I'm figureing that Racing Q & A is not the most whidly read page on the site. I know I don't read it much, becouse I don't race, so I landed it here under "Other".

The following information I had previously posted over on the “Racing Q & A “ board.

These times were from last spring, letting the transmission shift for its self at 4000 rpm:


[quote]Bad news she had to shift into third gear when shifting automatically way before the finish resulting in a first run of 62.15 mph at 10.752 seconds, and 63.47 mph at 10.730 seconds in the 1/8th.[/quote]

This time was from Oct 2 where I unknowingly left the gear selector in second, and not first. The intent was to manually shift 1-2 at 5000 rpm, and run the balance of the 1/8th in second gear:

[quote]My reaction sucked at a comatose 1.134 sec.
60 foot at 2.408 sec. (unaffected by early 1-2 shift)
330 ft at 6.923 sec. (most likely slowed by premature 1-2 shift)
1/8th at 64.56 mph
1/8th time; 10.673 sec.[/quote]

To put this in chart form:
1. 10.752 sec @ 62.15 mph - calculated 1/4th 16.751 sec
2. 10.730 sec @ 63.47 mph - calculated 1/4th 16.717 sec
3. 10.673 sec @ 64.56 mph - calculated 1/4th 16.630 sec


An update to modifications made to my 225, 67 Dart rag top:

Build:

[quote]Oversized ENDG valves, ported, gasket matched, and shaved 0.075â€￾ cacluated 9.5:1 compression peanut head.
Clifford intake & shorty headers, Holley 390 4V carburetor (60 jets).
Dual exhaust.
Bored over 0.030â€￾ block.
Unknown hot cam that loves 3000 to 5000 rpm.
Up-date on cam
Clifford’s hottest racing cam for 1993 was installed, don’t know the particulars, but measured 0.530â€￾ lift at the top of the push rod.
Orange box, blaster II coil.
904 driven by a 2600 (on paper) stall converter.
3.55:1 8 ¾â€￾ Suregrip, D70/14. [/quote]


[quote]Haven’t weighed the car, but is most likely on the heavy side north of 3100 pounds because of; HD suspension, anti sway bar, sub frame connectors, 8 3/4â€￾ rear, and sound deadening on floor. Nor has it seen a dyno, so I don’t know what the torque, and power curves look like.[/quote]



I don’t have a clue as to what would be an acceptable time/speed for my state of build. I know it isn’t a slug, but it also doesn’t feel as strong as it perhaps should be from what I have been reading here… I do plan to degree the cam soon after I put the car away for the winter, might even pull the engine for an engine compartment freshening up.

Slow, average, lots of room for improvement… Anyone any thoughts?

Bill

_________________
67' Dart GT Convertible; the old Chrysler Corp.
82' LeBaron Convertible; the new Chrysler Corp
07' 300 C AWD; Now by Fiat, the old new Chrysler LLC

Too much cam for the combination and intended use.

What is the cranking compression in PSI?
If you can find the intake valve closing point at .050 lift, we can calculate the DCR to see how far off you are.

You have a good group of parts but one big "mis-match"... swap cams to improve the DCR and move the power lower in the RPM range.
DD

I agree with Doc. Degreeing cam would be the "absolutely necessary gotta do it or we'll kick you off the board" procedure... New cam AND degreeing it is probably in order.

If you have 2500 stall or so, you should run 15s with a well tuned combo like yours.

Lou

_________________
Home of Slant6-powered fun machines since 1988

I’m cogitating….

Got to go cook sup'ah, and than eat the slop...

Back in an hour or so.

Bill

_________________
67' Dart GT Convertible; the old Chrysler Corp.
82' LeBaron Convertible; the new Chrysler Corp
07' 300 C AWD; Now by Fiat, the old new Chrysler LLC

Doc, Compression is 150 psi in # 1, 2, 5, 6. 157psi in #3, and 145 psi # 4. # 4 exhaust had a little upset this summer making a lot of noise for about 20 miles, showed hot around the rocker & rocker shaft, but has been fine since. I’m thinking that valve may have been compromised a bit, and needs to be lapped in again, or replaced.

