Technical Cadillac Flathead Chronicles - Tell Us How You Are Doing.

Way to go Randy! Now you are officially the ONLY FlatCAD guy that I know that has trophies in two different FlatCAD powered cars -- ours at Bonneville and Medusa for the 1/8 mile. She's quite the Snake Headed****** now isn't she! LOL

Will give you a call to catch up - has been FAR too long my friend.

 

Yeah dale she’s not really an 1/8 mile car cause that’s about where she really starts pullin hard can’t wait to get to a 1/4 mile track to see what she will run

 

Makes sense, given the stroke and weight of the lower-end, takes awhile to get it spun up! LOL

 

Hey wrenchbender, happy to see one more FlatCad in a dragster race!
Congratulations for the 8.501 and first place!!

2 weeks ago I race 9.732 at 1/8 mile, but engine runs not optimal. Lot of issues with carb or ignition.
At last I find out that sparkplugs misfire. I make all sparkplugs new in spring and they work fine on dyna testing.
On any time one or two begin to misfire, but I do not realize that sparkplugs can make bad engine run, because they where new. After I take my old sparkplugs -> the engine runs most better.
I think the Champion J12YC are no longer good for my performance engine with 260 grind cam, 2 carb Burrell intake and Pertronix ignition.
Which sparkplugs are you using? Is the Champion H10 better?

 

I'm not sure of the reach of the threads on the original cast iron FlatCAD heads. You need to measure the thread depth to determine which plug class you need to run. You don't want plug threads hanging down into the combustion chamber and you don't want too short of plugs with threads exposed in the heads.

If Randy sees this, he'll know what plug length to run - as he's running stock heads.

One recommendation is to NOT run Champion plugs. I've had huge issues with them fouling and not running once they've been fouled. On our Bonniville FlatCAD engine, I had some good "discussions" about my issues with Champion plugs (nobody believed me). That was until I was the last guy to show up at El Mirage for a race - by the time I arrived everybody was all "hang dog" - as they had the car out of the trailer and had tried to warm it up. They were saying the ignition was all screwed up, that the car tried to start and then wouldn't start, was only firing on a couple cylinders, etc, etc, etc.. I asked "what plugs do you have in it?". The answer was Champion - I told them I was going to take those back out and go back to NGKs. They all thought I was smoking the crack pipe - saying I was nuts; it definitely wasn't the plugs - had to be the magneto.

Anyway, I put the NGKs in the engine - she fired right up. Needless to say, we converted a few folks into NGK believers. LOL

If you can get me the thread length for the correct plug, I can tell you what plugs to run in NGK,

Best of luck!
B&S

 

Thanks B&S!
I believe you and I am complete close to you regarding experience with the Champion.
Maybe they work fine with nearly stock engine, maybe in the past they have had better quality.
May first intention was that the carbs have wrong function.
Regarding this, I write 2 day`s with carbking and do any testing.
Than change ignition coil, check ignition cable and so on...
I would not believe that Champion sparkplugs bring the bad engine performance.
But thats the fact!!
The Champion has 14mm thread diameter and I think 11.2mm thread reach/length.
The NGK B6L 3212 is the right alternativ sparkplug.
I know this since longer time, but has anyone a tip for a more "performance" or "stronger" sparkplug than the NGK B6L?
Any experience with NGK B6L??

Thanks Dirk

 

I run NGK B6L in my Ford Flathead - with older Navarro heads. It is a 7/16" reach plug. Do your heads require a 7/16" reach plug? You have to know the thread LENGTH of the head - before I can tell you what to use.

 

Right now I was checking the thread length in Kevins Cyclone heads.
Why I am so stupid, have not checked before?
At first:
What I know -> Champion H10 is 7/16" thread length like NGK B6L also.
Champion J12YC has shorter thread length around 0.354".
The thread length I have in the Cyclone heads is around 0.64" - 0.65"!!
What means the ignition spark is inside the thread hole, whats ineffective.
Regarding the longer thread length, I think there are much more possibility`s for spark plugs now...

