1 month to 8.1 swap, then another month to Nv4500 swap

[#Burbslut]

Great update. Been wondering how another 8.1 brother was doing. Heck of a score on the pcms and hydro clutch parts too. Mileage isn't shabby with the trailer.

I probably could get a tad better mpg if I wasn’t having to rev the crap outta it to get into 4th. It takes about 4 seconds when shifting from 3rd into 4th for it to slide into gear without grinding. From 5th to 4th I have to toss a high rev with the clutch in and 30% of the time it doesn’t grind. So I’m shifting at a higher rpm than I want and having to hold it in 3rd longer than I want. I also think that the Burb would benefit from a 3.73 to 4.10 swap.

I actually scored a bunch of cool stuff at the right price with those pcm’s. I got a legendary k5 chassis with all the fiberglass body panels , a Dana 44 flat knuckle 8 lug Gm axle and a fully forged 496 short block with a Stephs oil pan. Now I’m considering selling the grey K5 and using the Dana 60/14bff I got for that project, for the tubed K5. I’ve been asking my son what kind of truck he wants and he keeps saying he wants a squarebody pick up or a suburban.

 

[#Burbslut]

So here are my rpms in 5th at 55, 65 and 75. When I’m hauling my fully loaded camper and loaded down it’s ok on flat ground, but any headwind or hills and I’m sitting in 4th. I feel like I could benefit from a gear swap from 3.73 to 4.10. I’m running a 255-85-16 tire.

I feel like it’s just chugging at 1400 and 1600 rpms. If I drop a gear and speed up to 80 and then go into O/D, I’m into my power band and it actually holds that speed better.

4th gear at 55 nets 2200 rpms.

 

[ZooMad75]

So here are my rpms in 5th at 55, 65 and 75. When I’m hauling my fully loaded camper and loaded down it’s ok on flat ground, but any headwind or hills and I’m sitting in 4th. I feel like I could benefit from a gear swap from 3.73 to 4.10. I’m running a 255-85-16 tire.

I feel like it’s just chugging at 1400 and 1600 rpms. If I drop a gear and speed up to 80 and then go into O/D, I’m into my power band and it actually holds that speed better.

4th gear at 55 nets 2200 rpms.

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It does sound like it's lugging a little bit with the gears/tire size you have. Here's what mine is doing at those speeds with 4.10's and 315/75-16 size tires.
55mph ---> 1620 rpm
65mph ---> 1914 rpm
75mph ---> 2209 rpm

Using my Tremec gear calculator app if I plug in your tire size with the 4.10 ratio it should put you up to these numbers:
55mph ---> 1696 rpm
65mph ---> 2005 rpm
75mph ---> 2313 rpm

If you bumped all the way to 4.56 you'd pick up a bit more at a cost of top end speed and fuel mileage.
55mph ---> 1886 rpm
65mph ---> 2229 rpm
75mph ---> 2572 rpm

I think 4.10's are well suited to the 8.1's torque curve. 65 mph cruise rpm is right in the meat of the torque curve. Many times I've found no need to downshift when climbing as the 8.1 will continue to pull in 5th if I lean on it.

 

[RootBreaker]

Good updates!
mine isnt done, but getting there more and more!!! CANT WAIT!!!!!!
gonna go update my thread now too

 

[Blue85]

My 8.1L rig has the smallest tires in the world,so it's never lugging!

 

[#Burbslut]

I figured I should maybe flushed the fluid in the Nv4500. Another $120 in fluid.

go figure…

These are just the pieces I grabbed from the pan. There were shiny silver,chrome flakes that the rag wiped up too. They are the size of grains of rice.
The transmission now makes a odd chirping sound now.

 

[Babaganoosh]

Ahh man, I remember that pac fab K5 back in the day, sad to see it in the shape it is but glad you are going to put it back together.

 

[#Burbslut]

Pulled the Nv4500 out a few days after my last post. In the extension housing area was small needle bearings and more slivers. This Burb is sure trying my patience.

I called up my builder and it looks like it could be a few weeks or more to source all the parts for a complete rebuild. I packed it up and sent it off with a visiting family member to start the daisy chain of rides to the transmission guy.

Meanwhile. I got camping trips and stuff to haul coming up for the next few months so I need my Burb back sooner than later. So it looks like I’ll be spending lots of time swapping things around.

I have decided to put a Sm465/205 into my Burb for now. I know I’m not going to like it, but I’ll deal with it. So, the Grey K5 has a 32 spline 465/(round pattern)205 in it with a manual linkage clutch and bellhousing. That is what I am going to put into my Burb. I have not decided 100% if I’ll put my np208 in. I would have to have a driveshaft made for the fixed output 205.

The K5 needs to be able to move under its own power, so I scored a 10 spline 465/205 combo and I’ll be putting that into the blazer. I’ll leave the mechanical clutch setup in the k5 and dig up the hydraulic bellhousing I’ve been sitting on to use behind the 8.1.

I believe all that I’m going to need for the Burb will be the bellhousing, squarebody slave cylinder, hose and maybe a driveshaft if I use the 205. Oh, and drill another hole in the floor. Fml.

