I think putting a J code intake on will pleasantly surprise you.
CK5
Register an account today to become a member! Once signed in, you'll be able to participate on this site by adding your own topics and posts, as well as connect with other members.
Just bought k5 , is the 6.2 really that big of a turd?
- Thread starter 82detroit diesel
- Start date
82detroit diesel
Registered Member
What does the governor do? And what kind would I need if I got a 350? Size ?style? And what kind of torque converter?/size I’m trying to make a list cause I’m got a free 350 I can get my hands on, thanks for all the help guys
Mostly she just tells the whole state to stay in their homes.
Oh wait, this is the garage, not the political forum. There are 2 governors at play here. The 1st is the device that keeps a 6.2L diesel from revving any higher than something like 3600RPM (I don't know the exact number). If you go with a gasser, they don't have a governor, except for valve float and whatever rev limit is built into the ignition system.
The governor everyone is talking about here is the one in the back of the transmission. It's connected to the output shaft and creates a hydraulic signal based on how fast the driveshaft is turning. The centrifugal force on it's weights are balanced against its springs based on how fast it's spinning (as those little ears on the side move outward, a little valve in the center bore moves up and down). The governor paired with a diesel has more weight than the governor paired with a gasser, which makes the transmission shift at lower engine speed with the diesel. You can easily swap the governor by removing a little cover and it slides right out.
82detroit diesel
Registered Member
Ok cool thank you, I like that it’s easy to do lol now I’m going down the rabbit while watching videos how to rebuild a 350 and I’m getting excited
so as far as the governor going to order one , just look up the part for a k5 350/t400 setup and I should be good? And what torque converter?
so as far as the governor going to order one , just look up the part for a k5 350/t400 setup and I should be good? And what torque converter?
I'm going to jump in here about once. I'm about the last guy you want advising you on a diesel engine.
I own exactly two, one Mitsubishi on my tractor that is a real joy to run, and a '70s model 100hp turbocharged Allis Chalmers on my genset.
Other than fuel filters and oil changes, I call in experts to work on them.
But, while I quite understand your not wanting to put money in an engine you are going to swap out, consider this:
Its spring of the year, probably some of the nicest wheeling days are just starting, and you own a running truck.
Not a good running truck, but it will run and drive. If you stop driving it and start on the swap, you will no longer own a running truck for a while, maybe quite a while.
Ask anybody here when was the last time a major project with a truck that old came off on time.
You could try modifying the air intake system, maybe just pulling off the filters and washing them. They look like K&Ns or clones. Diesels must breathe easy to produce power.
Plus do a fuel filter change and some minor tuneup work. If that restores the engine to what it should be, then you have a useful wheeling truck for cheap, and more time to do a better job researching the engine swap and finding just the right replacement.
Also, in working on the engine, you will be much more likely to spot other problems before you hit them during the engine swap.
Cracks in the frame, bad steering parts, all kinds of stuff that a replacement engine will not fix, but can be easily accessed during the swap.
If you want to tinker with the engine, a tach would be nice. I assume that it has to be mechanical on a diesel, and that your truck does not have one. Otherwise the RPMs its getting to would have been mentioned by now.
You certainly do not want to buy one, no sense in putting that much in an engine you won't keep, but maybe someone here has one in their scrap pile they could loan or donate to you.
That would tell you what the engine is doing. If the transmission were slipping, I would assume you could tell from the engine sound, but a diesel is very heavily governed, and its just not going to over-rev like a gasser with a bad tranny.
That slow maximum speed you are getting just does not sound right to me. Especially if the engine sounds smooth and not skipping or bucking.
But, by all means pay attention to the other guys here, they are the experts when it comes to 6.2s
I own exactly two, one Mitsubishi on my tractor that is a real joy to run, and a '70s model 100hp turbocharged Allis Chalmers on my genset.
Other than fuel filters and oil changes, I call in experts to work on them.
But, while I quite understand your not wanting to put money in an engine you are going to swap out, consider this:
Its spring of the year, probably some of the nicest wheeling days are just starting, and you own a running truck.
Not a good running truck, but it will run and drive. If you stop driving it and start on the swap, you will no longer own a running truck for a while, maybe quite a while.
Ask anybody here when was the last time a major project with a truck that old came off on time.
You could try modifying the air intake system, maybe just pulling off the filters and washing them. They look like K&Ns or clones. Diesels must breathe easy to produce power.
Plus do a fuel filter change and some minor tuneup work. If that restores the engine to what it should be, then you have a useful wheeling truck for cheap, and more time to do a better job researching the engine swap and finding just the right replacement.
Also, in working on the engine, you will be much more likely to spot other problems before you hit them during the engine swap.
Cracks in the frame, bad steering parts, all kinds of stuff that a replacement engine will not fix, but can be easily accessed during the swap.
If you want to tinker with the engine, a tach would be nice. I assume that it has to be mechanical on a diesel, and that your truck does not have one. Otherwise the RPMs its getting to would have been mentioned by now.
You certainly do not want to buy one, no sense in putting that much in an engine you won't keep, but maybe someone here has one in their scrap pile they could loan or donate to you.
