|
Sponsored Links (Register now to hide all advertisements) |
|
|
Thread Tools | Display Modes |
10-18-2017, 06:48 PM | #1 |
Senior Member
Join Date: Jun 2014
Location: Williamsburg, VA
Posts: 1,627
|
Turtle Gear Change
Because of an ill fitting repro floor board that takes five different kinds of fasteners to hold it to various stripped and rusted out screw holes, I will do almost anything to avoid taking the floorboard out of my '41 coupe, including attempting to change the turtle gear from underneath the car.
It takes some contortions and working by feel, but it can be done! A 1/4" drive ratchet can be used when the bolts are near all the way down, but further out than that, you have to use a 7/16 box end, one twelfth of a turn at a time. Luckily I could run the bolts with my fingers, once they were loose. I could have avoided the problem altogether if I had changed from the stock 19 turtle to an 18 turtle when I changed from the 19 tooth gear to the smaller radius 17 tooth gear when the rear end was out to change from 3.78 ring and pinion to 3.25. The 17 tooth fiber gear from Braton in the 19 housing just barely engages the worm gear on the drive shaft. The speedometer worked at first, then started skipping, then quit in about 100 miles. You can see the worn off teeth in the photo. The turtle from Mac's is unmarked, but they swear it matches the 18. It is hard to measure from the curved surfaces, but best I could tell, the shaft centerline is about .030" closer to the mounting surface than the 19 housing. I left out the gasket to gain another .002. What's another little leak? Long story for a little job, but I thought some future thread searcher might benefit from the experience. |
10-18-2017, 08:44 PM | #2 |
Senior Member
Join Date: May 2010
Location: Tinley Park Ill
Posts: 1,061
|
Re: Turtle Gear Change
One of those cheesy ratcheting box wrenches may work.
|
Sponsored Links (Register now to hide all advertisements) |
|
10-18-2017, 09:05 PM | #3 |
Senior Member
Join Date: May 2010
Location: Near Rising Sun, Maryland
Posts: 10,858
|
Re: Turtle Gear Change
I thought you would have followed up on this post.....
https://www.fordbarn.com/forum/showthread.php?t=229971
__________________
John "Never give up on what you really want to do. The person with big dreams is more powerful than one with all the facts". Albert Einstein |
10-19-2017, 02:00 AM | #4 |
Senior Member
Join Date: Jul 2011
Location: SF Bay Area
Posts: 6,645
|
Re: Turtle Gear Change
I wouldn't call a tool cheesy if it performs the task it was designed for. Consider the need to remove and flip a box wrench multiple times in a tight spot such as described above. I think those ratchet box wrenches are a fabulous addition to my toolbox.
__________________
Alan |
10-19-2017, 07:44 AM | #5 |
Senior Member
Join Date: May 2010
Location: Tinley Park Ill
Posts: 1,061
|
Re: Turtle Gear Change
Well I found the Quality varied a lot. The ratio in the swing of the wrench leaves a lot to be desired.And the ones I got worked but not well. But then again I got what I paid for.
|
10-19-2017, 10:22 AM | #6 | |
Senior Member
Join Date: Jun 2014
Location: Williamsburg, VA
Posts: 1,627
|
Re: Turtle Gear Change
Sponsored Links (Register now to hide all advertisements)
Quote:
This forum has been a huge help for me in the numerous projects I have had on my '41 coupe and '34 pickup, but is not always easy to find the information needed. I have not found a way to narrow a search topic; if you search using two words, it does not find just posts that contain both words, it finds all posts containing either word. I would be great if there were some way to flag posts with "how to" information, for search with key words. |
|
10-19-2017, 10:30 AM | #7 |
Senior Member
Join Date: May 2010
Location: uk
Posts: 367
|
Re: Turtle Gear Change
thanks for the info. I have just bought A 17 tooth gear from brattons to try and correct my speedo however I think it will still be out even with a 17 tooth gear. Maybe I'm better just leaving the 18 tooth gear in it and marking the glass lightly with a waterproof marker to I know what speed I'm travelling at now?
|
10-19-2017, 12:55 PM | #8 | |
Senior Member
Join Date: May 2010
Location: Near Rising Sun, Maryland
Posts: 10,858
|
Re: Turtle Gear Change
Quote:
With 3.54 rear gears, #18 (39-11) turtle housing & gear, and 6.00 x 16 rear tires, the speedometer and odometer in my '35 fordor are reading right on the money based on GPS mph readings.
__________________
John "Never give up on what you really want to do. The person with big dreams is more powerful than one with all the facts". Albert Einstein |
|
10-19-2017, 04:20 PM | #9 | |
Senior Member
Join Date: May 2010
Location: uk
Posts: 367
|
Re: Turtle Gear Change
Quote:
Someone put up a chart about turtle sizes for different gears/tyres but it said 20 tooth was fine for 6.50sx16 - the chart is on this thread https://www.fordbarn.com/forum/showthread.php?t=226134 Last edited by weemark; 10-19-2017 at 04:27 PM. |
|
10-19-2017, 10:05 PM | #10 |
Senior Member
Join Date: May 2010
Location: Near Rising Sun, Maryland
Posts: 10,858
|
Re: Turtle Gear Change
[QU. E=weemark;1541332]hi john - this is for the roadster. I have an 18 tooth gear in the turtle, well at least I think its 18 tooth but ive never counted the teeth, I have 3.54 gears in the axle and running 6.50 x 16 on the rear. the speedometer reads about 24/25mph when im doing 30 - the needle bounces around a little so it could be one or the other. So even if I changed to a 17 tooth speedo gear the speedometer would still be out.
