How many miles are too many?
 

How many miles would you consider as too many for a donor motor/trans? What should be replaced before completing a swap with a 100k+ mile motor?

Re: How many miles are too many?
 

I had a personal truck with a stock 6.0 ly6 that had 340k on it. ran like a top still. so I would say check its maintenance logs and see how it runs, any blowby? oil pressure after warmup? color of oil, trans fluid smell burnt? so on...

Re: How many miles are too many?
 

My BIL, got rid of his 2004 Silverado at 360k because the front diff needed replaced. still ran great though!

Re: How many miles are too many?
 

We have a fleet customer with 680K on a 6.0 ly6 that is still going strong. Now on the other end of the scale I put a 4.8L in a 2014 Express van last month with 12K miles on it. The dealer said no warranty due to customer never changed the oil. It was a ride share commuter van that is giving to them by their company the sad part is there maintenance is paid for too. I see LS motors with 200-300K miles everyday it all comes down to the maintenance.

For my personal truck I bought a 60K LY6 off ebay that I'm replacing all the gaskets other then the head gaskets. It will be getting a new water pump and thermostat too before its installed next month.

Re: How many miles are too many?
 

I am seeing more 320 K plus trucks in the sale that will have motors ending up in sales racks.I have also seen a railroad truck in the ride and drive portion of my salvage sale that still ran great with 556K on it.I would feel very comfortable with selling a motor going in a hotrod with 180K on it as long as I heard it I have several that I heard run and even some the customer could do the same.

Re: How many miles are too many?
 

My donor had 130K, I replaced the water pump, oil pump, The little oil barbell thingy, timing chain, all gaskets, front and rear seals. I was swapping the heads and cam, so I figured I might as well change it all while it was apart.

Re: How many miles are too many?
 

Thanks for the advice so far. How difficult is it to replace the oil pump? I'll have to swap the oil on to an f-body pan for extra ground clearance

Re: How many miles are too many?
 

You don't need to swap the oil pump to change pans. Just the oil pickup tube.

My 5.3L had 148k running and driving in the donor truck. I pulled it and found excessive oil leakage around the valley pan, valve covers and oil pan so replaced all those gaskets. Otherwise it ran great. I also re-gasketed my PS pump as it was leaking, turned out the pump was bad so I swapped on the 1986 PS pump.

Re: How many miles are too many?
 

I have a 2004 GMC van with a LQ4. It just went over 370,000 miles this week. It tows and hauls drywall..At about 305,000 it burnt a valve. I removed the heads, replaced the valve, re-seated the others, put it back together and shes still running. I did have to replace the transmission though (3 water pumps, 2 starters, 2 alternators too).

Re: How many miles are too many?
 

I know the pump doesn't have to be changed to change the pan. I suppose it was more of a cautionary swap while the motor is out and the front accessories are off to paint the block.

Re: How many miles are too many?
 

I agree with the consciences here. My son's 99 5.3 Z71 had 400k on it when he sold it. Still very strong with no smoke. The 4L60E on the other hand had lots of trouble standing up to his abuse. after rebuilding it 3 times I did it all with top line very expensive parts and he still managed to kill it.

The LSx engine is nothing like the old small block. At 100K these engines are just starting to get broke in.

Re: How many miles are too many?
 

Yeah, the 4L60E isn't known for it's longevity. There's some chance I'll end up with one but if I do and I kill it, I'm swapping for a 4L80E or something else.

Re: How many miles are too many?
 

Changing the oil pump is not bad, 4 bolts and use a feeler gauge to set the spacing. I think its a .20 feeler blade but not sure at the moment, might as well change the timing chain too. You will be looking at it.

Re: How many miles are too many?
 

A 1986 power steering pump will fit into 5.3 Truck accessory brackets?

Re: How many miles are too many?
 

News to me, but they all run around the same pressure, so it wouldn't be the biggest surprise.

You can mix and match (gear, pump, rack n pinion if you have it) between them all if you have the right fittings. I've used the latemodel pump on old steering gears, new racks, and mid-year metric gears. Hydroboost's can also be interchanged similarly, with a few limitations.

Re: How many miles are too many?
 

Yes, I cross-referenced it, exact same Saginaw pump. The 86 pump was marked "Metric" so i was able to reuse all the hardware from the newer pump, and the reservoir popped on from the 2000 pump. I even bought an off the shelf stock replacement line for my 86 and it lined right up.

Re: How many miles are too many?
 

You guys running 300k+ junkyard stuff are my heros.

I used to think I was cool running 160k mile junkyard engines for my turbo setups. Never had a problem that wasn't self inflicted with any of those engines.

Re: How many miles are too many?
 

All the mileage helps loosen up the ring gaps on the oil ring, which is actually how most of the FI setups crack ring lands on these. The junkyard motors are more suited for a turbo than a fresh build! I'm sure you've seen, but those guys on theturboforums beat these like race mares.

Re: How many miles are too many?
 

Agreed. If it has good oil pressure and is clean under the valve covers you are probably fine.

I used a 2005 LM7 core that was an all Mobil1 engine with about 150K on it. I ended up replacing gaskets and stuff for the cam swap, but really I did not have to touch anything. Later I went back and replaced the rod bearings, main bearings, and cylinder rings - but that was a waste of time as they were all in fine shape. Even the timing chain was in spec.

I sold our old Escalade with 180K to a friend and he has 250K on her now without problem. Only issue was the 4L60E, replaced at 140K.

The newer 6L65E (?) is a much better transmission if you can swing it.

So yeah. Just run it if she looks clean on the inside.