Some Thoughts On Slant Geometry

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Slant with "one of" aluminum head
 
Current official slant six records N/A on gas. Just to give you something to shoot for.

Weight of 2000-2349#
Class .......Date.............Driver..............Record..........ET/MPH..........Car……………………Location……………….Weight
Gas Only
A/G......7/16/11.....Mark Etheridge............1/4 Mile ET.....11.436………….’62 Valiant…………Eureka, CA…………….XXXX#
A/G......7/16/11.....Mark Etheridge............1/4 MPH.........115.51MPH…..’62 Valiant………..Eureka, CA……………XXXX#
A/G......10/14/06...Seymour Pederson.......1/8 Mile ET......7.250…………..’62 Valiant…………Piedmont, NC..…XXXX#
A/G......5/8/04.......Dale Rose....................1/8 MPH.........92.632MPH….’80 Arrow…………..Farmington, NC……XXXX#


Weight of 2350 -2699#
Class .......Date.............Driver...............Record.........ET/MPH..........Car…................Location……………….Weight
Gas Only
B/G......4/9/16......Rusty Heisten.............1/4 Mile ET.....11.237……………’61 Lancer.………….Asbury, MO....….2471#
B/G......4/9/16.......Rusty Heisten.............1/4 MPH........117.28MPH........’61 Lancer.………....Asbury, MO..…2471#
B/G.....10/14/06....Seymour Pederson.......1/8 Mile ET......7.333…………..’62 Valiant…………Piedmont, NC…..….XXXX#
B/G.....10/14/06....Seymour Pederson.......1/8 MPH..........91.91MPH…….’62 Valiant…………Piedmont, NC…..….XXXX#
 
My car is in that 2000-2350 Pound range, but those numbers are a lot quicker than I feel I need to go N/A to have a fun little grudge car on the bottle.
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Work on the car this winter, and come to some slant six races, in 2017. Usually have a race at Bristol, and Knoxville dragway in Tn, and Clay City Ky. All not too far from you.

My 66 Valiant was built as a real low budget car. Runs 9.0's in the 1/8 and 14.3's in the 1/4 on motor. Has gone 7.8's in the 1/8 on spray. Bone stock short block.
 
Charrlie_S said:
Work on the car this winter, and come to some slant six races, in 2017. Usually have a race at Bristol, and Knoxville dragway in Tn, and Clay City Ky. All not too far from you.

My 66 Valiant was built as a real low budget car. Runs 9.0's in the 1/8 and 14.3's in the 1/4 on motor. Has gone 7.8's in the 1/8 on spray. Bone stock short block.
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We had planned on making the Clay City race, but the car was too far off from where I wanted it to be. Next year, for sure.
Budget build? If I told you how.much I have invested in this car, you'd call me a liar.
 
You say the timing is locked in at 34*? If your thoughts are correct about the leverage on the crank being too small due to the angle at peak combustion pressure being too near TDC at low RPM's, and that it improves with RPM as the pressure peak occurs later when the piston is further past TDC, then isn't the solution to retard timing at lower RPM's to move the pressure peak later in the stroke? Sounds like you would benefit from unlocking the timing and putting in an aggressive mechanical advance set up.....
 
nm9stheham said:
You say the timing is locked in at 34*? If your thoughts are correct about the leverage on the crank being too small due to the angle at peak combustion pressure being too near TDC at low RPM's, and that it improves with RPM as the pressure peak occurs later when the piston is further past TDC, then isn't the solution to retard timing at lower RPM's to move the pressure peak later in the stroke? Sounds like you would benefit from unlocking the timing and putting in an aggressive mechanical advance set up.....
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I have worked from 28 degrees on up..and I honestly thought that because the chamber/cylinder was so small that not much lead was going to be necessary....but 34 is where it hits the hardest.
All that was with the automatic. Perhaps now that it has a clutch, we can back it off a bit. But, at this point the car needs to be on a track to accurately figure that out.
 
So you are saying that 34* gives the best initial launch? Without measuring accurately, it seems like it would be hard to call... but then again, you do this stuff all the time!
 
nm9stheham said:
Can we just do that anyway without knowing how much it cost? LOL
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Cost? You mean profit. I lost actual count a while ago because of much wheeling and dealing, but I am ahead somewhere between $500 and a grand on this build.
Started with a complete, high trim car that had rotted framerails and floors. Sold off everything but the unibody, and built this from the proceeds and scraps. Total build time so far is 13 months
 
If around 6.5" rod length, the Mitsu 2.6L 4G54 rods are 6.535" with a big end bore of 2.205", big end width of 1.175" and pin of .866" (22 mm), which I think may work with some machining. The crank pins could be turned down offset a bit (.050") with these to help angle and stroke. They will hold up fine to 75 HP per rod all day long. You can put in larger pins; I have some with 23 mm pins. Get the ones from the later Starions/Conquests, not from the K-cars, mini-vans, or trucks. I have put thousands of miles racing on them.

If you want shorter, more looking is needed.
 
nm9stheham said:
If around 6.5" rod length, the Mitsu 2.6L 4G54 rods are 6.535" with a big end bore of 2.205", big end width of 1.175" and pin of .866" (22 mm), which I think may work with some machining. The crank pins could be turned down offset a bit (.050") with these to help angle and stroke. They will hold up fine to 75 HP per rod all day long. You can put in larger pins; I have some with 23 mm pins. Get the ones from the later Starions/Conquests, not from the K-cars, mini-vans, or trucks. I have put thousands of miles racing on them.

