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Topic author
Craig Leach
- Posts: 1906
- Joined: Tue Jan 08, 2019 12:22 am
- First Name: craig
- Last Name: leach
- * REQUIRED* Type and Year of Model Ts owned: 1919 Firetruck/1922 Speedster
- Location: Laveen Az
Post
by Craig Leach » Mon May 12, 2025 5:26 pm
Hi Everyone,
I'm looking to install a RICARDO PAT NOV 13 1923 HEAD & would like to send it out to have it surfaced .010 to get a better gasket seal but I'm
concerned about piston clearance. The current area over the piston is .423 so I would end up with .413 with a gasket crush of .050 to .060.
I have found info on line of the stock compression pistons being from .378 to .412 proud of the block. The pistons I have use the 5/64" rings
& I have been told they are Jann's. As far as I know the block has not been decked. Doe's anyone have a engine apart that could measure how
proud their pistons are? Thanks Guy's.
Those are not cracks!
Craig.
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Kevin Pharis
- Posts: 1556
- Joined: Thu Jan 10, 2019 3:54 pm
- First Name: Kevin
- Last Name: Pharis
- Location: Sacramento CA
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Contact:
Post
by Kevin Pharis » Mon May 12, 2025 5:39 pm
You will find that the only consistency in model T production… is the inconsistency! I agree that the 3/8” piston height is the target, but rod lengths are determined by a tape measure on many babbitt boring setups. Have seen tapered blocks, long/short rods, etc… You should measure what you’ve got
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Allan
- Posts: 6609
- Joined: Sun Jan 06, 2019 7:21 pm
- First Name: Allan
- Last Name: Bennett
- * REQUIRED* Type and Year of Model Ts owned: 1912 van, 1917 shooting brake, 1929 roadster buckboard, 1924 tourer, 1925 barn find buckboard, 1925 D &F wide body roadster, 1927LHD Tudor sedan.
- Location: Gawler, Australia
Post
by Allan » Mon May 12, 2025 7:59 pm
You could put the head on with no gasket and turn it over. No interference = no problem. There is no need to surface the head to .010" if it cleans up at .005" After this, you may have variables to deal with.
Allan from down under.
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Dan Hatch
- Posts: 5009
- Joined: Tue Jan 08, 2019 7:31 pm
- First Name: Dan
- Last Name: Hatch
- Location: Alabama
Post
by Dan Hatch » Mon May 12, 2025 8:04 pm
In picture of bottom of head. The top cly is that a crack?
I always pressure test any head I send to be decked.Dan
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Topic author
Craig Leach
- Posts: 1906
- Joined: Tue Jan 08, 2019 12:22 am
- First Name: craig
- Last Name: leach
- * REQUIRED* Type and Year of Model Ts owned: 1919 Firetruck/1922 Speedster
- Location: Laveen Az
Post
by Craig Leach » Tue May 13, 2025 12:44 am
Hi Dan, no it is not a crack it washed off with brake clean. I did Magnaflux the head but not able to pressure test. The pits around the water ports are more than .005
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bobt
- Posts: 288
- Joined: Tue Aug 13, 2019 5:43 am
- First Name: Robert
- Last Name: Thompson
- * REQUIRED* Type and Year of Model Ts owned: 1915 touring 1926 roadster
- Location: virginia
Post
by bobt » Tue May 13, 2025 9:05 am
Put a ball of modeling clay on top of each piston then put the head on and crank it over and remove the head and see how much you squish the clay. You can buy the clay at the dollar ($1.35) store. bobt
