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

Porting and Relieving a 1942 Merc Block - Numbers to Work From:

Spent the greater part of the weekend with a dang porting tool in my hands. It is one of those jobs that I really don't like, but I can't help myself.

Original Plan: I was going to do a 'Street Port' type of job . . . but I lied to myself! It seems that once I get a damn air grinder in my hands, I just can't help it - the cast iron has to fly and I'm not satisfied until I have done a lot of rework. So, WTF - the ports are pretty big . . . whups, my bad!

Sonic Testing Numbers:

I know that most of you probably don't have a sonic tester with port type probes - the only reason I have one in my wife bought me one so I could port the FlatCad block for Bonneville 2 years ago. Thanks Amy! My sonic tester cost about $2,000 or so with the different probes I have. BUT - if you're going to screw with these old motors, decide how far to bore, do heavy porting, etc. - you just about have to have. If not, you're just gambling a LOT . . . even with one, I still get nervous when the cast iron is flying and I'm working the areas that I know are thin.

This is the first time I've had a sonic tester when I've been porting a Flathead Ford - does help to say the least.

Flathead Intake Port:

Here are a couple pictures of a cut-away port that I made a couple years ago - I dug it out because I wanted to see if this particular 42 Merc block had the same meat as the 59AB that this cutaway was made from. (I was worried as Pete1 told me some of them are very thin in the ports). If you're porting a flathead - study this VERY CAREFULLY, as you can ruin a block very quickly if you don't!





Anyway, with the Sonic Tester numbers for this block are almost exactly the same as this cut-away . . . cool! (At least I know what I have to work with.)

Where you need to be really careful is in the area where the port chokes down - about 2.5 inches into the port. See the '160' number on the floor and the .150 on the sides - lots of folks try to take the 'hump' out of the floor, only to hit water - or they go too wide trying to open up this area (no can do!).

Another place to notice is the overall bowl side-wall thickness. I found on the Merc that I had roughly .130 or so before I stated the bowl work - so I only worked them until I was between .100 and .080. The sides of the ports are thinner than the back, so watch what you're doing!

Okay - next post will show some pictures . . .

B&S

 

Intake and Relief Pictures

There are enough 'Porting and Relieving' articles on the HAMB and other places, so I'm not going to bore you with any sort of instructions. Not only that, there are so many opinions on the subject - don't feel like getting into a contest or debate.

These are fairly big ports - if it was a 100% competition engine, I would go out bigger (as my wall thickness is around .100 to .125 in most areas). For a street engine - doesn't really matter. Also, I'm only running 1.6" valves - so at some point, enough is enough (and I'm tired of this***** today!).

Intake Ports - Sandpaper Grit:

Okay - I know you're just like I used to be - I want those intake ports just as smooth as possible and looking like chrome! Then I'll take cool pictures or just stare at them for hours (just drooling over your own work). You just want to go to 120 grit, 220 grit, 320 grit, 400 grit, 600 grit - until they are like mirrors! Well - hate to tell yah, that is the wrong thing to do on intake ports. You want them to have some bit of roughness to them - I always stop at 80 grit on the intakes. Exhausts - different story . . . we'll get to that later.

Intake Ports and Bowls:













Stepped Relief:

You might think 'Hmmmm - looks a little different?' - well it is. I've studied a lot of Harley KR racing cylinders and reliefs . . . they do some funny stuff with the intake - tend to make a deeper trough and build a sort of 'flow wall ' toward the exhaust. The purpose is to direct the intake charge and reduce the amount that goes over to the exhaust side of the chamber and/or gets*****ed out the exhaust port on overlap.

Will this work on a Flathead Ford?? Who the hell knows! I'm not claiming a dang thing, but I thought I'd try it and see what happens.






Interesting Side Note: Was looking at Mike Davidson's 'FlatAttack' website after I did this relief and I couldn't believe it - very similar relief style. Maybe we're both crazy?

The picture below is from one of his engines - going in a dual-engine LSR streamliner that he is building - it appears to be very Bad****! I wish him the best. You guys should checkout the SOHC flathead heads he is building and going to sell - who wouldn't want a set.



Okay gang - enough for this weekend. This porting***** wears my back out (and the funny angles) and makes my hands numb.

I'll be onto the exhausts this week - won't take as long as you just can't get into them much to do much.

B&S

 

How deep is the stepped releif ?

 

Awesome stuff, Id be really interested to see how well the stepped relief flows Dale. What did you sue to do the relief...hand held die grinder or a router?

Also, what heads will you be using?

 

Relief Work: I always do the reliefs by hand - same porting tool that has become a part of my damn body it seems. I start with a carbide rotary file with a semi-flame profile, then switch over to sandpaper rolls to polish it out.