If you want shorter, more looking is needed.
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The 5.7 inch 170 rod, on the 198 crank is a bolt together deal with stuff I already have on hand. The 170 block will only need some minor grinding to make it all work.
 
replicaracer43 said:
Very cool project Tony, will be following!
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We post fairly regular updates on our Facebook page, Street&Strip Garage
Couple of videos on there as well.
We are also working on a Slant Bracket car called the SloPar, and a Blown Fuel Hemi B Body called the Hell-vedere.
Everything we do is super low budget and as basic as we can make it
 
nm9stheham said:
So you are saying that 34* gives the best initial launch? Without measuring accurately, it seems like it would be hard to call... but then again, you do this stuff all the time!
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Its not rocket science. At 28 degrees, it would not even squeek the tires anywhere. At 34, it would move about a foot, and then start hazing them.
I held it at 34, because I was not real comfortable going beyond, and I don't want the N/A tune up to be radically different than the Nitrous one.
 
whitepunkonnitro said:
Its not rocket science. At 28 degrees, it would not even squeek the tires anywhere. At 34, it would move about a foot, and then start hazing them.
I held it at 34, because I was not real comfortable going beyond, and I don't want the N/A tune up to be radically different than the Nitrous one.
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Did you check the timing marks, to make sure the damper hasn't slipped? I am questioning this, as I can't believe it would even crank over with that much initial timing, without kicking against the starter. Most N/A slants (key word "MOST") like a lot of initial advance (around 10-15*), and run best at less then 30* total. I will garuntee anything over 25* degrees on nitrous will break parts. My 66 Cuda 170 on nitrous runs between 15 and 20* fixed, depending on how big a shot. It has run a 12.905 at 101.65 mph at 3250 lbs.
 
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Charrlie_S said:
Did you check the timing marks, to make sure the damper hasn't slipped? I am questioning this, as I can't believe it would even crank over with that much initial timing, without kicking against the starter. Most N/A slants (key word "MOST") like a lot of initial advance (around 10-15*), and run best at less then 30* total. I will garuntee anything over 25* degrees on nitrous will break parts. My 66 Cuda 170 on nitrous runs between 15 and 20* fixed, depending on how big a shot. It has run a 12.905 at 101.65 mph at 3250 lbs.
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Now that's impressive! The more I look at the 170, the more I think the little guy is the one to use as a foundation.
As for my car, the damper is indexed dead on at TDC, and has 2 degree notches beginning at 28 and ending at 36.
Yes, at 34 it wants to lightly kick back against the starter if I don't give it at least two healthy pumps before hitting the button.
 
that 61 lancer listed in records at Asbury, Mo is local car from Carthage mo. rumor has it that it has a heavy custom flywheel and $14000 in engine. runs NA. pretty cool. I image the details are top secret!
 
barbee6043 said:
that 61 lancer listed in records at Asbury, Mo is local car from Carthage mo. rumor has it that it has a heavy custom flywheel and $14000 in engine. runs NA. pretty cool. I image the details are top secret!
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We ran against that car, with my 66 Valiant, 1st round on Sat, at Clay City, Ky. last month. It flies, he was dialed 10.99 or 10.98 if I remember correctly. Nice people, and answered any questions I had. Runs an air shifted 5 speed.
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Just some more numbers for you: (Sorry, you got me started! LOL)

The rod/stroke ratio for the 170 rod and 198 crank is 1.567. Your piston speed will peak at just over 6000FPM at 6000 RPM. IIRC, that's getting up into Pro Stock pistons speed territory. (IF they use peak piston velocity as a measure....I am not entirely sure.)

Now if you wanted to push the rod/stroke ratio and forget budget limits, then a Chevy L6 (6.000") rod (SCAT makes them in H-beams BTW) with the 225 crank offset ground for max stroke would push the rod/stroke ratio down to 1.422 and the displacement would move up into the 235-240 range depending on exact boring. Max piston velocity would peak at 7000 FPM at 6000 RPM. F1 engines up into this piston speed range. So I suppose this would be a low RPM engine, but the intake suction would presumably increase substantially. A lot of big stroked motors run road/stoke ratios in this range so it is not virgin territory.
 
nm9stheham said:
Just some more numbers for you: (Sorry, you got me started! LOL)

The rod/stroke ratio for the 170 rod and 198 crank is 1.567. Your piston speed will peak at just over 6000FPM at 6000 RPM. IIRC, that's getting up into Pro Stock pistons speed territory. (IF they use peak piston velocity as a measure....I am not entirely sure.)

Now if you wanted to push the rod/stroke ratio and forget budget limits, then a Chevy L6 (6.000") rod (SCAT makes them in H-beams BTW) with the 225 crank offset ground for max stroke would push the rod/stroke ratio down to 1.422 and the displacement would move up into the 235-240 range depending on exact boring. Max piston velocity would peak at 7000 FPM at 6000 RPM. F1 engines up into this piston speed range. So I suppose this would be a low RPM engine, but the intake suction would presumably increase substantially. A lot of big stroked motors run road/stoke ratios in this range so it is not virgin territory.
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A couple of thoughts on that.
First, I would like to get this engine package as close to square as possible, so adding stroke is the LAST thing I want to do.
Second, its important to me that whatever package I eventually evolve will be based mostly on stock parts. No crazy stuff I need to hunt down or funky machine work. As a bracket car, anything in the 12s will make me happy...in grudge form, I want to be able to spray and lean and spin this thing as hard as I can without giving any thought to it tossing the crank on the ground.
I like junk. Junk is fun, cheap and usually a whole lot stronger than the text books will indicate
 
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