Projects FlatCab: 1932 Cabriolet, Hot 1941/42 Merc Flathead Build

subscribed!!
thanks for sharing the flathead build knowledge - fascinating stuff, I need this information for my doctorate mate.

 

Haha...GOLD Mickey !!

Well Dale, what about it mate ?

 

Great thread Dale, looking forward to hearing that thumper sing when its turn comes.

Cheers,
Drewfus

 

I think you could have a bucket of those . . . and I still wouldn't do it!

 

Some More Porting Pictures - With a Macro Lens:

Just bought a macro lens for my camera and a LED light ring - to make close-ups of ports a lot better. You can focus in on a very small area.

Here is a collection of pictures:

 

Some More Porting Pictures - With a Macro Lens:

 

Block Prep - Cleaning Flash and Casting Imperfections Up

I always spend quite a bit of time with the rotary grinder cleaning up all sides of the block, getting rid of casting flash, casting sand pockets, rough edges, etc.. Now is the time to do all of this - before you bring it to the machine shop:

I also hone the lifter bores with a brake cylinder hone - to smooth them out.

 

Crower Groove-Lock Roller Lifters

Here are some pictures of the Crower 'groove-lock' roller lifters, the jig that is used to drill the lifter bores and the resulting view from the bottom.

Pretty slick setup if you ask me!

 

Checking Compression Height - Before Piston Ordering

I don't trust the 'off the shelf' pistons to magically match my crankshaft stroke and deck height. Due to this, I measure the compression height on both cylinder banks.

So some are asking - "WTF is Compression Height" and why should I give a shit? Well, it is the distance from the center of the pin-end of the rod bore to the deck surface. In theory it should be the same on both sides - rarely is this the case in the real world.

I first use a dial indicator to setup the max stroke height - then I use a depth gauge to measure the top of the piston pin. Take this measurement and add 1/2 the pin diameter (.375) and you have compression height.

On this block, the passenger bank is .008 taller than the driver's side. So, when I have the block head surfaces square-decked, I'll have the machine shop take off an extra .008 on the passenger side (to true it up). Then I will custom order the exact pistons I want from Ross. This will put the DOME and squish height of the heads exactly where I want it to be . . . which is about .040.

This is very important stuff - not a lot of guys take the time to do it.

Note - Don't Think Your Stroke Is Exact on a Merc Crank: Another reason is that if you have a 4 1/8 stroker Merc crank, don't count on it being the exact stroke they say . . . that is usually off as well. So, specifying the exact compression height number when you order your pistons will get everything the way it should be.

Custom Pistons Cost: Custom Ross pistons with the GOOD Total Seal rings are about $250 or so more than the off the shelf pistons with those totally crap Grant rings. Don't use them, go to the 1.5, 1.5, 3.0 millimeter ring packages!

B&S

 

Awesome work Dale..this is what seperates a good engine from a great one. Right click, save....repeat.....

Boy Id love to hang out in your garage for a while

 

Sunday Fun: Compression Height Example - As Compared to Off the Shelf Pistons

Here is how my numbers worked:

Height From Deck to Pin, 1/2 Pin Thickness = Compression Height
__________________________________________________________

Pass: 1.030 + .375 = 1.405

Drivers: 1.022 + .375 = 1.397

Now, lets say we're going to square deck the block.

Amount to deck the block, on Drivers = .010, Passengers = .018 (to fix the unequal deck heights).

1) Gross Compression Height: 1.397 - .010 = 1.387 (but a few more calcs to consider below . . . )

2) Wait - The Head Gasket: Thought I was done now didn't yah! What piston to head clearance am I looking for - .040. How thick is a head gasket when it is compressed (that depends on brand). I always measure my head gaskets when I take them off - or keep them around. The ones I just measured came in at .050 compressed.

3) Heads - Milled or Not? We're reworking my ancient Eddie Meyer heads - so they will have a complete/fresh dome.

That means that with a .050 gasket thickness, that my pistons will still be .010 'down' from the correct height (due to the gasket). So, I'm going to scwag the CH number to account for this. I'll add .010 back, giving me the new/calculated CH of:

1.387 + .010 = 1.397

4) Milled 'EBay' Heads: If your heads are milled - any amount, and you bought them used, then you need to consider the dome depth and redo these calcs!. You'll notice a LOT of the old used heads have small dome areas, that is because they've had the shit milled out of them. BEWARE! Having your nice new pistons and/or valves hitting the heads - not good.

