Bellhousing alignment question
Thread Starter
Le Mans Master
Joined: Jan 2001
Posts: 6,692
Likes: 1,366
Bellhousing alignment question
I am preparing to align my bellhousing and after reading a bunch of old threads I'm kinda confused. Here are my direct dial indicator readings:
3 o'clock = 0
9 o'clock = .0095
delta = .0095
12 oclock = .002
6 o'clock = .007
delta = .005
Can I use the .007 dowel pins to correct his misalignment?
3 o'clock = 0
9 o'clock = .0095
delta = .0095
12 oclock = .002
6 o'clock = .007
delta = .005
Can I use the .007 dowel pins to correct his misalignment?
Thread Starter
Le Mans Master
Joined: Jan 2001
Posts: 6,692
Likes: 1,366
I thought so too....
but my tranny is really hard to insert, and the engine drags the input shaft in neutral.
My starter gap is good, I've changed throwout bearings, installed an adjustable pivot ball, and I even replaced the forward bearing on the Richmond ROD.
My starter gap is good, I've changed throwout bearings, installed an adjustable pivot ball, and I even replaced the forward bearing on the Richmond ROD.
Race Director
Joined: Apr 2000
Posts: 17,673
Likes: 199
From: Who says "Nothing is impossible" ? I've been doing nothing for years.
Normally if the tranny is hard to insert, you connect the linkage and drepress the clutch, this allows the clutch disk to center itself and the tranny should now slide in easily.
Have you checked the condition of the pilot bearing ?
What I am getting is you think the motor is spinning the tranny input shaft with the clutch depressed ? I doubt it is the pilot bearing, or an alignment problem with your runoout specs. Sounds more like the clutch is not disengaging for one reason or another.
How are you checking runout, are you running the dial indicator inside the bellhousing opening for the tranny or outside on the mating surface ?
Have you checked the condition of the pilot bearing ?
What I am getting is you think the motor is spinning the tranny input shaft with the clutch depressed ? I doubt it is the pilot bearing, or an alignment problem with your runoout specs. Sounds more like the clutch is not disengaging for one reason or another.
How are you checking runout, are you running the dial indicator inside the bellhousing opening for the tranny or outside on the mating surface ?
Last edited by MotorHead; Jul 26, 2007 at 11:38 PM.
Race Director
Joined: May 2006
Posts: 16,528
Likes: 53
From: Dayton, Ohio
How far did you drive the pilot into the back of the crank.If you drove it in flush there is a good chance the inside end of the pilot is smaller now. If it is smaller it will gauld the input shaft.I have gotten in the habit of leaving the clutch out and trial fitting the trans and then putting the trans in a gear and rotating the output shaft to make sure it turns smooth.Then I put the clutch in bolt it all up and push on the clutch and turn the output shaft and see if the clutch is releasing and rotating smoothly.Its extra work but its worth it.
Thread Starter
Le Mans Master
Joined: Jan 2001
Posts: 6,692
Likes: 1,366
It stops making a racket when I depress the clutch..
And when I let it back out, it starts dragging. When the car is cold everything is nice and quiet...once it warms up, the noise starts...that's why I suspect a tolerance issue.
I have been installing the pilot bushings to the "flush" condition. Is that improper? I've changed pilot bushings 3 times, changed the throwout bearing once, and as I mentioned before; even changed the forward bearing on the tranny.
I took 3 sets of readings with the dial indicator....I run the dial indicator on the inside the bellhousing opening.
I was reading some old posts and I saw that some tranny manufacturers want a maximum .005 total.....I guess I'll try to attain that.
SO, I just ordered a pilot "bearing", how far should I insert it? I'm going to align the bellhousing since I'm already halfway there and I'm getting tired of pulling this tranny.
I have been installing the pilot bushings to the "flush" condition. Is that improper? I've changed pilot bushings 3 times, changed the throwout bearing once, and as I mentioned before; even changed the forward bearing on the tranny.
I took 3 sets of readings with the dial indicator....I run the dial indicator on the inside the bellhousing opening.
I was reading some old posts and I saw that some tranny manufacturers want a maximum .005 total.....I guess I'll try to attain that.
