LTX Pilot Adapter

Does anyone have the symptoms of a bad pilot bearing in these conversions? Launching/take-off problems? strident cries of pain from underneath?

Would be excellent info. Especially to those who have no idea or cant remember what the hell they installed 8 years ago! All this talk about PB's is scaring the shiat outta me and ive noticed a weird shutter at 2 gear take-off's. Tell me its not PB related!!!

Oh, in case, heres some background info, its 1987 944 with NA box and rebuilt TT. I havent daily driven it in over a year and a half...actually, I havent driven it at all except to move it in and out of the garage. So maybe its the clutch or flywheel acting up since it hasnt really been burnt-in in awhile. Everything is from RH so maybe I installed one of those crappy ones that they claim has a 1% failure rate?

Thanks!

944-LT1 wrote:...maybe I installed one of those crappy ones that they claim has a 1% failure rate?
Thanks!

Actually, they only dealt with two people directly, so their REPORTED failure rate was 1%.

("We had ONLY two calls/issues with customers that had experienced failures and contacted us regarding this potential problem. If we sold 200 kits (actually more), that would be a 1% failure rate.")

To quote Paul (948)...

"The fact that only 2 customers called can't be used as a method to establish DPPM, you might want to say "that would be a 1% REPORTED failure rate". How many of the needle bearings, of the 200 kits sold, did you inspect after 6000 miles?? If 2 was your rate of sample then the failure rate was 1,000,000 PPM or 100%"...

Also, it was a needle bearing that failed, although we have seen a misaligned roller bearing fail. The vibration more than likely is not the TT bearings. Which BH are you running? RH cast Al.? What better time to upgrade to a roller bearing, C5 BH (that you motivated me to make work with the LTX, trouble-maker!), and 11 or 12" clutch?

Check that PB, then make the C5 a cozy new home in that 948!

HaHaHa! PORH.

The C5 BH will save us all!!!

I have the RH cast LT1 housing and they sent me their 10.5" clutch (I wonder if I can install an 11" disc or what the limit is in there???). Id love a C5 housing/plate but am low on dough (student). But if you are telling me that it could be the PB, then Im correct to be scared (since you said its not the TT...damnit). Mannnnnnn thats gonna suck.

10.5" is max for the SBC-based RH BH. If you want to keep the existing clutch assembly for now, and save some $$$ on the BH, the AUTO version of the C5 BH can be had for scratch...I got mine essentially for $50! The auto BH (GM part # 12551118) depth is the same as the MT version, but is limited to a 10.5" clutch.

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NOTE: *10.5" clutches will easily handle 500H.P. ...

PORH

NOTE: *10.5" clutches will easily handle 500H.P. ...

Thats what RH claims...

Yeah, I believe I can source the BH easily enough...I was talking about the adapter....thats alot of scratch! I would have to redo my clutch system, clutch disc, and PP, flywheel, pilot assy., etc.

********It should be noted that if your driveshaft doesn't insert all the way into the stock 944 Pilot bearing (15x35x11) then you can go up to a 15x35x14 pilot bearing.
This will save you alot of headache and keep the Bushing adapter from walking out towards the back side of the clutch disk and causing havoc like friction welded tips and chewed shaft splines.
I did this and it gives the shaft tip more insertion.********

Double shielded roller type may be all you need.

944-LT1 wrote:...Yeah, I believe I can source the BH easily enough...I was talking about the adapter....thats alot of scratch! I would have to redo my clutch system, clutch disc, and PP, flywheel, pilot assy., etc.

I think everyone has forgotten something here, and it's good news for you, MK. The C5 will bolt to the SBC/LT1. The SBC/RH BH should likewise bolt to the LSX. Actually, Keisler has already proven it will...same O/A depth...you could re-use your clutch components if you utilized the McLeod conversion flywheel. The downside is the $$$. ~400/450.

Posted in the LSX BH Options thread...

"The Renegade Hybrids SBC / LT1 BH had a depth of 6.375”. A pilot adapter was necessary for the Gen I engines, but at a thickness of .600” (...LS is 1.00” - .600”=.400”). Easy enough. We know already that the bellhousings will bolt up, but what works with what? For the 944, the McLeod flywheel (or a re-drilled & counterbored LS flywheel to allow use of 3/8”-16 shouldered bolts on the PP) , a pilot adapter, and Gen I clutch components...

