Engine/Transmission (1994 - 1998) Endplay?

[98rammer]

What's the spec on how much endplay is allowed on the hx-35 turbos?



Tom

 

[Andy Redmond]

. 004-. 006

 

[98rammer]

is that back and forth or up and down? either way i think i'm past that- will have to get a dial indicator.



i floored it from 70mph and the boost went on hard-power went hard, then i lost boost and power through around 75-85 and then it took off again. plus i heard a weird (non-typical) whining sound that i didn't like either.



thanks,

Tom

 

[mschoenheider]

From the Holset Spec sheet, axial endplay (in and out) is 0. 001-0. 005 inch.

Radial endplay (side to side) is 0. 013 to 0. 020 inch.

Mark

 

[Whitmore]

The service manual says

Allowable radial bearing clearence is0. 326- 0. 496 and the end play is 0. 038-0. 089



Cheers, Kevin

 

[mschoenheider]

There seems to be some confusion, so here is the service data sheet.

Holset HX service data sheet



Mark

 

[illflem]

The easy way

I've always heard as long as the blades aren't coming close to hitting the housing you're fine. Due to the turbo's high rotational speeds and heat there are no bearings but rather bushings, the shaft rotates on a film of oil. Until the truck is running there will be some play, it's normal don't worry about it.

 

[98rammer]

if i push on the turbo, it doesn't seem to rub against the side of the housing. it does get harder to turn though- i assume because no oiling is being pushed through it.



well, i was hitting 32-33 pounds of boost at 7200ft. well, going WOT- it lost power and boost there for a while and went back up. i have a bad whine on the top end. well, yesterday i drove out of school and noticed that it's making that whining sound above 25 psi. i backed my power down to 24-25 psi and i still hear that whining sound above 24psi.



this isn't the typical whine that you'll get above 30 psi or so, this is much more like a jet engine. sounds like something isn't right... i dunno, but the fact that it went down in boost #'s to make the sound has me a little worried.



rebuild kit?



Tom

 

[HoleshotHolset]

Tom: Look for boost leaks before you go too crazy on a rebuild kit for your CHRA. (Center Housing Rotating Assembly)



Matt

 

[98rammer]

Matt, i'll look, but i did tighten up all clamps a couple weeks ago.



as i went down the road i hit full boost WOT in 4th locked. 70mph-75 went fine and pulled hard. then, from about 75-85 the boost went down about 4 psi and i lost a noticeable amount of power. i kept my foot into it the whole time and the boost came back on with the power after 85mph. mind you i had the #0 plate in the stock position so it wasn't defueling.



then i noticed that weird whining sound that i've never heard. i could only do it at WOT at around 32psi. the next day (yesterday) i turned on my truck, and it's whining above 24psi.



mind you i did lose oil pressure 4 times on my way to Cheyenne, but all was well on the ride home with some fast spurts on the throttle.



Tom

 

[98rammer]

maybe i'm going crazy i put my #0 plate back in the stock position. 32 pounds of boost and it whines... but that's equivalent to around 40pounds of boost at sea level. i've only hit 35pounds (it would slip too easy in OD locked WOT at sea level to even try). however, i have hit 40 before with some different mods at sea level and i don't remember the turbo ever sounding like this.



maybe it's just nothing and pushing the turbo to its max



Tom

 

[Whitmore]

Tom, just a warning, on my oem hx35 I used the turnbuckel methed on the wastgate so I could get 38 psi boost, well it lasted about a year and I launched it, the bearing on the compressor side came loose, when I disected it half the bearing thickness was missing in action. Still have it sitting on the bench.



cheers, Kevin

 

[98rammer]

kevin, was that at this air level? it seems that these turbos can take 40psi for a long time, but that's at sea level to my best knowledge. i lost about 8psi up to 7200 feet here so i add that to what i'm currently running. that'd make you be running 46psi at sea level



still, you have a point. i'm only hitting 32 psi, but i might just back it down again tomorrow. although not as fast, it feels nice to put my foot into the throttle and know that the lockup clutch wont slip



Tom

 

[Whitmore]

Tom, yes that is at 4k-8k elevations... ... ... ... ... ... ... ... heck I never been no where sept ol Wyo, I did take a real long trip last weekend down to Tim's place in Cheyenne for the Wyo TDR gathering and the Cheyenne front and rear days... ... ... ... ... ..... oh ya you were there I rememberin now



Cheers, Kevin

 

[98rammer]

oh man, you have to head down to the ocean... . eat some fresh lobster and friend clams, smell the ocean and feed the seaguls.



man was i surprised to see seaguls here i guess you call them landguls



yeah, i'd say that you'd be running around 45pounds of boost at sea level like that



i gotta get in another truck with an hx-35 and over 30 pounds of boost and listen to it

 

[TORQUED TAYLOR]

I am having a very similar problem. I am getting a high pitched chirping and it get louder as the boost goes up to 30psi. Sounds like a cricket on crack!

 

[ToolManTimTaylor]

Sounds Like a Boost leak there Double T. Go check your intercooler boots, I bet one juuust may have a loose clamp. It's allways easier to eliminate the simple things before going tech.