T head engine by Brian

[brian Rupnow]

Today seen the beginning of a new engine.---The design phase, at least. After recently seeing an Upshur T head coming together on HMEM and a post by Vederstein about building a T head engine I thought that would be an interesting engine to design and build. I'm in no rush to start building, but I know how that generally works. I spent most of today bringing the design along to this stage, and will probably finish up the cylinder head tomorrow.

[J Tiers]

For hints, you can look at older Gravely tractors. There are manuals online. They are a T-head vertical design..

gravelymanuals.com You want the model L

[nc5a]

Damn! Brian you don't mess around when it comes to engine designs. You no sooner get done with one and out comes another, well done.


Jerry are you a Gravely guy?

[Jim Stewart]

Wondering: is the T head superior to the ubiquitous L head?

-js

[J Tiers]

Damn! Brian you don't mess around when it comes to engine designs. You no sooner get done with one and out comes another, well done.


Jerry are you a Gravely guy?

Not me but a buddy of mine has an L. we've had it apart here, and I have worked on the valves, as well as head and jug, crankshaft, etc..

[The Artful Bodger]

Wondering: is the T head superior to the ubiquitous L head?

-js

The T head has some useful characteristics including the isolation of the exhaust valve heat from the inlet valve. They have also been said to have superior reliability.

[J Tiers]

They may have more "quenched" area that inhibits combustion. Pretty much all non-overhead cam designs that have valves outside the diameter of the bore will have that. Lowers efficiency and increases wasted fuel/pollution unless a stratified charge is used. And, they require double camshafts, or a more complicated pushrod scheme.

The crossflow may be better for reduced carryover of mixture to exhaust, and it may also have some advantage in "extraction" of exhaust if pipes are tuned. Would seem to mix the charge better, whether that is an advantage or not.

[brian Rupnow]

Great progress made this morning. I decided to keep the engine air cooled. I think the grooves in the cylinder and cylinder head look good.

[aostling]

This engine has a relatively long stroke. This might yield higher peak torque during the power stroke and aid slow-speed without stalling, a wise decision.

[brian Rupnow]

Okay---We've got a carburetor, carb adapter, heavier crankshaft and an exhaust system. Also a set of tappet guides and two very long valves, riding in valve cages. Tomorrow I will stick a set of points and an ignition cam on it, and probably a gas tank.

[brian Rupnow]

The Tee Head engine design is finished. Fortunately, I was able to sneak the ignition points and condenser in behind one flywheel (which is hidden in this model), without offsetting the flywheel any. I also added a gas tank and a pleasant looking mounting bracket. None of the detail drawings are made yet, but the design is finished, so detail drawings are pretty simple now.

[brian Rupnow]

-I added some valve springs for you.---Brian

[Dan Dubeau]

Looks neat Brian.

When you design a new engine do you follow the same recipe every time? Bore stroke, timing etc all that jazz? Just curious.

[nickel-city-fab]

me likee --- spent last night imagining ways to do it with one cam. I do want to get into the engine building scene

[brian Rupnow]

Nickel---Build a Webster. They are a simple engine, but will teach you 90 percent of what you need to build engines---and the plans are free. Dan--I pretty well standardize on bore size. One inch is my favourite bore size, mainly because that is the size of my largest reamer. I have built 7/8" bore and 3/4" and 1 3/8" bore engines, but 1" seems to be what I'm comfortable with. I find that engines with a stroke of 1 1/4" seem to go with that 1" bore size. The shorter the stroke is, the faster the engines run. I pretty well standardize on cam lift and duration, because I know what cam grind works for me, and the physical shape of the cam pretty well dictates the valve timing on the engine. I always use the same ignition points and condenser from mid 1970's Chrysler products because I am familiar with them and know what to expect from them. I like to make engines with different configurations. I have many horizontal engines with open crankshafts, both water cooled and air cooled. Some are throttled engines, some are hit and miss. I have vertical cylinder engines in both hit and miss and conventional style. I have a two cycle water cooled engine with vertical cylinder. I have engines with flat head, overhead valve, and overhead cam configurations. I have engines on which the camshaft is gear driven, and one on which the camshaft is driven by a timing belt. I have a couple of twin cylinder opposed engines. It is getting harder and harder to find engines with a different configuration that I am still capable of building with the machinery I currently have. That is why I'm designing this current T head engine. I haven't built one of those before.---Brian