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Discussion Starter #1
I have been driving the truck a couple of days now since the swap and I am a little disappointed in performance. The 6.5T I took out ran about as good as the 6BT....

The problem is that there is zero low end responce. The engine does have a large unwastegated HX35, but I dont think that is the only issue. The engine will not smoke any at all if you flog it off idle; it just lazily revs up. In pulls better in 2nd and third gear once it gets a little bit of load and begins to make boost, but first gear is really gutless. It is as if the engine gets no fuel until it starts making boost. After it loads good in a high gear and makes boost it comes alive, but it takes a while for that to happen.

I know the preboost fuel can be adjusted, but I am wondering if there could be something I am missing here. It seems to me if it was a boost lag problem there would be some smoke?? The truck is a Chevy V3500 4x4 with 4.10 gears and no OD. The engine is a 190HP from a Ford Truck and is suppose to have 475lb/ft of torque at 1600RPM....no way this thing is making that much power at low RPM.

Any ideas are appreciated.
 

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What kind of tranny? If it is the Getrag, start in 2nd. If it is a auto, it might be the torque converter.

What pump does it have? A p-pump or VE?
 

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Discussion Starter #4
Thanks for the link. I will do some reading there.

The engine is a p-pump mated to a chevy automatic. I am using the 11.5" chevy diesel converter, and it is new.
 

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1. you need to advance the timing.
2. install gov springs .
3. adjust your star wheel.
4.grind your fuel plate or buy one.


The 6b from trucks and bus are slow ,they will not pull like the 6b in the dodge trucks.

with the auto and t/c will also cause it to be on the slow side as well.

* note if you do these mods that trans will not hold *
 

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Discussion Starter #6
Thanks CrewCab.

I know that the TH475 will not hold up to a real strong 6BT, but this thing could not break any tranny as it is right now. I just want to get up to a decent level of power. The governor spring should not make alot of difference in the torque output, so I am planning on doing that. Have you every tryed the washer trick instead of buying new springs?

Also, I have read that you can adjust the fuel plate to get more power over stock location, so that probably makes the most sense for my setup. What is involved in the star wheel mod?

Thanks,

Chris
 

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Thanks CrewCab.

I know that the TH475 will not hold up to a real strong 6BT, but this thing could not break any tranny as it is right now. I just want to get up to a decent level of power. The governor spring should not make alot of difference in the torque output, so I am planning on doing that. Have you every tryed the washer trick instead of buying new springs?

Also, I have read that you can adjust the fuel plate to get more power over stock location, so that probably makes the most sense for my setup. What is involved in the star wheel mod?

Thanks,

Chris
The Gov spring will make a big difference ,it runs out of RPM ,the problem that you have is the lack of fuel and air .

The star wheel adjustment , remove the 8mm screw on the AFC housing on the injection pump ,make the stock location of the wheel .Screw the wheel to the front of the housing ,do a little at a time ,all the way forward you'll see a black cloud of smoke .

I don't like using the washer ,I think the spring kit is the better way to go.

You can slide the plate forward just make sure you make the stock location very good . I just grind all my plates .
 

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1. you need to advance the timing.
2. install gov springs .
3. adjust your star wheel.
4.grind your fuel plate or buy one.


The 6b from trucks and bus are slow ,they will not pull like the 6b in the dodge trucks.

with the auto and t/c will also cause it to be on the slow side as well.

* note if you do these mods that trans will not hold *

I may be confused here, but don't you mean he needs to retard the pump timing? It was my understanding that advancing is to rotate pump body toward engine, retard is away from engine. Advancing it kills bottom end but makes more power top end, retarding peels some off the top end and gives it to the bottom. I may be wrong on this but want to be sure he gets the right info.
 

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I may be confused here, but don't you mean he needs to retard the pump timing? It was my understanding that advancing is to rotate pump body toward engine, retard is away from engine. Advancing it kills bottom end but makes more power top end, retarding peels some off the top end and gives it to the bottom. I may be wrong on this but want to be sure he gets the right info.
He need to advance the timming ,they are retarded from the get go .Yes you loose a bit of bottom end but that's not his problem .

