I've only once had a real rod knock. It didn't affect the way the engine ran, it just made a hell of a racket when I hit the throttle. I'd keep checking before doing anything invasive.
Calling the CSC brain trust (2 Viewers)
- Thread starter 1972FJ55
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splitshot
Head cook, Bottle washer, and Peace keeper.
For what it's worth, might want to check your rockers. I had the copper oil line that fed them split on and old F and it took out the valve guides, valves, and seats on the front 3 cylinders.
- Thread starter
- #23
No rockers
but here's what I know so far: pulled off the valve cover and everything looks ok. Checked the timing and everything lines up per the manual, however I could easily turn the motor over with a long ratchet even though I had left the plugs in. No sound of compression as it came up to TDC. So I'm still a ways from solving the mystery. Tonights plan is to pull the lower oil pan and see if I can see anything from below.
but here's what I know so far: pulled off the valve cover and everything looks ok. Checked the timing and everything lines up per the manual, however I could easily turn the motor over with a long ratchet even though I had left the plugs in. No sound of compression as it came up to TDC. So I'm still a ways from solving the mystery. Tonights plan is to pull the lower oil pan and see if I can see anything from below.
How many miles are on your rig?
- Thread starter
- #25
238k but has run pretty flawlessly since I purchased in 2009.
It's amazing how clean these motors are inside, even with high mileage.
- Thread starter
- #27
Saturday update: Checked a couple other suggestions, that the balancer might be spinning on the front of the crank or the cam gears were no longer affixed to the cams, but both are ok. Removed the lower oil pan and strained the oil through a paint filter-found some bits of carbon but no metal shavings. Pulled the spark plugs back out and checked that #1 piston was indeed at TDC-it was, and stuck a magnet down each one to see if maybe it was a bolt rattling around in a cylinder. No luck there either. So the next step is pull the head-fun central-not! Should anyone need something to do on 520s lovely afternoon, I'll provide the cold beverages and a burger...call if you need directions 520-982-2533
There is a good bit of varnish in there, but no sludge. These motors do run clean. Message tools. He has been working on a truck with a knock similar to yours, but I don't think it has the compression issue. Have you done a block sniff test or leak down test?
- Thread starter
- #29
Thought about the leak down test but don't have a tester. At this point I'm into it far enough that I might as well take the head off and hope there's something obvious.
Well if you pull the head it as least gets the HG out of the way.
- Thread starter
- #31
Pulled the head this last weekend, yes it was a pain! Anybody see anything wrong with this head gasket? I don't. Probably didn't need to pull it. One more theory is that there's a leaky injector (or 2) that dripped into the cylinder overnight and caused the rough running and knocking. The plugs were somewhat wet on all cylinders. So now my debate is whether to pull the motor out and check it over and make reassembly easier. Any thoughts?
murf
Lifer
How do the cylinder walls look? Any scoring?
- Thread starter
- #33
I finally had some time to do a bit more work on the 80. The cylinder walls are in great shape, no scoring and the hatch marks are clearly visible. Head comes back from the machinist tomorrow and the block will be extricated this weekend.
Hope you get it figured out.
Thanks for sharing
Wish I was closer to offer a hand
Best of luck
splitshot
Head cook, Bottle washer, and Peace keeper.
Rex, any update?
- Thread starter
- #37
Not much to report. Hurt my back lifting the head out of the trunk, so that put working on it on the back burner. The injector guy cleaned and flow checked the injectors and reports none of them were leaking, so much for that theory, maybe a bad fuel pressure regulator? Have been collecting parts and pieces to get it back together and cleaning 240k miles of grime from various parts. Hope to have the block out this weekend.
- Thread starter
- #38
Last nights accomplishment
splitshot
Head cook, Bottle washer, and Peace keeper.
I can only look at the good at this point (since it's not on my dime)
Think of it as a great investment.
Think of it as a great investment.
