M1008 Powertrain Upgrade

[engineman2]

Hello all,

I've never posted in the hot rodding section of the forum before. However, I'm glad to say that that time has arrived. My M1008 will be receiving quite an upgrade in power and speed. I will warn those who wish to follow this thread that this is a long term project that is already under way. Following are the details of the build thus far:

6.2 from a 1986, 18,xxx original mile CUCV blazer with the following:
-rebuilt 6.5 heads with standard 6.2 J code precups (for fuel efficiency and better cooling water flow)
-all new bearings and bushings throughout
-turbocharger set up from 6.5TD with non-egr intake and GM4 turbo
-Melling oil pump
-6.5TD serpentine belt setup with air conditioning and vacuum pump delete
-high volume 6.5TD water pump
-Mahle gaskets everywhere
-standard thickness head gaskets
-ARP head studs
-Oregon Fuel Injection DB2 pump, tuned by them to match engine/turbo
-electric fuel pump

1994 4L80e from 6.5TD truck, 190,xxx miles and another 4L80e from 1995 suburban
-All new bushings and bearings
-new planetaries (more than likely, I've yet to tear down the transmissions)
-new frictions and steels
-new seals everywhere
-new sprags
-pump rebuild
-all new solenoids
-TCI automotive torque converter
-TCI automotive trans controller
-heavy duty trans cooler (most likely B&M)
-some form of shift kit, as of yet undecided

 

[richingalveston]

Curious why not use 6.5 block? All of that upgrade to stay 6.2 you can still detune a 6.5 and have a little better block.

I would stay away from TCI controller. The US shift is the same or I think better. I had a real bad experience with TCI. They sent me a trans controller with an efi program in it and it over-pressured a brand new rebuilt 4l80e. They sent a second one that was bad. I paid shipping both ways, and they were unwilling and complete A-holes on a third. I estimate it cost me about $1500. I had to have tranny rebuilt and had to buy a new controller.

I really like the US shift 1. I mounted the controller in my dash where the volt meter was. You can connect it to a laptop and tuning is easy.

There are also better torque converters in my Opinion but I am definitely biased now.

Welcome to the hot rod forum

Rich

 

[engineman2]

Rich,

I had access to the entire 6.2 blazer for nothing other than a tow. The 6.5 truck I got the turbo and 1 trans from had a bad block. It was a parts truck at the diesel shop I worked at.

And thanks for the notes about TCI. I don't have a ton of experience with them so any insight would be useful!

Additionally, I hope to get some pics up when times allows.

 

[rustystud]

I also agree with Rich about "TCI" . Nothing but bad from them !

 

[richingalveston]

The 6.2 can be a good motor if you do not push it to hard. putting a turbo on will wake it up and give it more power but be careful one the gearing.

a 6.2 run at heavy load and low RPM is know to have crank failures.

When you put the 4l80e in you may need to change the gears. The motor will not like doing 75mph at 1700 rpm.

I am not sure what your final drive is but the 1009 has highway gears in it already without the overdrive.


I have 4l80e with 4.56 gears and 39 inch tires. at 75 mph I am in the 1800 rpm range and the 6.2 non turbo does not like it. I can feel the cylinders firing when I hit an overpass and I know the crank is getting stressed to the max. I am upgrading to a new 6.5 because I am sure my 6.2 wont last long with the gearing I have. I like the gearing and I think with a 6.5 optima I wont have any problems.

I may have to go to a 5.10 or close to that in the future. I will see how it goes after the motor change.


Your truck will be fine if you watch out on the gearing. The 6.2 are loud at high rpm but that's what they like when loaded.

rich

 

[gringeltaube]

.....................................
I have 4l80e with 4.56 gears and 39 inch tires. at 75 mph I am in the 1800 rpm range and the 6.2 non turbo does not like it. I can feel the cylinders firing when I hit an overpass and I know the crank is getting stressed to the max. I am upgrading to a new 6.5 because I am sure my 6.2 wont last long with the gearing I have. I like the gearing and I think with a 6.5 optima I wont have any problems.
.......................

