New 4" exhaust to be installed on a 260000km engine.

[Martin R]

Hey all yow, I'm installing a 4" exhaust system on my pickup with a engine that has 260000km. I know it'l get it to breath but will it hurt it adding the extra hp. How can i be shur. Thank's. Martin

[DmaxMaverick]

Exhaust upgrades are all gain, no pain. If you get a performance boost, it will come free, with no risk to anything else. Typically, an exhaust improvement won't increase power significantly in itself, but excels when complimented with other upgrades. A larger exhaust system alone can allow for quicker turbo spooling and lower EGT's. However, the exhaust is only 1/2 of the aspiration equation. Improve the other end with a 97+ intake system, or opt for a good aftermarket.

If you pursue "other" performance modifications, consider a "routine" head gasket refresh. Any modification that increases cylinder pressure will push the OEM gasket well beyond what it has seen during its lifetime. 200-300K miles is a typical MTBF in OEM trim, so plan on shortening that if you try dumping in more fuel/air/heat.

[Robyn]

I agree 100% with Maverick.

The 200K mile marker seems to be a good average on the head gaskets of the 6.5 TD engines.

Been through that a few times in the past.

My last head gasket failure was on a 94 Burb and came at 233K miles

This issues seems to also be influenced by the coolant in the thing

The coolant mix (water used) will really effect the longevity of the head gaskets.

If the coolant mix has a lot of Iron in the water as well as other minerals it seems to contribute to an condition of errosion around the fire rings on the number 1 and 2 cylinders.


Your fresh 4 inch exhaust will definately let the little creature breath a lot easier.

This addition will help keep EGT's down some.

Definately plan on a head gasket change before ramping up the fuel and the boost in search of MORE "giddyupgo" :)

Keep in mind that a head gasket change also requires fresh bolts on these engines.

Let us know if you have any questions on this sort of task.


Have fun and keep us posted.

Missy

[Martin R]

Looking for part's i ran into a blog from Heath Diesel performance blog and he has a valve cover vacuum test that determines the health of the 6.5 pistons, cylinders and ring's so i performed the blow by test and the engine failed it miserably. A plastic 3\8 clear pipe in the dip stick, the other end in water, at 2000rpm the water in the pipe is supposed to be vacuumed up 1" = healthy but instead it went down 1/2". Could my cold air intake hookup create a bad reading now that the (CDR) valve blow by pressure on the valve cover is not being suck't in the turbo.

[DmaxMaverick]

I don't believe that test to be reliable to reveal anything, outside of absolute extremes. However, 1.5" water column is NOTHING. 4-6" would be well within the margin of error (air filter type and wear can vary the system vacuum as much as 10" or more, and still be "normal"). Your replumbing of the CDR will definitely have an effect on the crankcase vacuum at higher RPM's, and your results are close to what I would expect, all else being perfectly normal and within spec.

[Robyn]

Here is my basis for judging the health of one of these engines.

With the engine warm and idleing, remove the oil fill cap (be careful of the fan)

Now there should be very little to zero vapor present on a real healthy engine.

With high miles, I expect to see a small amount of "Blow by"

"Huffing" large amounts of vapor/smoke indicates worn/stuck rings and generally poor health of the cylinder/piston/ring assemblies

So if you find little to no vapor coming from the oil filler, your engine has good health in that area.

Also another measure of this, is to remove the air inet from the turbo (rubber boot)

Now, if the area in the turbo inlet is sloppy with oil that has come from the little CDR tube, then this means that you have a fair amount of blow by.

I have seen very low mile "near new" 6.5 engines that puke oil into the turbo like crazy

The area will usually have some oil pull over present.


Have a peek and let us know.

Missy

[Martin R]

Brain storm trubleshooting continues then. There is quite a bit of vapor/smoke coming out of the oil filler cap and dip stick that is for shore, is there a cheep way to find out if pistons rings and cylinders are working properly and i guess compression details would be important. My guess is to have it plugged on a computer somehow and compare with healthy specs. Where i'm from most people are jealous of the looks of the truck and DISS the fact that the 6.5 even exists. ( garage soap opera, propaganda). Anyway, enough winning! Thank's again for your feedback.