Technical ***June 2020 Banger Meet Thread - So Four So Good***

If you don't race the A clutch is fine,check flywheel housing for run out and pressure plate fingers for correct height..toss a new disc in every time you open it,35 bucks is cheap insurance to prevent rework.

 

my disc is specific to a s-10 in put (26 spline) . when its out (if needed ) i have it relined ........

 

Likewise on all my cars - but over here they're none too cheap so I'm curious to see if there's an off the shelf diaphragm clutch that will work. Plus they tend to be lighter which is a 'good thing'.

 

What jets are you running stock is .35 . I was told to change mine to .51 or .42

 

I am running 81s with. 41 , Jim b book states .41 or .42 for the 81s . I have an A block 60 over with balance crank and 36 lb flywheel. D price 6:1 aluminum head and one Jim's R1 cam. Runs good for, electric fuel pump.

 

Single Holley 94, winfield 7.5 red head, late b high lift cam, reds 4 into 2 header,B distributor 2psi rotary fuel pump.I dont race,Im looking for maximum performance at peak efficiency.Building a performance engine is like building an air pump,matching the airflow in and out with the fixed flow rate of the pump maximizes the pumps output.the fixed flow rate of the model a ford engine in stock or slightly modified form like you and I have flows at about 160 CFM,you can shade that a little higher with the volumetric efficiency increase afforded by the improvements.The Holley 94 flows at 170 cfm or so.When pulling fuel through the jets with two carbs if your jetted close generally wont cause an overfuel condition,the engine basically 'pulls' what it needs..however,the enrichener circuits,accelerator pumps and power valves are blind,they aren't affected by engine demand,only by operator input..this is where the problem with running dual carbs lies,the pumps push more fuel than the engine can handle.That's where progressive linkage comes into play,if you set them up to work in progression the second carb rolls on as demand increases.Once again,Im not racing,I'm street driving,with an eye to long engine life.

 

i just dropped my compression for long life . 7-1 to 6-1 . alot more forgiving & fun as a daily driver

 

I am going to drill an A crankshaft for oil pressure feed from the mains to the connecting rod brgs. I plan to do this on my engine lathe (see lay out picture). In reading the locations and dimensional position of the holes I am see holes should be drilled at 34 degrees off the centre of the con rod brgs. I have measured my crankshaft and drawn up with the 3/16" diameter holes and they come fairly close to breaking through at the instection between the bearing diameter and the throws from the main brg to the con rod brgs.

Being that I have drilled a C crank before for pressure there seemed to be a little more meat so the feed holes were not so close to breaking through and on the center main the feed holes exited the bearing almost at the same point rather than about 5/16" apart as they appear to be on the A crank.

Has anyone here drilled an A crank before? did you also use 3/16" drill or maybe drop down to 5/32" drill to gain some additional clearance? and correct that the holes on the centre main are split apart?

thanks for your comments.

 

Bob,
I am not sure the "A" crank should be drilled. For a stock-ish 50 HP motor it may be fine.
I have had the chance to look at a few broken "A" cranks, and the breaks pretty much followed the oil feed holes in the rod journal.
This would lend me to think the amount of material removed is sufficient to cause enough of a stress riser that propagates the break.
Depending on what your intentions are, I would seriously consider a "B" or "C" crank and use "B" rods.
I would not grind the "A" journal mains onto the crank, instead have it ground to 1.850 dia and use inserts.

Good luck, John

 

Pulled pan on the pickup last night to check clearances. Down to one shim on mains, two in the rods. Babbit looks pretty good, no cracks or anything. Found out I have one of those custom-balanced cam gears so project expanded some...

 

my A crank has been drilled for like 10 yrs . not a racer but a daily driver . i ran a 7-1 lion head for several years with 126# per cylinder . just changed to 6-1 head for ez daily driver . no problems as of now

 

Time to go metal..they are noisy but dont self destruct and clog oil pump pickup screen..

 

Steve,
Yep, it has been done successfully.
I don't think the issue is compression only, it is more than likely a combination of factors.
Timing is probably one of the main and so is operating speed of the motor.

OK, my opinion is based on simple concept. If you look at the rod journal of the "A" drill a 5/32" hole thru it, you are taking about 13% of the cross sectional area out of it. Based on ellipse of 34°
This IMHO causes too much of a stress riser in the journal.
Take into account, this is a full 1.500 dia journal, under size causes even more of a stress riser.

When I have some time, I will model this up in FEA and we can look at the stress concentrations. But for now, I am reading the book on the Miller Dynasty. Fantastic the assumptions made in the 30's and 40's. And how the technology changed.

John

 

I've got an alum. gear already. I was planning on doing a cam etc. later but this might be as good a time as any.
-When the gear let go in my roadster, the backfires were extraordinary!