That would tell you what the engine is doing. If the transmission were slipping, I would assume you could tell from the engine sound, but a diesel is very heavily governed, and its just not going to over-rev like a gasser with a bad tranny.
That slow maximum speed you are getting just does not sound right to me. Especially if the engine sounds smooth and not skipping or bucking.
But, by all means pay attention to the other guys here, they are the experts when it comes to 6.2s
He might want to make sure the throttle cable is opening the lever on the injector pump all the way to "wide open"too--my truck had about 2" of carpet and jute padding stuffed up under the gas pedal when I got it..
After I removed the jute padding under the carpet,it felt like it gained 50 HP,it wasn't getting full throttle..it then also started hitting "passing gear" like it was supposed too,the switch on the gas pedal wasn't getting pushed in far enough to activate it..
When I added an electric fuel pump close to the gas tank,in addition to the mechanical one on the engine,that perked it up even more..
But that crude intake & dual small filters aren't helping his engine any..
After I removed the jute padding under the carpet,it felt like it gained 50 HP,it wasn't getting full throttle..it then also started hitting "passing gear" like it was supposed too,the switch on the gas pedal wasn't getting pushed in far enough to activate it..
When I added an electric fuel pump close to the gas tank,in addition to the mechanical one on the engine,that perked it up even more..
But that crude intake & dual small filters aren't helping his engine any..
I DD'd an 86 M1009 for years. Highway miles. 70mph everyday. It cruised great with 6.2/th400, 3.08 gear 10 bolts and 37" humvee tires. It wasnt fast off the line but I loved driving it on the highway. Something is wrong if you cant get above 50. The 6.2 gets a bad rap. I liked it honestly. Can't complain too much getting 19 or 20mpg with 37" tires
Agree with others,, 14 bolt ff and 10 bolt front. Are both 8 lug ,, if so probably 4:56 ,, but still should do 65 + trans or transfer case need need serious attention
If you saying that having 8-lug axles means they are likely stock 4.56 gears that is not accurate. Not even sure if a 10-bolt front axle ever came from the factory with 4.56 gears, and a 14FF rear axle with 4.56 is fairly rare also. 4.10's are very, very common.
If it were my truck, I'd spend more time on diagnostics and not rush into an engine swap. It's been said many times already, but you almost certainly don't have enough gearing to keep the engine happy with those tires. And, if the 6.2 engine is healthy, a 350 will have even less power with those gears, because it will be even further from its power band. So first I would jack the truck up and verify your actual ratio, so you don't wind up with a brand new truck that's still a dog.
Second, if your truck has high gears and still can't go fast on the highway, check your fuel filters. Your truck still has the secondary fuel filter behind the intake. I find it funny that whoever did a bad job making "intakes" went far enough to make a mount for the secondary filter, while a lot of guys just pitch them. GM stopped using those after 2 years, they're a bit of overkill. But, being finer filters than most trucks get (5 micron), they do plug. And when they plug, there just isn't much fuel getting into the engine. A fuel pressure reading taken at the outlet of that secondary filter just might tell you a lot.
Same for plugged air filter(s). These engines need a lot of air.
Bottom line, you probably have more than one problem here. But a healthy stock 350 paired against a healthy stock 6.2, given the same gear ratios, will be struggling harder to get up to its power band. And overall, a 1982 Q-jet 350 will give you similar power levels with less torque. It's not going to make a big difference unless something else is wrong with the 6.2.
Last edited:
Another thing to note, TH400 transmissions were not used in stock civilian Blazers, so someone has already been swapping stuff around. It may or may not have a diesel torque converter and governor in there. I'd crawl under there and count torque converter bolts. You also appear to have an A/C truck which has had A/C deleted. I say this looking at the holes in the firewall and the remote P/S fluid reservoir.
Both of those are fuel filters. The one on the firewall is upstream of the fuel pump, while the one in the valley is downstream. That's why the fuel lines look funny, the factory routing isn't as neat and pretty as you would have expected. This setup was only used on 1982-1983 trucks, in 1984 they switched to a single filter setup.
Common 6.2 issues:
The fuel socks are notorious for clogging with rust on these older rigs.
Timing chain stretch/ I.p. pump timing.
Fuel pump/ delivery.
Sometimes the original rubber fuel lines get brittle and crack, allowing air to be sucked into the system.
Really need to know your gear ratio to match it to your tranny. Or put an overdrive in it.
I'm sure I'm forgetting some things....I'm sure someone will speak up.
The fuel socks are notorious for clogging with rust on these older rigs.
Timing chain stretch/ I.p. pump timing.
Fuel pump/ delivery.
Sometimes the original rubber fuel lines get brittle and crack, allowing air to be sucked into the system.
Really need to know your gear ratio to match it to your tranny. Or put an overdrive in it.
I'm sure I'm forgetting some things....I'm sure someone will speak up.