5) What if I was a Lazy or Cheap Bastard (Not that there is anything wrong with that! )

Say I didn't order custom pistons, then the 'stock' 4 1/8 stroker ones from Ross will have a CH for a 4 1/8 stroke of 1.374. This translates to the piston being .023 thousands too short and 'down in the hole' that amount. Will it run - sure . . . will it perform at it's best, probably not.



5) Ring Location: When you order custom pistons, you can specify the ring types and locations. I'll be using the 1.5, 1.5, 3.0 mm total seal rings. I'll specify the top-ring to be .300 down from the deck edge. This keeps it below the 'relief' I put in the deck and shields it a bit from the heat of the chamber.
-----------

Taking the time to do this can make a big difference in how any high performance flathead runs. I want as much compression as I can get and a tight squish area - so this is what I need to do to accomplish this.

It isn't hard . . . really the most simple math there is . . .

B&S

 

Come on over, us Vintage Yankees don't bite . . . and we don't drink 'Fosters' either, so just bring a few oilcans of VB for me!

 

Awesome work and detail. I've enjoyed reading so far.
Is this car the one featured as a barn find in RJ recently?

 

Okay - you caught me, time to come clean . . .

The story of where the FlatCab came from . . . Part 1

http://www.jalopyjournal.com/forum/showthread.php?t=871291

Enjoy!

Now back out to the shop - need to complete the lifter keyways . . .

B&S

 

Wow we wow wow! Nice work!

 

I have been chasing the same 32 for almost 45 years, I still hold out hope. Had a deal made on it back in 1981 but he backed out. I first saw it as a 9 year old boy and fell in love with it. still hoping.........

 

Throwing some good Karma your way - hopefully it will work out and you'll finally realize your dream.

B&S

 

Hey Dale That there is called porting porn, and i just soild myself!
Your details are really to learn from. You adviced me, and my Block was off by 0.020" !.

/K

..................................
Taildragger&fenderless

 

Glad you checked your compression/deck height. It never hurts to get things the same side-to-side and know your clearances, CCs, compression and squish area. Can't wait to hear your motor fire up - should be some real fun!

B&S

 

Any updates? I suspect that you are busy with the cad engine, but it never hurts to ask...
Thanks for all the pictures an information.

 

Yeah, was swamped working with the crew to get the FlatCad assembled and on the dyno last week. I have been getting ready to test cam timing and getting my valve package figured out - will be updating some more at the end of next weekend.

Thanks for staying tuned!

Dale

 

Great thread mate, joint the forum just to follow it. Love the relief work, similar to the approach I would take. Roller cam is cool as we'll.

Sorry if I missed it, but what intake are you running?

It would be good to see a sectioned intake to go with the sectioned port.

 

I'm building the 'exterior' of the engine to be pre-war in style. This means I can only run 2 carbs (as I'm not aware of any 3 carb manifold that early). I'm going to run some reworked original Eddie Meyer heads and manifold - though I'll port the manifold all the way up to the carbs. I'm going to initially fire it with Stromberg 48's (they're a bit bigger than 97's), but may also try Holley 2110 carbs (they flow quite a bit more than the 48's). I'll put the motor on a dyno and try both - as I'm a curious bastard and don't believe all the 'stories' and common flathead myths passed down by history.

 

This thread rules! Very informative....like reading the old "How to hop your Ford or Mercury V8" by Roger Huntington.

 

Great thread, Thank You. JJ

 

Any updates?

 

Anything new to report?.
Al.


Posted using the Full Custom H.A.M.B. App!

 

Thanks for checking back - will post a report on Sunday evening . . . getting some engine stuff done fo the machine shop next week.

 

This Flathead is gona "Roar" D. Your last sentence is sooo true That why we do Flatheads!!
Eddie Meyer is most beutiful Head/intake combo there is Please post more pics, when you have the time!?

/K

.......................................
Taildragger&fenderless

 

anything ?.
Al.