the piston and bottom of the stroke. Take a length of 1/4" vacuum line and start feeding it in the hole. It helps to lube the hose with some of that P'Blaster you have. Stuff as much hose in the hole as you can. Then turn the crank and mash the hose up against the valve with the piston. I used to use this method when replacing valve springs on race cars at the track. It works great. Just move the piston back down and remove the hose when you are done. If you get the valve up, chuck the stem in a cordless drill and rotate it slowly while applying liberal amounts of blaster. It should free up unless the stem is bent. UFM82

Trent · Sep 16, 2003

Re: 350 GM Bongo Drum engine noise - Problem solved.

Rope works well also... Better check and find out why the valves are stuck. My bet is your getting water into the cylinders. Id pressure check the manifolds and risers before its too late. Just my thoughts.

cobra 3.0 · Sep 16, 2003

Re: 350 GM Bongo Drum engine noise - Problem solved.

I'd pull off the head on this one and work on it off the block. It's more work, but you will not be taking any chances with you engine. As mentionned earlier, you don't know why this happened in the first place.

ndemge · Sep 16, 2003

Re: 350 GM Bongo Drum engine noise - Problem solved.

on my '71 van.... was running like CR@P... no compression on 4 cylinders... I pulled the engine to rebuild. After pulling the engine, take off valve covers, saw all those rockers sitting to the side. engine looked VERY clean inside, had the block boiled and honed since I had it out and apart, when mic'd everything was standard. re-used old pistons (re-ringed) ... could have gotten by just fine new heads if I had just pulled those pesky valve covers. Took the heads to local machien shop, as the studs had pulled out the head half inch... after inspection, find both heads were cracked.

rhartSilverdale · Sep 16, 2003

Re: 350 GM Bongo Drum engine noise - Problem solved.

Am wondering if you have a bent valve stem or a problem with the valve guide. If the valve was stuck in the opened position while the engine was turning, that might have caused the piston crown to strike the valve, which would usually bend the valve stem. Just adding my 2 cents worth.

loadnet · Sep 16, 2003

Re: 350 GM Bongo Drum engine noise - Problem solved.

The engine will be fired up soon.. We got the valve to break loose after spraying the death out of it wiht PB blaster like every couple of hours for a day.. then let is sit over night... We then grabbed the top cup of that sits on top of the valve spring with a slide hammer puller and started hammering it upward. The valve broke loose.. We then hit it back down using a piece of Trex Deck board and a ballpeen hammer, and spraying it with PB Blaster at the same time. It's now bouncing down and back up again on it's own.. Whew! To top it off we found the other part of the push tube inside and managed to pull it out with a magnet, and a few new swear words we made up along the way.. We just have to throw the covers, riser and shifting mechanism back on and fire it up to see how it sounds with all 8 firing.. I'll let you know what happens.. I really thought the rubber hose and rope idea was terrific.. and will remember that for any future projects like this that pop up. Thanks to all for your input on this excursion. PB

loadnet · Sep 17, 2003

Re: 350 GM Bongo Drum engine noise - Problem solved.

The engine is all set now.. Installed the valve covers, riser etc. and threw in a set of new plugs, and the engine runs like brand new. Thanks to all for your help as this engine bongo player has been eliminated.

Trent · Sep 17, 2003

Re: 350 GM Bongo Drum engine noise - Problem solved.

Sorry Bud.... I bet you will be back here soon....I hope not!!!!!

Bondo · Sep 18, 2003

Re: 350 GM Bongo Drum engine noise - Problem solved.

I'm with Trent..... You've Still got a problem.... Valves Don't Just Stick Open, there IS a Reason, You just haven't Found it.... Pull the head,+ get it rebuilt.... Good Luck...

loadnet · Sep 19, 2003

Re: 350 GM Bongo Drum engine noise - Problem solved.

The problem IS over for sure - I would never kid you guys on stuff like that. Those 2 valves were for sure stuck and I'm thinking it must have been poor winterizing method by previous owner. This boat only sat out one season. My local machine shop says they get calls every spring on boat engines with stuck valves and rocker studs lifting up. Took the boat out last night and ran it around for about 45 minutes at 2500 to 3000 RPMs then buried it at WOT for 3 minute intervals every 5 or so minutes, then ran it at WOT for approx 5 to 10 minutes straight... - no water temp problems - oil pressure holding steady between 40 - 50psi - no noises what so ever. - engine runs like brand new, nice and quiet. Cruised around at 2500 to 3500 again for awhile and pulled her out of the water. Only thing we noticed was an occasional drip of water coming from the shift cable which is dripping right on top of the intake manifold. I posted for help on that because I can't find a previous post I saw on the same subject. The outdrive oil is looking a little milky too, so I'm assuming the water drip and the milky colored fluid in the outdrive are probably going to be related in some way.. I'll know for sure if someone who knows these systems in and out replies to my request for assistance on that stuff.. Thanks, PB

kenimpzoom · Sep 19, 2003

Re: 350 GM Bongo Drum engine noise - Problem solved.

One suggestion... Check the compression now so you have a baseline of what it should be when the motor is running good. Also, keep an eye on oil consumption cause the valve guides/seals may have been messed up by all the hammering. Ken

350 GM Bongo Drum engine noise - Problem solved.

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