Projects 3 port Olds on a T motor - Poor Mans Rajo

BB back in the day I believe that most (taking winfield out of this pack) everyone thought biggest is best. What is the T firing order? (Chevy 1243), What cubic inch, At what RPM do you want your power band, at what RPM do you need best response? I think that the Olds head will respond well with better porting and valve sizes, not just bigger. Us that have the "well raced" heads are kinda stuck with what we have.

 

The picture of Chapel's first streamline is a Chevy engine (out of his 24 Roadster) with the Cyclone head on it and with a Fonty valve cover. Reread Carters post #42. They did get the dual carb wrong, and maybe the RPM and cubic inches.
What is the cubic inches on a T engine?

 

Stock T is 176”

 

Definitely a Fronty valve cover... but not a Fronty head. The exhaust port spacing is consistent with the Olds head, and SR had a square flange on center with slip fit at both ends.

Carb is a mystery... I don’t see any of the Winfield silhouettes in that fuzzy pic, except for a Winfield 2 up 2 down inspired intake manifold

 

The Tornado Chevy heads used Ford Frontenac valve covers, or copies of the same. Every period picture I've found of Tornado Chevy heads has had the Ford Frontenac type cover except Zeke Miller's Chevy roadster. I posted more pics in the thread I linked in post #42 if you'd like to see more. I also describe the unique center exhaust port flange shape that helps in identifying the Tornado Chevy heads in old pictures.

I have some more pictures I'll share here of the Tornado head for comparison's sake.




Intake port, looking in at the valve guide and stem:



Intake ports are nearly 1-7/8".




Valve heads are around 1.75" or a little more.


Spark plug 'port'.


Steel rocker stands, different from the only other I've seen pictures of up close, in the photo @Blackbob posted of a bare head.



End exhaust ports are between 1.7 and 1.8" depending how you measure, and center is right at 2".


Another view of the rocker stands and arms.




I believe the rocker arms are '41-53 Chevy, so not likely original as built by Lee.

 

Carter Are the spark plug ports threaded for smaller plugs? Or smooth. What dia.?
Looks like the valves are centered on the bore, Olds are offset to spark plug side.
By doing away with the valve pocket, the Tornado had much more flow through the ports. I'm going to say it again WOW!

 

@Carter Great info. Thank You for contributing.

 

Cyclone was a whole other company! Haha, wrong weather event!

Spark plug hole is 18mm, blind hole, with smaller, maybe 1/4" diameter smooth hole into the combustion chamber. I haven't measured, but yes, the valves appear to be centered in the chamber.

Tried to take a picture down through the spark plug hole, if you zoom in, you can see the small port through into the chamber.

 

Got it fixed! I just get all fouled up on weather!!!
As far as the spark plug, wouldn't this have a very shrouding effect? Just thinking, it is a lot like the old international tractor diesels and they're precups, but they were on the injectors. (not the same as a gas engine)

More #2 Olds

Exhaust ports: rear 1.65, center 1.68, front 1.64


Intakes: 1.6

All are better blended than Head #1

Intake: relief on #4 1.683, seat 1.90
Exhaust: relief on #4 1.555, seat 1.85

 

More of #2 Olds head

These are the rockers that were with the Midget 28 when Rich got it. For some reason he did not like them. (Maybe bad angles with the new valves?) Anyway he sold them and ended up putting 28 Chevy rockers on.


Dam, fat finger again and too dumb to fix!
I have taken these off because I have seen too many "stock" Chevys with bent or broken rockers. Will have to make up another rocker arm setup. I have a set of cam grinder "make your own length push rods" so not worried about wrong angles.

 

I reckon taking it a step at a time will help get the kinda results I'm after. For trials I need the motor to be responsive from low down and not lug on hills, the ability to rev to around 3000+ instead of 1500-2000rpm will make better use of the stock 2 speed + 2 speed Ruxstell but that is also down to getting the bottom end of the motor sound. I think a bit of porting and maybe a bit bigger valve will help it breathe without over doing it. I have 1.375:1 rockers that look like they will work length wise so that's my starting point. Stock T cams have a lift of .250" so the extra gained is still significant, I can get up to just over .300" lift cam shafts before having to mess with the block so again more room to improve.. I like the experimental approach, modify in small steps .. suck squeeze bang blow then modify again . ride wrench repeat!

 

Those look very much like the ones I got with my Olds head from Andy McCann, the 1.375:1 set

 

Another visit to the barn this morning and a brief (its too cold to hang about for long) measuring session. there's definitely room to take the valves up in size and still get it within the bore diameter. As has been said above the valves are off centre with an Olds head so there is room, depending on the rocker length to centre them up a bit more. My rocker set are of unknown origin, might have been Gaby's head before he got it, can't be sure but they measure 3.00" so help centre the valves. there's a pic of them propped up on a T block to show the relative positioning below

 

.. and the rockers

 

BB Those rockers do look like from the same donner as the ones that Rich sold.
The 28 Chevy only has a .196" lift stock (minus tapit clearance) So you are already better off. I do not have the "premium" rocker length required for the stock valve location right now but know that it is over 3" and very hard to find. (Here I am thinking Chevy again) You may have found the solution!
Looking forward to your ideas on this combo! By the way, what is the T's firing order?

