Wow.
I haven't seen one of those trucks that clean in a LONG time
I haven't seen one of those trucks that clean in a LONG time
'90s Chevy truck elusive engine knock. Rod/Main bearings, or what?
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In spite of its clean condition, this was my work truck for many years. Hauled vintage car parts, including years of parts pulling from salvage yards and lots of construction projects around my home and workshop. So it's seen a fair amount of hard work. Kept it garaged/carported throughout its 32 years. Really bums me out about this engine issue, but that's life. I'll be putting it on jack stands this weekend and pull the pan. I might pull the valve covers just to see what things are looking like in there.
Pic from a few weeks ago:
Pic from a few weeks ago:
Looks in good shape for the age and shouldn't be giving you problems at those miles being well maintained. Could just be bad luck?
I'd throw a new oil pump at it since it is cheap and easy enough. With the pan off use a pry bar to see if the crankshaft moves side to side...could be a worn out thrust bearing. It is really hard to see if a main or rod bearing is bad by moving things around. If they move that much it won't be a slight knock, it will sound like its ready to grenade!
Also consider taking your valve covers off and checking your valve lash. A loose rocker arm, bent pushrod or a failing lifter can make some pretty ugly sounds.
If these don't fix it....you may just be due for a re-build or replacement. Run 20W-50 until it dies.
I'd throw a new oil pump at it since it is cheap and easy enough. With the pan off use a pry bar to see if the crankshaft moves side to side...could be a worn out thrust bearing. It is really hard to see if a main or rod bearing is bad by moving things around. If they move that much it won't be a slight knock, it will sound like its ready to grenade!
Also consider taking your valve covers off and checking your valve lash. A loose rocker arm, bent pushrod or a failing lifter can make some pretty ugly sounds.
If these don't fix it....you may just be due for a re-build or replacement. Run 20W-50 until it dies.
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Valve covers removed. Not seeing any metallic bits here. Nothing seems suspect, as far as I know what to look for.
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Pull the pan and look at the pan and oil pickup tube. If they look clean, put a HV oil pump in and just run it. I may have missed it, did you put a mechanical gauge on it or are you relying on the dash gauges?
I'd get a mechanical gauge on it if you have not. Could be metal debris from holes drilled in the oil filter...uuummm WIX. Change the oil and filter with a Donaldson or Baldwin and some M1 10w30 and see what happens AFTER you drop the pan and inspect it and bolt on a HV oil pump. I bet everything is fine.
Removing #2 plug wire, are you absolutely sure it's not an arcing spark that you hear? Noises are different for different people.
Pop the hood at night and run it, look at #2.
if not that, I'd suspect a wrist pin.
I'd get a mechanical gauge on it if you have not. Could be metal debris from holes drilled in the oil filter...uuummm WIX. Change the oil and filter with a Donaldson or Baldwin and some M1 10w30 and see what happens AFTER you drop the pan and inspect it and bolt on a HV oil pump. I bet everything is fine.
Removing #2 plug wire, are you absolutely sure it's not an arcing spark that you hear? Noises are different for different people.
Pop the hood at night and run it, look at #2.
if not that, I'd suspect a wrist pin.
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Dash gauges only. Will certainly connect a mechanical after I get it all back together. I don't mind going to a HV pump, as long as it doesn't cause excessive leakage with engine seals (light leakage now front/rear seals). Is it possible to check/test wrist pins from underneath?
Based on the description id be looking at Skirts and Wrist Pins.
Nice truck.
Nice truck.
You stated the knock changed when the tension on the accy belt was changed. That's a clue to main bearings, as the belt places a load on the crankshaft nose, and changes how the crank 'orbits' in the bearing shells.
Most of the time, the force from the accy drive is upward on the crankshaft, or at least it generally opposes the downward forces from the con rods during a power stroke. With excessive clearance, the crank can cause a knock when it gets driven to the opposite side of its orbit by a power stroke on the front cylinder(s).
Have you warmed up the engine to the point where it begins knocking and then removed the accy belt entirely? That may provide a more conclusive diagnosis.
Most of the time, the force from the accy drive is upward on the crankshaft, or at least it generally opposes the downward forces from the con rods during a power stroke. With excessive clearance, the crank can cause a knock when it gets driven to the opposite side of its orbit by a power stroke on the front cylinder(s).
Have you warmed up the engine to the point where it begins knocking and then removed the accy belt entirely? That may provide a more conclusive diagnosis.
I have a 1990 Ford Ranger XLT with the 2.9 liter Cologne motor. It has blown out the oil pressure sender 2 times and still has good oil pressure but it does have a slight knock under acceleration. If I use premium gas the knock is greatly diminished. I got to looking in my owners manual about the required octane and could not find a listing except to say unleaded fuel only. I believe that at the time it was built or regular fuel had a higher octance than today. Try some premium gas and see what happens.
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A local mechanic also told me it was main bearings (unfortunately he does not do lower engine repairs). In fact, I swapped in a tighter belt to show him the knock issue. I tried running a slightly slacker belt for a while but had slipping noisy ac compressor. Yes, removing the belt does stop the knocking.
