Top of top ring to engine deck recommended distance?
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
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
-
Topic author - Posts: 796
- Joined: Sun Jan 06, 2019 4:14 pm
- First Name: Joseph
- Last Name: Andulics
- * REQUIRED* Type and Year of Model Ts owned: 1926 Fordor, 1926 Truck, 1927 Roadster GOW, RAJO Sprint car
- Location: North Ridgeville, OH
- MTFCA Number: 9766
- Contact:
Top of top ring to engine deck recommended distance?
Working on a custom piston and was looking for suggestion on what is a recommended distance from the top of the top ring to the deck? Thanks
-
- Posts: 6443
- Joined: Sun Feb 14, 2021 10:08 pm
- First Name: Pat
- Last Name: McNallen
- * REQUIRED* Type and Year of Model Ts owned: 1926-7 roadster
- Location: Graham, Texas
- MTFCA Number: 51486
- Board Member Since: 2021
Re: Top of top ring to engine deck recommended distance?
All modern automotive type pistons I've ever seen have around 3/8" above the top ring, probably to give some protection from heat and facilitate keeping some lube available to the ring. Reducing the dimension could improve efficiency, but would most likely place the top ring in a more stressful environment.
-
- Posts: 3873
- Joined: Fri Feb 12, 2021 12:24 pm
- First Name: john
- Last Name: karvaly
- * REQUIRED* Type and Year of Model Ts owned: 14/15 wide track roadster. 23 touring, 27 roadster pickup, 20ish rajo touring
- Location: orange, ca
- MTFCA Number: 14383
- Board Member Since: 2020
Re: Top of top ring to engine deck recommended distance?
I have seen rings go just below the top edge of the deck. I believe my 292 pistons over an A crank rajo head are this way. Not had an issue & the motor has been in operation since the late 60's. Extra heat could be something to consider, but in such a motor, they tend to run rich. I might consider 1 ring width from the top as extra safe.
-
- Posts: 6443
- Joined: Sun Feb 14, 2021 10:08 pm
- First Name: Pat
- Last Name: McNallen
- * REQUIRED* Type and Year of Model Ts owned: 1926-7 roadster
- Location: Graham, Texas
- MTFCA Number: 51486
- Board Member Since: 2021
Re: Top of top ring to engine deck recommended distance?
Antique wide rings can go to the top. I'd be cautious about pushing a modern, narrow ring too near the top.
-
- Posts: 3002
- Joined: Sun Jan 06, 2019 4:06 pm
- First Name: Jerry
- Last Name: Van
- Location: S.E. Michigan
- MTFCA Number: 24868
Re: Top of top ring to engine deck recommended distance?
The block in my Touring had the top deck milled .060" The top ring comes just about even with the deck. Been running that way for 45 years now.
-
- Posts: 1361
- Joined: Thu Jan 10, 2019 3:54 pm
- First Name: Kevin
- Last Name: Pharis
- Location: Sacramento CA
Re: Top of top ring to engine deck recommended distance?
If you are ordering pistons from Ross... I would trust their guidance. They have basic designs on file for both Model T and A pistons, and they are experts in this field.
I ordered pistons from Ross years ago before they had a T piston on file... simply told them to build an A piston with specific bore dimension, pin to deck height, and dome dimensions. They decided the skirt type and ring pack details. Still running strong 10+ years later
I ordered pistons from Ross years ago before they had a T piston on file... simply told them to build an A piston with specific bore dimension, pin to deck height, and dome dimensions. They decided the skirt type and ring pack details. Still running strong 10+ years later
-
- Posts: 1302
- Joined: Mon Jan 07, 2019 2:42 pm
- First Name: Frank
- Last Name: van Ekeren
- * REQUIRED* Type and Year of Model Ts owned: 1916 touring, 1916 pick-up, 1924 coupe, 1926 touring, 1927 touring
- Location: Rosedale Vic Australia
Re: Top of top ring to engine deck recommended distance?
Can also depend on who did the machining of the rod bearings, not all have the center to center spot on.
-
Topic author - Posts: 796
- Joined: Sun Jan 06, 2019 4:14 pm
- First Name: Joseph
- Last Name: Andulics
- * REQUIRED* Type and Year of Model Ts owned: 1926 Fordor, 1926 Truck, 1927 Roadster GOW, RAJO Sprint car
- Location: North Ridgeville, OH
- MTFCA Number: 9766
- Contact:
Re: Top of top ring to engine deck recommended distance?
Thanks everyone for the help. The issue I'm facing is that the crank (Model B) has been stroked giving the engine a 4 5/8" stroke, so the new aluminum version of the model T piston will have the top ring pop out above the deck.
-
- Posts: 6443
- Joined: Sun Feb 14, 2021 10:08 pm
- First Name: Pat
- Last Name: McNallen
- * REQUIRED* Type and Year of Model Ts owned: 1926-7 roadster
- Location: Graham, Texas
- MTFCA Number: 51486
- Board Member Since: 2021
Re: Top of top ring to engine deck recommended distance?
Maybe you need short rods and slipper skirts.
-
- Posts: 3873
- Joined: Fri Feb 12, 2021 12:24 pm
- First Name: john
- Last Name: karvaly
- * REQUIRED* Type and Year of Model Ts owned: 14/15 wide track roadster. 23 touring, 27 roadster pickup, 20ish rajo touring
- Location: orange, ca
- MTFCA Number: 14383
- Board Member Since: 2020
Re: Top of top ring to engine deck recommended distance?
In the day, there were other make pistons used. Olds possibly. 292 ford. My rajo T has 292's. A crank & rods. With the stroke you may be forced to custom made. Does Scat have any input. He is a real friendly resource.henryford2 wrote: ↑Fri Sep 24, 2021 7:17 amThanks everyone for the help. The issue I'm facing is that the crank (Model B) has been stroked giving the engine a 4 5/8" stroke, so the new aluminum version of the model T piston will have the top ring pop out above the deck.
-
Topic author - Posts: 796
- Joined: Sun Jan 06, 2019 4:14 pm
- First Name: Joseph
- Last Name: Andulics
- * REQUIRED* Type and Year of Model Ts owned: 1926 Fordor, 1926 Truck, 1927 Roadster GOW, RAJO Sprint car
- Location: North Ridgeville, OH
- MTFCA Number: 9766
- Contact:
Re: Top of top ring to engine deck recommended distance?
The rod I'm using is 7" the same as the Model T
-
- Posts: 3873
- Joined: Fri Feb 12, 2021 12:24 pm
- First Name: john
- Last Name: karvaly
- * REQUIRED* Type and Year of Model Ts owned: 14/15 wide track roadster. 23 touring, 27 roadster pickup, 20ish rajo touring
- Location: orange, ca
- MTFCA Number: 14383
- Board Member Since: 2020
Re: Top of top ring to engine deck recommended distance?
Look into the 292. the top is square but can come up from the bore to the top ring. That's how mine fits.
I dont know the exact dimension differences you are working with.