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Carl Heideman
Carl Heideman
1/9/20 8:40 a.m.

In reply to frenchyd :

I just talked with my machine shop and we both agreed with that.  I'm either putting in another used engine or doing experiment #3.

Cooter
Cooter UltraDork
1/9/20 9:11 a.m.

Great project, and a good looking A!.

I have this 1929 waiting in the wings, and probably should just get started on it.   My uncle bough it in '76, and never brought it up to his home in Alaska.  Instead my dad kept it at his house, and ended up wth it when my uncle died in early '90s.   



My dad is now '82, and I doubt I will be able to get either this or his '40 Ford Tudor done before he passes away, but I need to make an effort.

Robbie
Robbie MegaDork
1/9/20 9:34 a.m.

I have 0 experience with flatheads, but I say go for #3.

How different is the truck with 80 vs 100 hp? 

How different is it driveable vs sitting in the corner waiting for machine work?

stuart in mn
stuart in mn MegaDork
1/9/20 10:00 a.m.
frenchyd said:

In reply to stuart in mn :

Trouble is it's never just a sleeve. Once you open that can of worms, you know something you don't want will be crawling out.  

Maybe sometimes, but not always...my brother has a 1950 IH pickup; the rest of the engine was good but it had one cylinder wouldn't clean up with an overbore, and the machine shop (Wagamon Brothers in Columbia Heights) was able to successfully sleeve it.  I think it only added around $100 or so to the rebuild cost.

frenchyd
frenchyd PowerDork
1/9/20 11:58 a.m.

In reply to Carl Heideman :

Unless you know otherwise the other used engine is SSDD  so #3 it should be.  For you it's not really a risk. Worse case it breaks and goes all cafuyee. Engine build time.
   The likely outcome is years of use and buying a little extra oil. Much rather have a driver than a garage queen. 

GIRTHQUAKE
GIRTHQUAKE HalfDork
1/9/20 1:21 p.m.
frenchyd said:

In reply to GIRTHQUAKE :

Actually parts availability for flatheads is good...( no more poured Babbitt)

Wow, that's awesome!

all quality products made in China  well accepted and durable. 

oh no laugh

 

But seriously, that's good to hear stuff is so available- but considering their affect on car culture (and Henry Ford refusing to get rid of them until his wife forced him out in the 50s) I should have known. Wild to think people are up to 300HP on flatheads.

Considering GRM, will you use an OEM throttle body injection setup from a junkyard? Should be cheap cheeky

In Reply to Robbie:

With these cars and how light they are, a 20HP difference will be huge and make it able to keep up with modern traffic. The real fear would be however, if Carl feels comfortable taking an old vehicle like this to that power level. Old sprung-arm suspensions are better than people give them credit for, but these still have plenty thin tires and mechanical breaks.

Samebutdifferent
Samebutdifferent New Reader
1/9/20 2:24 p.m.

V8 flat head made from parts from China...  Then add twin Chinese turbos.surprise 

Just seems wrong on so many fronts.

frenchyd
frenchyd PowerDork
1/9/20 2:36 p.m.

In reply to Samebutdifferent :

Hate to tell you this but some NASCAR PARTS ARE FROM China too 

Carl Heideman
Carl Heideman
1/9/20 4:13 p.m.
Robbie said:

I have 0 experience with flatheads, but I say go for #3.

How different is the truck with 80 vs 100 hp? 

How different is it driveable vs sitting in the corner waiting for machine work?

Thanks for the vote for #3.  I'm feeling a bit like a hack if I do it, so I'll take the validation.

I don't think it will be down 20 HP, more like 3-5ish.  As the dyno examples from the Miata and Alfas show, the losses with one bad cylinder on 4 cylinder cars aren't actually as bad as you'd think.  I've talked with my engine shop about this quite a bit, and we both feel that the higher the RPM an engine goes, the less these cranking numbers vary.  In other words, the cylinder may be down 60psi (50%) at the 300RPM cranking speed of a compression test.  We're convinced that at 3000 RPM, the percentage difference in pressure is lower (maybe 20%) and that's why the HP doesn't take as big a hit as you'd think.  There still is compression, there still is combustion, etc., so there's still pressure.  I can't do it mathematically, but it makes sense in my head and those 2 dyno sheets help validate it.  A compression test isn't measuring combustion pressures, just compression pressures.  It's a good diagnostic tool, but not as apples to apples with a running engine as we'd like it to be.  

