Discussion in '6.9L IH & 7.3L IDI Diesels' started by Travis Skavenski, Jul 10, 2019.
Cowl seal is garbage and it happened when we had all that rain in pa
Compression is what ignites the fuel on a diesel, a bent rod takes compression away. No spark plugs to light the fire means you get a miss.
I think the old adage is Suck Squeeze Bang Blow, but if you don't squeeze enough (bent rod) you don't get the (full) bang! Heat will help it catch some if it's borderline but all in all it's no good
Before you start thinking about bent rods, did the engine actually hydrolock on you? As close to the head as these pistons get, it doesn't take much water in a cylinder to hydrolock. When it does that, the engine won't turn over to start. If you got in after a rain, hit the key, and the engine wouldn't turn over, that it hydrolocked. If that didn't happen, then you most likely don't have any bent rods. Then I'd be looking back into your fuel system. I'm pointing all of this out since I didn't see where you said that your engine actually hydrolocked and you got it running again. I read your first post as somebody suggested that your engine hydrolocked. In that case, don't listen to that person any more. Another thing that I noticed was that you said the shaking almost stops and the tap dies down. If it was a rod, then the engine temperature probably wouldn't affect the sound. I'm pretty certain that a bent valve would be the same. If your engine has a lot of miles on it, then your thoughts about a bad lifter may be valid too. If it's a weak lifter, then the problems starting during/after the rain is probably just a coincidence. When you had the valve covers off, did you happen to check the valve springs? I know that they can and do wear with age and they also break. Your engine can still run with a broken valve spring. That's just another suggestion to look at before assuming that you have a bent rod. If all else fails, I believe that Mel is in Pennsylvania as well. You may give him a call to see what he has to say.
When we had all that rain my truck was pointed down hill a small grade I got in it made I believe 2 rotations then locked up I thought it was the starter so I smacked it a couple times and messed with the key and it fired up that’s when I heard the knock when I had the valve covers off I double checked all the springs and everything seemed fine I rolled the push rods and they were all straight I’ve changed injectors so far and the noise is still there as far as fuel goes I do have a leak in my tank but it’s been that since I’ve bought it and has never made the noise/problems and how do I go about getting ahold of Mel I’m willing to try anything at this point
Spending money on fuel parts isn’t going to fix your problem, these pumps and injectors are pretty robust, and don’t fail overnight. I’d bet money on a bent valve or rod, a compression test will answer that for you.
What numbers would I be trying to look for and how do I determine if it’s valve or rod or is that basically down to tearing into it and finding out that way
You want to have at least 300 psi, if they vary more than 75 psi it’s typically a problem. No way to really know until you tear into the engine, but compression numbers would tell you if it’s a mechanical internal issue.
When I suggested this, I was thinking that maybe he could take a look at your truck. I wasn't suggesting that you buy fuel system parts. You can give him a PM here. His user name is Agnem. You could try to get a hold of him at work at 717-806-5561. If you have a bent valve, that cylinder won't have much compression at all.
This still doesn't sound like hydrolock to me. I could be wrong, but usually you can't "unhydrolock" an engine by hitting the starter and messing with the key.
OK, question about how it reacted when this happened?
Did the engine "coast" to a stop, like you released the key? Or did it come to an abrupt stop, like thud and the starter was still trying to turn the engine over and you let off the key?
If it coasted like you let go of the key, that sounds like an electrical issue. Which is why fiddling with the key got it to start.
If it was the sudden stop, that sounds like possible hydrolock. If it did hydrolock, and was able to start after a brief time, the little bit of water could have leaked past the rings, or if a valve started to open, the water could have passed through the valve and made room.
My 1st time did just as yours. Thought the starter had a problem. Was parked at an angle & cowl seal was toast. Water got in the intake past the rubber seal on the air intake. etc, etc ,etc. Starter has a lot of torque on that flywheel and bent 1 rod. I went ahead & honed + re-ringed & changed all bearings except cam bearings. New seals and gaskets. I got everything from ebay when ebay was cheap. More $$ now. Only needed 1 rod which I purchased from member here (icanfixall).
Has been a while but now have to do it again. Still have more parts from this era + a type4 early cam, ported heads & intake, stainless valves from type4. Lots more extras to finish up nicely now.
Bingo! Compression test.
This may be a stupid question but... How is so much water getting into the engine from just rain ? Did you have something open? I've only hydrolocked an engine once and it was from going completely under water.
If the rubber seal underneath the air cleaner hold down bolt isn't perfect, or even just a little but loose, then water will collect in the middle of your aur cleaneer lid and leak past the seal into the intake manifold.
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