XXO/BVGC '38 Chevy Coupe Build

[Roseville Carl]

Great goin guys for all the hard work this year!!!

[BoredAndStroked]

Thanks Carl . . . seems all of us fellow 'flathead gangs' are having some fun now aren't we!   We have an amazing community of family, friends and fans - we're very fortunate to have met all of you and to have the chance to make and share some great experiences!   In the end, life is about creating memories . . . and we're doing everything we can to make some good ones.

I'm tearing the engine apart this weekend . . . I hope that all the 'surprises' are good ones!   I'll post pictures when I have them . . .

B&S

[BoredAndStroked]

Picked up a set of race car corner scales – from my circle track friends.   

Here is the setup:

1.   Radiator Tank – Filled about 1” above pressure caps:  Water circulated through the engine
2.   Intercooler Tank – filled to 5” below the top:  Water circulated through the intercooler
3.   Oil:  Running levels (will measure later).
4.   Rear Weight Added (like the lead):  325 pounds
5.   Fuel Tank:  ½ full
6.   No driver
 
There are two sets of weights - one without and one with the driver.

The second set of images/numbers are with a grossly over-developed, muscular and athletic driver . . . that would be ME!   I have about
15 – 20  lbs of clothes and gear (figure that was pretty close).  I weight about 210 lbs.

Looks like we have about a 40 front / 60 rear weight bias.   I would not have guessed that we had that much weight in the rear – but we do.   

I’ve been doing a bit of reading – seems that most folks DO NOT like to add weight behind the rear axle – very bad place to have it in a spin situation (acts like a pendulum).   

We probably should move the weight to just ahead of the axle and as down low as possible.   Maybe some thick steel plates?   Anyway, thought I’d send this your way.

Time to start taking things apart!

Would appreciate any opinions/perspectives on our weight bias numbers . . . 

Thanks!

B&S

[38flattie]

Wow, the car weighs about 600 lbs more than I thought!
 
The car is balanced very well though, considering we never had it on scales! Randy and I will bring the total weight to about 5000 lbs for next year. We may look at moving the rear ballast, if I can find some more used lead. I plan on adding some lead filled 'cross members' on both sides of the axle, and may even fill the axle cross member brace- this would move the weight directly over the rear axle.

What do you guys think?

[RichFox]

I don't understand why you want to add weight.

[38flattie]

Rich, we still have wheel spin over 160 mph- we only gained 3 mph between the 1/4 and the 3 mile, but gained 12 mph between the 2 and the 2-1/4.


The other reason is the loooong area under the trunk. These cars like to get light at speed, so we need to address the bellypan some more. Both of the other 37/38 coupes that are running have spun due to this, and at slower speeds than we are running.


Makes me think weight is our friend!

[pops29]

Here is some pics of the flow test chambers for the flatcad being cut on our CNC. Buddy will be having flow bench work done in a few weeks .

[pops29]

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[pops29]

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[BoredAndStroked]

Good stuff Don!  I'm really looking forward to testing some new designs and seeing how flow and compression are influenced.   

Tear Down Update:

We pulled the engine last night and will be taking the long-block apart this evening.   Amy is now an official 'FlatCad Engine Crew' member - she worked with me to pull the engine, pull the tranny\bell-housing\clutch and manned both the impact wrench and air-wrench to remove various nuts and bolts.  Don't put anything with a 'gun handle' in her hand - she'll go to town!   Is always nice to have somebody helping with these projects - and she wants to learn more . . . which is way cool by me.

Attached is the LAST picture of this engine, in the car in it's 2012 state . . . fair-well good friend!   May we see you even stronger on the other side! 

Also, you'll see Amy - working away with me on the engine lift . . . dang, she is cute!

[jl222]

Wow, the car weighs about 600 lbs more than I thought!
 
The car is balanced very well though, considering we never had it on scales! Randy and I will bring the total weight to about 5000 lbs for next year. We may look at moving the rear ballast, if I can find some more used lead. I plan on adding some lead filled 'cross members' on both sides of the axle, and may even fill the axle cross member brace- this would move the weight directly over the rear axle.

What do you guys think?

  Are you allowed a spoiler in your class? It would help on getting light and add downforce without adding weight.

   Formula I cars run 60% [+or - rear weight and go around corners. If you move your weight forward your traction will be less.

                JL222

[38flattie]

Don, That looks great! I can't wait to get out there next week, and get them on the flow bench!


Dale, Amy sure beats those ugly mugs you usually have helping you!


I'm not uncomfortable with our weight, or weight distribution- the car handled like it was on a string, up to 166 mph. My goal is to try and bump the /ALT record into the 180 mph range, and use the runs as a test and tune for the comp coupe class.

We had some wheel slip this year, so I am going to add weight for the altered class. My plan is to add it just in front of the axle, for more weight on the wheels, and a slight shift of the weight towards the front of the car-very slight.

Comp coupe is a different story. We'll take the car to the wind tunnel, and try and address as many issues as we can. I'm hoping some tweaking of the bellypan will help with the lift. We'll get the car as sleek as possible, hopefully get rid of the lift and get some downforce, then start adding/dropping weight as needed.

200 mph won't be easy, but I think it's FAR from impossible!

[38flattie]

I've spent a lot of time this past week exploring transmission options. The main thing everyone of the tranny guys have told me is that I should stay away from overdrive- no surprise, the same thing was said on this board!
 
Currently, I have the pro-shifted Liberty top loader, with 2.78, 1.93, 1.36, 1.0 gearing.

I can get the tranny re-geared and freshened up, for about $700.That would be with 2.32, 1.69, 1.29,1.0 gearing.

I have one other option, and that is changing the gear on the input shaft, and going with the close ratio gears. I could get the ratio down to 2.10, 1.45, 1.14, and 1.0. Add the face plating charge, and I'm looking at about $1500.

With this old, slow turning flathead, it seems to me the closer gears would be desirable.

So here's my question- is it worth $1500 to get the gearing? It will definitely help me stay in the power range I want, but will it make that much difference in 3, 4, or 5 miles?