XXO/BVGC '38 Chevy Coupe Build

[38flattie]

Thanks Tom!

I talked to Jimmy Stevens, who drove with/for McCain & Houtz. He said the aluminum works,but not as good as copper. He said he didn't have o-rings at the time, though.

He thought that instead of using the rubber coated Flatout gaskets, we should burn the coating off while annealing the gaskets.

So, the plan is to make and etch the aluminum gaskets, anneal the copper gaskets, and try them both on the dyno.

[38flattie]

What if we quit trying to get the gasket to crush into the receiver groove? We enlarge the gasket cylinder opening, until it is just to the outer edge of the receiver groove, and have the o-ring go directly into the groove. We could use copper wire, and that would become our 'fire ring'.
 
The only remaing issue at that point is sealing water. We could used acid etched mild steel, aluminum, or copper, and seal with spray on Hylomar.
 
What do you guys think?

[Dynoroom]

Some of the racing Boss 429 Fords (among others) ran a "dry deck" block, no head gasket. Just sealing rings around the bores and o-rings around the water jackets. (top photo)

I also took a VQ35 Nissan that I turbocharged and used sealing rings around the bores with a corresponding receiver groove in the head. The gasket was used to seal coolant & oil only. (next 3 photos)

Then again, the old Offys never used a head gasket or any type of sealing rings at all.....    

[ronnieroadster]

  When "O" ringing my ARDUN block I did not include a receiver ring in the head I found the deck "O" ring which is a .041 stainless upon torquing made a perfect locating ring in the dead soft copper head gasket that I make. The copper sealed perfectly against the head with the additional pressure produced from the "O" ring pushing from below. The narrow width deck just above the cylinder on the flathead Ford block shows no sign of leaking cylinder pressure into the area of the where the valves were once located. While this application is only on my street motor I still push 10 pounds of boost when I feel the need to play. Just saying  in my opinion the receiver grove is not needed. Even with the 24 head bolts holes  I know on the Ford flathead block the weak point for sealing would be in the location of the lone bolt hole between the end cylinders.
     But not having any experience with the Flatcad block is there a lack of clamping force you are trying to help with by including the receiver grove? 

[Rex Schimmer]

Mike,
The sealing ring that you show with the Nissan head, is it a hollow ring with gas inside or does it have a grove that allows combustion gas to get into it to expand it to make the seal. I once was 1/2 owner of a BMW 320 that was raced in IMSA and it had the 2 liter turbo motor, well we "blowed her up"! one time on Drakes dyno so I got to see how they sealed the cylinder and they used a Vee shaped ring that fit into a bored relief in the cylinder, similar to the Nissan. The open part of the V faced the combustion area so the combustion pressure helped energize the ring to force itself against the cylinder and the head. Also the ring stood a few thou proud of the top of the deck so when you put the head on it compressed the V and initiated the seal. There is a name for this type of seal ring which Stu told me but it has completely slipped my mind. (Age strikes again!)


Nice try on the OFFY not having a head gasket!!! That was because the head and the block were a single casting! Also probably why they would take 50-60 lbs of blower boost in qualifying trim.

Rex

[Dynoroom]

Cooper seals was the original name on the sealing rings we used in the 60's & 70's. These were filled with nitrogen and reusable. I've also used the type that were "wound" and used compression gases to load them to the head/block seal.

Here's a couple more pictures of the current sealing rings in the Nissan...

Oh, and that Offy head gasket issue...... I knew you'd get it!   

[Peter Jack]

Nice try on the OFFY not having a head gasket!!! That was because the head and the block were a single casting! Also probably why they would take 50-60 lbs of blower boost in qualifying trim.

Rex

Just as a point of interest Rex, we played around at one point and found that by blocking off the line running from the plenum to the blow off valve we could get a reading of 80 pounds on the gauge. They were tough engines with a somewhat weak lubrication system and a bit of a challenge for those doing the valve grinds.

Pete

[DND]

After yrs of using the copper wire I switched to the ' Soft Black Steel Wire ' that held its round shape

The top of the copper wire would get flattened out some, where the soft steel wire would stay round and push into the head gasket better

Plus on a rebuild you did not have to replace the wire like with copper

Just my 2 cents worth

G Don

[38flattie]

Thanks guys!  You’ve given me a lot to think about!

One of the options I’m considering was suggested by Dynoroom 2 years ago, and I failed to follow his suggestion, although it’s obvious now that I should of. He suggested using ordinary sewing thread, like your wife uses to put buttons on your shirt, and put a single loop (with the ends parallel to each other) around each water and oil port. Put them in place with some spray on Hylomar.

