Flathead Rebuild What NOT To Do Thread

I have read a ton of flathead tech but never have I seen a list of grave assembly mistakes, common assembly errors, parts combinations to avoid or just typical things that guys get wrong that seem obvious.

 

First thing to remember is install the oil galley plug behind the cam drive gear.
There are a lot of other things that are peculiar to flathead Fords. Most have been covered in the popular books available.
If you have a question or problem, STOP and find the answer.

 

I will be bookmarking this thread.

 

Mee too!

 

I could write a book on how not to build a flathead just from taking apart a "fresh rebuild" my customer bought recently and brought it to me to get it to run better. Not a lot particular to flatheads, they did things like putting new rings on some really bad pistons and put them into heavily rust pitted bores and using a crank missing the thrust face (I could move the crank back and forth almost a 1/4'!). The best was they broke the block I guess with a valve removing tool leaving a huge hole in the intake port to the valley, we were wondering why it seemed to have a bad vacuum leak.
In reality they are simple engines, a good book and some decent engine building skills and they are easy to do. As far as combinations, well ask 10 people and you'll get 10 answers!

 

Here's one: Don't cut the decks unless you absolutely have to.

Another: If you modify for "full flow" oil filter, don't ever plug the lines and run it without a filter otherwise you will have a "no flow" oil system.

 

First things first, MAG the block!

More "stupid" things- running early rods on an 8BA or ECM crank (or vise-versa)
49-up cam gears have a reverse cut on the teeth then 48 and earlier
early cams have a longer snout then later (on 32-48 style cams)...but adapters are made either way to fix that

They are super simple but the wrong combo of parts can really screw ya up!

 

Don't forget there is a bolt inside of the water pump that needs to be reached through the opening where the hose attaches.

Charlie Stephens

 

Don't bore the blocks ANY More than what's nesesary ! scrubba

 

If it's an 49-53 style block, align the squirt holes in the connecting rods properly.
Some of the early 49-53 engines did not have squirt holes and just used the "splash" system of the crank rotation.

Also, don't rely solely upon the press fit of the small distributor drive gear (#6250) on the camshaft as it can come loose. Use a set screw to prevent rotation. I saw a thread about this a while back.http://www.vanpeltsales.com/FH_web/FH_images/FH_engine-pics/Flathead_Engine_camshftassy_1949to53.jpg

 

Thanks guys. Keep 'em coming, I"m going to build my first flathead up this fall.

 

Huh interested to see what gets put up...

 

Like Mike51Merc says................ Never cut the decks. Too long of a story about my big mistake.

 

The crank journal's are hollow. It's a good idea to pull the plug's and clean them, then tap some threads and install screw in plugs.

 

Good thread.

 

AANNdddd...When you tap in your oil pump idler gear take the time to check and make sure it's not in backwards, or it won't engage the rear cam gear, and hence, the oil pump gear...

 

It's not only a good idea, it is essential.

 

Get the hollow lifters and drill the bosses. The adjustment with the wrench to hold the rotation is almost impossible. Check to see if you can even turn the adjustable lifter screws. Some are extreamly tight. Don't use copper head gaskets with aluminum heads. It makes a battery and erodes the heads quickly. Put in a new pump and pick up. I see no use for the one piece front seal. The stock system works fine and it is easier to get the front cover or pan off if the seal is split. Cut the seal long and cut the pan gasket back so there is not a gap at the end of the gasket. I used a SBC dip stick by putting a compression fitting on the pan boss and clamping the chevy tube. They can be bent to clear headers and has a seal when using a pvc. Use a long stud in a front cover hole to make a timing pointer.

