Projects =Rebuilding the Plymouth Flathead=

Reasons to eliminate the stock fuel pump:

Just another point of failure.

Cleaner access to front exhaust connection.

Cleaner routing of fuel lines to carbs.

Excuse to craft a spiffy block-off plate.

I recommend the 'solid state' pusher pump that you mount near the tank. They are available in 6 volt or 12 volt versions. They can be used either positive or negative ground. They are available with 2-3 psi output, perfect for B&B or Stromberg carbs, and no need for a regulator. These pumps are very popular with the Jaguar crowd. They cost around $40. Mount a good inline filter between the tank outlet and the pump.

 

Great, Hammertite is gone? Good thing I have a nice stash - all colors.

It is not clear to me whether the replacement studs you bought are Class 3. It sounds like you chased the threads with a Class 3 'tap'. Can someone respond to my question regarding Class 3 threads, and whether you can retap to regular and then use different head bolts??

 

If no one has told you about the P15-D24 forum it has a lot of information for flat head I/6's. The P15-D24 home site has a list of vendors that supply almost everything you could ever use in your rebuild. Also Inliners International has a MoPar site in their forum which has a lot of useful information. Also you need to use some type of thread sealer on all of the bolts that go into the water jacket which is all of the head bolts except for the three over the intake ports and all of the bolts that go into the block on the timing cover, if in doubt put sealer on the threads of any bolt that goes into the block where water might be present.

 

Great engine. Glad you saved it. We had a a 1949 Pilot House Dodge Truck. The engine was amazing. Tuff stuff. They used them in everything including Arc Welders and Generators. The engine was in production into the 60's I believe. Great work. Thanks for all the pics.

 

I think re-tapping the thread hole AND going over with a die on the bolt will do the trick, just for safe measure. I actually spoke to some tech specialist @ Vintage Power Wagons and he said he's never heard of 'Class 3 Taps'. In any event, I'll go with my plan and tap and die ALL bolts and holes.

 

That sucks about Hammertite. They have/had some nice colors available.
About the valve seats:
The metal tubing we used is the same metal my buddy's shop uses when they need to make or replace race seats on their motors. They are hardened and take some lickings! So I was reassured they'd hold up to the little flatty. Heck! if they weren't, the shop that did the angle cut on the seats wouldn't be weary of damaging their cutters, I don't think. I didn't blame them when they asked me to file them as close as I could get them haha.

Also true about the chevy bolts you found for the cylinder head. I've heard that a lot of manufacturers back then would have bolt lengths and sizes almost interchangeable! Still, I'm looking to replace mine with the chrome acorn-type. Know where I could find a supplier?

 

We've got quite a similar project going! I bored mine .60 over, 3/4 race cam, aluminum pistons (through vintage power wagons), milled cylinder head, milled block, original valves reground clean, original rods (that still need to be re-cut to specs), I plan on porting, port matching to gaskets and polishing myself real soon! Crank needs to be reground as well. I just scored a swell looking Tattersfield Dual Intake manifold I'll polish and hope to get some of Langdon's dual exhaust headers later on, as I keep finding junk to sell! hahahha
50 hp?! I would think a little more with that race cam and the bore and compression from decking the cylinder head..
Don't forget to post pictures!

=Adrian=

 

Excellent! No worries then! Gee whiz! That sure is a fine looking motor!!

 

James Curl, Im on the p-15 forum. Same name And I've learned a lot, not just about these motors, but about maintenance on these cars! Lovely site with an endless number of knowledgeable people!
I'll most likely use Locktite to seal my threads. And I'll use it on any bolt that looks funny. Thanks for the tip!

 

Well folks, next up, I want to redo my connecting rods and resize them. Once they're finished, I plan on balancing them and then attaching them to the pistons.
Need to take my crank to get machined. In case it's not perfectly straight, they straighten it out and magnaflux if for some reason there are cracks, too. My buddy's shop send all their cranks to a guy who machines cranks and cams all day long. I'm impressed by his work! Then it's time for bearings. Once crank is installed with rods and pistons, the bottom-end will be done. Then, after I port and polish the intake and exhaust chambers I'll install the cam, valve tappets, springs, retainers, and valves. That's it for the top-end. Then it's assembly and accessories! Easy enough Stay tuned and thanks for letting me share.

=Adrian=

 

Crazy, thanks.

 

Yes, I have recently heard about Class 3 threads, as well. Apparently it is the same diameter and pitch but the threads are pointier and deeper so that there is more meat to grab.

