I am going to rebuild the engine in our 27 roadster and would like to perc it up a little.
I have been running a Z-head every since I bought this car 9 years ago and with good luck. The car is equipped with a 3:1 Ruckstell.
Go to high dome pistons or a Z-head?
How about a 250 or 280 Stipe cam?
I already have a hi-volume intake and straight thru NH.
Any other ideas would be considered and appreciated.
Just curious as to what others might do.
In addition to the 200 things you should do during the rebuild here is my view on performance enhancements.
Stipe 250 cam
Standard 3.56 axle with Ruxstell
High volume intake manifold
Try a straight thru NH, but you may not like the low end performance.
Without getting very exotic this will give you bump in performance and not beat to lower end out of it.
Ron the Coilman
As Ron mentioned above, we will do the "other things" needed to be done, new babbit, rods, valves, etc. I just wanted comments on increased performance stuff and things.
I'll disagree with Ron a little, but try to explain. He's got LOTS more experience than me. Since it's a roadster instead of a heavier car, I'd use the Z head and the .280 cam for a little more top end performance.I'd drop back to a 12 tooth rear pinion for an increase to a 3.25-3.33 (depends on whether you have a 39 tooth or 40 tooth Ruxtell ring gear) ratio in the rear without much, or any, loss of top end. This would give better low end and braking than the 3:1. I'd definitely put auxilliary brakes on if not there now. Your high volume intake and NH are fine. Consider a dual exhaust system. Balance and true the heck out of it. If money isn't a big question, consider a new counterbalanced crank with 1.5 inch mains and rods so your great grandkids can drive it in 2100! If you go with the increased stroke, you may need to open up the Z head a bit to avoid contact. I would guess the heavier crank could hold the higher compression. While you are at it, add at least one auxiliary oiler to the front.
Brakes. You gotta' have brakes. Even the best you can get or adapt are barely good enough.
I would trade the puddle carb for a real carb, like Stromberg OF or larger. You'll get better all around performance, and better fuel economy.
After the running is stabilized, I would add a 180 thermostat. If it overheats too often then, I would add a waterpump.
Oh boy. Here we go.
Before I got it, dad had the engine rebuilt. 280 cam,Z-Head, Truefire Ignition, 3/1 Ruckstell. Plenty of power for a T. If I was to do anything more, maybe a little better carb. Has Rocky's on the back and they work well, but I want to use it for a daily driver, here in L.A. and keeping my eyes out for a front brake system. RD"S right !! Got to be able to stop 'er. 'Early '27 Touring
George n L.A.
Have everything in your engine and transmission properly precision balanced before you consider adding any accessories that increase power.
I always tell my customers to have everything balanced if they ask about a performance head or cam. A properly balanced engine and trans is the proper foundation for any performance enhancing accessories. What a lot of hobbyists don't realize is that there are imbalances inside their powerplant that often can not be recognized or noticed from the drivers seat. Once you begin to make more power, you are also multiplying those stresses and imbalances which in many cases severely affects the longevity of the engine. A properly balanced & blueprinted STOCK Model T engine is dead smooth from the time you shift into high gear to well past 50 mph and that is with a properly re-ground stock cam and a regular, low compression 1918-1927 cylinder head. I've told customers that they should put about 1,000 miles on one of these balanced engines to break it in before they add any performance enhancing accessories. Most customers do decide that the engine is just fine as it is and requires no extra power. However, I have to note, that if there is anything you might want to try, the first thing to add to a fully balanced engine is one of the 280 cams Manufactured by Bill Stipe in Plymouth, WI. Install the cam and try it out for a season of driving before you think about adding a high performance cylinder head. The 280 cam, in my opinion, idles just like the stock cam, the only difference is the extra power on the road.
Balancing and blueprinting a T engine generally ends up adding about 10 to 15 additional hours on the average complete engine/transmission overhauls I do here.
My engine is currently at a machine company being bored, etc., and the machinist recommends installing hardened valve seats (I'm putting in stainless steel valves) at least for the exhaust valve seats.
Good idea? Bad idea?
I have always opted to have stainless seats put in with very good luck. An engine that was recently taken out of the car for a transmission repair had stainless seats and valves and after 10 years, the seats and valves looked new.
In my opinion, good idea!
Bob and Tom,
Premium seat insert material should contain some Cobalt. I believe it helps to form some very hard and wear resistant carbides. There are other materials that are very good, most of them scintered powdered metal, and will do a fine job in a "T", as the engine speed is relatively very low.
"Stainless" is a very vague term. Intake valves don't need to be stainless, but exhaust valves should be Austenitic Stainless due to the high temperature. A magnet will not have any pull on this type of material. An example would be "21-4N", which was used extensively from the mid '50s through the '80s and even today with small variations in the alloy mix. There are Martensitic stainless materials that are very good for intake valves, and some were used for exhaust valves before Austenitic materials became common.
With the unleaded gas we now have, it is a big help to reduce wear if the stems are chrome plated.
I have done all the things you have done plus the stipe .280 cam and it is peppy and fun to drive without loosing that T character. In a liter car like yours, should be plenty, as mine is in a touring and really pulls the hills with 4 aboard.