 

T firing order is 1-2-4-3 , I had another short session this afternoon, once id shifted the horses onto a drier paddock. I loosely fitted a pair of new T valves in the olds head (might just use them) and marked the centre line of the valves on the Olds head then set it on a par of 3/4" machinists blocks on top of the T lump, with the push rod positions lined up the valve centres are 1/8" off the bore centreline and the 1.375:1 rockers shaft should sit nice with the existing blocks milled down flat to offset it by 1/4"

 

BB Thank you very much for allowing the hijack! And thank you everyone else for contributing. I just hope that everyone that views my comments, realize that they are just assumptions! (and there are better modified heads out there)
BB you are looking very good for the T-Olds. combo! I will be watching.
Hope it worms up there so. Be safe and have fun!

 

Its great to get this kinda feedback and info

this afternoon I've been messing about with squish and working out the lift, in between getting hay bales out and walking the dogs

The lift - clearance works out at 0.367" which is a big improvement on the stock T 0.250"

Combustion chamber, choice is whether to build in a bit of squish or just go with a simple bore in the adapter plate and skim to get around 7:1 CR

 

This is a really interesting project, thanks for continuing to post it up. I would build in some squish to the adapter plate if it were mine. The 28 Chevy head with its flat face 'combustion chamber' needs a huge amount of spark lead on the 4 banger motor which could probably be reduced a lot if there was some means of building in squish rather than just bumping the compression ratio.

 

Stueeee is spot on. Squish gives turbulence also which improves mixing. Now if you can build in the squish so that the mixture is moved towards the sparkplug that will help with speeding up combustion. And reducing the need for big timing lead.

 

Those are Buick rockers----says right on the side with the part# I can't read. Probably the same ones I need for the Fronty head.

 

I believe those particular rockers are 1932 Buick model 60. Apparently, Buick rockers of the era were popular for OHV heads as the Miller Schofield/Cragar heads came equipped with '28 Buick Standard Six rocker arms.

 

Thanks guys, useful info

 

Thats the route I'll go, on the drawing Ive set the squish at 0.0625 which is probably too loose. I have it set at 0.030" on my hot stroked Indian Sport Scout flathead but that might be a tad tight for this motor?

 

So glad to see all the chatter on this and sorry for dropping out for a few days- wrapping up a very challenging fall semester at my middle school (our 6th grade class was in 4th when Covid hit and are stuck in "elementary school" behavior/mentality)

Really appreciate all of the info and comments- so (asking with total ignorance)... what is the difference between "compression" and "squish"?

 

There probably is a scientific answer that I haven't a clue about, but my understanding is that compression is the overall effect of reducing the contents held within a sealed space, squish is the effect used to push the compressed gas (in this case) in the required direction, ie towards the spark, rather than it finding its own way

 

You are on the nose with your analysis. I suppose if I dug out my text books relating to thermodamnamics (if you ever studied it, you'd call it that too), there would be 10 dollar or 7 euro words that describes what you said in a way none of us would understand, but economy of words is good!

See, the Scots are even thrifty in speaking... that's when my Italian side always tends to get involved. And I can't even use my hands for emphasis!

 

I had always thought that squish had to be at the highest point so to speak. But if I am thinking rite, it could be anywhere that causes the gasses to move to where you want them. Is that correct? BB I am thinking that I am seeing your squish at the left side of the piston where it comes up close to the adaptor plate.
The other thing that I am wondering about is pre-detonation. Can squish help, or hurt pre-detonation? (sp)
Mac If your Olds head is still out, can you get an overall flat surface to flat surface distance and let us know if it is stock or machined on top? (Sorry about the snot gobblers)

 

When all assembled, there will be an area between the piston and the head/adapter plate which is essentially flat to each other. Usually it's best to leave some clearance, say 0.060 inch give or take 20 or 30 thousandths of an inch, depending on factors like piston rock, bearing clearances, wrist pin clearance, and you or your engine guy's willingness to have a clash between the piston crown and the quench area, which is what you really want to avoid (it gets expensive fast).

Quench should cause turbulence, which improves mixing, which helps lessen the probability of detonation. It all comes down to getting as homogeneous a mixture as possible. The more thoroughly mixed the air/fuel is, the better the flame front across the combustion chamber. Also, this helps lower temperature gradients across the combustion chamber which also helps resist detonation/precombustion.

An interesting side benefit is a lowering of emissions, which actually shows that you have more complete combustion. That uses the energy in the fuel more efficiently, making more power. On a dyno, that shows up as lower brake specific fuel consumption (BSFC). This is a measure of the fuel used divided by the brake power.

Now that I've gone all nerdy, I'll stop! It's the field of research I spent the last 30 years working in. Only blew up a few boat engines on the dynos. They were stern drive engines from the manufacturer who painted their engines gray.

 

This is as far as i got with a combustion chamber sketch today before my cad skills met their limit and i realised id be quicker with a die grinder .. as for pre-detonation, i'm not sure, perhaps having a more directionally efficient charge allowing for less advance would help to stop it?