SO, I just ordered a pilot "bearing", how far should I insert it? I'm going to align the bellhousing since I'm already halfway there and I'm getting tired of pulling this tranny.
Race Director
Joined: Nov 1999
Posts: 10,643
Likes: 8
From: Foxfield CO 1970 Convertible
And when I let it back out, it starts dragging. When the car is cold everything is nice and quiet...once it warms up, the noise starts...that's why I suspect a tolerance issue.
I have been installing the pilot bushings to the "flush" condition. Is that improper? I've changed pilot bushings 3 times, changed the throwout bearing once, and as I mentioned before; even changed the forward bearing on the tranny.
I took 3 sets of readings with the dial indicator....I run the dial indicator on the inside the bellhousing opening.
I was reading some old posts and I saw that some tranny manufacturers want a maximum .005 total.....I guess I'll try to attain that.
SO, I just ordered a pilot "bearing", how far should I insert it? I'm going to align the bellhousing since I'm already halfway there and I'm getting tired of pulling this tranny.
I have been installing the pilot bushings to the "flush" condition. Is that improper? I've changed pilot bushings 3 times, changed the throwout bearing once, and as I mentioned before; even changed the forward bearing on the tranny.
I took 3 sets of readings with the dial indicator....I run the dial indicator on the inside the bellhousing opening.
I was reading some old posts and I saw that some tranny manufacturers want a maximum .005 total.....I guess I'll try to attain that.
SO, I just ordered a pilot "bearing", how far should I insert it? I'm going to align the bellhousing since I'm already halfway there and I'm getting tired of pulling this tranny.
Race Director
Joined: May 2006
Posts: 16,528
Likes: 53
From: Dayton, Ohio
And when I let it back out, it starts dragging. When the car is cold everything is nice and quiet...once it warms up, the noise starts...that's why I suspect a tolerance issue.
I have been installing the pilot bushings to the "flush" condition. Is that improper? I've changed pilot bushings 3 times, changed the throwout bearing once, and as I mentioned before; even changed the forward bearing on the tranny.
I took 3 sets of readings with the dial indicator....I run the dial indicator on the inside the bellhousing opening.
I was reading some old posts and I saw that some tranny manufacturers want a maximum .005 total.....I guess I'll try to attain that.
SO, I just ordered a pilot "bearing", how far should I insert it? I'm going to align the bellhousing since I'm already halfway there and I'm getting tired of pulling this tranny.
I have been installing the pilot bushings to the "flush" condition. Is that improper? I've changed pilot bushings 3 times, changed the throwout bearing once, and as I mentioned before; even changed the forward bearing on the tranny.
I took 3 sets of readings with the dial indicator....I run the dial indicator on the inside the bellhousing opening.
I was reading some old posts and I saw that some tranny manufacturers want a maximum .005 total.....I guess I'll try to attain that.
SO, I just ordered a pilot "bearing", how far should I insert it? I'm going to align the bellhousing since I'm already halfway there and I'm getting tired of pulling this tranny.
On the pilot I usually leave them out by about 1/8".But you need to measure the depth of the bore.Nothing special needed- a pencil with no eraser will work-slide it in to the bottom of bore-put your finger on the pencil to mark depth and compare to length of pilot bushing.Mark this depth on pilot and only go in this far.Too far will crush end of bushing and make bushing too tight on input shaft.The pilot bushing is around .800 long,I see bore depths of only .650 about 20% of the time.(auto trans. crank? hmmm)
In your first paragraph you talk about dragging-please explain more.
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Thread Starter
Le Mans Master
Joined: Jan 2001
Posts: 6,692
Likes: 1,366
What I mean by "dragging"....
First of all, thanks for all the info....
What I mean by dragging is that when the car warms up it appears to start "dragging" the tranny input shaft ...and yes, the clutch is disengaged.....that's why I'm suspecting a misalignment condition.
Anyway, as far as the pilot bearing/bushing insertion issue; is the bore tapered inward at the forward end? Is this what you mean by crushing the bushing? What is it that I accomplish by measuring the depth? It seems that the bore ends, and there is an open area ahead of it.
I will measure the depth, and not insert past this point, however; what is the most that would allowable to extend aft of the bore surface? 1/8"? 1/4"?