What would be different, with a 6.5L crank....?

 

[engineman2]

I will be sure to examine TCI as my source for these transmission parts more critically after these negative reviews, thanks guys!

I have the standard 4.56's in mine and with 33 inch equivalent tires. At 75 MPH I will be turning just over 2,600 RPM which is pretty fast, but far from 1,800 RPM range you specified. I will probably cruise in the 65 to 70 MPH range, a vast improvement over 55 on the interstate!

Finally, the majority of crank failures in these engines are related to harmonic balancer or flex plate failure. I don't think that running at lower RPM's should cause any issues as long as the engine is mechanically sound otherwise and the user is not asking for more power than is available at that RPM. You are correct that lugging the engine under high load at lower RPM's is not good but this normally leads to bent connecting rods. However, I can see how an increase in low frequency harmonics delivered to the crank at these lower RPM's could cause stress on the crank while not physically increasing the load.

 

[richingalveston]

through all of my reading over the last 6 years since I got into the 6.2 and 6.5 is that the 6.2 has more crank failures and the 6.5 has more head failure due to cooling issues.
In many threads on the 6.2 I read they believed heavy torque at low rpm broke the crank. It may just be coincidence. since they probably broke the crank off road and not driving down the high way.

I believe most of the 6.5 cranks are on average 10 years newer and may have some better metal. I don't know why the 6.5 crank does better but I have been reading many forums for the last 6 years and the 6.5's seam to have head and cooling issues in general and not crank problems.

Yes the bad harmonic balancer will cause it also which could also be because people run them 10 years to long.

I put about 1500 miles on my truck much of it at highway speed 65 to 70 and with the gearing I have you can feel the engine struggle on overpasses. The motor does not produce enough power to keep it in 4th a turbo will probably be just enough for the small hills. At 70 I think I am doing 1800 (it has been 6 months since I drove the truck, excuse my earlier post) no matter what your gearing is, 70 MPH in a 5000lb brick is a heavy load on a 6.2 when below 2000 rpms.
I started to turbo my motor and decided against it because in order for me to keep the 6.2 I believe a re-gear or smaller tire was going to be needed to get the rpm's up.
I like my tires and don't want to re-gear until I try it with a 6.5 turbo.

I am not criticizing your build, I enjoy seeing others in the Mod section. If you keep the rpms up, the 6.2 you are building should be a good motor. I was only giving you something to look out for.

Once you get the 4l80e installed, the 6.2 is a different animal than when it had the th400. When you hit 4th your realize how little power it actually has. Don't try to suppress the rpms to much all of the HP is above 2000. I am interested in what your final speed and rpms. We will have the same tranny and axle set up just different size tires.

I will also be curious to what your fuel mileage will end up being. I was getting 16 mpg on the highway. Which I thought was pretty good for my setup. my 2014 duramax gets the same.

Thanks for taking the plunge into the modified world.
Rich

 

[rustystud]

Some of the "crank" issues on the 6.2 are also caused by lubrication problems. Since you appear to be going with a better oil pump you might just eliminate those issues. I would also look at the main oil galley and side galleys for full flow since GM loved to use "step-down" drilling on those. What I mean is the galley might start out as a 5/8" hole and drop-down to 3/8" at the last few crank journals. IHC also did this a lot. I have bought long drill bits to drill out the galley holes to the full length thus providing full pressure and flow to the last journals. This has saved my front two connecting rods on my 392 IHC engine when it was revved up.

 

[LeaDeR]

How's the build coming along these last few months?

 

[The FLU farm]

at 75 mph I am in the 1800 rpm range and the 6.2 non turbo does not like it. I can feel the cylinders firing when I hit an overpass and I know the crank is getting stressed to the max.

Downshift?

 

[corelokt]

Just don't put a lot of money into the 6.2 and you'll be fine when you decide to go with a late model 6.5