Heads: As this is a pre-war style build, have an original set of the first Eddie Meyer 24 stud heads. Have them being worked on at the moment - was a crack in a combustion chamber. I'll do some rework on them for flow - but I'm trying to keep compression up - so kind of a balance to strike. They have a chamber design that is about 1/2 Ford original and 1/2 like everybody else. They do can't the roof over the valves to match the valve angle (for compression). Don't probably flow quite as well as an opened up set of heads like you get from everybody - but it is a compromise on the street (at least I think so).

B&S

 

It is about 1/8" on the exhaust side (same depth as the original relief, just blended in toward the seat and polished) - and .187 on the intake side.

I'll do exact measurements this evening - and take some close-up pictures.

Will be interesting to see if it works - kind of like the idea in my mind anyway!

B&S

 

I really like the idea of the KR-style relief That's what Flatheads are about, testing new, old stuff

And to anyone who's planning to buy a Flathead book, save your money and follow this thread!

K

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

 

Looking forward to the KR reliefs final verdict. I have wanted to do that for years.

 

sure looks like it would help on a huffed block Dale sure would like to see some comparative numbers run..............hummm

 

could you tell us about when you discovered/found it ?.
Al.

 

Any updates? I really appreciate the detailed description and pictures so far, thanks.

 

Was side tracked for a few weeks - just getting back to the block this weekend. Will have it ready for the machine shop on Monday.

Also, have a slew of parts here - for suspension, brakes, steering, etc.. It will be a mad dash to get it done for the summer, so time to get******** on my end.

You'll see an update by Sunday night!

B&S

 

Exhaust Porting
Have been porting the exhaust side of the block this last weekend and this evening. As noted before, lots of opinions on what to do and how far to go.

I've seen lots of folks concentrate on the intakes on flatheads and not put much effort into the exhaust. To each his own - to me it makes no sense to do 1/2 the equation . . . flow is flow. If you're filling the cylinder better - you also need to help the exhaust get the heck out. Also, on a naturally aspirated motor, the exhaust has a LOT to do with pulling the intake charge into the cylinder - during valve overlap.

Plan: As this is 'supposed' to be a street motor, I probably didn't really need to do as much as I did, just can't help myself with the porting tool.

Bowl to Port Choke Points: There is a LOT of obstruction coming out of the valve bowl and into the ports - so I try to do a lot of work in these transition areas. As the flow wants to go to the top of the bowl (and on most blocks it is a LOT thicker toward the top of the bowl), I try to make a nice rounded sweep from the bowl into the port. I also remove quite a lot of the obstruction into the port entry and open up the bowls. See the picture where I show sonic tester thicknesses - notice that in my case I had alot more to work with at the TOP, then the bottom of the bowls. Knowing what material you have to work with is very important - especially if you're "new" to this game.

Do Both Sides: It is easy to get carried away and only do the valve bowl/port side, but there is quite a bit you can do on the outlets.

Outer Port Outlets: You can make them more of a 'D port' and move the outlet OUT a bit. If you're making custom headers, than you can move the port way outboard, machine a face for a plate and make a flange plate that bolts to the block and becomes the new header flange location. I'm not getting that wild (as I"m running original Sandy Belond headers). I'll port my header flanges a bit (for the D-port shape), but nothing more than that.

Center Port Outlets: If you're a 'Port Proctologist' and you have a 6" to 8" carbide cutter, than you can reach way up inside the center port and open up the choke point in the middle. I probably opened these up about 1/8" or so - which should help center flow. I also ported/smoothed everything from the choke point outward.

Here are a bunch of pictures - kind of hard to see things, but check them out and you'll see what I'm up to.

First Set:

 

Exhaust Porting - More Pictures

Checkout the dimensions on the second picture - will give you an idea of what material I started with and what I have left. In a full-on competition flathead, you can get down to about .080 safely - just no reason to do that on the street.

 

Cam: Oh Hell, Time to Go Big or Go Home!

I have a story to tell - don't believe I've told it before . . . but who the hell knows . . .

Rewind: 35 Years Ago - Went to See My Friend Ed Iskendarian

Roller Cam: It is a long story, but when I was about 20 or so, decided I wanted to make a flathead roller cam (as my neighbor was a big Harley KR guy and had ALL the Harley KR cams, all were rollers - and I'd profiled a few).

Went to talk to Ed Isky - he said roller cams don't work well in flatheads. I said that was funny, because that is all Harley KR's run - and they are the most advanced flathead built. So I asked him IF I was going to make one, how would I go about it. He said he can't make me one - as he has no billet steel cores. So I said, "Well, IF I was going to make a steel billet core, how would I go about it?". So we talk all about 8620 Steel, rough grinds, copper plating, heat treating, finish grinds - the whole process . . . blah, blah, blah.