Anyone have a better understanding?

Robbie
Robbie MegaDork
1/9/20 4:24 p.m.

In reply to Carl Heideman :

I would agree with you 100%. I was trying to take a worst case scenario.

But as to explaining why, I think you are right on. For a given leak size, I'd bet there is a pressure where above it you really can't get more air to leak out in the same amount of time. And at 300 rpm there is ten times the amount of time for air to leak out than at 3000 rpm. So if a very similar amount of air is leaking out of the cylinder per second, there would be 10 times less leakage at 3000 rpm than on your compression test.

Also, a running engine will have more oil splash and such that might even fill in the gaps a bit more.

Robbie
Robbie MegaDork
1/9/20 4:28 p.m.

Think of it like the air gun attachment for the air compressor. This would be easy to test.

Does double the air come out when you pull the trigger at 120psi on the compressor than at 60? Or do you get a similar amount of air in both situations? Sure you probably get a little more air at 120psi, but I don't think you'll get double. 

But if you only hold the trigger for half as long, it's easy to see you only get half the air leak.

GIRTHQUAKE
GIRTHQUAKE HalfDork
1/9/20 4:28 p.m.

I guess with that logic and mindset, since you're still having a compression stroke and since the crank isn't still spinning by inertia, the losses in power wouldn't be nearly as bad as say, having a cylinder whole-ass not fire. You also wouldn't notice the poor cylinder very well, since (again) you still have something going on.

Hm, it's really difficult to say what would be the easier route to take. I guess it all comes down to how much money you're willing to spend and how much time you're okay with this thing not running, which honestly is what all project cars come down to. You said you had another engine available?

frenchyd
frenchyd PowerDork
1/9/20 5:57 p.m.
Carl Heideman said:
Robbie said:

I have 0 experience with flatheads, but I say go for #3.

How different is the truck with 80 vs 100 hp? 

How different is it driveable vs sitting in the corner waiting for machine work?

Thanks for the vote for #3.  I'm feeling a bit like a hack if I do it, so I'll take the validation.

I don't think it will be down 20 HP, more like 3-5ish.  As the dyno examples from the Miata and Alfas show, the losses with one bad cylinder on 4 cylinder cars aren't actually as bad as you'd think.  I've talked with my engine shop about this quite a bit, and we both feel that the higher the RPM an engine goes, the less these cranking numbers vary.  In other words, the cylinder may be down 60psi (50%) at the 300RPM cranking speed of a compression test.  We're convinced that at 3000 RPM, the percentage difference in pressure is lower (maybe 20%) and that's why the HP doesn't take as big a hit as you'd think.  There still is compression, there still is combustion, etc., so there's still pressure.  I can't do it mathematically, but it makes sense in my head and those 2 dyno sheets help validate it.  A compression test isn't measuring combustion pressures, just compression pressures.  It's a good diagnostic tool, but not as apples to apples with a running engine as we'd like it to be.  

Anyone have a better understanding?

A leak down test will tell you more.. you should have decent pressure there until the rings hit the rust spot. 
I'm trying to remember if that piston has 3 rings or 4. If the 4th is at the typical bottom of the piston you should get a really high percentage of the power and not use too much oil. 

BrianC72gt
BrianC72gt New Reader
1/10/20 6:23 p.m.

I've got the same valves on my briggs and stratton lawn mower engine, the old one.  LS swap it.

Totally joking.  Flathead Fords are gorgeous.  The laced wiring looks an awful lot like the way a good old school butcher would tie up a roast or a stuffed roll of meat.  I bet you the technique is similar.  You might pick up some pointers there.

wheelsmithy
wheelsmithy UltraDork
1/10/20 6:40 p.m.

I agree with approach #3.

I have a bad tendency to always shoot for 100%, and that is exactly what no mechanic ever does. Good enough is good enough. Think of all the third world or WW I/II engines that were put together to simply get the job done. At bare minimum, it will be an interesting experiment.

Azryael
Azryael Reader
1/10/20 7:56 p.m.