By advance the timing .

1.You get better throttle responce.
2.Starts better ( up to 18* ) after that hard to start when cold.
3.Better fuel milage.
4.The engine isn't a slug bug .
5.Moved the tq off the bottom end and moves to mid .


Now what his problem is the 6b from a med duty truck has lots tq on bottom at low RPM and low HP ,buy that with that size of truck the engine is set up different from a 6b in a dodge truck .That med truck stops making power under 1800 rpm and it's done .
1.Injectors
2.timing
3.fuel
4.gov springs
5. fuel plate

So buy changing a few things around it will come around and won't be so dang slow on the bottom end.

The biggest thing he need to watch out for is that trans ,the engine is over 400 lb tq as is , when he changes a few things it will eat that trans .That trans was set up for the 4b rpms and it's not the same on his 6b.
 

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Just my 2 cents

I test drove a 96' dodge with a 5 speed, It to was very sluggish.

I took to a diesel mechanic friend who found the injection pump gear was mis-aligned. this happens about every 100k and needs to be lined up. There is no key way to line them. I haven't tore into a 4b/6b enough(yet) so I'm going off his advice.
 

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whoa first off most the big trucks have hx35's without WG's if it has a WG then its a 12cm W/G or 14cm(rare) W/G. otherwise it could be a HX40 which wasnt unheard of int he fords.

The Gov springs help alot. the injectors int he 190 are just find to push 300 hp out of that motor. the P pump is not like the rotor pumps of earlier. you cannot rotate the pump instead you find TDC push the small pin into the gear from underneith the pump, put a dial indicator over the top of the 1st injector delivery valve this will help you measure out the lift of the plunger in the pump while setting timing, loosen the nut on the front of the pump gear and then rotate the motor to the amount of lift for corresponding timing 16-17* is a good balance 17 is pushing it on a 190 or a 215 pump, they get a little lazy on the bottom after that. on a 160 or 175 hp pump as well the 180's they seem to accept 17* & 18 degrees more happily.

also just cranking the star wheel doesnt help a whole lot off the bat, as there are several things that all work together in there. you will get much better results if you remove the AFC housing then remove the fuel plate. grind the fuel plate with a 1/2 moon shape a little deeper than the current pattern goes. when you pull the plate out you will see about 3/4 an inch of notches and steps with slopes that is the only are you need to grind, polish it with a little emery cloth to clean it up. when you re-install the plate after grinding it, install it but leave the two screws loose on top now lift the fuel shut off arm and throttle linkage till you see the gov arm move inside the housing it shoudl travel up and hit the bottom lip of your gropund out 1/2 moon on the plate, if it slide under then you will need to move the plate back or adjust the gov arm once you get the plate situated where the arm hits it tighten things down then install the AFC housing and slide it all the way forward before tightening it down. now loosen the star wheel. the looser the spring the more fuel that will be applied without boost the tighter the less fuel off the line. then as soon as the motor builds boost the fuel plate and gov arm take up the job of the fuel curve. thats where the gov springs will help you as they will allow the motor to contiunue fueling longer as the stock 190 hp pump should begin to defuel at 2100rpm and redline at 2400 rpm
its peak power is at 1700-1750 rpm.

Carefull your torque converter if stock will slip naturally right up to 1800-2000 before allowingthat motor to put power to the ground or higher and thus not load up the turbo which in turn without the added boost the fuel pump will not ramp up the fuel being fed to the motor. common with the TH475 especially when additional power is put to it. most motors like the 6.5 and even the 4bt benefit from being allowed to wind up a little before the tranny starts putting a load up against them where as the 6bt and in truth the 4bt produce most of thier power once under a load where the turbo can spool, hence why 6spds and 5spd work so well vrs autos in most of thier applications.


check out piersdiesel or it may be pdr now for some diagrams and better descriptions of what i was talking about for adjustments. as well id probably pay a shop to set the timing typically its $150-$175 on a bad day and saves ou having to retorque that nut to 300 ft/lbs
 

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Fuel

Put a 6BT in a Chev. Well over 100K ago.
Fuel lines for Chevy diesel are smaller than Dodge. Lift pump sucking thru small straw, so to speak. I used the std in line 6.5 pump and truck has boo-koo power. Disconnect pump (and / or bypass with no pump) and the symptom you get, no smoke, dogged power are there.

