• Welcome to The Truck Stop! We see you haven't REGISTERED yet.

    Your truck knowledge is missing!
    • Registration is FREE , all we need is your birthday and email. (We don't share ANY data with ANYONE)
    • We have tons of knowledge here for your diesel truck!
    • Post your own topics and reply to existing threads to help others out!
    • NO ADS! The site is fully functional and ad free!
    CLICK HERE TO REGISTER!

    Problems registering? Click here to contact us!

    Already registered, but need a PASSWORD RESET? CLICK HERE TO RESET YOUR PASSWORD!

Harmonics

John Romann

John Romann

Member
Messages
40
Reaction score
21
Location
New york
I'm trying to figure why our engines have bad harmonics that caused the crank to snap. Realistically our camshaft and firing order are the same as a race cam with the timing reconfigured for a sbc. The sbc guys swapped the 4 and 7 and 3 and 2 to reduce hot spots and improve power so why do we have shit power, hotspots and bad harmonics
 
IMO we don't necessarily have bad harmonics we have an engine the bean counters cheaped out on. Namely a forged crank. Other bottom end issues I attribute to a cheaped out cooling system, I believe the engine running to hot (especially in the head) contribute to preignition which severely stresses the bottom end. Keep these engines cool and they're pretty much trouble free.
 
What would happen if we took out the 3 cups and instead machines them to have the same volume but have the injector spray against the pre cup into the cylinder instead of spraying in a controlled free cup effectively using this pre cup as a combustion chamber similar to a gas truck head that should keep a substantial amount of heat out of the head
 
A bit of the trouble can be attributed to cylinder pressures on top of poor manufacturing designs..

The P400 is a altogether a different motor inside, it will withstand more than the average 6.x .

The thought of making a different style of precup has been talked about before, the cup serves a purpose in a IDI vs direct injected, not sure what to think the outcome would be myself...

As for keeping heat transfer out of the head, that can be done a lot easier and much more efficient with a certain ceramic coating in the runners, precup, combustion chamber, piston tops...
 
Twisted Steel Performance said:
A bit of the trouble can be attributed to cylinder pressures on top of poor manufacturing designs..

The P400 is a altogether a different motor inside, it will withstand more than the average 6.x .

The thought of making a different style of precup has been talked about before, the cup serves a purpose in a IDI vs direct injected, not sure what to think the outcome would be myself...

As for keeping heat transfer out of the head, that can be done a lot easier and much more efficient with a certain ceramic coating in the runners, precup, combustion chamber, piston tops...
Click to expand...


I know coatings can be applied. I was thinking of redesigning the precup simply because I don' know why it can' be improved. If the fuel is injected into the cylinder where the air is already swirling I'd think it would help combustion instead. Granted all of that would occur faster then we can blink but I'd think it' help. The only concern is not having the cups hot enough to ignite any fuel. But I'm sure timing can help that issue.
I wish there was more aftermarket for the 6.5l with a r and d department. Instead of everyone looking to the duramax as the holy grail.
 
There is a LOT of R&D going on, just not being published, redesigning the cups isn't one of the areas being worked on that I know of anyway.. the cups work well at doing their job in a low injection psi motor me thinks.. The reason DI motors work so well is they are high psi injected, not like ours, the cup is the spark that starts the chain..

But I'm not going to play the idea down, be my guest and spend the money in R&D, and see where it goes, I
d like to see results either way !

Your new here, believe me their is lots of testing going on in lots of different area's by some here and other places..
 
You're hitting a few different points here.
Harmonics: crap crank with weak mains and psycho high compression and a mediocre HB. I’ve pushed 6,000 rpm using extreme measures and had the crank hold fine. The ultimate fix for all of it is p400, shy of that optimizer crank or scat crank and fluidampr balancer & Leroys billet pulley. In the fleets we saw many broken cranks and EVERY ONE had bad or highly questionable balancers. 100,000 MAXIMUM imo if the AC Delco or GEP (which may be AC Delco). 500,000 fluidampr
As for firing swap, gains are minimal on engines living at 4,000 rpm max so wasted $ imo on 6.5

The low power issue: they never figured to want over 220 hp or 500 torque even in concept. This is a fuel miser engine with low maintenance costs was the whole plan. Better power is available: big turbo,exhaust, pump/tune, cac, wmi, even if wanted propane works wonders in idi. Pick a target and have a realistic wallet to do it. Diesels are not gassers- no $250 power gains here.

Hot spots: were from coolant flow issues (especially amplified by rear head cooling kits), cheap metallurgy, and thin castings- basically 1 error and profiteering penny pinching. The optimizer fixed the metal and thickness. The spin on fanclutch/ balanced flow waterpump with restrictor fixes much of the overheating-with more help from better fanclutch. Then cheap radiator is the other part. Higher quality radiator with thermal coating to make up for undersized radiator and things can be happier. In fleets we ran hundreds and hundreds of trucks over 1/4 million miles and never suffered heat issues once set up right.

As for your cooling: Leroydiesel.com
What waterpump, fanclutch, fan, and since you have dual stat- what are you running as restrictor?
 
Will L. said:
You're hitting a few different points here.
Harmonics: crap crank with weak mains and psycho high compression and a mediocre HB. I’ve pushed 6,000 rpm using extreme measures and had the crank hold fine. The ultimate fix for all of it is p400, shy of that optimizer crank or scat crank and fluidampr balancer & Leroys billet pulley. In the fleets we saw many broken cranks and EVERY ONE had bad or highly questionable balancers. 100,000 MAXIMUM imo if the AC Delco or GEP (which may be AC Delco). 500,000 fluidampr
As for firing swap, gains are minimal on engines living at 4,000 rpm max so wasted $ imo on 6.5

The low power issue: they never figured to want over 220 hp or 500 torque even in concept. This is a fuel miser engine with low maintenance costs was the whole plan. Better power is available: big turbo,exhaust, pump/tune, cac, wmi, even if wanted propane works wonders in idi. Pick a target and have a realistic wallet to do it. Diesels are not gassers- no $250 power gains here.

