|
Sponsored Links (Register now to hide all advertisements) |
|
|
Thread Tools | Display Modes |
05-10-2024, 10:58 AM | #1 |
Member
Join Date: Apr 2022
Posts: 43
|
Tight crank gear
In replacing the timing gear with aluminum, I am installing a new crank gear. The new gear is tight. I know they are supposed to be tight because of harmonic reasons.
I was going to deep fry the gear to make it easier to go on, but before I did that I measured things up. Crank: 1.351" Old Gear: 1.350" New Gear: 1.349/1.3485 .001" press fit I get, .002+ is tons, like literally. I don't want to put force the gear on and then have it split or something stupid down the line. Anyone have the drawings/measurements of what everything is supposed to be? Crank snout and gear bore? |
05-10-2024, 11:08 AM | #2 |
Senior Member
Join Date: Jun 2010
Location: Temecula, CA
Posts: 4,112
|
Re: Tight crank gear
Heat the gear with a oxy/acet or blow torch. Heat it quite but not enough to show any color on it. It should then slip on, at least part way, then gently pound it on all the way. I made a driver out of iron pipe, with a notch cut out in it to clear the keyway.
|
Sponsored Links (Register now to hide all advertisements) |
|
05-10-2024, 11:21 AM | #3 |
Senior Member
Join Date: Jan 2020
Location: SF Bay Area
Posts: 1,154
|
Re: Tight crank gear
For applications like this, I wait until my bride is elsewhere, then heat the oven up to 450-500 and put the gear/race/bearing/whatever in for a half hour or so after the temperature stabilizes. Bearings that are pre-greased tend to leave a telltale odor in the kitchen...
__________________
JayJay San Francisco Bay Area ------------------------ 1930 Murray Town Sedan 1931 Briggs S/W Town Sedan |
05-10-2024, 11:58 AM | #4 | |
Senior Member
Join Date: Mar 2012
Location: Ohio
Posts: 2,028
|
Re: Tight crank gear
Quote:
|
|
05-10-2024, 04:55 PM | #5 |
Senior Member
Join Date: Jan 2012
Location: Western North Carolina
Posts: 4,052
|
Re: Tight crank gear
I have used the propane powered grill outside to heat things. Avoid pounding on the gear put use a series of bolts and washers to press it on. Pounding may damage the trust bearing in the engine. The ball bearings used for wheelbarrow wheels will avoid turning the gear that has to be carefully aligned. Put the transmission in high gear and put on the parking brake and block the wheels. You can use the pulley instead of a section of pipe.
__________________
A is for apple, green as the sky. Step on the gas, for tomorrow I die. Forget the brakes, they really don't work. The clutch always sticks, and starts with a jerk. My car grows red hair, and flies through the air. Driving's a blast, a blast from the past. Last edited by nkaminar; 05-10-2024 at 05:03 PM. |
05-11-2024, 10:40 AM | #6 |
Member
Join Date: Apr 2022
Posts: 43
|
Re: Tight crank gear
Sponsored Links (Register now to hide all advertisements)
|
05-11-2024, 10:56 AM | #7 |
Senior Member
Join Date: May 2012
Location: Chillicothe, Missouri
Posts: 1,211
|
Re: Tight crank gear
I would replace the gear if you think that gear is a cast blank and not machined the concentricity won't be correct you don't wanna find this out once you get the engine assembled and running!
__________________
"If I asked people what they wanted they would have said faster horses." -Henry Ford "Primitive technology is not a design flaw" 1928 Ford Model A Roadster Pickup 1930 Gordon Smith Air Compressor 1941 Willy's Pickup 1960 Thunderbird-For Sale 1964 Buick Riviera 2x4 425 1965 Pontiac GTO, 455 Super Duty 2004 Dodge Ram SRT-10, V-10 Viper 1977 Charger Jet Boat,460 Ford,Jacuzzi Jet Front Engine Nostalgia Dragster,Supercharged 296 "Fullrace Flathead" Ford Engine Build up on DVD ask |
05-11-2024, 11:05 AM | #8 |
Senior Member
Join Date: Jun 2010
Location: Temecula, CA
Posts: 4,112
|
Re: Tight crank gear
I always use a steel gear, a good, old, steel gear is better than a new cast iron gear.
|
05-11-2024, 11:11 AM | #9 |
Senior Member
Join Date: Aug 2010
Location: SF Bay Area
Posts: 209
|
Re: Tight crank gear
Your gear bore should be somewhere in the neighborhood of 1.3745"
Heating the gear is good advice. A CI gear may not change color enough to help you here. Welding supplies sell temperature indicating crayons that work well. As above 400-450 F is about as high as you want to go and should be enough for the gear to slide on. |
05-11-2024, 11:37 AM | #10 |
Senior Member
Join Date: May 2023
Posts: 172
|
Re: Tight crank gear
Contact whoever you bought it from and get them to replace it for you
Alternatively, take it down to your local shop and have them bore it to the size you're looking for |
05-11-2024, 05:09 PM | #11 |
Senior Member
Join Date: Jan 2012
Location: Western North Carolina
Posts: 4,052
|
Re: Tight crank gear
Yes, 0.0025 seems excessively tight. Cast iron is brittle. I would not chance it. Cast iron will expand if it goes through a heat cycle. You could try heating it to 500 F then cooling it and them re measuring the bore. A few heat cycles like that may expand it enough.
I am breaking in a new antique engine that has a steel cylinder and a cast iron piston. No rings. The instructions say to go through a series of heat cycles to "hone" the piston to the cylinder. Many heat cycles. The piston wears a little but also expands a little. At the end there are mirror finishes on the bore and piston with the correct line to line fit.
__________________
A is for apple, green as the sky. Step on the gas, for tomorrow I die. Forget the brakes, they really don't work. The clutch always sticks, and starts with a jerk. My car grows red hair, and flies through the air. Driving's a blast, a blast from the past. |
05-11-2024, 06:15 PM | #12 |
Senior Member
Join Date: Feb 2015
Location: Australia
Posts: 1,984
|
Re: Tight crank gear
There has already been one Burtz engine shredded a cast crank gear. Photos should be on the Facebook page.
|
05-11-2024, 08:34 PM | #13 |
Senior Member
Join Date: Nov 2010
Location: Lambsburg Va
Posts: 305
|
Re: Tight crank gear
Here"s how I install the crank gear
https://youtu.be/s2vTWWAYo1I?si=p7n_T-AyVSOxqtXb |
|
|
Sponsored Links (Register now to hide all advertisements) |
|