PARTS LIST
NOTE: Only the McLeod flywheel is a true “conversion-ready” item, utilizing a bronze pilot bushing. If using the factory GM LS1 flywheel, it will need to be re-drilled and counterbored, and a 1” pilot adapter must be used.

LSX FLYWHEEL PART NUMBERS
460535 McLeod Conversion Flywheel
12562765 GM LS1 Flywheel

PILOT BEARING ADAPTER
Machined Adapter to utilize 944 roller bearing (McMaster Carr #6202)
* 14MM thick bearing will give more TT contact area

BELLHOUSING OPTIONS
1) Custom QTI Steel Scattershield (bolts directly to 944 TT)
2) GM #12554980 C5 Bellhousing / CNC Adapter Plate, .600” thick

HYDRAULIC T/O BEARING OPTIONS
1) Ram #798-78125 (JEG’S), must use with Richmond style Bearing Retainer #1304027001
2) S10 / Corvette T/O slave assembly, used with C5 BH

CLUTCH / PRESSURE PLATE
QTI and GM #12554980 BH accommodate the 168T flywheel and all 11” clutch assemblies

STARTER
LS1 / factory GM

OTHER PARTS
Additional parts, such as engine mounts, headers, wiring harness, etc. remain the same as with the RH LS1 kit. The only parts that do not have an RH alternative at this time are the headers. Everything else can be sourced through other vendors."

So, the LT and LS engines are more "friendly" than you think...and if you skip the McLeod flywheel, just have the LS flywheel re-drilled and counterbored to work with the SAE bolt patterns on the crank and pressure plate.

Have ya bought your LS yet? HeHeHe!

944-LT1 wrote:Does anyone have the symptoms of a bad pilot bearing in these conversions? Launching/take-off problems? strident cries of pain from underneath?

Would be excellent info. Especially to those who have no idea or cant remember what the hell they installed 8 years ago! All this talk about PB's is scaring the shiat outta me and ive noticed a weird shutter at 2 gear take-off's. Tell me its not PB related!!!

Oh, in case, heres some background info, its 1987 944 with NA box and rebuilt TT. I havent daily driven it in over a year and a half...actually, I havent driven it at all except to move it in and out of the garage. So maybe its the clutch or flywheel acting up since it hasnt really been burnt-in in awhile. Everything is from RH so maybe I installed one of those crappy ones that they claim has a 1% failure rate?

Thanks!

Just got done replaceing pilot bearing after 6 miles. Bad aligment I believe. I used the roller bearing and adaptor purchased from black forest. Took me a day to tear the entire thing down and had to cut the shaft of the torque tube off to finally get it free. Took me three days to put it all back together including rebuilding the a torque tube-from my parts car-(thanks to Marc for the fast work on the torque tube bearings). I also added an LSD while I had it apart.
The symptoms from my car started out by sounding like a squelling drive belt. This only occured when the clutch petal was pushed in-pressure on the pressure disk. After only a short run down the road the squelling became a scream and grinding from the bell housing area. The noise also became constant-but was always greater when the clutch was ingaged.
Hope this helps any that are concerned about their bearing...

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Picture in my gallery of blown bearing...

What is the min/max that the driveshaft needs to fit into the pilot bearing.
I measured mine up and looks to be abit over 1/2 inche in the pilot bearing when I have the backplate on that came with the QT BH.

PEEP THIS...

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The TT needs @ least 1/4" to 3/8" of support from the pilot bearing, but if the face of the bearing rides against the TT (more than .700" insertion in the bearing), the bearing will eventually fail / friction weld to the TT.

1/2" to MAX 5/8" insertion depth into the pilot bearing should be adequate.

Thank you very much for the reply, this answers my question and should be able to use the backplate that came with the QT BH.

Doh whahappned I clicked on a green bar next to the diagram thinkin that it would let me resize the pic, instead it seems that I voted against somethin! Please disregaurd what ever that vote was cast on (from now on well set on hands while reading)

That would be: "Thanks"...NOT.

...Killin' me, dude.

[JK, no harm done... ]

Whenever I see gregs avatar, i immediately hit that (-) sign.

TWO can play that game...

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