So I want to give the Touring a little more umpf... which way would you go first?
Head or Manifolds?
I figure that the manifolds will be 'easter to instal, and I say this cause I have read that sometimes the aluminum heads might need shaving to make perfectly flat.
Both ways cost roughly the same.
From what I understand and have read the Head will give you about another 7 hp and the Manifolds about 5 more hp
All items from Chaffins...
So which way would you go?
What carburetor are you running?
Z or Prus head would be my first change assuming the car runs well already.
I'm running both..... a "Z" head and an original aluminum "high volume" intake and E-Timer..... and very pleased with the result.
By the way, have you ever lived in New Jersey ???
Thanks, Bob Jablonski
Robert, I think most Forum members will agree on a high compression head. I, too, have heard some say that the combustion chamber clearance sometimes is a little close, necessitating a little work on either your pistons or the head for proper clearance. Then again, I have heard even more members say that the heads are satisfactory, right out of the box. It is one of those parts that you are going to change, later, if you want maximum 'umpf', so why not do it first. The after market exhaust manifolds will not be "stock" looking and I have heard that the high flow intake manifold, actually flows too good to make maximum power. I have actually had better results out of the 1913 style aluminum intake or the 1914 iron intake which apparently was cast from the same mold. If you don't have a 'straight through' Holley NH or an after market carb like a Simmons, Wizard, or Stromberg, you aren't going to gain anything with a high flow intake. As for intakes and exhaust, if you want to do things on a budget, run a Model A intake, carb, and exhaust. They are a lot cheaper and a lot of speedster owners run them.
IMHO, one of the new Prus cast iron heads and a good carburetor will do more than changing the manifolds. Intake flow is limited by the size of the venturi in the carburetor. Exhaust flow is probably more important that intake flow for performance. As I said. IMHO.
Robert; I put on a high volume intake and holley straight through carb with out any real noticeable difference . So I would try the head first.IMHO
When using a high comp head or pistons make sure there is clearance between the head and pistons. You may not know how many times the blocked was decked in the past. I run a Z head and modern crank with no problems but I'm building another engine and I'm thinking about going with high comp pistons this time. What is the difference in Prus head?
Seth, she is running a Kingston L-4...
But she is not with me... I just bought her!
I'll announce it when she arrives, with pictures and all...
Anyway, looks like the head is the way to go... I will double check before it goes on...
Robert, I made similar mods to my tourer, and ran the car on a dyno to quantify the results. Adding a straight through Holley on an early large bore intake yielded 2hp over standard. Then fitting a Z aluminium head gave an additional 6hp.
The Z heads do vary a bit in shape at the face next to the gasket, and this need to be checked. I place the head on the block with no gasket, and turn it over to check the clearance. Then I check the gasket against the head face. When installing the head, I always have two of the pistons cranked to the top to be sure the gasket is in the correct place and can't move. Then, before tensioning the bolts, I hand crank the motor to make sure there is no interference between pistons/head/gasket.
Hope this helps.
Allan from down under.
A high-compression head will improve power at all RPMs.
A high-flow intake will only help at high-RPM, if at all, and possibly hurt performance at low-RPM as it will decrease intake velocity.
Robert, I offer this only as a review of my experiences. I installed Chaffins split exhaust manifold, high volume intake manifold and a Z head. I'm sure all three made contributions to the Zoom I experienced. It's my opinion the Chaffin manifolds made the most significant contribution. But keep in mind your adding stress to a tiny crankshaft. Just be careful. Jerry.
I want H/C pistons and milled stock high head
Route haven't had it out but sounded strong stock intake humpback NH but trying holley G brassy once done
Hey Bob I got a low head for sale that'll squeeze those HC pistons even better.
The difference with the Prus head is that it's machined in the areas above the pistons so it will not interfer. Thus no need for grinding the combustion chambers for clearance like some had to do with Z heads.
I ran an ORIGINAL aluminum intake for a while on my car. (Stock engine except touring grind cam and 7.5 timing gear) Ran both Kingston L4 and Marvel straight thru, never really liked it all that much at the speeds I drive around here, mostly 35. I think it was the amount of inside volume in the manifold and the lighter fuels we run today. ?
I would start with the head and if you are wanting better breathing, get one of the Zenith intakes and pare it with a updraft Stromberg. I ran an OE-1 for a while with the Zenith intake on the same engine. Little harder to start but seem to run good through the speed range and not bad gas mileage. Plus it has the "COOL" factor going for it!
I bought one of the repro high volume aluminum intakes and it had a big casting flaw (hole) that had to be welded up. Also it was cast really thick so I had to grind it on the top quite a a bit to clear the exhaust manifold.
I did not notice any difference in performance. I already had a straight thru carburetor, high compression aluminum head and a Stipe 280 camshaft. I recommend all of those items highly.
I have a high-compression head, a hi-flow intake manifold and an NH carburetor. _As long as I get a nice straight-away before a hill, I can sustain a fair speed without slowing to the point of lugging the engine, though I do reduce power gradually as I approach the crest of the hill (No point in straining that delicate crankshaft any more than necessary). _My car does the typical, begrudging, grumbling pick-up after the up-shift and I think that's unavoidable in a car that really needs an intermediate gear.
Bob: Redrilling your timing gear for 7.5 degrees advance of the camshaft might be what it takes to move the max torque to a lower rpm where you better need it when shifting to high and when pulling up a hill.
I'm quite pleased with the combination of a milled Prus head, a 7.5 degrees advanced reground 3/4 race camshaft from Antique Auto Ranch in Spokane and std manifolds with a swayback NH. Will try other carbs when the snow and salt is off the roads..
My 2 experiences with Z heads are both extremes. On my friends car, we dropped the head on the block and had no issues at all with clearance. On my engine, we put the head on with no gasket, and it would lock up in a quarter turn. I spent the better part of an afternoon marking the top of the pistons, and relieving where they touched the head ever so slightly. Repeat, relieve, repeat...... Eventually we got it to hand turn over with just a rhythmic tick, and then we found all of the last slightly higher spots, and it would roll over quiet. No issues with clearance after that, especially with a gasket in place. It just took a lot of patience, and wrench turning to get there. The first engine, in my fiend's car appeared to be an original engine that had never been rebuilt, but who knows. I bought my short block outfitted already with new Babbitt, rods, pistons valves and valve job from a club member who was retiring from the hobby. It obviously had been decked some where in the past.
I also have a Chaffin Traveler cam, high volume intake, Webro carb (say what you want it works well and does not leak a drop of fuel)and Texas T distributor. I am very satisfied with it's performance. My only T driving experience is my car with an engine that knocked, and only had 30# compression in each cylinder, my T with this engine, and 2 T's with similarly equipped engines. I have let other T club members drive or ride in my car, and they are impressed with it. I feel the modifications make it a more enjoyable drive, and safer, as it keeps up with traffic okay, not a modern car, but I am not in the way often, I'm very careful of where and when I drive the car with respect to traffic . There are a fair amount of hills in my area, and the modifications help to keep the car moving to the top. One of the best things about the T is running Saturday errands, to the bank, grocery store, home center, or going to get the spring bedding plants.
I would consider one of the dual manifolds, but everything in my exhaust from the manifold back is already new
Robert, Most people add a high compression head, our high volume intake manifold and one of our high performance cams. If you want 3 HP more you add the Exhaust manifold. All of these things are good and will cause no problems. Doug, Thats a Driver Cam not Traveler cam. Good Cam