The Jalopy Journal
Discussion in 'Traditional Hot Rods' started by Jiminy, Feb 1, 2015.
My problem with Scat was with delivery not mechanical
What is the diameter of oil passages ?
I don't recall, it didn't seem too big.
The issue as I see it is when the journal is length equals diameter it will flex and fatigue.
The rear main is always going to be issue unless the bolts are moved, so use very large fillets to help minimize breakage.
Thanks for that Dan its what I needed to hear just as a matter of interest what gap is your Pop using on the valves in the Rutherford? Mines almost at the fireup stage now but I have pretty much had to guess the gaps.
I sure like the thread you did on the oil pump drive gear mods and remember a article in either secrets or fast?
I look thru several of both but was unable to find it. Do you remember which one it was in and when?
Thanks for sharing your great work with us!
Sidewalks; got it. Handrails?
Sometimes those kind of fractures are factory flaws from the drilling process. If so there is no real way to know it's there until it fractures. Did it have a polished mark or all grey in the split
Lake car, or a street car?
I only did the tech write here on the HAMB. If the write up I did made it's way to S.O.S., then I got no word of it (or credit for that mater). I am not a subscriber. I am a FAST member and I know it was not in their news letter.
Are you referring to the finish the drill leaves as to the cause / starting point of the crack? The surface left by the drill bit as a stress riser?
A polished / shinny section of the crack would be an indication of where the crack started, and that the crack was there a while before the eventual catastrophic failure. If there is a polished section of the crack closest to the oil hole then that would indicate that the crack started at the hole. If the polished part of the crack was some were else, then there is another issue.
I'd be interested in seeing the failed crank, is that possible?
Have you talked with Tom, or anyone else at Scat about the failure?
I don't recall seeing any obvious signs of a stress riser or discolored area. It looked pretty clean and did follow the hole for quite a ways. There was obvious marks from the two pieces rubbing together before the assembly stopped rotating. As for seeing it, I don't have it, sorry. As I understand it, this was discussed with Scat, but this is from the Guy with a pile of parts in his truck and none too happy.
IMHO, the journal was just too small in diameter for the abuse it was taking. If you take the 1-5/8 dia journal and drill a 5/32" hole through it on center, you have less than 90% area of material left. I didn't measure the hole, but that is not an un-reasonable size.
While I do not like some aspects of the Price 4 port head, I have to admit that I have seen more than one over power the bottom end of a "B" motor.
And this was a Street Roadster, not Bonneville car.
Thanks for the input John.
Thanks Dan, Maybe I'm mistaken where I saw it and it was a HAMB thread. No wonder I couldn't find it. I ordered the bearings and plan to make it next week. Great idea!
Here is a link to the post:
January banger meet ... 2013
As you guys know I work in some pretty crappy little motors. Most rev pretty high and have rod throws much smaller than A's and B's THESE DON'T BREAK CRANKS It's not about size but other factors
This months don't pass it up at a swap meet.......... Know what it is ?? USE? MAKER?
intrastellar motivational tool for perpetuation of printed newspaper based knowledge whilst providing of uncrumpled pages? aka...an aligner of thoughts?
No Doug it is actually a useful banger tool.
Cracks ALWAYS start at the outside surface, as it is the most stressed area in any cross section. While it may contribute to an overall lack of strength, an oil hole (unless it breaks through the surface of a web on it's way to the journal) CANNOT be the area where a crack will originate.
Oil feed holes better break thru the surface or you have no oil feed
Hi guys, been following this thread off and on for years now, thanks for all the great info!
I think I’m finally ready to join the ranks and build a better banger!
I have a 31 Coupe that I have owned for 7-8 years now and I’m going to start doing so work on the engine. I’ll have to improve the steering and breaking after that, but one thing at a time.
The plan is to build up a spare engine and swap it out to keep my car on the road and then rebuild the engine that came in the car (using what I learned on the first engine to build an even better permanent engine).
So with that said here are the specifics on my planned build…
I’m doing my first engine rebuild with the goal to make a beefy touring car (something that will keep up with traffic from light to light or safely handle 55-60 on the highway).
With that said I have collected some parts and 2 spare engines (a 28 that had a multi clutch trans/flywheel and a 30).
Some parts I have gathered for my 28 engine rebuild:
Thomas aluminum 7.1 head and sacrifice Anode (newer run from Snyders I think – bought it a few years ago).
High Compression Head Gasket - GraphTite - For High Compression Cylinder Heads
New high compression head studs
Burns Dual down draft (came with two 94’s – will need rebuilding – May block off one to start with just to simplify my life then add the second one once I understand what’s going on with the first one).
Lightened flywheel with v8 clutch (I bought one already lightened off ebay and have a friend of the family shaving a spare one as we speak on his lathe).
