Engine/Transmission (1994 - 1998) Turbo spin

[NHays]

I am doing some wiring work to the truck and took the intake off. I went to spin the turbo and it was firm to spin. How hard should the shaft be to turn. I have under 10K miles on this thing. I am thinking its fried. It got hot once when my engine failed (1600* plus). I could not cool down, but that was 7000 miles ago and it was working fine. I am very strick on letting it cool to at least less than 400* preturbo. I run Amsoil. I don't ever get it to hot.

 

[WDixon27]

it should spin with little to no resistance, 400* id say is way too high even with synthetic, maybe a water cooled turbo wouldn't mind but i sure wouldn't do that to a oil cooled unit, if it's not screeching or pumping oil it's probably ok for the time being, i let mine get to a hair under 300* as the temp rises due to heat soak after you shut down, if you have a manual transmission you can reduce the idling time a little by down shifting and coasting in gear, i coast down my street and by time i roll into my spot in the driveway it's almost ready to kill and i live only a half mile from the interstate

 

[pwerwagn]

Well, my stock 35 with 70,000 miles was waaay easier to spin than the dodgzilla with 3,000 miles is. I thought the dodgzilla was already toast a few days ago. But after checking quite a few others, they all seem to vary for some reason. if I happen to side load the comp wheel before spinning it, it spins hard. If I just let it shut down and spin it, it spins great.



I also let mine cool down to about 275* no matter what. I do the same coasting into the driveway trick too.

400* is just waay to hot for my liking. I used to get my hx35 to well over 1600* and very often. but I would always let it cool to 275* and I never managed to kill it.

Shaft play was still well within spec after tons and tons of 40+ psi jaunts over 1600*. I dont think I would worry about it if I were you.



If you pull the inlet hose of, start the truck, let it run for a few seconds and get out, by the time you walk to the front of the truck is the compressor still spinning??? mine spins for about 10 seconds or so...



-Jeff

 

[NHays]

I can't get mine to cool below 375ish, even if I idle for 5 minutes. I usually idle my truck through the neighborhood and then sit in the driveway for about a minute. I always idle for a bit after driving, and i don't shut down ever when I go in to stores for less than ten minutes.

 

[NHays]

Sounds like I need a different pyro.

 

[pwerwagn]

Does the pyro read close to the correct outside temp when you get up in the morning or when it has sat for like 8 hours??

If its an isspro, you can stick your finger in the light hole and move the pointed.



I think andy redmond can calibrate pyro's. Try contacting him.



--Jeff

 

[DBogo]

what about for us guys that are volunteer firemen when we get the the station we dont have time to let it sit there and cool off it we want to make it on a truck, is it going to hurt it

 

[WDixon27]

one of these would take care of that i will probably get one before next summer, or if i need to do any more serious towing before then

what about for us guys that are volunteer firemen when we get the the station we dont have time to let it sit there and cool off it we want to make it on a truck, is it going to hurt it

 

[pwerwagn]

what about for us guys that are volunteer firemen when we get the the station we dont have time to let it sit there and cool off it we want to make it on a truck, is it going to hurt it

Whats happening is the turbo itself has absorbed a lot of heat. Standard petro based oil cokes around 450* I believe. Synthetic oil is more resistant to this, it cokes at higher temps.

When this happens, it will create a sort of solid material. This material will be in the bearing section of the cartridge, and it is very abrasive. If a lot of this develops, your bearing section will wear out prematurely due to the abrasiveness of the coke'd oil.



I would say if its only slightly warm (350*) and you havent accelerated much in the last while, and you only do it occasionally you are probably fine.



The reason why you want to idle for a while at low egts is so that the cooler air will extract some of the heat from the housing to prevent the oil from coking.



If I were you I would do any of these:

coast into the station for the last short distance or at least refrain from accelerating much. keep the EGT as low as you can. And possibly switch to a synthetic oil if this isnt possible, since it will resist the heat better.

Or invest in a turbo timer or something like the isspro unit mentioned.



--Jeff

 

[Gary - K7GLD]

Have someone shut the fully warmed engine off while you're at the tailpipe - listen to see if you can hear the turbo spinning down to a stop - should take 15-30 seconds or so. As mentioned above, some turbos seem somewhat stiffer than others when cold - but quickly loosen up when heat is applied, and function quite normally...