If we're going to pick on the 6.2's for issues, don't forget:
Broken crankshafts
Cracked blocks at the mains
Won't start in the middle of summer without glow plug help
Glow plugs are unreliable, as are their controllers
Glow plugs seize into block and break off when replacing
Broken crankshafts
Cracked blocks at the mains
Won't start in the middle of summer without glow plug help
Glow plugs are unreliable, as are their controllers
Glow plugs seize into block and break off when replacing
^ Gee,I thought that was ME posting for a minute there!..
red EOD
1/2 ton status
Honestly the 6.2/6.5 gets a worse reputation from people that think "maintenance is the same as a gas engine, why doesn't the damn choke work on this diesel?" It's not a badass tow rig engine, but for a rock crawler k5 it works really well. Sips the fuel and make decent torque down low unless you want a high rpm rock bouncer.
Drop the engine swap plan until you know whats wrong with the truck. Swapping to a small block will just piss you off if it turns out there's non engine issues. Find out the gear ratio first. 3.08's and 33"s worked well enough in my 84 k5 with 6.2/th400 for daily driving and rock crawling in Utah (including Moab), 3.73's or similar and 37"s won't pull a greasy string out of a cats ass.
Once you figure out the gear ratio, setup a pressure gauge after the fuel filter to measure fuel pressure. Ideally under full load (hook up a decent sized trailer with cargo) should be 1+psi. If less than that, there is a fuel system issue (plugged filter/pickup, dead lift pump).
That is one odd custom air intake.
Drop the engine swap plan until you know whats wrong with the truck. Swapping to a small block will just piss you off if it turns out there's non engine issues. Find out the gear ratio first. 3.08's and 33"s worked well enough in my 84 k5 with 6.2/th400 for daily driving and rock crawling in Utah (including Moab), 3.73's or similar and 37"s won't pull a greasy string out of a cats ass.
Once you figure out the gear ratio, setup a pressure gauge after the fuel filter to measure fuel pressure. Ideally under full load (hook up a decent sized trailer with cargo) should be 1+psi. If less than that, there is a fuel system issue (plugged filter/pickup, dead lift pump).
That is one odd custom air intake.
82detroit diesel
Registered Member
The guy said it has stock 3:42 gears in the front and back.
If I do a 350 with the turbo 400 what gears should I do? Keep in mind I will never go or want to go faster then 60mph in this thing. It’s for staying on the local streets and trails. And I might go to 40” tires some day.
Oh and driver side was smoking bad too, took header off to see what piston was smoking. It was closest one to the firewall , I swapped injectors with one that wasn’t smoking and put new glow plug and nothing. It’s loosing oil so at this point I’m not trying to resurrect the 6.2 maybe cracked block? Bad valve seals? Idk but yeah gears which ones guys thanks for all the info so far I’m glad I subscribed to this site
If I do a 350 with the turbo 400 what gears should I do? Keep in mind I will never go or want to go faster then 60mph in this thing. It’s for staying on the local streets and trails. And I might go to 40” tires some day.
Oh and driver side was smoking bad too, took header off to see what piston was smoking. It was closest one to the firewall , I swapped injectors with one that wasn’t smoking and put new glow plug and nothing. It’s loosing oil so at this point I’m not trying to resurrect the 6.2 maybe cracked block? Bad valve seals? Idk but yeah gears which ones guys thanks for all the info so far I’m glad I subscribed to this site
With those tires (about 36" tall if the tread is new) and 3.42 gears, the 3600 RPM governor will limit your top speed to 107MPH. In other words, it's power limited, not governed. The rule of thumb is that if you have overdrive, go deep on gears and never look back. Like 4.88 or even 5.13 for 37" radials (i.e. 36" tires). Not having overdrive changes the scenario. Here's your RPM at 70MPH with those tires and different ratios:
But the fact remains your 6.2 isn't running right. Unless it has serious internal issues, the cheapest + fastest + easiest approach to acceptable performance will be fixing what you have.
EDIT: something is wrong with my top speed math. I know the M1008 can't go fast with 32" tires, but with something more like 37", it can cruise on the highway with ease.
- 3.42 = 2360 RPM
- 3.73 = 2573 RPM
- 4.10 = 2829 RPM
- 4.56 = 3146 RPM
- 3.42 = 1643 RPM
- 3.73 = 1791 RPM
- 4.10 = 1969 RPM
- 4.56 = 2190 RPM
- 4.88 = 2343 RPM
But the fact remains your 6.2 isn't running right. Unless it has serious internal issues, the cheapest + fastest + easiest approach to acceptable performance will be fixing what you have.
EDIT: something is wrong with my top speed math. I know the M1008 can't go fast with 32" tires, but with something more like 37", it can cruise on the highway with ease.
Last edited:
I will not give you advice on gears until I know what engine you end up with.
The 6.2 likes to cruise around 1800 rpm and has a max rpm of 3600.
A gas 350 is more happy at 2200 rpm and go easily up to 4500 rpm while a 454 might be happier in between at 1900-2000 rpm and can still go low 4k rpm.
If you know you will go to 40" at some point, get gearing that gets you comfortable with the engine you want and 40" tires, that way you end with gears that get you at least 60mph now.
But first decide what you want.
I think you can get this one going for a while if you fix little things in it.
Even if you have one dead cylinder you can go a while.
This. The last thing we want to do is swap in gears that won't work with your final drivetrain combination...