What I mean by dragging is that when the car warms up it appears to start "dragging" the tranny input shaft ...and yes, the clutch is disengaged.....that's why I'm suspecting a misalignment condition.
Anyway, as far as the pilot bearing/bushing insertion issue; is the bore tapered inward at the forward end? Is this what you mean by crushing the bushing? What is it that I accomplish by measuring the depth? It seems that the bore ends, and there is an open area ahead of it.
I will measure the depth, and not insert past this point, however; what is the most that would allowable to extend aft of the bore surface? 1/8"? 1/4"?
Thread Starter
Le Mans Master
Joined: Jan 2001
Posts: 6,692
Likes: 1,366
Pilot Bearing versus Pilot Bushing question...
I ordered a pilot "bearing"...I've never installed one of these units. Is there a different strategy than installing a pilot "bushing"? I don't want to damage it; do I just find and adequate socket and tap it in?
Race Director
Joined: May 2006
Posts: 16,528
Likes: 53
From: Dayton, Ohio
First of all, thanks for all the info....
What I mean by dragging is that when the car warms up it appears to start "dragging" the tranny input shaft ...and yes, the clutch is disengaged.....that's why I'm suspecting a misalignment condition.
Anyway, as far as the pilot bearing/bushing insertion issue; is the bore tapered inward at the forward end? Is this what you mean by crushing the bushing? What is it that I accomplish by measuring the depth? It seems that the bore ends, and there is an open area ahead of it.
I will measure the depth, and not insert past this point, however; what is the most that would allowable to extend aft of the bore surface? 1/8"? 1/4"?
What I mean by dragging is that when the car warms up it appears to start "dragging" the tranny input shaft ...and yes, the clutch is disengaged.....that's why I'm suspecting a misalignment condition.
Anyway, as far as the pilot bearing/bushing insertion issue; is the bore tapered inward at the forward end? Is this what you mean by crushing the bushing? What is it that I accomplish by measuring the depth? It seems that the bore ends, and there is an open area ahead of it.
I will measure the depth, and not insert past this point, however; what is the most that would allowable to extend aft of the bore surface? 1/8"? 1/4"?
Taper? no taper just the end of the bore -but there is not a tall lip so you can drive it in further and it would act like a taper.
Crushing-the end towards the engine outside ID is reduced thereby reducing the inside ID and squeezing the end of the input shaft-causing it to "drag" and eventually gaulding the tip of the shaft.
I think you said your tranny went in "hard"-(with more resistance than you think it should)what we are talking about "could" cause this but also dragging(slow clutch wind down time-12 seconds at the most)can be caused by the clutch not releasing properly.
I dont care for pilot bearings.If you are having alignment issues it will make it worse and could destroy your input shaft.
Last edited by ...Roger...; Jul 27, 2007 at 12:36 PM.
Team Owner
Joined: Apr 1999
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From: Reno Nevada
2024 C3 of the Year Finalist- Modified
The .007 offset would really get you in close. Like within a few thousands. IMO - long dowel pins are the way to go
http://www.jegs.com/webapp/wcs/store...51799_-1_11495
http://www.jegs.com/webapp/wcs/store...51799_-1_11495
Racer
Joined: Nov 2006
Posts: 438
Likes: 1
From: Hunington Beach California
How far did you drive the pilot into the back of the crank.If you drove it in flush there is a good chance the inside end of the pilot is smaller now. If it is smaller it will gauld the input shaft.I have gotten in the habit of leaving the clutch out and trial fitting the trans and then putting the trans in a gear and rotating the output shaft to make sure it turns smooth.Then I put the clutch in bolt it all up and push on the clutch and turn the output shaft and see if the clutch is releasing and rotating smoothly.Its extra work but its worth it.
I do the same thing
Thread Starter
Le Mans Master
Joined: Jan 2001
Posts: 6,692
Likes: 1,366
I will do the pre-fit....
before installing the clutch.
I ordered the alignment dowels, so I should be able to get really close. I also ordered a pilot "bearing"....never wanted to use one before...I thought perhaps I could use one if I was able to get my specs really tight.
I can eat that cost, do y'all recommend I just get pilot "bushing"?