Yes, I tried some higher octane gas last month when I was trying to rule out everything else that might be causing the knock.
As a bandaid, you could try stepping to a 15w-50 or 20w-50 in the mean time to see if that helps reduce the knock and restore pressure.
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I drained the oil and removed the filter (K&N), found just a few metallic flakes in the oil. Saw virtually nothing in the filter pleats, maybe a speck or two. I have the truck jacked up, and will go ahead and pull the pan and check things out. I feel like I can do a bearing repair, as long as I can access them. My biggest concern is ordering the correct size bearings, as that certainly seems to be a critical part of the process.
They sell main bearings in .001" & .002" undersize....You can use a Plastigauge to get an idea what the clearance is.
Clevite......
.001" under is part# MS-909P-1
.002" under is part# MS-909P-2
After that it's .010", .020", & .030" under & would require grinding the crankshaft.
I'm not advocating for this type of repair as it doesn't always work out.....A Plastigauge won't tell you if the crank journal is concentric, The main bearing bore is concentric.....Or if the block has experienced Core Shift & needs Align Honed.
Here's the bearing clearance specs.....
Clevite......
.001" under is part# MS-909P-1
.002" under is part# MS-909P-2
After that it's .010", .020", & .030" under & would require grinding the crankshaft.
I'm not advocating for this type of repair as it doesn't always work out.....A Plastigauge won't tell you if the crank journal is concentric, The main bearing bore is concentric.....Or if the block has experienced Core Shift & needs Align Honed.
Here's the bearing clearance specs.....
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Thanks clinebarger. That will give me something to work with.
Got the oil pan off this evening, went pretty well actually. The oil pump screen was clean with no debris, and the tube assembly was tight and in the correct position. Nothing really seemed out of place inside, at least with my initial peek before I quit for the night. Where the connecting rod bearings meet the crankshaft on pistons 1 & 2, those has a little movement front to back. Did not notice any up/down movement, though. I'll have more time tomorrow to check out things a little closer.
Got the oil pan off this evening, went pretty well actually. The oil pump screen was clean with no debris, and the tube assembly was tight and in the correct position. Nothing really seemed out of place inside, at least with my initial peek before I quit for the night. Where the connecting rod bearings meet the crankshaft on pistons 1 & 2, those has a little movement front to back. Did not notice any up/down movement, though. I'll have more time tomorrow to check out things a little closer.
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Oddly enough.....Had a customer lose the LO5 in his '92 Stepside.....Spun a rod bearing @ 190,000, Took great care of it.....Never ran low on oil, Never got it hot.
Had a 436 horse Blueprint 383 stashed back from some horse trading on a LS swap, Had a Fast EZ fuel injection system on it & it was the biggest pile you could think of.
Owner didn't want to lose fuel injection....But good systems are very expensive then you need someone familiar with said system to tune it.
I think he'll be happy with the 4160 750cfm BIGS prepped Holley, In the middle of bending fuel lines to mimic the TBI lines....Running a bypass fuel pressure regulator under the truck to knock the pressure down to 7 PSI using the in tank pump.
Had a 436 horse Blueprint 383 stashed back from some horse trading on a LS swap, Had a Fast EZ fuel injection system on it & it was the biggest pile you could think of.
Owner didn't want to lose fuel injection....But good systems are very expensive then you need someone familiar with said system to tune it.
I think he'll be happy with the 4160 750cfm BIGS prepped Holley, In the middle of bending fuel lines to mimic the TBI lines....Running a bypass fuel pressure regulator under the truck to knock the pressure down to 7 PSI using the in tank pump.
Oddly enough.....Had a customer lose the LO5 in his '92 Stepside.....Spun a rod bearing @ 190,000, Took great care of it.....Never ran low on oil, Never got it hot.
Had a 436 horse Blueprint 383 stashed back from some horse trading on a LS swap, Had a Fast EZ fuel injection system on it & it was the biggest pile you could think of.
Owner didn't want to lose fuel injection....But good systems are very expensive then you need someone familiar with said system to tune it.
I think he'll be happy with the 4160 750cfm BIGS prepped Holley, In the middle of bending fuel lines to mimic the TBI lines....Running a bypass fuel pressure regulator under the truck to knock the pressure down to 7 PSI using the in tank pump.
Love your junk pile
What’s that black intake plenum off of in the top left of your first pic?
2001 F150...2V 5.4L Modular. It's a Dorman replacement that got over torqued which lead to it leaking coolant.....Had to use my extra long 3/8" ratchet to break the bolts loose accompanied with a loud snap.
Had to use a Dorman also
Had to use a Dorman also
2001 F150...2V 5.4L Modular. It's a Dorman replacement that got over torqued which lead to it leaking coolant.....Had to use my extra long 3/8" ratchet to break the bolts loose accompanied with a loud snap.
Had to use a Dorman also
Found a pic of it online, I see the coolant crossover tunnel on the front.
Yick, seems like a bad design.
If you do replace the oil pump check out some stories about the stock melling m55 replacements. They seem to have a tendency to break. Some rumors about the casting getting thinner. There is there shark tooth models that are supposedly the ones to get with better pump gears and stronger castings.