help with valve clearance

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Emeraude
Posts: 85
Joined: Tue Jan 08, 2019 10:00 am
First Name: George
Last Name: Loranger
* REQUIRED* Type and Year of Model Ts owned: 1921 touring
Location: Grafton ND
MTFCA Number: 32239

help with valve clearance

Post by Emeraude » Mon May 03, 2021 6:22 pm

I just bought a 1925 roadster that had not run in 10 plus years. The first thing I did was a compression test and all 4 cyl were at 25 lbs. I I then did a leak down test and did leakage from both the intake and exhaust but none thru the crankcase. I preperation to do the valves I researched the forum and found a post in 2010 by glenn chaffin where he described bring each valve to tdc then rotating 360 degrees and checking valve clearance. I did this on all the valves and found the clearances within specs. Another source describes bringing the piston to tdc then setting the clearance. When I brought #1 to tdc there was no clearance .
My question is,which is the proper way, glenns or the second? On the second way I would have to grind down the stem (i do not have adjusable lifters) so I am hesitent grinding them until I get some advise


Scott_Conger
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* REQUIRED* Type and Year of Model Ts owned: '13, '15, '19, '23
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Re: help with valve clearance

Post by Scott_Conger » Mon May 03, 2021 6:41 pm

The "other source" assumes it is on compression stroke. You have it on exhaust stroke and intake is starting to open, thus the no clearance.

In any event, it doesn't matter. Your compression appears to indicate worn valve seats and if that is the case, you need to do a valve job before you are worried about valve clearances (particularly since you've already established that they are in spec).

HOWEVER:

All that said, if the car has sat for 10 years, you should be able to get it fired up and you may be very pleasantly surprised to find that within a month of driving, compression is up considerably from where it is. DO NOT PULL THE HEAD just to see what's inside...I'll tell you: a bunch of black carbon...now you don't have to look. Just start it and drive it a bit after you've done a safety check. After sitting for 10 years I think 25 pounds compression is pretty good. Once rings reseat and valves snap the old gunk off of them you may well have a driver with no further engine work.
Scott Conger

Tyranny under the guise of law is still Tyranny

NH Full Flow Float Valves
Obsolete carburetor parts manufactured


Kerry
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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: help with valve clearance

Post by Kerry » Mon May 03, 2021 6:52 pm

Still got the original 2 piece valves?


speedytinc
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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: help with valve clearance

Post by speedytinc » Tue May 04, 2021 8:34 am

Scott's thought on running it is a good one. Squirt a little ATF into the cylinders & run it. Compression likely will come up. Nothing to lose either way. Then assess if you need a valve job and or rings by new compression readings.


J1MGOLDEN
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* REQUIRED* Type and Year of Model Ts owned: 1926 Model T Roadster
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MTFCA Number: 14294
MTFCI Number: 13562

Re: help with valve clearance

Post by J1MGOLDEN » Fri May 07, 2021 7:42 pm

The real problem with compression that low is that you cannot create enough suction to suck in any gas charge.

I had a 1950 Ford like that, if it sat long enough (about two weeks) to drain all the oil off the cylinder walls, it could not get any gas to fire.

I had to remove two spark plugs and add a shot glass full of engine oil followed by a shot glass full of gasoline.

Firing on two cylinders would give enough engine speed to suck in some gas on the other cylinders.

Then it would run fine, but just did not have a lot of power.

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