Someone put up a chart about turtle sizes for different gears/tyres but it said 20 tooth was fine for 6.50sx16 - the chart is on this thread https://www.fordbarn.com/forum/showthread.php?t=226134[/QUOTE] Mark, I can't speak to the correctness of that chart, and if that chart was taken from the Green Book, or as some call it the Green bible, that would make me suspicious of its correctness like other info published in that book. The first thing I would do is determine why the speedometer needle is bouncing. My guess would be the lubrication on the inner cable is either gummed up. or it's possibly lacking in the proper lubrication (i.e. graphite). Or there could be something wrong in the speedometer head itself. My next recommendation would be to verify which turtle housing number you actually have, and how many teeth are on the gear that's in that turtle housing. If it has an 18 tooth gear, that may be as accurate as it's going to get with 3.54 gears and 6.50x16 tires. If you were running 7.00x16 tires I believe the 17 tooth gear would give a more accurate reading. JMO
__________________
John "Never give up on what you really want to do. The person with big dreams is more powerful than one with all the facts". Albert Einstein |
10-20-2017, 02:17 PM | #11 |
Senior Member
Join Date: May 2010
Location: uk
Posts: 367
|
Re: Turtle Gear Change
John yes the chart is from the green bible - I have just realised that though.
I think the needle is bouncing a little due to a lack of graphite, I think its only lubed with oil and grease. I have several turtle housings, the one im using though is a brand new one, possibly from macs, which is unmarked but I think ive also got an 18 tooth housing, ive got a 19 and a 21 too. |
10-20-2017, 02:52 PM | #12 | |
Senior Member
Join Date: May 2010
Location: Florida and Penna.
Posts: 4,471
|
Re: Turtle Gear Change
Quote:
mostly different in diameter and the housings have a different depth depending on the OD of the gear. That's why your replacement gear won't engage. G.M.
__________________
www.fordcollector.com |
|
10-20-2017, 05:11 PM | #13 | |
Senior Member
Join Date: Jun 2014
Location: Williamsburg, VA
Posts: 1,627
|
Re: Turtle Gear Change
Quote:
|
|
10-21-2017, 09:14 PM | #14 |
Senior Member
Join Date: Jun 2014
Location: Williamsburg, VA
Posts: 1,627
|
Re: Turtle Gear Change
The 17 tooth turtle gear worked with no skipping or flutter of the needle, so the 18 turtle housing from Mac's did the trick. Finally got to do a GPS check on the speedo gear change. With 3.25 rear end gears and BFG 205/75R15 rear tires, the speedometer matches the GPS as close as I can read it in that unfortunately dim and low contrast instrument panel.
|
10-21-2017, 10:00 PM | #15 | |
Senior Member
Join Date: May 2010
Location: Near Rising Sun, Maryland
Posts: 10,858
|
Re: Turtle Gear Change
Quote:
__________________
John "Never give up on what you really want to do. The person with big dreams is more powerful than one with all the facts". Albert Einstein |
|
10-22-2017, 09:14 PM | #16 | |
Senior Member
Join Date: Jun 2014
Location: Williamsburg, VA
Posts: 1,627
|
Re: Turtle Gear Change
Quote:
Just got back from the first long road trip with the new 3.25 gears. They took me over Afton Mountain on I-64 at 65 mph. Temp went up to 180, but otherwise, no strain. Cruised all day at 65 and averaged 16.7 mpg. Visited cousins in Staunton, a very hilly town. Caught some stop lights on very steep hills, and got going easily without excessive clutch slipping. Anyone else considering going to such tall gears needs to remember that my flathead is 284 cubic inches and has a ton of torque. |
|
10-23-2017, 09:06 AM | #17 | |
Senior Member
Join Date: May 2010
Location: Florida and Penna.
Posts: 4,471
|
Re: Turtle Gear Change
Quote:
It should take EXACTLY 60 seconds to go 1 mile. This will tell you how close your speedometer is. G.M.
__________________
www.fordcollector.com |
|
10-23-2017, 11:59 AM | #18 |
Senior Member
Join Date: May 2010
Location: Star, MS
Posts: 4,024
|
Re: Turtle Gear Change
|
10-23-2017, 12:39 PM | #19 |
Senior Member
Join Date: May 2013
Location: Harrisonburg, VA
Posts: 842
|
Re: Turtle Gear Change
Are you using a tachometer? I am curious how many r.p.m.'s you are turning at 65.
__________________
The more I learn about new automobiles, the more I value my old ones. |
10-23-2017, 02:07 PM | #20 |
Member
Join Date: Nov 2010
Location: Wadsworth Ohio
Posts: 48
|
Re: Turtle Gear Change
Great to see results of diff. and speedometer gear changes. Will order parts as you recommended. Thanks much
|
|
|
Sponsored Links (Register now to hide all advertisements) |
|