Hot spots: were from coolant flow issues (especially amplified by rear head cooling kits), cheap metallurgy, and thin castings- basically 1 error and profiteering penny pinching. The optimizer fixed the metal and thickness. The spin on fanclutch/ balanced flow waterpump with restrictor fixes much of the overheating-with more help from better fanclutch. Then cheap radiator is the other part. Higher quality radiator with thermal coating to make up for undersized radiator and things can be happier. In fleets we ran hundreds and hundreds of trucks over 1/4 million miles and never suffered heat issues once set up right.

As for your cooling: Leroydiesel.com
What waterpump, fanclutch, fan, and since you have dual stat- what are you running as restrictor?
Click to expand...
I' running stock cooling system. I haven't had an issue yet but I also don't tow. I already have a fluid damper. Otherwise peformance is a s366. Ftb mod. Lift pump, and kojo tune.
 
Twisted Steel Performance said:
There is a LOT of R&D going on, just not being published, redesigning the cups isn't one of the areas being worked on that I know of anyway.. the cups work well at doing their job in a low injection psi motor me thinks.. The reason DI motors work so well is they are high psi injected, not like ours, the cup is the spark that starts the chain..

But I'm not going to play the idea down, be my guest and spend the money in R&D, and see where it goes, I
d like to see results either way !

Your new here, believe me their is lots of testing going on in lots of different area's by some here and other places..
Click to expand...
Yes I know I'm new here. But I do know the ford Idi guys run very low pop pressures because they think the fuel actually makes it out of the precup and doesn't burn entirely making more power. Hence why my idea came up of ditching a precup design all together, maybe running 2500psi pop pressure and adjusting injection timing to make it run.
 
“Stock” cooling doesn’t help us understand. It changed so many times over the years and who knows what previous owner did that looks stock.

Filling out signature line helps, btw.

Is it a spin on fanclutch?
 
W
Will L. said:
“Stock” cooling doesn’t help us understand. It changed so many times over the years and who knows what previous owner did that looks stock.

Filling out signature line helps, btw.

Is it a spin on fanclutch?
Click to expand...
What do you mean filling out signature. I filled out the information section in my profile.
 
Will L. said:
“Stock” cooling doesn’t help us understand. It changed so many times over the years and who knows what previous owner did that looks stock.

Filling out signature line helps, btw.

Is it a spin on fanclutch?
Click to expand...
The truck is a 98 sierra 3500. Used to be a dually. I don' remember honestly if it was a spin on or not.
 
BC2F6727-9983-438D-9E02-F5AA579028AA.jpeg FFA7A568-2326-4124-B76B-91E4FAB65B2C.jpeg

See where AK diesel driver can just say “my 99 has this issue” and we can see truck details with mods to respond or me is the 95 hummer?

I don’t remember how to alter signature line, but that is that area. Fill out truck details there and we can see what you have. Reading threads we cant tell what you have on profile page so we donit in signature.

Take pics of your waterpump, clutch and fan and post them here. If fan is metal Look on blades for stamped number. Getting the complete system makes it work well, having 90% of the right parts doesn’t mean it is getting rid of 90% heat. Infact if people they add parts one at a time, then finally add last part and it works good all the sudden and think- oh it was that one thing. Then tell others- get this one part and it doesn’t help them. It is a collective approach that works.

If you have a 4 bolt waterpump, your passanger side(where the hot spots are) could be as much as 15* hotter than driver side. Many times saw one side of engine perfect and other side cracked and blued.
 
Will L. said:
View attachment 52009 View attachment 52010

See where AK diesel driver can just say “my 99 has this issue” and we can see truck details with mods to respond or me is the 95 hummer?

I don’t remember how to alter signature line, but that is that area. Fill out truck details there and we can see what you have. Reading threads we cant tell what you have on profile page so we donit in signature.

Take pics of your waterpump, clutch and fan and post them here. If fan is metal Look on blades for stamped number. Getting the complete system makes it work well, having 90% of the right parts doesn’t mean it is getting rid of 90% heat. Infact if people they add parts one at a time, then finally add last part and it works good all the sudden and think- oh it was that one thing. Then tell others- get this one part and it doesn’t help them. It is a collective approach that works.

If you have a 4 bolt waterpump, your passanger side(where the hot spots are) could be as much as 15* hotter than driver side. Many times saw one side of engine perfect and other side cracked and blued.
Click to expand...
Very good to know. Truck is 70 miles away at the shop so I'll post pics this weekend. Thank you
 
Ok. What turbo and exhaust?

Spend time searching precups or combustion chambers. Several have modified the heck out of them. Many tried the complete bypass cut- um if no video proof then I didn’t- but if someone finds video then let me search past Presidential answers- haha.

Like Chris, I wouldn’t want to stop someone from experimenting. But there are a LOT of proven places to spend cash first imo.
 
Will L. said:
Ok. What turbo and exhaust?

Spend time searching precups or combustion chambers. Several have modified the heck out of them. Many tried the complete bypass cut- um if no video proof then I didn’t- but if someone finds video then let me search past Presidential answers- haha.

Like Chris, I wouldn’t want to stop someone from experimenting. But there are a LOT of proven places to spend cash first imo.
Click to expand...
Turbo is a s366 with 6+6 billet wheel with a t3 .82 open scroll housing. Exhaust is nothing special, diamond eye crossover, downpipe modified with a 90 and 3 8nch vband to bolt to the s366 and their 4 inch exhaust without a muffler
 
You must log in or register to reply here.
Back
Top