Aluminum cam gear
Going to get a Stipe cam (not sure what grind - I forget what the recommended street/touring cam was).
Adjustable tappets (single self-locking).
Going to get insert bearings (I live in Illinois so will probably go to AER in Skokie – my engine is currently in Michigan so I could have work done there as well – Anyone recommend a shop in MI?).
Crank is at a machine shop getting re ground and polished now (there was just a little pitting that were going to clean up).
Crank has been rough balanced (it will get a second final balance after the grind and polish).
Model B distributor (was rebuilt already – I also have a Mallory dist and a Wico Magneto, but don’t plan on using them for now).
Fuel pump and low pressure regulator (plan on running 1.5 – 2.5 lbs).
Thermostat - 160 Degrees
B-6335 Model A Ford Engine Rear Main Oil Seal - Nitrile - For 4 Cylinder Model B Engine (will this work on an A block?)
I’m definitely going to be seeking advice from you guys who have already done this sort of build!
Does anything stick out as mission or just plain wrong to you guys? Any recommendations, tips advise going into the machine work stage?
Hold the brake pedal (mechanical modelA) for adjustment?
My question is ...... Do you really want to reduce the engines life? If your only going you drive a few hundred miles a year it doesn't matter BUT if you want to go out touring with a bunch of other guys you'll no doubt get into little challenge races and shorten the engines life a ton.
You could always just buy a Donovan D motor and save yourself a lot of grief
To counterweigh a A crank. Is it really going to help keep a engine together?
Is it true that if you add counterweights to a standard 3 bearing crank it can cause more torsion stress to the crank as the weight is actually offset to only one side of a piston.
The engine feels smoother but the crank is actually under more stress as each piston fire, the crank has more "whip"due to the offset counterweights
Love to hear all your views
The Donovan D Motors are a thing of beauty, but I have always been under the impression that for a price of one of those you could build 2-3 good solid A motors! I could be wrong.
I don’t tour at all, but who knows down the road it might be something I do (I’ll cross that bridge when it comes). I currently like the idea of driving to the Woodward Dream Cruise in Mi once a year (that’s 350 miles one way +/-). With my current driving habits I’m fine with sacrificing a little life for a little more fun.
I was hoping that inserts and a balanced crank would really add a bit of life to an engine and counter act the addition of a higher compression head or single/dual downdrafts. I have considered adding a balancer as well, just for good measure (get rid of that torsion stress I heard you guys mention). I do understand the more power you add the more life you rob, that’s just how it is. I’m trying to go about it in a semi-smart way and just not make foolish 1st time builder mistakes.
There are instances where the Donovan cannot be used. In these cases, it gets very pricey to play.
If you want to think of it this way, use HP levels to determine the cost of admission.
Speed cost money, how fast do you want to go?
I have done a few pretty extreme motors, if you can buy the Donovan, do it. You are money ahead.
If I had all the money I spent messing around with these old cars I would build 1 with a minimum Scat crank, forget them 80 year old crankshafts. I would also stick with the dip and splash system of oiling. Maybe improve a little on the dippers. Later design Pistons with narrower rings are very good . Either a B grind or a Jim Brieley SU1R (personal choice) I am building an engine right now with .080 over Pistons I bought from Egge that have been on the shelf since 1995 an I'll run them, wide rings an all. Babbitt looks good onI will run that. Hope to pick up block later this week after Pistons are fit, Egge says .002 but I'm going with .003. I will modify oil pump for volume. After my earlier comment regarding crankshafts in this engine I'm going to use a stock non counter weighted crank. The only modification will be an oil line to the center main from the pump. Gonna run a B distributor with lighter springs, wing cap. Got 3 or 4 a those speed round caps but I don't think you gain anything from them.
It is my impression that a lot is being developed for banger motors talking to two well known professional motor builders here this is what they do and garantee their work
hotdip and inspect the block they wont work on cracked blocks
line bore crank in relation to cam they find many are not inline
perchase new crank rods and pistons no aged and posibbly damaged components
decide with owner if they are to have poured bearings or shells cost is about the same
buy new crank and cam gears so they know what they have and will suit the engine output
one valve piece guides and modern style valves
new type of back main seal
the engine is bored or sleeved all surfaces are machined and matched includeing inlet and exhaust manifolds the engine is then assemble useing all new gaskets the fitted in the car and they do the first startup then the car goes on a rolling road for tuneing they find fitting a modern electronic distributor (such as a early nisson ) and converting to 12 volts well worth the effort all distributor shafts checked or replaced
Spendy yes but not over the top remember they offer a garantee their work cant get better than that and now I would not go any other way. For what is really a new motor in the long run it is the cheepest and best way to go.
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