I will also measure the depth of the bearing support surface and not go too deep. I just finished removing my old pilot bushing...had to destroy it to get it out. Tried 2 different pilot bearing removal tools...one didn't fit and the 2nd one couldn't pull it out. I suspect the 2nd one may have just been worn out...didn't have much in the way surface lip to grab the inside edge of the old pilot bearing.
I ordered the alignment dowels, so I should be able to get really close. I also ordered a pilot "bearing"....never wanted to use one before...I thought perhaps I could use one if I was able to get my specs really tight.
I can eat that cost, do y'all recommend I just get pilot "bushing"?
I will also measure the depth of the bearing support surface and not go too deep. I just finished removing my old pilot bushing...had to destroy it to get it out. Tried 2 different pilot bearing removal tools...one didn't fit and the 2nd one couldn't pull it out. I suspect the 2nd one may have just been worn out...didn't have much in the way surface lip to grab the inside edge of the old pilot bearing.
Instructor
Joined: Jun 2001
Posts: 231
Likes: 0
From: Cedar City UT
Tight pilot bushing
I've run into pilot bushings being too tight with 327 crankshafts that were used with automatic trannies. If you have to wail away to install the bearing ,it's too tight and compressing the bushing which is whats making it tight on the trans input shaft. Go to Rock Auto and look up pilot bushings under 67 corvettes and you will find an undersize bushing that may cure your problem. Dorman part # 14651. It has a .593 inner diameter and an outside diameter of 1.060 about .030 than normal. LOL
Bob
Bob
Thread Starter
Le Mans Master
Joined: Jan 2001
Posts: 6,692
Likes: 1,366
Dorman 14651???
That might be the hot ticket.
Something got lost in the last message; am I to understand that the outside diameter of this bushing is .030 inches "smaller" than a regular SBC pilot bushing?
Something got lost in the last message; am I to understand that the outside diameter of this bushing is .030 inches "smaller" than a regular SBC pilot bushing?
Instructor
Joined: Jun 2001
Posts: 231
Likes: 0
From: Cedar City UT
Yeh ,the word "less". Sorry. I had this problem and my machinist installed one of these bushings. Saved the expense of machining the crank. Found them latter online at Rock Auto if needed again.
Bob
Bob
Thread Starter
Le Mans Master
Joined: Jan 2001
Posts: 6,692
Likes: 1,366
I saw the "lip" inside the pilot bushing hole...
Funny that I hadn't seen that before.
SO I'll do the following:
1. get the pilot bushing with the smaller outside diameter as recommended above, measure the depth to the lip, and not insert any further than that depth.
2. index the bellhousing since I already pulled the old dowels and ordered the new ones.
3. prefit the tranny before installing the clutch and check that it turns smoothly.
.....also, from the feedback here, I really should NOT use the pilot "bearing" and just use a bushing.
Any other recommendations?
SO I'll do the following:
1. get the pilot bushing with the smaller outside diameter as recommended above, measure the depth to the lip, and not insert any further than that depth.
2. index the bellhousing since I already pulled the old dowels and ordered the new ones.
3. prefit the tranny before installing the clutch and check that it turns smoothly.
.....also, from the feedback here, I really should NOT use the pilot "bearing" and just use a bushing.
Any other recommendations?
Race Director
Joined: May 2006
Posts: 16,528
Likes: 53
From: Dayton, Ohio
Funny that I hadn't seen that before.
SO I'll do the following:
1. get the pilot bushing with the smaller outside diameter as recommended above, measure the depth to the lip, and not insert any further than that depth.
2. index the bellhousing since I already pulled the old dowels and ordered the new ones.
3. prefit the tranny before installing the clutch and check that it turns smoothly.
.....also, from the feedback here, I really should NOT use the pilot "bearing" and just use a bushing.
Any other recommendations?
SO I'll do the following:
1. get the pilot bushing with the smaller outside diameter as recommended above, measure the depth to the lip, and not insert any further than that depth.
2. index the bellhousing since I already pulled the old dowels and ordered the new ones.
3. prefit the tranny before installing the clutch and check that it turns smoothly.
.....also, from the feedback here, I really should NOT use the pilot "bearing" and just use a bushing.
Any other recommendations?
One thing to note concerning the smaller bushing.If you dont have a set of calipers to measure the bore ID then buy both size bushings just in case the smaller one is too small.