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Why is the intake runner so darn long??

Posted: Sun Mar 16, 2025 10:09 pm
by drzomber
I'm new to T's (I have had a bunch of A's in the past) and don't understand why they make the intake runner so long. Even on aftermarket intakes (except for the Winfield) it seems excessive. I guess I could understand it if they were building a high revving engine but given the application it seems really odd to me. Can someone explain the reasoning to me??

Re: Why is the intake runner so darn long??

Posted: Sun Mar 16, 2025 10:20 pm
by Ed Baudoux
I believe that the length of the intake drop is intended to allow enough drop for the gravity fuel system. Some earlier body styles had a longer drop.

Re: Why is the intake runner so darn long??

Posted: Mon Mar 17, 2025 8:25 am
by Tadpole
If you think Ford was bad, look at Chevrolet’s!

Re: Why is the intake runner so darn long??

Posted: Mon Mar 17, 2025 9:22 am
by TXGOAT2
Longer, small bore intake manifolds work very well on low speed engines with mild cam profiles. Short, large bore intake runners with no manifold heat would give very poor results on a stock Model T engine, especially with the gasoline commonly available in the 1920s. An intake manifold can be "tuned", much as an exhaust header can be "tuned". Modified T engines that run at higher speeds with high lift, long duration camshafts and larger carburetors can take advantage of shorter, larger-bore intake runners.

Re: Why is the intake runner so darn long??

Posted: Mon Mar 17, 2025 7:38 pm
by Erik Johnson
As Ed posted above, the gravity flow fuel system is the reason the carburetor sits so low and the intake is so long.

My father's 1910 IHC Model F roadster has overhead valves and has a much longer intake than a Model T Ford.

Re: Why is the intake runner so darn long??

Posted: Mon Mar 17, 2025 8:13 pm
by got10carz
Here's my theory. The firing order is wrong. The model T is 1243 as are most early 4 cylinder cars. This requires the front 2 cylinders and rear 2 cylinders to suck 1 right after another. The long manifold has more fuel stored in the manifold. A better firing order would be 1324.

Re: Why is the intake runner so darn long??

Posted: Mon Mar 17, 2025 9:52 pm
by Craig Leach
The firing order on a T does as I understand causes a flow issue that would be rectified with a 1423 or 1324 configuration. Reversing the ports
has been tried with some success as I understand. Now that cams are being manufactured again maybe someone will bump the program & make
some. Kirk Wright built a 6 cylinder out of T engines & somewhere there are pics of him making the crank & cam. A stock came could be cut up
& put together to do this also. Didn't Winfield's 2up 2down engine have a modified firing order?
Craig.