I used the chevy oil sender setup to control the pump and gage.

Pulls 25 boost any scenario floored, with max boost about 36. Routinely sees 30. Rarely need over 20 boost to pull. Without the 6.5 electric pump, all I can do is 15 PSI boost and and the RPMs above 2000 without pump are limited.

I found that when my electric pump does not work, or oil sender don't power it, I have no RPMs over 2000, no smoke, and only bottom end power. About your symptoms.

The electric pump brings it to life. Its debate-able whether running the larger fuel lines like the Dodge will fix all problems.

I have not went to larger fuel lines, because I don't think my clutch would stand too much more power.

Fuel delivery, fuel flow first --then timing and then springs for more RPM.
Wayne
 

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Discussion Starter #14
Thanks for all the info. I did not realize that the 190 truck version had lower governor springs, but I did suspect it with my low top speed. That would actually make sense because I was gauging power range based on defueling thinking it was 2700 like the dodge(no tach right now). I also did not know that they sometimes had HX40's. I will have to measure it since it does not have the tag anymore.

As for the fuel line, I have the 3/8" factory line, but it does have the 6.5 inline electric pump to help things along. I dont think it is a fuel delivery problem due to the fact that at higher RPM and boost it makes pretty good power, which requires more fuel.

Does anyone have good instructions for grinding a fuel plate. I find alot of talk, but I need pictures and measurements. I would also like to know if it can be ground to a sort of intermediate state to try to save my little Chevy transmission the punishment.

Thanks,

Chris
 

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ive only seen a handful of hx40 6bt's so most likely you have a hx35.

fuel line is a possibility but on a 12v witha p pump the factory lift pump is an animal. it can move alot of fuel it may actually be starving due to the electric pump blocking it off at high demand times. on a 12 valve p pump cummins 20 psi at idle 35 psi at WOT 2000 rpm and higher for fuel pressure. The P7100 and hte lift pump on those trucks had zero problems and can be impeaded performance wise by electric pumps. guys who changed to the FASS pump ona p pumped 12v had to ditch thier factory lift pump off the side of the engine all together and most reported it wasnt necessary to change to the FASS as the stock system moves so much fuel and can lift it from long distances. i would recommend bypassing the electric pump and just using the stock lift pump they have a life span of 150-200k miles and have supported over 600-700 hp without mods (granted the injection pump needed a few minor upgrades but the volume of fuel pushed to it by the stack engine mounted lift pump was never in question.


Check the fuel return check valve on the pump the spring and ball maybe getting weak. if it is it will let the pressure level inside the p7100 drop to a level that lowers power output

3/8" supply line is good 5/16 or 3/8 for return.


location of the plate full forward 1/2 forward (centered) or all the way back every 1/8 or 1/16 of an inch that you slide the plate forward means the gov arm (which swings from the back of the pump forward ) is traveling further increasing the amount of fuel delivered per PSI of boost.