The other option I’m considering, although not as much as Dynoroom’s suggestion, is stacking two copper head gaskets, and In between, milling receiver grooves for a wire coincident with the path of the block O-rings. We could adjust the loading by way of the wire diameter.



We’re still working to get our aero better, but I’m very encouraged with our progress so far! Using Sumner’s worksheet, http://purplesagetradingpost.com/sum...20A%20Lakester ,and my fastest run of 189 MPH, I would estimate between a .4 and .45.

So, my HP needs look something like this:

CD                            .4             .45             .5

RWHP for 189 MPH       482           535           587

RWHP for 201 MPH       571           635           698



This, of course, assumes my CD estimates are close!

HP Needed for a Specific Speed:
= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =

Input Rolling Resistance ======> .024 <== (Note:
Input Car Weight =============> 5000
Input Frontal Area in Sq. Ft. ====> 24.00
Input Cd For Car Body Only====> 0.45
Input Velocity in MPH =========> 201

Body Drag Force = 1064

HP for Rolling Resistance = 37 HP
HP Needed for Car Body = 598 HP
HP For 4 Tires/wheels = HP

For this Speed = 201 MPH

Total RWHP Needed is = 635 HP

So, what's the point? The point is, 200 MPH becomes far more achievable when one looks at the HP needed! If we can lower our CD, to under a .4, it will only get better and better!

[SPARKY]

how much have you whittled off the requirement with your aero efforts?   

[38flattie]

Sparky, intially we ran both classes open wheeled. I believe we went from about a .55 CD, to between a .4-.45. Our goal is to get under .4, as close to .35 as possible.

We have some aero engineers from University of California, Merced, looking at the car on their computers, to try and maximize our efforts.


       
Input Rolling Resistance ======> .024 <== (Note:  I'd use .015 for speeds of 0-150, .024 for 150-250, .039 over 250 mph)
Input Car Weight =============> 4600       
Input Frontal Area in Sq. Ft. ====>  24.00  (NOTE : For a Car or Streamliner make Inputs below here zero)
Input Cd For Car Body Only====>  0.55       
Input Velocity in MPH =========>  163  Input Front Tire Cd ====>  0.00   
   Input Front Tire Dia. ====>  24   
Body Drag Force =  855  Input Front Tire Width ===> 5   
   One Front Tire's Frontal Area =  0.833 Sq. Ft.   
HP for Rolling Resistance =  30 HP HP Needed For One Front Tire =   HP   
HP Needed for Car Body =  390 HP     
HP For 4 Tires/wheels =   HP     
       
For this Speed =  163 MPH     
       
Total RWHP Needed is =  420 HP

[Geo]

Like the new paint! 

I don't remember.    Did you get a hp reading from the engine build / tune?

If so, how does it compair to the speed you ran and soes this confirm the numbers calculated from the spreadsheet?

Geo

[Sumner]

Like the new paint! 

I don't remember.    Did you get a hp reading from the engine build / tune?

If so, how does it compair to the speed you ran and soes this confirm the numbers calculated from the spreadsheet?

Geo

I think he put the HP numbers in and then played with the Cd till the mph matched.  So he is trying to back into the Cd number for the car via the known HP and Speed.  With that know he can figure out what the new Cd has to be or HP has to be to run the 201.  I think his .40 to .45 are probably close.  I'm not sure if there is enough that can be changed though to get down to .35.  I am beginning to believe with the 189 run that 200 might be there in the right conditions  .

I was trying to help John (who did the body work) figure out how to improve the front last spring and wanted to see the lower part of the front in the tire/fender area go further out front and be more rounded back into the fender tire area with a smoother transition into the sides.  I guess that was not possible with the piece of fiberglass that they found to work with for that area.  There is no doubt though that what John did sure helped.

[38flattie]

Sumner is correct- I took known values, then 'backed into my CD. It's only a best guesstimate, but it's more than I started with. He is also correct in the fact that what John K. did helped us immensely!

Sum, your probably right about it being tough to get to a .35 CD, but we still have some things we can do, if the computer backs up our theory.

Change our exhaust exit, cover/bring the windows out flush with the body, mount our spoiler lower (suggested by Blue), and possibly make the front end mods you suggest.

We'll go in this year with a top tune from the start, where last year we were 'sneaking up on it. Add the extra HP to the mods we'll do this winter, and I'm confident we have a pretty good chance!

As you know, these numbers are meaningless, unless we can prove them on the salt! What they do tell me, though, is the HP needs I once thought might be near impossible, are probable!

Of course, all things are probable when one is bench racing-the salt will tell the tale!

[Roseville Carl]

Yea but isn't it neat to be able to bench race with all the great mathmatical formulas available now, gives ya some hope that what you are thinking just might work. ......................