I was coming from work last Tuesday night, had just gotten up to speed on the freeway, when I heard a loud knocking rattle from the engine. Checked the guages, all good, pulled over onto the shoulder,shut it off,got out to look. All fluid levels ok, started it and slowly rolled down the shoulder to home. (4 miles) It gradually got quieter, but still there. I suspected a rocker arm, so pulled VC and checked, no issues there. Now for a couple of weeks, its been getting hard to start, so checked the GPs, all 8 dead. pick up new Motorcraft's from O-reillys, come home & change them while its still warm. The first 4 come out looking ok, the next 4 all had 3/8" missing from the tips. Dang Autolites. I put them in 2 years ago when I first got the truck before I knew any better. Now I can only assume that the knocking noise I heard was one of those tips getting smashed around in the combustion chamber. The noise is gone, I guess I got lucky!
Listen to the senior members about GPs
- Thread starter grog85
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icanfixall
Official GMM hand model
Lucky is correct. Usually the tips smash down till they imbed in the pistons or blow out the exhaust.... If you have a turbo then your hot wheel is going to take a few hits... Thats a real bad thing too... Bigger question is why you left the crapolites in so long.....
Diesel JD
Full Access Member
I think most 6.9/7.3s have been traumatized like this at some point in their lives. I know I had a couple of piston tops all dinged up when I changed my head gaskets back in 03. I'm sure that's what did that.
icanfixall
Official GMM hand model
The dings in the piston crowns isn't too bad but... Think about how hot we get these engines and you see those tiny points causing a glow plug effect and preignite the fuel a bit. But then again it may help to burn all the fuel too... BTW... All the pistons I have measured that came out of these 7.3 turbo and non turbo engines have the same dome thickness. Thats around 560 to 570 thousands at the thinnest point in the center... These pistons oem makers is and was Mahle... Funny that way back in 89 they had the forthought to install a quality product....
BTW... All the pistons I have measured that came out of these 7.3 turbo and non turbo engines have the same dome thickness. Thats around 560 to 570 thousands at the thinnest point in the center... These pistons oem makers is and was Mahle... Funny that way back in 89 they had the forthought to install a quality product....
alienturtle
Human
not sure if it was a GP from the PO or cavitation.
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that isnt from a tip. that looks like water or coolant was in there. i had a kubota look like that from coolant.
Holy cow, it looks like that could pinch a ring in the groove if it didn't do anything else. And to Icanfixall's question, I didn't replace them earlier because they worked up until then, and I'm about as broke as anyone as anyone else around here, and didn't have cash to spend if I didn't have to. But that is why I posted about it, put the right Motorcrafts in to start with, and you wont have to worry.
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that can happen trying to pass a tip. u got lucky.
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I have a couple motors around here with the heads off that have GP damaged pistons. Personally, if I end up using one of them I'll just sand the dent out until its smooth with no sharp edges and throw it back together. These pistons will take ALLOT, I only have one here that has a hole in it and I'm guessing it ate the valve face that was no longer on the stem that was hanging over that cylinder.
Wow! Were the others like that? What were the EGT's on that thing. Looks like they got a bit high.
Heath
My truck had autolights when I got it. Sure they worked for a few months but then slowly but surley they started dying. I found a set of 8 ZD-9's on eBay for about $10 a pop, well worth the price. The autolights surprisingly came out without a hitch. I was sweating bullets pulling them waiting for one to get stuck.
Thankfully there are now a few ways to pull broken tips without pulling the heads. Which gives a little peace of mind when changing out older non-motorcraft plugs.
Thankfully there are now a few ways to pull broken tips without pulling the heads. Which gives a little peace of mind when changing out older non-motorcraft plugs.
And this is why the Moosestang has been parked since October. Had an Autolite put in it on purpose, to force me to pull the motor.Problem is, winter has been a *****!
supposed to get into the 50's here soon! get a break from this cabin fever
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