Today I picked up the 10 spline combo and I hope to get it swapped into the K5 this weekend.

 

[#Burbslut]

Dang…. It’s been almost a year since my last update.


I couldn’t justify the 4500 to a 465 just to swap the NV back in. I ended up just waiting on parts. It took 4 months and I got it back in. I luckily had my wife’s Burb to drive, so at least I was still in a Squarebody Burb.

 

[#Burbslut]

Let’s see. Not much to report. Just been doing the same sh*t. Working, hauling parts, picking up vehicles, hauling campers. The 8.1 never misses a beat.

My only complaint is my exhaust. It’s still the factory dual exhaust with just magnaflows and tips. The headers are constantly blowing out the collector gaskets. I went to copper gasket’s and it helped but they still have to be changed every few months.

Fast forward to last week, and the Sanderson headers started cracking where the pipes meet the collector. I had them welded up but I know it’s a temporary fix. I’ll start planning on saving for new headers and a full exhaust system upgrade. I’d like to step it up to a combination of 2.5”/3” duals.

 

[ZooMad75]

Glad you got it back up and running. I feel you the nv4500 woes. Mine shelled an input bearing and barfed shrapnel all over. I didn’t have time to wait so I picked up one from a local rebuilder. He upgraded the syncros to full brass units to eliminate the stock fibrous units. Love it.

I’ve been fighting exhaust leaks on my 8.1 also. I keep blowing out donuts at the manifold to pipe connections. Did one on the trip last week.

I think mine needs some flex pipes added between the x-pipe. My exhaust is so rigid it’s not moving with the engine.

When you redo the exhaust do try to install a crossover of some type to balance out the pulses. They sound funky without it.

Keep trucking with it though!

 

[6872xtc]

Cool to see this going again!

I had to pull a set of Sanderson headers off of my small block for the exact same reason.

 

[#Burbslut]

Glad you got it back up and running. I feel you the nv4500 woes. Mine shelled an input bearing and barfed shrapnel all over. I didn’t have time to wait so I picked up one from a local rebuilder. He upgraded the syncros to full brass units to eliminate the stock fibrous units. Love it.

I’ve been fighting exhaust leaks on my 8.1 also. I keep blowing out donuts at the manifold to pipe connections. Did one on the trip last week.

I think mine needs some flex pipes added between the x-pipe. My exhaust is so rigid it’s not moving with the engine.

When you redo the exhaust do try to install a crossover of some type to balance out the pulses. They sound funky without it.

Keep trucking with it though!

Adding a small sect of flex pipe and some type of crossover has also been in the list. I think a combination of small tubing and no crossover, it definitely has a pop to it.

I’m hoping to avoid more nv4500 problems. Only time will tell.

 

[#Burbslut]

Cool to see this going again!

I had to pull a set of Sanderson headers off of my small block for the exact same reason.

I’m looking at some full and mid length replacement options. I’ll probably go with Super Comps by Hooker

 

[#Burbslut]

I found a 8.1 Burb in the wrecking yard in Salinas but it was already picked clean. I think I made out with the intake and the fuel pressure regulator. Everything else was picked cleaned or damaged upon removal.

 

[#Burbslut]

I started having some voltage fluctuations so I went with the larger case higher amp option from the local parts store to put in temporarily while my 240 amp replacement came in.

 

[#Burbslut]

Just scrolling through some timeline pictures and it reminded me of when I started to notice a slight miss and discovered a loose plug wire and another one pulled apart.

After replacing the plugs and wires it started having a long cranking issue. It tossed a cam position sensor code. I went through 3 brand new standard ignition brand sensor. Crap right outta the box. I eventually went to one of my spare complete core motors and took a original equipment one off. No problem since.

 

[imiceman44]

Just scrolling through some timeline pictures and it reminded me of when I started to notice a slight miss and discovered a loose plug wire and another one pulled apart.

After replacing the plugs and wires it started having a long cranking issue. It tossed a cam position sensor code. I went through 3 brand new standard ignition brand sensor. Crap right outta the box. I eventually went to one of my spare complete core motors and took a original equipment one off. No problem since.

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So I have an 8.1 with cam position sensor code, a replacement didn't solve it.
You're saying it could be a bad sensor out of the box?

 

[#Burbslut]

Possibly… I had 3 in a row that were junk.

So I have an 8.1 with cam position sensor code, a replacement didn't solve it.
You're saying it could be a bad sensor out of the box?

 

[#Burbslut]

We also upgraded our camper trailer. Our old one had a shot roof. The guy that sold it to us lied about it leaking and the fact I knew nothing about trailers or what to look for, we got screwed. I hastily did a shotty repair job over a weekend and basically took a tarp with us everywhere the trailer went.

So…. We went this route. 2022 Winnebago Micro Minnie 1800bh. It’s perfect for what we need. Bunkhouse for the kids and a queen for mom and dad. It’s 3750 empty. As soon as we got it home, we emptied our old one and immediately took it on our annual trip to Northern Idaho up past bonners ferry. 2,800 mile round trip. It hauled beautifully. I’ll do a trip report later.