So I leave, buy some 8620 steel bar stock and get to work on my Dad's small 6" lathe. Was a bit of work, but after I make two billet cores, then I go back and see him about 3 weeks later. I told him "I'm here to get those roller cams ground for my flathead." He says "Dale, you weren't supposed to make them - we were just talking about them . . . but now, since you did . . . I guess I'll have to grind them for yah". We talked all about profiles, duration, lifters, etc -- I wanted some BIG duration (like Harley uses).

He made me TWO cams - and I've had them stored in grease ever since - just never got around to making the roller lifters. But - here we are . . . time for some fun!

Fast Forward: I've had two big bad-ass rollers for 35 years - huge duration, one is 420 lift and one is 440. So since I'm making a fun motor for the 32 Cabriolet, told myself 'Screw it' - time to dig them out and try one. Why the hell not - if it doesn't work out . . . I'll put a Potvin 425 in it.

Both have a ton of duration, so I'm sure they will***** down low, but I just want to run one and hear it. So I had Crower send me some roller lifters (too busy to make them right now). The lifters are heavy, but WTF, going to see what this cam sounds like if nothing else!. FlatDog ran them with only about 100 lbs of pressure on the seat - so I'll do the same.

These cams would surely run better with a blower (due to duration), but they've been sitting all these years - so time to try one of them.

One cam is .420 lift and 272 duration at .050 (about 312 at .010)

Other is .440 lift and 282 at .050 (about 322 at .010)

Probably won't run worth***** as compared to the 425 Eliminator - but time to dust these*****ers off and give it a whirl.

Here are some pictures of the 'Smaller' cam and the Crower roller lifters I just got.

Should be fun!

 

Hi dale,
Very good reading!

You opend the middle exhaust port quite a bit!
How thick is the material deep in there?

How much do the crower lifter weight?

Great article and pics!

Show some pics of the headers, please!

 

I'll weigh the lifters this weekend - with adjusters installed. I plan to use Isky 185G single valve springs - with 100 lbs on the seat. This is less than I'd run in a competition engine - but for the street, it should be fine.

I'm also doing some timing comparisons between this cam and the Isky 404-A, I suspect there are a couple things to learn about profile/cam advance.

B&S

 

WOW thats a lot of duration @ .050" Dale...should sound nasty 100 lbs on the seat, what will it be "on the nose"?

Are those Crower rollers keyed?

 

I haven't measured the new springs as of yet - will get that information. The Crower lifters have little radiused 'buttons' on the side. They're sending me the 'drill jig' that is used to drill the lifter bores. Will post pictures once I get the jig and get the bores setup.

Yep - lots of duration . . . will probably be a big fat PIG down low and idle way high! Who cares!

 

really nice lookin so far Dale, like all your work..........

 

Great stuff! I too love and have run potvin cams, I have a 276 ci motor with the .375 lift and sounds wildly crisp!

 

Ahhhh - the wonderful 'Potvin 3/8' cam - a fantastic stick for a stout street flathead . . . perfect for a 276! Great choice - one of my favorite.

B&S

 

Enough of the porting and cam saga, how about the story of the awesome find!!!

We the need pictures or did not happen, just kidding but pictures would be nice.

 

Hi Dale
With that much duration on either cam, will you use center port exhaust baffles? Seems like it would really be necessary due to the amount of overlap?
Jim

 

Yep - I will install center baffles . . . whether or not if makes any difference, who really knows. I will use the standard 'extended stud' to hold them - and will add a iron-tite pin as well (don't want them to rotate/move around). I will post pictures of the work - hopefully the parts I buy are nice quality and fit well in the ports.

B&S

 

As allways, great job D. Regarding the cam, didn't you have a "505"?
And yes, You and Mike Davidson has alot of Flathead knowhow

K

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

 

Hey Kjell - how the heck are yah! Yes - I have the one '505' that Iskendarian made, but that is a cam that is only for full-out drag racing and I'd never attempt it on the street. Given the lift is over .440 or so, the cam journals are enlarged - to run right on the cast iron with no bearings. This gives it enough space for the larger profile and lift. It runs with radius lifters -- kind of the biggest brother to the 404-A. Someday I'll have to make an engine just to try it with.

Finished the rest of the exhaust porting last night - am pondering whether or not to go to 1.7" valves or stick with 1.6". As this is a street engine, will probably stick with 1.6" and save the labor of having to put new hard seats in it.

 

Very interesting stuff! Would love to pick your brain, especially about what you found while porting the Merc block. I have a couple of those stashed and am debating the direction of my next bellytank engine.

Did you get to weigh the adjustable lifters? A set of those need to be in my future.

Andy

 

man-o-man....cool stuff going on there....thanks for sharing !

 

Hi Dale, i would trade you a Max-1 or 77-b for your 505-a!!!
How does that sound hahahahaha