Hi. First, thanks for all the video lessons, they have been invaluable to me.
-2018 Silverado 4x4 5.3 L83
-Cyl. 7 misfire
-This happened very quickly, no previous indications of issues-- tapping, rough idle or smoke. Just boom, engine light and rough running, smoke etc. Truck was limped home immediately after and has only been started to test if tune-up resolved misfire and then to park in garage. Well, possible previous indications (in hindsight) of difficulties with transition from V4 to V8 that I had attributed to transmission issues, as the result was a kind of lurching, stutter-start type increase in speed that felt more like the tranny in the wrong gear for what I wanted or something worse.
-Oh, zero compression cyl.7
-Very back valve (intake?) barely moves during manual turn over and I can manually compress the lifter instead of the valve with a pry bar.
I believe this falls into the "have to replace the lifter due to ramping" category. I am waiting on my dial caliper, as I believe under no load, the lifter will accurately translate the camshaft lobe profile to the caliper to see if the lobe has any damage. I understand that there may also be damage to the roller, but I'm hoping for a good profile. But, I was also hoping for only a collapsed lifter, so....
I have the tools, space, time, and enough skills (I think) to replace the lifters.
I do not have the above to replace the camshaft. So if it's shot, then all this is moot and I need to find a shop or a very gullible buyer.
Questions:
Since I'm digging down this deep, I figured might as well:
1.) pull both heads and have them machined and the valves serviced
2.) Replace all 8 AFM lifters instead of just the failed one.
3.) Perform the VLOM delete
4.) Have the PCM/ECM tune service by lt1swap.
Does this sound like a feasible/reasonable compromise to a complete delete?
If this works, I will probably keep the truck, at least until I can find a more suitable replacement.
Parts needed:
1.) 8 X AFM lifter + guides?
2.) 2 X exhaust gaskets
3.) 2 X head gaskets
4.) Do I really need to replace the head bolts? Is this just cheap insurance?
5.) VLOM Service Kit w/both valve cover gaskets
6.) Pushrod upgrade ($14) this seems like a no brainer
7.) Oil galley feed plug
8.) Should I also install the oil block off plugs from lsexceleration? Can't have too many ways to control the flow of oil?
I checked with both your recommended sources and locally but I cannot find a set of AFM lifters, or am I just not seeing them? I mean, they are the ones with the spring on top. Any more suggestions?
Did I miss anything?
Thanks again for all the help, I'd still be scratching my head at this thing if I hadn't found your videos.
Chris
You have somewhat of an understanding but I'm glad you're asking questions.
Pull the valley cover first and inspect for roller/cam damage. You should be able to see the lifter on 7 without head removal.
If it appears good proceed with pulling the head.
To check the plastic trays, grab the AFM lifters while they are sitting in the tray and try to rotate them. If you can rotate them with very little effort the tray is no good. If it takes a decent bit of effort and it isn't rotating, move on to the next one. Don't overly force it. You can cause damage to the plastic.
Might want to replace all AFM lifters. However there is a way to take them apart for inspection if you like. They can be purchased at most parts store or online parts places. They will be individually purchased though and not a set. Just avoid cheap knock offs.
You definitely need head bolts, they are stretched during tq process. One time use only.
Pushrod upgrade at $14 is base price for a single pushrod. The full set of 16 is much more. Though the more you buy the cheaper per single one gets. I do this to promote buying a full set. While having the option to only do the problem pushrod.
Only do the VLOM plug and cutting of gaskets. Don't get the oil galley/tower plugs. If you block those oil towers with AFM lifters the main oil galley under the lifters will eventually fill up and pressurize the oil tower leading to lifter failure.
If I missed something let me know.