Just Installed My ATT and WOW

[THEFERMANATOR]

The Mechanical DB2's appear to already do this RPM timing variance and run well with the ATT. It is night and day the 1993 vs. my 1995. Enough that I have considered a DB2 conversion on this alone then there is the PMD costs... Even on the experimental 'Slim' tune the precups mess me up for smoke. Stock tune even smokes. However there is a big difference you can feel between tunes out there and what you and Slim are working on. The throttle is more progressive over the range of the pedal. With the BD valve I think I feel the timing change used to spool the ATT as a flat spot. (Got to pin that down more.) Light throttle around town the BD valve has cleaned it up a lot on all tunes.

Thanks to both you and Dennis for stepping up for the 6.5 community.

Didn't the 1994's GM tune clone a DB2?

From what I seen, the 94 and 95 tune files I looked at both mimicked what a DB2's timing curve would most likely be. And the DB2 isn't capable of doing what a DS4 can as far as the timing curve. With the DS4 you can pull the timing WAY down in your spool areas to help drive EGT's up and enhance spool-up, but in the power areas you can raise the timing up so that you can get your 50% timing split that most consider ideal. It is considered to have your timing set so that half your fuel is sprayed in before TDC and the other half after is considered ideal balance of timing and fuel distribution. But in an IDI this 50% can mean some high timing due to pre-cup's and slowed flame travel because of it. A good example is in a stock 6.5 tune file you can see timing numbers up close to 20 degrees at WOT due to the lag of the flame front leaving the pre chamber and entering the main combustion chamber, but in a DURAMAX GM would have the timing set to around 3-4 degrees for the same amount of fuel injected at the same RPM because of the direct injection and less ignition delay.

 

[JayTheCPA]

And on that note . . . All this talk of tuning gets me back to the question of: If I could ooooonly find out more about the box itself. :dunno::1zhelp:

Just to put the thought in perspective, there is a good handle on how much fuel a plunger in each model injection pump will push, how many fins each brand of turbo has on the compressor / turbine, what style pre-cups each version of head has, but seems that nobody has made the equivalent jump over to the digital element (ECM). Sure, we start to scratch the surface by looking at the coding (tuning), but all this has to run through a computer that (like the lift pump, turbo, filters, etc) has its capabilities and limitations; crack this nut and tuning steps up to a completely new level. :hihi:

 

[Chevypoor]

Was running some errands in town and stopped to pickup some Lucas for the tranny. Took the long way home and two good things happened. One the tranny stopped slipping and the second was I saw almost 24psi of boost

Bad news she shut off and I had to get towed home :mad2: Removed the intake, injector lines and the drivers side head. Five lifters on the turbo side of the motor just exploded. The little clips were gone and the pushrods were were actually inside the lifters. Two off the pushrods were galled on the bottom side. I think after I get her patched back up I am going to try and keep my foot out of it.... maybe

 

[btfarm]

Ummm. .. That's a pretty serious hiccup.

Sent from my SCH-I535

 

[Burning oil]

I wonder if timing chain let go?

 

[Chevypoor]

Burning oil
I wonder if timing chain let go?

Don't know. I installed a new timing chain when I installed the new IP.

Googled 6.5 lifters coming apart/ collapsed and several folks over at the "Place" had this issue. Maybe somebody here has seen a lifter let go like this. I will keep everybody posted on what I find. The plan is to yank the other head and the block on Black Friday.

 

[JiFaire]

Q#1 - How many RPMs were you getting to push 24 PSI boost from an ATT and how long did you hold it there?
Q#2 - How old (yrs, # miles) were the lifters?
Q#3 - What kind of oil has been run in them?

Lifters lose oil when compressed, then need to refill when uncompressed. Sticky check, varnish, plugged hole, thick gunk in lifter body, etc all slow down the rate of fill. If it can't fill fast enough between compressions, it empties, then the clip gets broke or dislocated, then things break.

The 6.5 is an interference engine... if the timing chain broke, you got more damage than collapsed lifters.

 

[Chevypoor]

JiFaire
Q#1 - How many RPMs were you getting to push 24 PSI boost from an ATT and how long did you hold it there?
Q#2 - How old (yrs, # miles) were the lifters?
Q#3 - What kind of oil has been run in them?

Lifters lose oil when compressed, then need to refill when uncompressed. Sticky check, varnish, plugged hole, thick gunk in lifter body, etc all slow down the rate of fill. If it can't fill fast enough between compressions, it empties, then the clip gets broke or dislocated, then things break.

The 6.5 is an interference engine... if the timing chain broke, you got more damage than collapsed lifters

I was turning about 3200 at about 80 mph throttle wide open. I backed out of it, she lost power, pulled to the shoulder and she shut off.

I thought I had melted a hole in a piston or something major had broke. I have pulled her down and removed the passenger head.... nothing other than the lifters.

I had heard a loud thumping through the intake twice and it went away quickly so I thought everything was ok. I now suspect that I had atleast 2 dead/ partially dead holes due to collapsed lifters when this happened. This may have been how I was able to hit 24psi.... the ATT builds boost on load right? Then the other lifters went.

The truck has 273K. When I pulled the heads down I found the springs were shimmed. I know from gasser work that is an old school trick to restore tension in weak springs. I also found the pistons were .010 above the deck at TDC. Based what I have been reading about collapsed lifters, what Warwagon stated in a earlier post about coolant in the oil, and the shims I suspect the motor was re ringed, the block was decked, and corners were cut by re using old parts. The PO bought it, ran crappy oil in it or used ether and the motor bent a pushrod. Then he ran her hard on 7 and blew a head gasket. I got her and from my experience coolant and oil never completely mix and in the gassers I have worked on lifters do not come apart. I broke my own rules by not pulling the pan/ complete disassemble of the motor and got in a hurry and just pulled the heads and cleaned up everything I could get to with the block in the truck. Upon a quick glance after the cylinder head removal I had 5 lifters that were apart on the passenger side of the motor. I did install a new timing chain with the new IP so hopefully no surprises when the drivers side head comes off.

