Technical ***August 2019 Banger Thread Hot August Nights***

woven are great

 

The sandpaper-in-drum technique sounds like the kind of foolproof method I need. I like it.

 

still kicking a few over and working em.......

 

Just made a test run with the new Westach tach. I'm running 50 MPH at 2200 RPMs. That's about right I reckon. The tach is working good so far but I'm a little less than impressed with the plastic body especially at the cost and delivery time on these.

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Why do you need a tachometer?

 

Insurance. I had no idea how hard I was pushing the motor. I actually thought I was running it harder than I was. Turns out I've been running under her full potential, as far as crusing speed goes.

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Has anyone used a P&G gapper to set the valve lash on a OHV banger?

 

Very hard to spin up a reasonably stock model a,valve springs and cam limit you.Torque tends to flatten out above 2200,basically when she quits pulling your done.,well below the 4k rpm threshold,where the rod dippers start moving through the tray too fast and starve.

 

Question of the day. Rebuild my 30 A motor with inserts and all that good stuff or buy a rebuilt B motor i have a lead on that is still babbit in the bottom?

 

Inserts and all the good stuff will take the A block beyond a stock Model B. That's the route I would take, left to my own devices.

 

How much is the "B" motor? How much to build your "A" motor?

 

1500 for the rebuilt B. For the A most likely over 1500 to rebuild a strong bottom end.

My plan this winter was to bore the A motor, new valvetrain, cam, new style seals and balance the assembly. I think in machine work/balance alone would be 1500. Then cost of parts like pistons, rings, rods and maybe a crank unless I use the stock A crank.

 

For a driver isn't the "B" a better deal? A crank "kit" (crank/rods/pistons/bearings/rings/etc) from SCAT is(was?) about $2000 on top of your machine work!!

 

Fresh grade 2 babbit? take the B..

 

Unknown on what babbit was used and there is no paper work. Think I’m just better off building my A motor knowing what I got in it.

 

Knowing what fleas your dog has is better than getting another dog or so the saying goes.
Some will say the "B" blocks are no good, too thin etc. IHMO, the "A" crank and rods are too small for some of the dumb stuff I do, so there you go. There are advantages to the "B", if not previously "fixed" by some back woods machinist. Not to say that I haven't thrown away "A" blocks due to just being junk, to get the "A" up to snuff will take some work too.
The real deal here is up to you. Given an unlimited budget, I wouldn't start with either one, J

 

Street guy? build the A, modified flathead.

 

Guess I’d have to find a diamond block Hahahahahha

 

@railcarmover yea I’m going to. It’s only for the street and some here n there ripping down an 1/8 mile. I just want it to be done right. Who ever rebuild my motor back then did not do a great job or the owner ran it low on oil but it’s still taking the bearings I’ve been giving it for 2 seasons now.

 

When you start it after the winter layover, do you pour oil into the valve chest and dipper tray via the distributor hole before starting it up? This is probably the worst time for any Model A as far as bearing wear goes . Oil in the sump does not necessarily translate into clean good oil for the big ends until the oil pump/engine has run long enough to fill the tray.... Pressurised engines excluded of course. Especially true if the tray has any small pits/holes .
Also have you dropped the sump in those two seasons to check the clearances and adjust via the shims?

 

Me too,modified flathead fits the bill.Although a buddy called me tonight,needs some dough,offered me a diamond B block with a C crank for 800 bucks..its like dope this stuff,you always want more

 

@97 usually in the winter I start the car once a week. Since I’ve had it. Bearing clearances were all good. I swapped out #4 rod for a new babbited one since the outside edge was starting to crack but caught it in time before it worked its way into the journal. Mostly on mine the cylinder walls are scored pretty good. These motors I believe ran .002 clearances which is too tight for today’s oils and we can get away with .003 now.

 

If you go with a slightly larger clearance run Ross pistons,the rings are narrower and seal better.

 

Good plan, starting once a week, but you still need to be careful of acids formed in combustion if the engine does not get up to proper operating temperature.
For me , if I a going to run a Banger, I prefer to stay with a Babbitt bearing A motor. I do have some B parts, but have a whole lot more A parts that should last me my lifetime.
Regarding clearances, do you mean that today's (synthetic?)oils need more clearance than old mineral monogrades? My experience is that the newer oils are thinner and stay that way across a much wider temperature range. Bigger clearances allow more movement which leads to more chance of pounding a bearing if you lug the motor or accidently over advance at the wrong time or overload the engine for some other reason. That being said , although I have read/researched a lot about Babbitt bearings but I am willing to listen to any argument .
Vince Falter, Model A Ford Garage, has a fairly simple concise page on Model A Babbitt.

http://www.fordgarage.com/pages/babbittgrades.htm
and an opinion on shims and burnishing which is hard to argue with
http://www.fordgarage.com/pages/bearingshims.htm

 

I’m talking only on the cylinder wall clearances. Bottom end clearances will stay the same or what ever is spec’d from manufacture of rods and crank. From what I’ve gathered a lot of scoring happens on the walls when going with the tighter clearance.

 

More than likely it is the piston skirt design/material expansion rates that require more clearance.

J

 

I have a "built" a motor . daily driver for years . good money spent . no problems with motor ……..

 

I don't agree with Mr Falters opinion of bronze shims and heavy babbit.Proper torque and the use of hard washers under main bearing nuts,as well as using a full nut instead of a castellated one and loctite creates a much better assembly than a castellated nut against spot faced grey iron. A proper assembly using quality fastening techniques will support the main cap reducing the chance of shim fret.So I do agree his theory may be correct,his reasoning is flawed,clamp the assembly adequately and the brass shim pack will stay captured in my opinion.

 

They are Brass not bronze, and I think they are possibly OK if you use the minimum number . I think the point is that a stack of them can lead to issues, and accurately ground steel shims are a different thing to those stamped from brass shim stock. More importantly the way they are used and the way some remetalling guys do the job is not always satisfactory.
Fords method was to use a couple of shims, then machine, then burnish and remove shim(s) to adjust clearance. Vince Falter is not the only one to subscribe to the theory and method, but he has described it in easy to read and concise terms. I too do not agree with everything he says , but all information is there to consider. His information is aimed at restorers , so in theory their engines will not get run as hard and fast as most hot rod bangers. I think those of us building hot bangers can only use the stock specs as a starting point , and make our own decisions from there. When it comes to white metal bearings, it is very hard to get anybody who does it, to tell you anything about their methods and theories. Most of what you see on the net is not posted by the successful doers !!
I cant see how a castellated nut will clamp less than any other nut, the castellated part is only there to allow the nut to be locked with a cotter/split pin, the rest of the nut is the same , the full threaded part only needs to be the same length as the diameter of the stud/bolt for max clamping force. They too can be used with loctite and no cotter pin.

 

Exactly brother,the use of modern assembly techniques changes the game in my opinion.Please don't take my comments on the main bearings as an indictment of Mr Falter,his site is a service to all of us. The most important part of babbitt bearings is quality work,proper tinning and preparation along with temp control is critical.

https://redirect.viglink.com/?forma...t=https://www.youtube.com/watch?v=JBL0Y3_yQ7I

Ill leave this here,you be the judge