Camshaft movement- tolerance question

Discuss all things Model T related.
Forum rules
If you need help logging in, or have question about how something works, use the Support forum located here Support Forum
Complete set of Forum Rules Forum Rules
User avatar

Topic author
Bill Robinson
Posts: 109
Joined: Sun Jan 06, 2019 2:24 pm
First Name: Bill
Last Name: Robinson
Location: Salty Bottom, AL
MTFCA Number: 22487
MTFCI Number: 17887
Board Member Since: 1999
Contact:

Camshaft movement- tolerance question

Post by Bill Robinson » Mon Oct 28, 2019 11:51 am

I have a Stipe 250 cam in a 1926 engine. 7.5 degree advanced bronze timing gear.
-My question- with the timing gear cover removed I have a camshaft lateral movement (in & out) of .0065".
-Up & down movement of the camshaft is .005".
Are these measurements withis tolerance or do I need to looking into finding a new front bearing?

User avatar

Mark Gregush
Posts: 1704
Joined: Sat Jan 05, 2019 1:57 pm
First Name: Mark
Last Name: Gregush
Location: Portland Or
Board Member Since: 1999

Re: Camshaft movement- tolerance question

Post by Mark Gregush » Mon Oct 28, 2019 12:15 pm

I would say the in/out is hardly nothing. Is the up/down the cam or shell in block?
My real question is where did you get the bronze gear with 7.5 degree advance? The info in Chaffins says not to use the advanced timing gear as the new cam is already advanced, Langs does not say. Is this a new engine or has it been run with this combination?
I know the voices aren't real but damn they have some good ideas! :roll:

1921 Huckster
1925 Cut down pickup


Scott_Conger
Posts: 2239
Joined: Sun Jan 06, 2019 11:18 am
First Name: Scott
Last Name: Conger
Location: Clark, WY
Board Member Since: 2005

Re: Camshaft movement- tolerance question

Post by Scott_Conger » Mon Oct 28, 2019 12:25 pm

Mark

the difference is that Glen's folks dialed in advance on the cam that they sell. The Stipe product is a straight up cam and is up to you to decide to advance it or not. I think that Dan McEachern will do the gear in bronze. His work is superb.
Scott Conger

Full Flow Float Valves - deliver fuel like Henry intended!

User avatar

Topic author
Bill Robinson
Posts: 109
Joined: Sun Jan 06, 2019 2:24 pm
First Name: Bill
Last Name: Robinson
Location: Salty Bottom, AL
MTFCA Number: 22487
MTFCI Number: 17887
Board Member Since: 1999
Contact:

Re: Camshaft movement- tolerance question

Post by Bill Robinson » Mon Oct 28, 2019 1:52 pm

The STIPE 250 cam was installed in 2012. It is not a Chaffin's cam. I'm thinking that the Stipe 280 Cam was not available at the time. The advanced gear is one of Dan's and was installed in 2015.
I don't know if the movement is in the shell, because as stated, only the timing cover has been removed.


Kerry
Posts: 308
Joined: Mon Jan 07, 2019 2:42 pm
First Name: Frank
Last Name: van Ekeren
Location: Rosedale Vic Australia

Re: Camshaft movement- tolerance question

Post by Kerry » Mon Oct 28, 2019 4:16 pm

Back to your question, yes you need to get a new bearing, with that much float in the cam it will sound like the engine has done a bigend.

User avatar

Topic author
Bill Robinson
Posts: 109
Joined: Sun Jan 06, 2019 2:24 pm
First Name: Bill
Last Name: Robinson
Location: Salty Bottom, AL
MTFCA Number: 22487
MTFCI Number: 17887
Board Member Since: 1999
Contact:

Re: Camshaft movement- tolerance question

Post by Bill Robinson » Tue Oct 29, 2019 10:15 am

Frank- please explain the phrase "sound like the engine has done a bigend". I'm not familiar with the word "bigend". Sound/noise is what I'm trying to eliminate. That is exactly my problem. 2 of my cars started making this loud rattling noise during acceleration about 4 years ago after changing from a nylon timing gear to a bronze gear. The noise is there even though the timing is advanced to the "sweet spot" and not overly advanced. One car is a '26 and the other is a '27.

So, my real question- is the noise coming from excessive play in the cam or is it because of the timing gear change.
Now, let me say this- I have installed the bronze gear in three other older cars and there is no rattling noise detected.


Kerry
Posts: 308
Joined: Mon Jan 07, 2019 2:42 pm
First Name: Frank
Last Name: van Ekeren
Location: Rosedale Vic Australia

Re: Camshaft movement- tolerance question

Post by Kerry » Tue Oct 29, 2019 3:30 pm

Bill, I think you covered it in your description, a bigend rattle is the connecting rod on the crankshaft, with the wear in the cam bearing you get a rattle that will drive you nuts. Like you say, an advance rattle. The later cams are easy to make a good fit bearing if a new one still gives to much end play, I take the early longer bearing and turn down to shorten the ends on the lathe for a nice tight fit.

Post Reply Previous topicNext topic