So now I am kicking myself for being an idiot and not doing this right the first time as I normally do. Plan is to pull the motor and teardown the motor. Pistons and crank out, the whole nine. If everything checks out and after cleaning new bearings, rings, cam, lifters, etc and back in she goes.

 

[JiFaire]

Well, you definitely are asking all the right questions. Good luck with the teardown and rebuild!

 

[btfarm]

I'd say you pushed a known questionable engine to beyond its limit and paid the price. Hell, if you're gonna scatter one you should do your best. :hihi:

 

[Paveltolz]

Here's a shot of the rockers Bill put in my build.
You might ask him about them when you call him next time...I think I see an HT-4 Cam kit in your future.

 

[ak diesel driver]

you need to post some pics here http://www.thetruckstop.us/forum/showthread.php?39865-6-5-carnage&highlight=6.5+carnage

 

[Chevypoor]

JiFaire
Well, you definitely are asking all the right questions. Good luck with the teardown and rebuild!

Thanks!

btfarm
I'd say you pushed a known questionable engine to beyond its limit and paid the price. Hell, if you're gonna scatter one you should do your best.

You do not know unless you try! :hihi: Glad this happened with no trailer and on the backroads. It seemed to be running fine.... not sure if it was a ticking time bomb or I pushed her a bit hard!

Paveltolz
Here's a shot of the rockers Bill put in my build.
You might ask him about them when you call him next time...I think I see an HT-4 Cam kit in your future.

You must have been reading my mind. Spoke to him today about the cam earlier in the day yesterday. When I call him back I will have to ask about those rockers arms you have. They look pretty cool.

The cam seems like a no brainer... the prices I have seen on the stock cam are really close to his after core return cam price.

:dr: Thats what I feel like after speaking to Bill. I have been a gas motor guy up until about the last 2-3 years. Now all I want to drive is an oil burner. Thought I knew a few things about the 6.5 but I still have some things to learn. Bill said that from the factory the valve springs had shims and that the factory pistons can be up to .007 out of the hole. I thought this block may have been re ringed and decked. Now I am thinking it was just an old tired 6.5 with 273k that had been sitting for 8+ years.... I guess I am lucky it did not put a piston through the block at 24psi!

ak diesel driver
you need to post some pics here http://www.thetruckstop.us/forum/sho...ht=6.5+carnage

I will try after the weather breaks... the truck is out side and they are calling for two days of cold rain. Yuk!

 

[JayTheCPA]

I'd say you pushed a known questionable engine to beyond its limit . . .

Not to mention double checking the speedo as I am *suuuuure* that you were not going faster than the posted speed on 64

 

[Paveltolz]

... the prices I have seen on the stock cam are really close to his after core return cam price.

That and the kit comes with the improved springs as well.

I don't know where he gets the rocker arms from. He used to market a set but no longer listed on the site. The ones I have aren't those though (if that makes any sense). Regardless, he'll be able to source them or give you a contact.

My best wishes to you in putting Humpty-Dumpty back together again...with main and head studs too. 24 PSI on a 270k motor resting for 8 years...you must be a former Warrant Officer too..."Hey, watch this! What's the worse that could happen?":rof:

My heart goes out to you though. I had a timing belt go on a gasser once...pistons hammering the valves to scrap is a sound you don't forget:nonod:

Any and all, please do come out to Utah and you won't be disappointed; in SSForce's rig, the scenery or the hospitality.:thumbsup:

 

[Burning oil]

Paul, whats the best time of year to see Utah?

 

[Paveltolz]

Paul, whats the best time of year to see Utah?

Pretty much anytime the kids are in school! Temperatures are lower and the crowds are way down with families tied to the homework schedule.

With our varied climate zones, I'd say early Fall to late Spring. Zion and Bryce National Parks in the south along with Moab with Canyon Lands and Arches National Parks are easy do year round though a little cool in the winter months.
With that car in your current Avitar, avoid anything above I-70 during the snow months. But then there's the skiing...went snow shoeing today for a couple of hours at the 8000' level.

There's two Salt Flat events after the August big show. Typically the second week of September and first week of October (you'd mentioned wanting to see that).

There's more but this is a thread for those morning the demise of a brother's motor.

 

[Paveltolz]

Correction about the Rocker Assembly in my motor. 635 texted to say that those are rebuilt units from Portland Engine Rebuilders. Send in your old Rockers and get them back reconditioned like those in the photo above. Was $160 back in 2009. Not sure about now. Thanks for the correction Ted.

 

[Burning oil]

Thanks.

 

[Chevypoor]

Paveltolz said:
My best wishes to you in putting Humpty-Dumpty back together again...with main and head studs too. 24 PSI on a 270k motor resting for 8 years...you must be a former Warrant Officer too..."Hey, watch this! What's the worse that could happen?"

I am not sure what I was thinking. This was the last of about 5 runs slowing down to about 10mph and laying the loud pedal to the floor. I hit 18psi then 20-21psi... I guess I was boost drunk!

I am thinking about studs on the mains and heads if the block looks good. If not I may be able to talk my wife into giving up her 93 599 block 6.2 for hybrid motor.