Such a cool truck! I've always wanted to get my hands on a flathead V8, and often wondered about acquiring one to turn a project of mine into driveable car, but I've always wondered about keeping up with modern traffic as I'd like to drive it daily when it can finally move.

Following along for more.

frenchyd
frenchyd PowerDork
1/11/20 1:26 a.m.

In reply to Azryael :

Stock they have 80 horsepower. A modest hop up budget can get 130-150 horsepower  with 250 horsepower possible.  

Depending on the weight of the car will tell you how easy it it will keep up with modern traffic.A typical hot rod weighs less than 2000 pounds. Giving you near Miata like performance.  

Azryael
Azryael Reader
1/11/20 6:07 a.m.

In reply to frenchyd :

Well, I believe factoring in the stock 1.8L motor and trans, the weight of the car comes out to just a little over 2600lbs. Stock motor made around 52HP, so even 80HP would be an improvement. I've no intention of shaving weight to build a true hot rod, as I'd like the outside and inside to look as original as possible.

The appealing thing about the flathead and associated transmission is the form factor; it should fit nicely in place of what was there originally.

Carl Heideman
Carl Heideman
1/25/20 4:34 p.m.

I had a little time to work on the fenders today.  The truck has a really solid steel body, but the fenders are fiberglass.   As I mentioned before, I scored some new steel fenders at the AACA Hershey swap meet a few years ago.  They're normally about $600 each and I got the pair for $400.  The only issue was a little surface rust, which got slightly worse while they've been waiting for me to prep and paint them.  

So I got out the chemicals and brillo pads to take the first layer of rust off.

The green stuff really cleans them up well.

Then I went over them with a DA sander and 80 grit to get them ready for paint.  The truck is painted PPG DP90 epoxy primer, which comes up as a nice semi-gloss hot rod color, so I'll be hitting these fenders with about three coats pretty soon.

 

frenchyd
frenchyd PowerDork
1/26/20 6:31 p.m.
Azryael said:

In reply to frenchyd :

Well, I believe factoring in the stock 1.8L motor and trans, the weight of the car comes out to just a little over 2600lbs. Stock motor made around 52HP, so even 80HP would be an improvement. I've no intention of shaving weight to build a true hot rod, as I'd like the outside and inside to look as original as possible.

The appealing thing about the flathead and associated transmission is the form factor; it should fit nicely in place of what was there originally.

Yes the 4 cylinder model B engine has 50 Hp however the Flathead V8 makes 80 hp. While the Flathead Mercury makes an additional 20 horsepower because of its longer stroke.      Considering the V8 came out in 1932 and was frequently swapped into both Model A and Model T the Flathead V8 is very legitimately part of a hot rod. 
As to weight,  a hot rod is lightened as part of  construction as a hot rod.  
It sounds like you are worried more about originality than a hot rod.  That's fine, legitimate collectors cars are certainly worthy but I doubt well suited for modern traffic. 
while a "vintage" Hot Rod can be great fun even in today's traffic. 

frenchyd
frenchyd PowerDork
1/28/20 6:35 a.m.

In reply to Carl Heideman :

Is that primer water proof? Can you use it as a finish coat without clear over it?   

Recon1342
Recon1342 HalfDork
1/28/20 7:16 a.m.

In reply to frenchyd :

He said it was an epoxy primer, so it should be...

stuart in mn
stuart in mn MegaDork
1/28/20 7:18 a.m.

The underside of my 1966 F100 pickup was finished with DP90 about 20 years ago, it still looks good.

Carl Heideman
Carl Heideman
2/2/20 7:34 p.m.

Yes, the primer is waterproof.  It's PPG DP90LF, which replaced DP90 a few years back.  LF stand for Lead Free, so it's apparently updated to be less bad for the environment.  I may be turning into a curmudgeon because I don't think it sprays out quite as nicely as the previous product, but what are you going to do?  And I do prefer to use products that are less nasty.

Anyway, I put down a few coats on the new steel front fenders this weekend, so they're ready to go on.

 

Carl Heideman
Carl Heideman
2/2/20 7:40 p.m.

I also got a bit of the zip ties replaced with proper cable lacing.  I get waxed string from a telecomm supplier:

And here's a little before and after on the firewall:

By the way, those modern hose clamps will be replaced with more appropriate ones as this goes back together.

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