Fuel System redone

[Paveltolz]

Motor came out 17 NOV 22 and today I get an update. The heads are not cracked but, the valves' negative protrusions are way in excess of -50 thousandths and could be as bad as -70. He'll get the gauge on them later.

 

[Big T]

Motor came out 17 NOV 22 and today I get an update. The heads are not cracked but, the valves' negative protrusions are way in excess of -50 thousandths and could be as bad as -70. He'll get the gauge on them later.View attachment 77766

What does that mean on the valves?

 

[Paveltolz]

Said the negative protrusion when new should be -30 to -35. Valve seats wear and when they get to the point that the readings would be more than -50...
Hard Starts
Smoke
Rough running....

Kinda sounds familiar don't it.

 

[Big T]

Said the negative protrusion when new should be -30 to -35. Valve seats wear and when they get to the point that the readings would be more than -50...
Hard Starts
Smoke
Rough running....

Kinda sounds familiar don't it.

Negative protrusion = negative vs positive?

Does that mean it’s an innie vs outie?

 

[Will L.]

How many miles on that engine/heads?

 

[ak diesel driver]

I wonder if the valve spring pressure is a little high? Shouldn't wear that fast.

 

[Paveltolz]

<25K on the motor.
Yes, Valves are Innies, pistons should be outies but, are flush with the deck per the original build done by Diesel Depot. Owner is dead, no dissing the dead.
Measurements completed. Valves were -40 thou on the exhaust side, same as when built. -70 on the intake. Pic is of exhaust side during build.


Spring pressure, if anything, could be too light allowing cylinder pressure to force past the closed valve.
Valves were not OEM and show wear on the stems as well.
Heads show no cracking and there's no wear on the valve seats.
Bottom end, pistons, cylinder walls all look as new as when the motor was built. Piston markings are very legible on top.
Basically, a self developing low compression motor trying to run at 17:1 or less.

Since the heads check out, they will be surfaced prior to reassembly. Spring pressures will be checked and, if needed, replaced. OEM Valves are on the shelf and will go in regardless.
HT-4 Cam is coming out, OEM going back in.
Truck will be driven up there for a couple of months after reinstall to ensure its correct before coming back.

It will be nice to have it right and able to do the other stuff I wanted vs. scrapping it and trying to sell you guys the new grille, bumper, weather striping, side moldings etc. that I have on the shelf waiting.

 

[Big T]

HT-4 Cam is the Heath Cam? What was it supposed to do?

 

[Will L.]

Heath said he had the timing of the lobes changed to offset the delay in flow from the driver side getting to the passenger side so it should flow much better in driving the turbo. He also told me he altered the opening spec a bit but not enough to be drastic, just enough to help it flow better.

Afaik there is still no one that built an engine with stock cam , dyno, then HT4 cam and dyno with no other changes to prove the difference.

 

[Big T]

Why non-OEM valves? Were these Chinesium valves?

Why would anyone go away from the stock cam?

 

[Big T]

Heath said he had the timing of the lobes changed to offset the delay in flow from the driver side getting to the passenger side so it should flow much better in driving the turbo. He also told me he altered the opening spec a bit but not enough to be drastic, just enough to help it flow better.

Afaik there is still no one that built an engine with stock cam , dyno, then HT4 cam and dyno with no other changes to prove the difference.

Delay in exhaust flow? If so, he’s chasing fantasies.

 

[EWC]

I went away from the stock cam . Had my heads ported too . Got tired of all the responses from the sheep telling me to just add more boast to get more power .

 

[Paveltolz]

Valves aren’t Chinese as I confirmed last night with 635 (AKA Ted, owner of the original build of this motor [longer old story]) but he doesn’t remember what valves he bought as he was still recovering from his big rig wreck at that time.

 

[Will L.]

@Big T

Keep in mind- the camshaft and valve springs in even 2022 made turbo optimizer is identical to the mid 1980’s 6.2 Non turbo. This is nonsense- just gm & gep not investing into r&d to realize gains available that any highschool mechanics class student at year 2 sees is a big error for better power, mpg, and/or life of engine.

Why people go for a different camshaft- the camshaft is like the brain of the mechanical side of things. If you are willing to give up power for mpg, or give up mpg for power- the camshaft has massive input to it.
In a n/a gasser engine you can build 3 identical engines and have a swing in power/mpg by just the camshaft swap of half the total number. A 200 hp can become 300. 8 mpg can become 12.

n/a diesel is not as drastic - about 1/4 instead of 1/2. Turbo diesel a bit less, but gains are still available. But because things like turbo change has more impact for less cost- most owners don’t bother with the camshaft. So this means the big manufacturers don’t bother with R&D investment to make options. Then we are an oddball platform so less customer base. It isn’t until a guy is trying to cross every t and dot every i that he wanta a custom camshaft in a 6.5.

Because of my job history I am all about comparison testing. And I HATE rip off sales to people. So thats what I push. But owners almost never have the time & $ to test everything and the 6.5 consumer base doesn’t demand it so when anyone has a SPECIAL part for sale- we don’t demand proof. It’s all how good is the sales pitch. Then word of mouth if the customers got seat of pants happy experience or not.