First I heard of this was on the HAMB, regarding the bolts that connect the axle tubes to a Ford banjo center section. Recently, someone said that the MoPar cylinder head bolts were also Class 3.

My gut tells me that you are fine to retap and rethread as you describe. This is a low compression motor, not a rocket ship.

Thanks for responding.

 

I recently ordered a set of Allen-head chrome bolts and chrome AN washers for my flathead from Gardner-Westcott. I was hoping that they would have been here by now so that I could post pictures. I will do so when they arrive.

G-W has pretty nice stuff. I know they sell chrome acorn nuts, but I am not sure if they sell acorn bolts.

 

I know you meant to say this, but you will port and polish before assembling the lower end, yes? If not you must watch out for the chips. Will you be posting some shots of the painted block and head after you clearcoat them? Can't wait to see them!

 

love them flathead sixes- great job!

here's mine http://www.jalopyjournal.com/forum/showthread.php?t=238372

I definitely recommend the crossdrilled crank

 

Hope mine comes along this quickly. Really diggin this thread, lots of good info on what to expect. Any idea of what kinda compression you're up to?

 

Whats the story on the crossdrilled crank Moparsled???

 

Helps keep the bottom end lubed at higher RPMs.

 

You can get the chromed acorn covers at just about any truck stop and the Ford repro sites sell them though they charge about 2x the truckstop ones. think they are all made in China these days.

 

Cool thread. My wife has a 55 Plymouth with the flat six. It dropped a frost plug and cooked the engine. Gunna have to pull it out and do some work to it soon.

 

Man, your really making me miss my Cranbrook!

 

That's swell! Please post pictures when you can! I checked Gardner-Wescott's website. May have to call to ask about my application. I only noticed the regular 'flat-top' bolts on there..

 

Absolutely. During the week I plan on doing the porting, port matching and polishing. I'll post pictures as I go, too. I'm excited! Never done anything like this and I've done my homework, so hopefully all goes well. The more I see this little motor coming together, the more I'm motivated to press on!

 

stand your crank up and get a piece of gas welding rod or something. Poke the wire through the oiling holes in the rod journals. you'll see that the 1/2 journals and 5/6 journals share oil. So the cross drilling is exactly what it sounds like- angle drilling from hole to hole to create more oil flow at the surfaces of the crank. Its a worthwhile modification on these engines, especially given modern highway speeds and distances.

Hudsonator posted on this over on the Inliners board, it's well worth the search. I think it was a thread titled "flathead modifications"

 

Ahhh. Quite sensible...certainly sounds worthwhile, And free Thanks for the tip man..

 

I have heard that the hole from the oil gallery to the cam bearings is the same size as the hole to the mains. And that this results in less that ideal oiling to the mains and rods. In the old days guys would restrict the oil to the cam bearings to direct more to the crank

 

My new G-W head bolts came today!!! Here are some pix.

We have the crusty original head bolt, a generic replacement from VPW, and the G-W chrome socket bolt. Also, a chrome AN washer, also from G-W.

The original bolts are what they are, looks-wise. Even though the VPW replacement would work mechanically, I am not crazy about its appearance. For example, it has a smaller hex that makes it look kind of puny. (VPW does sell NOS bolts; this one shown is one of their generic replacements (less $$$ than the NOS bolts.)

Then, there is the gorgeous (IMHO) chrome hex socket bolt. This, on a chrome washer, is more along the lines of the look I want.

Note the shots of my crusty old head (have not cleaned it yet) with each of the three bolts.

The AN washers are very thin so they do not take away from the overall length. See the shot of the bolt lengths with the washer in place.

I am going to paint my head gloss black, with a glossy dark brown block. Kind of a UPS brown.

I never would have thought of brown, so thanks to StreamlineDeco for that one!

 

Lets continue..
Today, I took a stab at porting and here's what I did..
Took the intake and exhaust manifold gaskets to mock up for port matching..

 

I wanted to taper-out to the inside line I marked. That way it would be a straight through chamber, passed the gasket and lining up with the intake and exhaust manifold, too.


From the top, through the deck view, you can see where I started cleaning..

 

Coming together. I'm trying to get it close to the edge and even all the way around.


Close..


Notice in the picture below, on the left-hand side, the Exhaust chamber. There is a rough cast spot that had to be smoothed out. These were almost in every chamber and I wanted to clean them up..