 

Make sure the oil pump drive gear on the cam is lined up with the FLAT spot, on the gear & cam
Jim

 

Early rods on late crank are fine, in fact theoretically at least an improvement due to minor reduction of frictional losses and elimination of the main cause of high rpm rod failure. And of course early on late is mandatory for building the traditional 4 1/8 stroker without the special parts that have become available recently. I believe that late rods were hardly ever used by racers, and of course no one ever started a build without the late Merc crank once it became available as it was a cheap and easy way to get more cubes or more more cubes when offset cut for earlier rods....
Late rods on early crank has nothing at all good about it with the oil delivery hitting between the rods (!), but apparently enough oil voluntarily reports to the right places somehow to keep such messes alive...
Go up and read Pete! Missing front plugs (early and late) are amazingly common...a good engine might survive, with just enough flow to tickle the gauge, one that is weak in the oil system will surely die. Early engines have a rear plug as well, and pay attention when assembling and sealing the plate ate rear of block. As with any engine except maybe those like later SBC with one piece gaskets, PAY ATTENTION and THINK when assembling pan gaskets, end ropes, and the seal holders at rear of block. Do something stupid or sloppy here and you get to take everything out of the car to do it right while working in a big puddle of oil.
Fully understand how valve assemblies assembled, installed, and removed and how the retainer clip seats before you mess with anything, and if you farm out the valve and seat work you MUST be able to teach this as the machinest has likely never seen anything like that in his life!

 

I am just doing my first flathead (59A) with a 4" Mercury crankshaft and was confused by what flywheel to use. I realized through reading that one is to never mix a 59A and earlier block with an 8BA-'49-up style flywheel.

 

Decks are thin, as several have said do not cut unless really bad. With 24 studs holding thin heads, those things will damn well conform.
Stud hole in block are extra-tight threads and studs have special bases to snug down into the little recess at the top of each hole. Original type studs in original or special lengths are available from Nacewicz.
Many blocks have already had the stud holes enlarged by a macinest tap, and with those you will need special procedures, but don't wreck one yourself! There are just enough threads in the deacks and loosening them up with a regular class 3 tap is plain wrong.
Give each hole a thorough cleanup with gun brushes and solvent and let them alone.
Ford made them tight so they would seal without goo and so that all 48 would stand in there straight up and they could assemble thousands of heads per day without fighting wonky studs. If you use generic studs or if some past criminal tapped out your block use the good gray modern sealant or the good old permatex, and before getting to final st up the studs to stand straight: Just drop on the gaskets, put in studs with your chosen sealant, then heads, washers, and nuts. Screwemdown firmly, but no need to approach assembly tightness, and let them stand for a day or so. This should get them planted square to the world even if Henry's work in there was damaged.

 

During teardown,..Do not stick the valve tool down thru an intake port to pry the valve assembly out of the block......The intake port will break...... I was once told that is fixable....but why have the headache ?

4TTRUK

 

PS; The new valve guides will all have a groove for an o ring seal....ONLY install them on the intakes.

4TTRUK

 

Do more than magnaflux, have a pressure test done. The 8BA that I'm currently building passed the magnaflux examinations just fine. However, when pressure tested it started seeping through a crack below the right front valve bore. My machinist has been doing these for 40+ years and has never seen one cracked here. Was a straightforward fix for them, but would hated to discover the crack after it was assembled and in my car. Bottom line is that they can crack ANYWHERE.

 

What? Can you elaborate? Which year flattie?

 

Alrightey now! A flathead thread for those of us new to flatheads! Have I got questions!
First, I'm not as much about performance as looks and dependability. I think a lot of us are more about the look, and having a good running engine that will get us there. If we want muscle, there is always an OHV we can stick in there.
1; I'd like to install a set of aluminum heads for the look, will they affect the dependability? Do they help with cooling?
2; can I run a 2 2bbl manifold with a stock cam, or will it be too fat? Thanks, Mike

 

The alum head won't affect dependability and will ehnance cooling. the major advantage is their lightweight as compared to cast iron.

I don't see why you still couldn't run two 2 barrel carbs without any "fatness."

 

whewwee....neat stuff......

 

I had my block pressure tested after reading this THANK YOU, everything checked out good and I have piece of mind