@EWC did you ever do a dyno, swap in just the cam and dyno again to prove gains/ losses? I am not expecting you did- most no one can.

Who do I expect that from? The parts sellers. But that is such a huge investment that most can not. They would have to sell a ton more camshafts- especially because they probably profit what- $100 MAX from each one they sell. So they have to sell 100 just to break even on that “proof investment”. How many extra sells will it get? 500 over 5 years? What kind of ROI is that?!

Because we are a fringe market- owners have to gamble more than normal at gains.
Much of the 6.5 modification crowd does it out of interest or the desire to do something different than everyone else.

As to chasing fantasy- no. It is a proven thing. Timing the exhaust flow to turbos is a gain of over all efficiency. But honestly making a tuned driver side long tube header would accomplish more. Because it can correct the same timing pulse issues and improve flow at same time. Doing a centermount turbo is a far easier solution to this issue. Just that gm didn’t design it into the truck originally. A raspberry award moment for sure, but that is gm. A far smarter move is dual turbos- one on each side but cost prohibitive.

 

[Will L.]

@Paveltolz what was the compression test results?

 

[Big T]

@Big T

Keep in mind- the camshaft and valve springs in even 2022 made turbo optimizer is identical to the mid 1980’s 6.2 Non turbo. This is nonsense- just gm & gep not investing into r&d to realize gains available that any highschool mechanics class student at year 2 sees is a big error for better power, mpg, and/or life of engine.

Why people go for a different camshaft- the camshaft is like the brain of the mechanical side of things. If you are willing to give up power for mpg, or give up mpg for power- the camshaft has massive input to it.
In a n/a gasser engine you can build 3 identical engines and have a swing in power/mpg by just the camshaft swap of half the total number. A 200 hp can become 300. 8 mpg can become 12.

n/a diesel is not as drastic - about 1/4 instead of 1/2. Turbo diesel a bit less, but gains are still available. But because things like turbo change has more impact for less cost- most owners don’t bother with the camshaft. So this means the big manufacturers don’t bother with R&D investment to make options. Then we are an oddball platform so less customer base. It isn’t until a guy is trying to cross every t and dot every i that he wanta a custom camshaft in a 6.5.

Because of my job history I am all about comparison testing. And I HATE rip off sales to people. So thats what I push. But owners almost never have the time & $ to test everything and the 6.5 consumer base doesn’t demand it so when anyone has a SPECIAL part for sale- we don’t demand proof. It’s all how good is the sales pitch. Then word of mouth if the customers got seat of pants happy experience or not.

@EWC did you ever do a dyno, swap in just the cam and dyno again to prove gains/ losses? I am not expecting you did- most no one can.

Who do I expect that from? The parts sellers. But that is such a huge investment that most can not. They would have to sell a ton more camshafts- especially because they probably profit what- $100 MAX from each one they sell. So they have to sell 100 just to break even on that “proof investment”. How many extra sells will it get? 500 over 5 years? What kind of ROI is that?!

Because we are a fringe market- owners have to gamble more than normal at gains.
Much of the 6.5 modification crowd does it out of interest or the desire to do something different than everyone else.

As to chasing fantasy- no. It is a proven thing. Timing the exhaust flow to turbos is a gain of over all efficiency. But honestly making a tuned driver side long tube header would accomplish more. Because it can correct the same timing pulse issues and improve flow at same time. Doing a centermount turbo is a far easier solution to this issue. Just that gm didn’t design it into the truck originally. A raspberry award moment for sure, but that is gm. A far smarter move is dual turbos- one on each side but cost prohibitive.

Seriously doubt there is much effect from this. More theory on the drawing board than reality. Turbo is not a mechanical connection to the engine as it’s driven by exhaust pressure. Specific pulses will be muffled across the length of the header and cross over until they just become pressure. Turbo spins and compressed intake, another twice removed buffered non-mechanical connection to the engine.

You diss GM for using the same cam across mutiple platforms of this engine, then rationalize the aftermarket’s limited economies of scale. Both are in the business to make money, but only one has shareholders to answer to.

 

[Will L.]

@Big T true, I understand the economics of it.
GM economically did the prudent thing as did Heath for not spending the money. Bad roi- me poking at them for it is more of wanting the results from a greedy customer standpoint.

The proof of timing the exhaust gasses is out there. I don’t have references I can give, but different engine building magazines, shows, dyno tests showing the results on other engines- dyno results from all the different header manufacturers show it.
It has to be a passion for a person to do all the research to learn it. It we had a perfectly organized internet library where one could just focus on these details and it was all condensed optimally-probably 40 hours of learning would go from asking what it is to understanding all the details.