 

There aren't many 5/8" reach plugs - what you should do is run 3/4" reach plugs (there is a ton of them available) - then use solid copper gaskets underneath them. "Tune" the installed height to get to exactly what you need. You can purchase solid copper plug gaskets in "kits" - with a variety of thicknesses. They're used in many racing engines to "index" the plug electrodes. Always use a slight bit on anti-seize with aluminum heads - so you don't run the risk of ruining the threads.

I'd look at: NGK B6ES-11

These are 3/4" reach plugs - the same '6' heat range.

 

Sounds very good!
Thanks for the nice explanation!

 

I use r43s ac plugs i am currently running the stock points ignition as I am waiting on a transformer for my magneto I may have to change them once I get the mag in it but at this time I’m using the ac plugs I also drilled and tapped the cylinder heads to accept those plugs I can’t remember the exact thread size I know it’s the standard plug thread the original plugs had a real small end on them and were very hard to find so I drilled and tapped the head I wouldn’t use a champion plug in anything (including my lawn mower) but a stock early mopar for some reason the stock mopar ignition likes a champion but no other car I’ve ever worked on will I use a champion plug in it my. Afx car i use ngk plugs in it but it’s a whole different animal

 

Thanks Randy - appreciate the info. Give me a call anytime today and we can discuss your mag.

 

Finally,
if you use Cyclone Heads from Kevin this can help:
(I write all in zoll + metric)
After any more measurement I find out that thread length from heads is 0,59" = 15mm.
The clearance between open valve and contact area from spark plug is 0,905" = 23mm.
Thanks B&S I find 3/4" spark plugs and I find NGK Iridium BPR6EIX!!
Like B&S say, I find solid copper gasket with 0,118" = 3mm thickness.
This all together works fine, that spark plug use full thread length from head and is not longer than needed.
Here are the pictures:

 

UPDATE!!
After one more 1/8 mile race and any more experience -> the Caddy Flathead is not running good with the Clay Smith 260 cam. The spark plugs NGK BPR6EIX will not work after a full throttle drive from a half mile.
The first 1-2 from engine left/right side are full black and will not fire up longer.
To rich, to much gas with the race cam I think.
Today I check "colder" sparks BPR8EIX and its only little better. The sparks a black but not wet after short running.
Tomorrow I take off the both carter 581s from military tank and take 2x carter 722s, maybe with little step smaler main jets. Also I think the stock valve springs are also bad for use with the race cam.
Today one valve kick a little to the first spark on left cylinder bank. I think this was on higher rpm...
I have clearance from 0,07874016 " between end of spark to open valve.
Tomorrow I will check with 0,15748031" clearance.
Anybody out there with idea where I can buy stiffer valve springs for the Caddy Flathead?

 

Trying to source a cam and pistons right now. Where are y'all getting them?

 

Engine parts you can buy on Falcon Global or Caddy Daddy, stock cams also. Race cams I do not know. I found my Clay Smith as NOS on ebay 2 years ago.

 

Caddy Daddy has a NOS one, I'm guessing that's better than the Chinese ones?

What pistons do you run? I had someone telling me to get forged but I'm not sure I want to spend $1500 on them.

 

Can not say which manufacturer makes the pistons. The engine overhaul was done in a old machine shop in Texas back in 2014. They buy the engine kit from a company in Dallas Texas. Maybe any other can give you better tip, sorry.

 

Thanks. I have the block at a machine shop now in Ft Worth (I live near Dallas) and ordered a few parts from Terrill Machine. He seems to have the best prices but I don't want to skimp with the cam and pistons.

I love seeing that engine in your truck. I can't wait to be running that same mill!

 

Nice to hear you are from Dallas area. The old man who built my engine was Nolan Wampler. He makes a very good job! Company Total Engines from Dallas would not overhaul the Caddy Flathead back in 2014, but then I found Nolan with lot of help from a friendly old man from Lubbock. From this guy I was buying the 34` Ford rolling chassi.
I hope the Flat Caddy Guys from this Forum will answer my and yours question in the next days...