The half moon shape is just a smooth fueling curve vrs peaks and valleys designed to limit emissions issues.

i'll post some pictures later or check out DTR


i still think its possibly a TC problem as its not placing a load on the motor low enough in the rpm range and therefore not building any boost. no boost equals no extra fuel and then if the TC is slipping too much you'll be pulling alot of RPM's and be out of the efficient range of the motor/turbo anyways
 

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Try a boost & a fuel pressure gauge, they are cheap and will help you to diagnose problems. I have a commercial 6BT that is rated at 210hp/520ft/lbs the torque is supposed to be at 1600 and power at 2500rpm it replaced a 6.5 chevy diesel. I have not had it on the road yet. As it is from a commercial I would expect it it move from a start pretty well as it was designed to pull weight, my 6bt was out of a vehicle that had a max train weight of 16t so moving that from a standing start is what mine was designed for and yours is very similar. You may have a large exhaust housing on your turbo and it will not be working hard enough in your truck to produce any boost at lower revs. What turbo and what size exhaust housing? Mine has a HX35 with a 14 wastegated housing my truck weighs 10500lbs so I am hoping the turbo size is about right. Find out more about your turbo and get some gauges.
Change your fuel filter and check and clean any fuel pre filters and heaters that may be on it. Check overflow valve is working, a basic check is to try and blow through it , if you can it is definitel toast. Does your shut off solenoid lift enough?. Is the boost line from head to AFC housing on pump OK? with a leak or if it is pinched it will not add enough fuel untill boost builds.

Gaza
 

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With my expirence with the 6bt and gm 4l80e transmission, I also had a dog of a truck, no power, little boost. My problems were all in the torque converter. On hard acceleration the engine RPMs would go straight to 3000 RPM and begin to defuel my truck. Yet I could not even brake torque and spin my wheels. I hooked up a scan tool and found around an average of 1400 RPM difference from ECM engine RPM to Trans input RPM. My engine was lazy because I could not load it and put the power to the ground. I was using a brand new converter for a 6.5 truck. You may want to check out the converter.
 

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Discussion Starter #18
Thanks for all the feedback. I do not think this is a torque convertor problem. I ran the convertor with the 6.5 and it is definately not slipping. It is good and tight and moves quickly with the blip of the throttle....at least now it does which I will get to. I also checked the shut off solenoid and it is lifting all the way up. I have not changed the fuel filter or checked the valve yet, and the truck does not have a fuel heater.

To get to the good news; I worked with the start wheel adjustment today. Wow, what a difference!! The wheel was set about 1/4" forward from the front of the plug thead edge, if that makes sense. When I went to adjust it there was alot of spring pressure. I ended up cranking it back about 3/16" and it made a huge difference. The engine has no lag now and runs strong right up to the defueling point. It smokes just enough to know it is getting fuel and pulls very strong. It pulls hard enough I get out of it before the 2-3 shift because I need to get the cable modulator in. The shifts are very soft right now and with all the torque I dont want to burn a clutch pack. It actually seems to make alot more power over the RPM range because it spools fast now and is able to load the engine at lower RPM. This kindof sets a reaction in motion as it revs fast and spools fast increasing fueling.

To be honest it makes plenty of power now and just needs the GSK to run the defuel point up so it can load longer. I may move the fuel plate and AFC forward, but I dont think I will be doing a grind right now since I would like to keep the chevy transmission together for now. Another 10-15% in power increase would be PLENTY at this point.

The bread truck modulator does not make for firm shifts and really just does not work well, so I am going to get a cable modulator up to get shifts back like the should be. With the cable modulator in and adjusted I can get the solid, snappy shifts back that I used to have(has a shift kit) with the vacuum regulator and it should be good to go.

Thanks again,

Chris
 

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Be careful if you decide to go with an upgraded fuel plate. I've got a '98 12-valve in my dodge and I'm running the mods you are talking about. I've got 3200 rpm springs, a #10 fuel plate (all the way forward), a plugged wastegate (hx35), and the star wheel almost all the way forward. Trust me, this makes well over 330 hp and 750 ftlb torque at the wheels and will cause an automatic trans to puke it's guts out in a heartbeat. But that much horsepower sure is fun to play with.

Kyle
 

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I forgot to mention that you are going to want to get at least a boost and pyro gage. I can see well over 1400 degrees if I really get on the throttle and that isn't good for long periods of time. When I tow I have to dial the star wheel back so the temps stay below 1200.
 
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