 

Turning the spring loaded plunger into a thrust button lets you 'adjust' down the clatter some..those fiber gears steal power without you noticing ..the teeth wear,slowly degrading valve timing.

Logic says reducing compression should extend life..what it does do is make the engine more tolerant of timing deviation,its why the manual distributor was effective with the stock compression.Bearing wear is caused by improper timing and torsional vibration,poor driving habits lend to it,like lugging the engine..Get a kick out of the purists who say higher compression destroys babbit..

 

john , don't scare me please . all i know is that mine works . but hardly ever go over 3k . everyone has a V8 , thus my banger looking forward to your next post ........... steve
"no salt " ??

 

About timing-I like a distributor I got, a fellow in FL sells them. Pretty easy to work on, I had to carefully file a small divot out of one the slots, the flyweight pin would hang occasionally giving erratic reading. The advance slot limiter is a sliding stop with a lock screw. I made little marks to correspond to my timing marks on the damper. A little time consuming to set up, but worth doing. It takes a pretty small adjustment on the slot to + or- the total 4-5 degrees. I need to add a convenient way to oil the bottom bushing.

 

Also on distributors- I have a rusty old (all five parts numbers intact) Mallory. Over a couple months of carefully soaking, I've gotten the top cap screws out and the shaft now turns. The rotor is absolutely stuck and I really don't want to risk breaking it. Has anyone dealt with this? Thanks

 

Steve,
Don't be scared, just be conscious of it. There is a harmonic that happens about 3k and another at about 5k revs.
I know the guys sometimes try too much timing on the dyno and break things like driveshafts and crankshafts.
If you try to drive it like a V8, you are asking too much of it.

Salt, I don't know. Reports are conflicting, imagine that.
Also, big concern for virus contamination, in hotels and restaurants. We will see.

J

 

Got a good B distributor and an FSI..run the B with modern points and condensor with a bosch blue coil,it "maps" nice with a timing light and a cheap impulse tach dwell meter..the FSI sits on the shelf,I like points..

 

FSI self advance 10* at idle

 

Doing routine lube on stock chassis.
How much grease do I pump into the U-joint housing?
How about the rear axle bearing?
Simple minds are simply perplexed!

 

I'll round out my month with my baby banger. My T block and Fronty fresh from cleaning. Slow progress, but progress none the less.

 

Cant put too much in the ujoint housing,you can basically pack it full.Be sparing with the axle bearings,three or four pumps is good..grease the bearing,dont push the grease past the seal.

 

*** john , work all year to have a bug stop most all activity suxxxx . i know that lockdown is necessary , but sure is borrringgg . we will hope for the best . i am aware of the problems , thus back down on compression , fsi timing @ 10* @ idle ............ be safe & good luck ........ steve

 

Steve,
not all boring in the shop, just have nothing to show yet.
as to your timing, it is not the initial that kills the motor, it is the advance.
try backing the timing off a couple degrees and see if it runs the same at 2k revs.
if it does, back it down again. once you know where the advance wants to be, then you can work on the curve.
I have been working on dist machine lately, the advance curves are all over the place depending on the motor.
Spark plug placement is important in FH motor, stock needs more advance, closer to bores needs less.
Research up some documentation on the timing of Ford "A" and "T" motors, performance was not the priority.

J

 

The July 2020 Banger Meet is open for posting https://www.jalopyjournal.com/forum...er-meet-thread-four-is-a-good-number.1198479/

 

Thanks John and steve for your comments.
This motor is going to be used in a street driven car, not for racing or hill climb, just easy street driving to get the car back on the road.

The motor will have stock crank and babbit bearings, +.100 pistons, winfield crowsfoot head, either winfield or stromberg single down draft, mallory dual point distributor, headers, B cam, lightened flywheel ~37 pounds, oil pump modified for increase volume. Motor may see 2500 rpm.

I wanted oil to the con rods, based on my experience of losing a con rod bearing many years ago with dip system, and since I am going to run pressure to the mains it is fairly simple to run pressure to the con rod brgs.

I did check out the reduction in area, and based on 5/32 hole with reduced con rod bearing diameter of 1.470, area of the oil hole is .0331 sq.in. and con rod bearing has area of 1.697 sq. inches so having the hole will reduce area by 2%

So I will give it a try, if the crank lets go it will most likely mean my right foot was feeling a little heavy......

every one south of the 49th, please take care.

 

Bob, you are correct the area of a .156 hole is .0331 sq in.
What you are not thinking is that this hole crosses the journal all the way through. so .156 x 1.47 is 0.229 sq in, subtracted from 1.697 sq in.

It sounds like you will be OK given HP and speed expectations.
Like Steve says, his has lasted a long time being driven reasonably.
I just cannot do that.........

Be safe, John