 

You have a picture from your car? Please post!

 

My block is at the machine shop and about ready for reassembly. I asked them to build the bottom end for me as I've never done it before. Everything has been going smoothly until now that I have to order pistons. I was going to get Racetec to send me some forged ones but they need to know the rod length and stroke. My guy told me just to send them an old piston and they could measure it but they won't do it that way. I wouldn't think it would be hard for a machine shop to provide those measurements but it's like pulling teeth to get him to do it.

Ross said they could take an old one and make me a set but that would cost me twice as much and I don't really need top of the line stuff, I just don't want Chinese pistons.

Looking for some direction

 

What the piston guys should want is the compression height of the piston --- which is from the center of the piston pin to the top edge of the piston. This tells them where the pin needs to go. Also, they should want to know the pin diameter, where the ring pack goes, ring sizes, etc.. The best way to do it is to provide them with a drawing of exactly what you need. If they read the drawing incorrectly and make the pistons wrong, then the issue is on them.

Also, what is super important is to know exactly what ring package you're going to run before you bore the block and order the pistons. I prefer to run metric rings in my engines these days - much better ring choices and a lot less drag than the old rings that came with these engines. I always determine which rings I can get for which bore size - then I discuss it with the ring manufacturer and then order the pistons.

We recently had new pistons made by Diamond for the FlatCad - which are custom. I supplied them an exact drawing in SolidWorks and they made the first set wrong. They had to "eat that set" and make me another set. They also sent the wrong set of rings - so they had to eat that too. I'm sure they made no money on this set of pistons/rings!

They were not cheap - about $200 each . . . so not a "budget" build. These are special pop-ups, so not your normal FlatCad piston. The beveled edge is something that I do afterwards (by hand) - to help flame travel over the pop-up.

 

I've been checking out your build, amazing stuff and way out of my league.

It's already bored 20 over with one cylinder sleeved.

Shouldn't an old piston give them the pin to top measurement they need? I'm using the same crank and rods so that should be the same, minus what they removed to deck the block right?

 

Yes - one would think they would be fine with that, but they know what they want! LOL. If the block was decked, then you can measure the compression height of the piston and decrease it by the deck amount. The RIGHT way to determine the compression height is with the crank in the block and a rod on each bank (with a pin in it), then mic the distance to the deck and do the math. That is how I always do it. The machine shop would have to do this to get you the right number.

Then validate it with a piston in your hand and the crude math****ociated with how much they decked the block. Remember, compression height is from the center of the pin to the top edge of the piston. Note, if they decked the block properly, they probably used a different measurement on one side versus the other. I've never seen a vintage block where it was dead nuts side to side.

 

It is hard to imagine that the cam is the issue - unless it was just plain ground incorrectly. It sounds to me like maybe you have a fuel distribution issue or maybe more likely an ignition issue. I've never fowled an NGK plug - and I just run their regular non-resister race type plugs. A #6 heat NGK range should be fine for what you're doing. If it were mine, I'd sure like to put a really good ignition on it and see if that changes things.

Keep in mind - I have no idea what you've been doing for an ignition! LOL I tend to run magnetos or MSD ignitions, so I have more than enough spark energy for all my race (or street) stuff.

 

Maybe I need a new machine shop.

 

I ran a stock distributor in my caddy at first while I waited on a coil for my magneto and after I put th mag in it the Ol caddy woke up not by a small amount either it was like a new engine the old ignition had all new parts in it but it just never ran real well. A good ignition should be top of the list

 

Good to hear Randy! Is that the mag that I gave you that I had FIE build? It should be pretty hot and will even fire alky. Hope all is well with you!

 

Is there a way to clean the inside of the valve covers and breather? They weigh a ton because of all of the sludge in there.

I like the nice aluminum ones some of y'all have but I guess they aren't available anymore.