Jerico grinds in reverse after street driving?

Weekiman · 02-22-2023, 07:23 AM

I have a bracket car with a Jerico that I drive on the street. I know most of you have dedicated race cars but probably the most amount of manual transmission experience out of any drag racing class. So I was hoping to ask if anyone experiences release issues after your drivetrain gets good and heated after driving an hour or so? It's a mild grind and can be stopped easily by easing into gear. I also hold the clutch in for five seconds or more to let everything spin down. When I had the Jerico pilot bearing it would grind so bad I had to turn the car off and then put into gear. I currently run a GM bronze bushing and its night and day improvement. My bellhousing is aligned to perfection both parallelism and concentric. I don't believe it to be an air gap issue either. I'm thinking that it takes so little power to turn these transmission that my pilot shaft may be dragging.

Mike Pearson · 02-22-2023, 09:02 AM

usually that is a sign of the clutch dragging a bit. check and make sure the disc slides easily on the input splines. Maybe a bit more air gap

TOSTO RACING · 02-22-2023, 09:03 AM

Sounds pretty normal to me. Thats just the way all of mine have been. I'm sure the clutch isn't disengaging all the way ,but I just dealt with it.

Adger Smith · 02-22-2023, 09:16 AM

Pilot bushing could be dry and dragging or too shallow and catching on the input shaft. It is normal to grind if the clutch air gap is not wide. I used to put in low gear, use syncro's to stop clutch and transmission insides from spinning and then go to reverse.

Rory McNeil · 02-23-2023, 12:27 AM

What type of clutch are you using? A bronze pilot bushing will not last very long with a sintered iron disc, like a McLeod Soft Lok. The dust from the clutch disc is abrasive, and will chew up that bronze bushing pretty quick, and allow the input shaft to wobble around.

Weekiman · 02-23-2023, 06:31 AM

Quote:

Originally Posted by Mike Pearson

usually that is a sign of the clutch dragging a bit. check and make sure the disc slides easily on the input splines. Maybe a bit more air gap

Thanks, I don't remember how easily it slides. I'll check it out.

Weekiman · 02-23-2023, 06:35 AM

Quote:

Originally Posted by TOSTO RACING

Sounds pretty normal to me. Thats just the way all of mine have been. I'm sure the clutch isn't disengaging all the way ,but I just dealt with it.

Thanks for the feedback, yea I dealt with it with my last combo for ten plus years. This combo is much better. I think removing the Jerico pilot bearing and going back to a bronze bushing made the difference. Sounds like it's pretty common.

Weekiman · 02-23-2023, 06:37 AM

Quote:

Originally Posted by Adger Smith

Pilot bushing could be dry and dragging or too shallow and catching on the input shaft. It is normal to grind if the clutch air gap is not wide. I used to put in low gear, use syncro's to stop clutch and transmission insides from spinning and then go to reverse.

Thanks for the input.

Weekiman · 02-23-2023, 06:55 AM

Quote:

Originally Posted by Rory McNeil

What type of clutch are you using? A bronze pilot bushing will not last very long with a sintered iron disc, like a McLeod Soft Lok. The dust from the clutch disc is abrasive, and will chew up that bronze bushing pretty quick, and allow the input shaft to wobble around.

Don't laugh too hard but I have a RAM Powergrip HD. It's there 9000 series disc with OE style diaphragm PP. It probably doesn't make as much dust. It worked great with my 12.0 combo, but this is a new combo I'm shooting for mid tens. I'm going to use a Clutch Tamer this time. It's 100% metallic and I believe sintered iron on both sides. I'm not sure if it's the same material as a Soft Lok and I don't remember excessive dust after disassembly last time. I'll keep any eye on it though, thanks.

Adger Smith · 03-06-2023, 09:14 AM

I know this is Hijacking the thread, But...I think the OP has his answer.
Has anyone used a 10,000 RPM brand multi disc metallic clutch with diaphragm? Looks like you shim the stand height to get it set up. (no instructions)
I have a new one that came to me as a spare when I bought all of a buddies racecar Estate.
Is it something usable or just old junk?

02-22-2023, 07:23 AM	#1
Weekiman Junior Member Join Date: Feb 2023 Posts: 6 Likes: 0 Liked 0 Times in 0 Posts	Jerico grinds in reverse after street driving? I have a bracket car with a Jerico that I drive on the street. I know most of you have dedicated race cars but probably the most amount of manual transmission experience out of any drag racing class. So I was hoping to ask if anyone experiences release issues after your drivetrain gets good and heated after driving an hour or so? It's a mild grind and can be stopped easily by easing into gear. I also hold the clutch in for five seconds or more to let everything spin down. When I had the Jerico pilot bearing it would grind so bad I had to turn the car off and then put into gear. I currently run a GM bronze bushing and its night and day improvement. My bellhousing is aligned to perfection both parallelism and concentric. I don't believe it to be an air gap issue either. I'm thinking that it takes so little power to turn these transmission that my pilot shaft may be dragging.

02-22-2023, 09:02 AM	#2
Mike Pearson VIP Member Join Date: Mar 2007 Posts: 2,367 Likes: 560 Liked 1,729 Times in 531 Posts	Re: Jerico grinds in reverse after street driving? usually that is a sign of the clutch dragging a bit. check and make sure the disc slides easily on the input splines. Maybe a bit more air gap __________________ Mike Pearson 2485 SS

02-22-2023, 09:03 AM	#3
TOSTO RACING Senior Member Join Date: May 2007 Location: DRAGSTRIP Posts: 844 Likes: 782 Liked 526 Times in 158 Posts	Re: Jerico grinds in reverse after street driving? Sounds pretty normal to me. Thats just the way all of mine have been. I'm sure the clutch isn't disengaging all the way ,but I just dealt with it. __________________ 5664 AA/SA 1970 NOVA

02-22-2023, 09:16 AM	#4
Adger Smith VIP Member Join Date: Dec 2001 Location: Texarkana Ark/TX Posts: 2,421 Likes: 518 Liked 784 Times in 294 Posts	Re: Jerico grinds in reverse after street driving? Pilot bushing could be dry and dragging or too shallow and catching on the input shaft. It is normal to grind if the clutch air gap is not wide. I used to put in low gear, use syncro's to stop clutch and transmission insides from spinning and then go to reverse. __________________ Adger Smith (Former SS)

02-23-2023, 12:27 AM	#5
Rory McNeil VIP Member Join Date: Jun 2007 Location: from Vancouver BC Canada, now in Nova Scotia Posts: 1,269 Likes: 255 Liked 970 Times in 271 Posts	Re: Jerico grinds in reverse after street driving? What type of clutch are you using? A bronze pilot bushing will not last very long with a sintered iron disc, like a McLeod Soft Lok. The dust from the clutch disc is abrasive, and will chew up that bronze bushing pretty quick, and allow the input shaft to wobble around. __________________ NHRA 6390 STK M/S 85 Mustang

03-06-2023, 09:14 AM	#10
Adger Smith VIP Member Join Date: Dec 2001 Location: Texarkana Ark/TX Posts: 2,421 Likes: 518 Liked 784 Times in 294 Posts	Re: Jerico grinds in reverse after street driving? I know this is Hijacking the thread, But...I think the OP has his answer. Has anyone used a 10,000 RPM brand multi disc metallic clutch with diaphragm? Looks like you shim the stand height to get it set up. (no instructions) I have a new one that came to me as a spare when I bought all of a buddies racecar Estate. Is it something usable or just old junk? __________________ Adger Smith (Former SS)