Engine/Transmission (1998.5 - 2002) Cracked manifold

[ISBPilot]

How much boost do you think this will leak out?



Todd

 

[KatDiesel]

Originally posted by ISBPilot

How much boost do you think this will leak out?



Todd

None. (boost)



It will just make a mess in the engine compartment with all the exhaust gas and carbon.

 

[ISBPilot]

Here is another.

Maybe a little clearer.

 

[chrleb1]

Depending on how much you are making to begin with, but it could leak enough to make a couple pounds less. It will also effect your spool up time.

 

[ISBPilot]

I guess my terminology was wrong.

I know boost is on the intake side.



What I was thinking was, the exhaust pressure that spins the turbo to create boost.

 

[jerrethomas]

Re: I guess my terminology was wrong.

Originally posted by ISBPilot

I know boost is on the intake side.



What I was thinking was, the exhaust pressure that spins the turbo to create boost.

Not totally correct, the heat from the exhaust gas is what spins the turbo from what i understand. i could be wrong but and i will be corrected quickly if i am. just wanted to point that out to ya.

 

[pro99]

Well it don't look like allot is leaking threw it because of the lack in carbon build up. But what ever is leaking threw that is not helping the spool up at all!! Why do we have so much concern on the boost side and not allot on the housing side when it comes to leaks? There is no doubt in my mind you are loosing out when that happens. If you loose the exhaust side you have no boost to begin with so... ..... But what do I know ... ... ... ... nothing:--)

 

[DavidD]

ISBPilot, looks to me like its time for a ATS three piece manifold!

Its just better and it wont crack. Mine cracked in the same spot at 85K, it just gets worse and it will make a mess out of you engine bay. I am not sure about how much pressure you would lose but the three piece is a free'r flowing manifold. Good Luck ehat ever you decide, Dave

 

[Steve St.Laurent]

The turbo is definately driven by the pressure of the exhaust not the temperature of it. It does happen that the exhaust temp will be higher when the boost is up because you are burning more fuel/running the engine harder. You definately want to replace the exhaust manifold when it is cracked - you don't want those hot exhaust gases releasing into your engine compartment and catching something on fire, regardless of the loss of boost/power.

 

[MCummings]

When my manifold cracked, I dropped to my all time low of 9MPG, and a very dirty engine compartment!



Your peak/max boost might stay the same if you are up against the wastegate, but spool-up time will be longer.



The ATS manifold will definatly test your patience. To save on some frustration, replace those allen head bolts with some grade 8 bolts,, or, be sure to get a ball driver allen wrench (9mm)

You'll have a dandy time gettin' the heater hose how you want it,,, I just let my mount rest on the manifold.



My $. 02

Merrick Cummings Jr



EDIT: When you are ballparking 30PSI boost on an HX-35, your boost pressure/backpressure ratio start to be in the 1:2 range.

35PSI boost, is 70PSI back presure!

Think of how much air willl leak out with 70PSI pressure in the manifold.

 

[OTRPU]

I found out with about 6 cracks in my stock manifold that it only takes about one day to plug up any intake filter with soot. When they saw mine they laughed out loud. . . then sold me the ATS 3 piece. Things are better now, cept the bolts keep backing out. Things move around in there more than one might think.



Cheers,

Steve J.



Steve, sitting in Flying J, Fairview, TN waiting for the sun to rise and to earn more hours to run another load someplace in NC.

 

[rweis]

I really like the ATS manifold. It's a great piece, very well made.



I'm doing an experiment on how the ATS bolts up to the block.



My hex cap bolts kept backing out also. I decided to go with studs.



I worked with RustyJC to figuer out a way to compensate for the thermal expansion and contraction of the manifold and also use a self locking nut.



I am going to bolt it on in a week or so and then run it for a couple of months checking the torque periodically.



I'll report back on how it goes.



Bob Weis

 

[ISBPilot]

Thanks for all the input. I do have an ATS that will hopefully go on sometime this week, along with a valve adjustment. With guages in the near future and other things to follow:-laf .



Any tips for the ATS install?



Todd

 

[Hohn]

Is there any reason at all that you can't use a stud/nut arrangement instead of the bolts? It would seem to me to be a little easier for mounting, plus you would have more options to keep the thing attached.



If you use the bolts, why can't you use some kind of lockwasher setup??



Is there not Threadlocker that works at the high temps?????? (loctite, etc. )





Justin

 

[rweis]

This is my version of what I think is the problem:



32 ft # torque stretches the bolt or stud to its plastic limit. It can not expand and retract as needed when the manifold boss grows thicker and thinner.



I put in studs and a common split lock washer and a nut. The temp took the spring out of the split lock washer so the nut started to be free to rotate. I also mistakeingly torqued the studs to 32 ft # (the plastic limit, did not know better then).



The stud by itself can not grow and contract as much as the manifold boss grows and contracts in thickness as the heat cycles take place.



Next attempt is to use new studs torqued to 16 ft# so they remain elastic, a lock nut that locks onto the stud, and a washer that is conical shape that the shape flattens and goes conical based on amount of torque on it (like a spring, but the washer can withstand 2000*). The manifold can expand and contract as necessary because the stud, washers, locknut will expand and contract right along with it and MAINTAIN 16 ft #.



Why did DC put such a LONG bolt with that huge cylinder washer and a stainless steel bolt head retainer (on my 2002)?



My take is that the LONG bolt has more elastic distance to meet the needs of the manifold growth, the cylinder washer shields heat and protects the bolt, and the stainless steel bolt locker keeps loose bolts from unscrewing.



You can't put a long bolt on a ATS because the manifold passages are much larger than the OEM manifold and a long bolt interferes with the casting.



I think guys are trying different things. I am going to try the 16 ft # stud, high temp washer, and self locking nut.



I'll let you know how it turns out.



Bob Weis



There is a high temp thread locker, but it is red (permanent) I think.

 

[ISBPilot]

So...........

Are there different bolts required to mount the ATS?



I bought it used without bolts or instructions.



Todd

 

[RustyJC]

Another inexpensive solution to the "loosening bolts" problem might be to go to the longer bolt (or stud) and spacer design like Cummins uses on my 2002, if the AFE design will allow it. The longer bolt and spacer provides a greater length for expansion and contraction (the cause of the short bolts losing prestress) and will prevent yielding the bolts when the manifold expands. Thus, the bolts/nuts should hold their torque much better.



Rusty

 

[rweis]

Rusty,



I'm pretty sure the ATS casting would not allow longer bolts, and then the cylinder washer has to be accounted for.



I first used 47mm studs and went to 52mm, but that is about as far as I think it can go (maybe a couple (1,2,3,4) mm) with out mechanical interference to the ATS body casting. Even then I need to put the manifold on and the washers and nut AS the manifold goes onto the studs. May not be enough room to work the washers and the nut between the ATS casting and the stud if the ATS were firmly in its final resting position.



Bob



I am not going to have the chance to try the way we discussed until 10/24 weekend. Wife goes out of town that weekend so it is a work on the TRUCK weekend

 

[RHARVEY]

Well... I just check the manifold on my wifes 2k and its cracked in the same place... .

Good reason to get the ATS!



Rick

 

[Pit Bull]

Originally posted by DaveD

Mine cracked in the same spot at 85K, Dave

Dave isn't this covered under your 5 year 100K mile engine warranty?