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Very high milage 5.3L LM7 gets some unexpected love from Cam Motion
So the 5.3L in my dads company Yukon XL started to develop a very audible valve train ticking/sewing machine sound about 3 weeks ago. The strange thing about this problem it was intermittent, most of the time it was quite as can be. I changed the oil and found nothing out of the ordinary on the drain plug magnet or any excess metal in the filter when I cut it open. So we filled her back up and put it back on the road, about a week later the ticking came back and stayed on the constant side. This time the oil pressure started to act up and was getting on the low side. We decided to put her on the lift and yank the top end off and see what was going on in side...
This engine has 376,xxx miles on the clock, and I was hoping to hit the 500,000 mile mark on the stock internals. Turns out the #7 intake lobe on the cam finally gave up the ghost
Now its time to give the top end a little needed love. After following "Thunderstruck507" thread about Cam motions 5.3L "drop in cam" for the last 2 years. I've wanted to try this for myself but haven't had a good reason to pull the trigger until now. So I decided to give them a call get some advice from them and ultimately place a order for their 5.3L stage 2 cam. In addition we had the heads gone through and milled at my local machine shop, new lifters, oil pump, timing set, and doorman truck intake manifold. Old intake was showing signs of warpage with lean conditions on the valves at all 4 corners.
Here are some pics of the the damage to the cam, and the lifter that is still surprisingly in perfect shape. I'll be reassembling this engine this week so we'll see how she comes out. Hopefully the stock bottom will last another 125,000 miles so we can see the 500,000 mile mark on the clock.
Exciting stuff! As far as you could tell, was oil pressure still good towards the end? If so, hopefully the bottom end should last. That truck is gonna feel peppier for sure! Let us know how it all comes out!
Exciting stuff! As far as you could tell, was oil pressure still good towards the end? If so, hopefully the bottom end should last. That truck is gonna feel peppier for sure! Let us know how it all comes out!
Oil pressure never fell below 20psi but it would only hit 35ish psi in the higher rpm range. Before this happened hot idle was 40psi and 70psi in the upper rpms. While I had the oil pan off I pulled the windage tray and removed the #8 rod bearing cap... Looks pretty good for 376,000 miles.
Did you ever get this running? I just did this swap also im gonna have to get a tune it seems sluggish. I did swap to 243 heads shaved .25 and mls head gaskets.
Did you ever get this running? I just did this swap also im gonna have to get a tune it seems sluggish. I did swap to 243 heads shaved .25 and mls head gaskets.
I don't know either, but there's a chance the new oil pump might have solved the pressure issue as well.
It would be great news if it did! My high mile 5.3 is losing pressure as well and I've often thought about changing the pump.
The only reason I said it might not have solved his problem is because he said the pressure issue started around the same time the lobe wiped out. Considering he didn't see any trash on the drain plug or in the oil I'm wondering if it didn't hurt a cam or main bearing? Hopefully we get an update on this one.
It would be great news if it did! My high mile 5.3 is losing pressure as well and I've often thought about changing the pump.
The only reason I said it might not have solved his problem is because he said the pressure issue started around the same time the lobe wiped out. Considering he didn't see any trash on the drain plug or in the oil I'm wondering if it didn't hurt a cam or main bearing? Hopefully we get an update on this one.
I changed my pump and oring out also and mine did go back up. I was getting about 34psi idle when warmed up. Now it's about 45 idle when warm. I have about 270,000 miles on mine.The reason I did the head and cam swap was I was getting coolant in the oil. I removed the oil pan and cleaned and replaced the Oil pump while I was at it.
Well since the op not responding I'll speak on my setup. I recently got mine back from Tuner and let me say this cam is bad ***!! Pulls hard till about 5800. Nice sleeper idle. Tuner was very impressed the way in turned out. Needless to say so was I. Mods are Cai,Magnaflow 3" cat back still have oe cats on 243 heads shaved .025 with 2.02 and 1.57 valves, stock porting. Stock manifolds. 270,000 plus miles no smoking at all!!
04-19-2017, 09:00 AM
Very high milage 5.3L LM7 gets some unexpected love from Cam Motion 