With all due respect- and then some because I call you friend- you are theorizing that it is a theory. Haha. No man- this has been extensively studied, tested, proven. Sure there is point of diminishing returns, like everything. No way does a “offset camshaft timing” undo the damage done by putting a turbo to one side of the engine. Physics and all, ya know? Is it worth it to include recouping some of those losses since a person is redesigning a better camshaft WHILE THEY ARE AT IT- sure. I see no harm in that.

Its like arguing for better oils in the engine. Does any old oil work- yup. Is it worth better oil- maybe. Situational results.

I don’t remember half the details and never heard the exact specs of this cam, he doesn’t share them. Knowledge of that is price of purchase. Bill called me back when he had a few hours to waste. We spoke about the hummer hood scoops we each designed and results. Along with some other stuff- we went into this exact camshaft into some detail. because I run a centermount- it was not worth it for me to buy the cam. It wasn’t just the pulse timing be changed.

GM never saw the benefit of a better turbo and larger exhaust, yet your suburban runs the ATT and 4”. Does that mean it wasn’t worth getting just because making those changes was not worth GM’s bottom line? Another site would erase your post or even kick you off for talking about the ATT in positive light.

6.5 Hummer owners fight overheating way worse than gmt400.
There is aftermarket aluminum radiators sold for well over a grand to help combat the issue. Problem is they all perform worse than a new factory copper one. I challenged everyone under the sun involved to do simple comparison testing. None will- at least non posted results. Haha. But i have helped guys remove there 3 month old aluminum and install new factory and they were happy with both the help and the results.
One guy listened when I said have the copper one rebuilt adding cores and that guy has more miles in his hmmwv than anyone else on that website. He even bought a ebay cheapy aluminum one he plans to experiment with one day. But now he is busy playing with the hmmwv in Death Valley this weekend- always out running that thing.
He is a member also.

Proving through testing is nice but rarely happens even when final owners buy the more expensive parts for that test.

 

[Big T]

@Big T true, I understand the economics of it.
GM economically did the prudent thing as did Heath for not spending the money. Bad roi- me poking at them for it is more of wanting the results from a greedy customer standpoint.

The proof of timing the exhaust gasses is out there. I don’t have references I can give, but different engine building magazines, shows, dyno tests showing the results on other engines- dyno results from all the different header manufacturers show it.
It has to be a passion for a person to do all the research to learn it. It we had a perfectly organized internet library where one could just focus on these details and it was all condensed optimally-probably 40 hours of learning would go from asking what it is to understanding all the details.

With all due respect- and then some because I call you friend- you are theorizing that it is a theory. Haha. No man- this has been extensively studied, tested, proven. Sure there is point of diminishing returns, like everything. No way does a “offset camshaft timing” undo the damage done by putting a turbo to one side of the engine. Physics and all, ya know? Is it worth it to include recouping some of those losses since a person is redesigning a better camshaft WHILE THEY ARE AT IT- sure. I see no harm in that.

Its like arguing for better oils in the engine. Does any old oil work- yup. Is it worth better oil- maybe. Situational results.

I don’t remember half the details and never heard the exact specs of this cam, he doesn’t share them. Knowledge of that is price of purchase. Bill called me back when he had a few hours to waste. We spoke about the hummer hood scoops we each designed and results. Along with some other stuff- we went into this exact camshaft into some detail. because I run a centermount- it was not worth it for me to buy the cam. It wasn’t just the pulse timing be changed.

GM never saw the benefit of a better turbo and larger exhaust, yet your suburban runs the ATT and 4”. Does that mean it wasn’t worth getting just because making those changes was not worth GM’s bottom line? Another site would erase your post or even kick you off for talking about the ATT in positive light.

6.5 Hummer owners fight overheating way worse than gmt400.
There is aftermarket aluminum radiators sold for well over a grand to help combat the issue. Problem is they all perform worse than a new factory copper one. I challenged everyone under the sun involved to do simple comparison testing. None will- at least non posted results. Haha. But i have helped guys remove there 3 month old aluminum and install new factory and they were happy with both the help and the results.
One guy listened when I said have the copper one rebuilt adding cores and that guy has more miles in his hmmwv than anyone else on that website. He even bought a ebay cheapy aluminum one he plans to experiment with one day. But now he is busy playing with the hmmwv in Death Valley this weekend- always out running that thing.
He is a member also.

Proving through testing is nice but rarely happens even when final owners buy the more expensive parts for that test.

I think GM saw CARB and EPA air quality requirements as their first priority, thus never considered a larger turbo. Individuals at the margin can get around those requirements.

As for chalkboard theory vs reality comment, probably should have dropped theory. Point that I was making is that resultant gains calculated on chalkboard probably far less in reality due to previously described losses through non-mechanical connections to the engine. Also as you pointed out, more power bang for the buck from other mods such as increased boost.

 

[Twisted Steel Performance]

I think it's funny that a lot of folks overlook the fact that the OEM cam is a fuel miser epa designed cam, this is the only engine platform that most say can't gain from a better profile cam, my cam designer laughed at it....

 

[DieselAmateur]

not to derail the thread, but seeing as how we're discussing cams and all,

@EWC care to share what cam you went with/ how it's set up differently from stock?