1986 J20 LS Swap

[Yeller]

Yeah I’ve had thoughts and concerns about the 6.0 in mine, I know it has 300k on it…. But I feel like I have core value in the donor so I feel like I have gotten my money out of it but it’s going strong.

[tgreese]

Is the flat cam a Chevy thing, or just a benign end to a worn-out engine (rather than the bottom-end failing)?

[SJohn]

Is the flat cam a Chevy thing, or just a benign end to a worn-out engine (rather than the bottom-end failing)?

I know the gen 4 engines with the cylinder deactivation are prone to lifter failures, not sure about gen 3. For my case it looks like an oiling problem, the rocker end of the pushrods had significant wear and the lifters had some wear where it rides in the lifter bore. I don't know how it happened as I never saw the oil pressure drop below 20 but maybe a crappy filter or trash built up somewhere? I haven't pulled the rod caps yet, but I suspect I'll find something there too.

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[Yeller]

This is not a common thing from what I’ve seen. never know could have been run low on oil for some reason.

Even the 4th gen motors typically the lifter collapses and doesn’t wipe the cam, at least on the ones I’ve looked at

[SJohn]

I was originally concerned it ran low on oil as I had to add oil right before the trip to East Texas towing the Cherokee, but after pulling the pan last night, I think that's unlikely. As low as the pickup tube sits in the pan, I don't believe the oil level ever dropped that low or at least during my ownership of the engine. When I found the glitter during the oil pan gasket replacement, I drained close to 5 quarts, so I know it wasn't empty or critically low. I haven't pulled the oil pump off yet but I want to inspect it to see if there's any signs of failure there.

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[SJohn]

Well that hurt the back pocket. Picked the long block up today and waiting on a box of parts from rockauto.
Assembly starts next week!

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[Yeller]

I’m excited to see what you think of the performance difference.

[SJohn]

Assembly has begun and hopefully I will have it ready to go in the truck by Memorial Day on Monday. When I ordered the engine I went ahead and ordered all the parts that I should go ahead and replace now so I can have a practically brand new engine when it is all back together. Water pump, AC belt tensioner, valve covers, knock sensors, harmonic balancer and bolt, thermostat, and maybe a few others I've forgotten. Summit supplied a whole box of felpro gaskets for just about everything as well as a melling oil pump and pick-up tube. I also went ahead and picked up new 36lb injectors as recommended by summit and a 255 LPH pump will be going in the sending unit.

Oil pump, timing cover, and waterpump installed. Oil pan and valley cover degreased and deep cleaned, ready for install.

[SJohn]

Soooo close!


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[SJohn]

And all back together! Engine is in, bolted up, plumbed and wired back in. It very badly needs to be tuned as it won't idle at all but runs decent above 1K RPM. Oil pressure is great with 50 psi immediately. I primed it with a pump sprayer and hose barb adapter threaded into the port on the front of the block. Next is getting it on a dyno and tuned so I'll be working on that this week. Also will be swapping in the 255LPH fuel pump when it arrives.


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[Yeller]

Good to hear uts back running. Running it will improve the no idle, still may not get perfect without a tune but will improve.

[Stuka]

Gen 3's have roller cams right? Thats a whole lot of wear for a roller cam. How did the lifters look?

[SJohn]

Gen 3's have roller cams right? Thats a whole lot of wear for a roller cam. How did the lifters look?

Sorry I didn't take pictures but there was some wear on the contact area of the lifter bores and similar wear on the roller itself. Nothing catastrophic but definitely not good.

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