Pilot Bushing Concern - ZR-1 Net Registry Forums

NWPzr1 · 11-09-2011

Hey guys... I'm in the middle of doing a lot of work on a 90 ZR1, one thing being a clutch kit. Car only has 11k miles but there were some weird noises coming from what I figured was just a noisey throwout bearing....

I pulled the trans today and this is what I find....

Being the first Z I've ever done a pilot bushing in, this looks pretty scary to me.... especially the way the crank looks ground and worn. How far is the bushing supposed to be pressed in? Flush? Or until it bottoms out?

I can insert the new bushing until it hits the machined surface.... thinking just press it in there, but it's not only a tight fit but tight enough to make me want to post some pics here and ask around.

HOPING there is no damage to the crank! What do you think?

Appreciate any input, thanks!

LGAFF · 11-10-2011

My crank looks the same way.......I have the pilot bushing tool and it drives the bushing 7.8mm into the crank. On my 92 I did it without the tool and drove it in as far as it can go and it seats.

mike100 · 11-10-2011

These LT5 bushings are prone to spinning in there and then the softer impregnated bushing metal gets hogged out. I was told that you do NOT grease the fluted pilot bushing as it will worsen the friction when it dries out helping to spin it.

mine was loose at 28k miles, but it didn't make noise.

NWPzr1 · 11-10-2011

Thanks for the replies, just to clarify.... the end of the new bushing should basically be butting up against the back section of the crank, as far as the freeze plug?

LGAFF · 11-10-2011

Want to just use the tool I have hell you are right down the street practically.

NWPzr1 · 11-10-2011

Sounds good to me, I'd really appreciate it! I've still got your phone number. Would sometime this weekend be ok to come pick it up?

LGAFF · 11-10-2011

Sure......give me a call...

LGAFF · 11-10-2011

You know what I am wrong, this is the tool for the oil cup that goes into the back of the crank. The pilot bearing just gets driven in as far as it goes it will seat on its own....just drive it in as far as you can

ammrpm · 11-11-2011

If you want to know for sure how far it should go in talk to Bill B. the ZFDOC. He can tell you exactly how far it should go in.

send him an email: billb@zfdoc.com

phone: (602) 319-6575

NWPzr1 · 12-20-2011

Sorry for the delay guys

Thanks for all the help.... I ended up getting everything worked out, trans is back in. Just waiting on a few other parts and this thing should be done in the next week or two. Then just to hand it off to Marc H. for a few days for the tune. I'll be sure to get a write up posted of my quest for speed in this '90 Z...

Thanks again!

11-09-2011	#1
NWPzr1 Join Date: Jul 2011 Location: McHenry, IL Posts: 19	Pilot Bushing Concern Hey guys... I'm in the middle of doing a lot of work on a 90 ZR1, one thing being a clutch kit. Car only has 11k miles but there were some weird noises coming from what I figured was just a noisey throwout bearing.... I pulled the trans today and this is what I find.... Being the first Z I've ever done a pilot bushing in, this looks pretty scary to me.... especially the way the crank looks ground and worn. How far is the bushing supposed to be pressed in? Flush? Or until it bottoms out? I can insert the new bushing until it hits the machined surface.... thinking just press it in there, but it's not only a tight fit but tight enough to make me want to post some pics here and ask around. HOPING there is no damage to the crank! What do you think? Appreciate any input, thanks!

11-10-2011	#2
LGAFF Join Date: Mar 2007 Location: Crystal Lake, IL Posts: 7,195	Re: Pilot Bushing Concern My crank looks the same way.......I have the pilot bushing tool and it drives the bushing 7.8mm into the crank. On my 92 I did it without the tool and drove it in as far as it can go and it seats. __________________ LGAFF 90 #966-150K miles-sold 92 #234-sold 1987 Callaway TT #17 1991 ZR-1 #1359

11-10-2011	#3
mike100 Join Date: Feb 2011 Location: San Marcos CA Posts: 1,801	Re: Pilot Bushing Concern These LT5 bushings are prone to spinning in there and then the softer impregnated bushing metal gets hogged out. I was told that you do NOT grease the fluted pilot bushing as it will worsen the friction when it dries out helping to spin it. mine was loose at 28k miles, but it didn't make noise.

11-10-2011	#4
NWPzr1 Join Date: Jul 2011 Location: McHenry, IL Posts: 19	Re: Pilot Bushing Concern Thanks for the replies, just to clarify.... the end of the new bushing should basically be butting up against the back section of the crank, as far as the freeze plug?

11-10-2011	#5
LGAFF Join Date: Mar 2007 Location: Crystal Lake, IL Posts: 7,195	Re: Pilot Bushing Concern Want to just use the tool I have hell you are right down the street practically. __________________ LGAFF 90 #966-150K miles-sold 92 #234-sold 1987 Callaway TT #17 1991 ZR-1 #1359

11-10-2011	#6
NWPzr1 Join Date: Jul 2011 Location: McHenry, IL Posts: 19	Re: Pilot Bushing Concern Sounds good to me, I'd really appreciate it! I've still got your phone number. Would sometime this weekend be ok to come pick it up?

11-10-2011	#7
LGAFF Join Date: Mar 2007 Location: Crystal Lake, IL Posts: 7,195	Re: Pilot Bushing Concern Sure......give me a call... __________________ LGAFF 90 #966-150K miles-sold 92 #234-sold 1987 Callaway TT #17 1991 ZR-1 #1359

11-10-2011	#8
LGAFF Join Date: Mar 2007 Location: Crystal Lake, IL Posts: 7,195	Re: Pilot Bushing Concern You know what I am wrong, this is the tool for the oil cup that goes into the back of the crank. The pilot bearing just gets driven in as far as it goes it will seat on its own....just drive it in as far as you can __________________ LGAFF 90 #966-150K miles-sold 92 #234-sold 1987 Callaway TT #17 1991 ZR-1 #1359

11-11-2011	#9
ammrpm Join Date: Aug 2006 Location: Houston, TX Posts: 67	Re: Pilot Bushing Concern If you want to know for sure how far it should go in talk to Bill B. the ZFDOC. He can tell you exactly how far it should go in. send him an email: billb@zfdoc.com phone: (602) 319-6575

12-20-2011	#10
NWPzr1 Join Date: Jul 2011 Location: McHenry, IL Posts: 19	Re: Pilot Bushing Concern Sorry for the delay guys Thanks for all the help.... I ended up getting everything worked out, trans is back in. Just waiting on a few other parts and this thing should be done in the next week or two. Then just to hand it off to Marc H. for a few days for the tune. I'll be sure to get a write up posted of my quest for speed in this '90 Z... Thanks again!