Lou, I’ll be ordering a cam degree kit and some other crap in a few days as soon as I cash the check from the sale of the old house. Cash flow has been tight since January during the new construction, and several failed sales of the old place. We close tomorrow!!!!, and after a three day rescind period, the fat lady can cash the check.

So what kind of options do I have to get the bits to play together better?

Some thoughts:

I have a 2600 stall converter, V8 rating, that locks up around 2200-2400 rpm. It helped over the standard stall; perhaps not enough head room for this cam.

According to the guy that built this engine many moons ago, he had a 10:1 compression ratio. I’m at 9.5 according to the web calculator I used when I had the head work performed. I’m not adverse to cranking up the compression as long as I can run pump gas to move up the DCR. I have a feeling I can easily get away with more static compression with the present cam. What would be optimal is in the air until I measure this cam.

Shaving the old peanut head another .025â€￾ to get to a total cut of 0.100â€￾ may require custom push rods. I don’t know what new pistons, rods, and any balancing needed would run to get a comprehensive compression increase. Or a different cam tossed into the mix.

The car builder, lets call him Dick for this discussion… raced with a 4.11 rear, and used a 3.55 for the street. I don’t think I want much more than 3.55 for the way I use the car, which is mostly putzing around to car shows, running to the store, and general hacking around when the weather permits. This a top down 90% of the time car.


Dick clamed this car ran a 13.6 second ¼ for a best time. That is a long way from 16.6 seconds…

If I de-cam a bit, will the result be quicker ¼ mile times, or in my case quicker on ramp times? My goal here is to spend as few greenbacks as possible to get this thing running better.

Lets say I spring for a bottom end freshening, new seals, oil passage way mod, perhaps new pistons & rods, a little of the top if needed, and dynamic balancing of the rotating assembly. What kind of money are we talking?

I kind’ah went nuts on this just now. Sorrry.

_________________
67' Dart GT Convertible; the old Chrysler Corp.
82' LeBaron Convertible; the new Chrysler Corp
07' 300 C AWD; Now by Fiat, the old new Chrysler LLC

Bill
I would think your looking at about $2500 for the changes you talked about. This would include Machine Shop fees and the New materials with you doing the work.
Frank

_________________
Scrapple: Because a mind is a terrible thing to waste.
73 Duster - Race Car
66 Dart Wagon - DD
178" FED
82 D150
All Slant powered

13.6 sounds dreamish for that combo. If it were me, I'd get a true 2700-3000 RPM stall converter (for a Slant), degree the cam, and not touch anything else until I had done those. You would pick up drivability and 0.5-1 sec or more with just those two things.

150 psi cranking is about what you want for street duty and 89 octane-ability.

Why bottom end freshen? If not burning oil, then I'd leave it alone. Balancing will not get you much until you are spinning high RPMS, unless you feel a big vibe right now while revving in neutral.

Lou

_________________
Home of Slant6-powered fun machines since 1988

Yikes…

On the “Dollars to Powerâ€￾ scale where efficient use of greenbacks is a bigger number, $2500 is halfway to a (gasp) drop-in 360. Comments at the show; -(dead air)---only glazed eyed look of indifference while sauntering to the next flawless sublime green, or plum crazy car down the line.â€￾

On the “Dollars to Look What the Hell He Did Hereâ€￾ scale, $2500 ain’t that much, I guess, if it runs right. The comments at a show will still be the same; “look a Slant Six, those were tough motors --- I had one, couldn’t kill it. --- Are those headers?â€￾

I guess I need to first evaluate what parts are all ready in the engine, if it was balanced, and go from there.

At a minimum, new crank seals, check crank & rod bearings, and trueness of bores.

The more I ponder this mess of parts I have bolted together, the more a new profile camshaft makes sense for the street car service my ride is used for.

Back to one of my previous ramblings; what kind of power/ torque difference will be gained or lost by changing cams aside from dropping the sweet spot into a more street usable rpm range?

_________________
67' Dart GT Convertible; the old Chrysler Corp.
82' LeBaron Convertible; the new Chrysler Corp
07' 300 C AWD; Now by Fiat, the old new Chrysler LLC

Yep $2500 is a lot to spend for that kind of "Possible" increase. Im with Lou to check what you have and make it work better.
Frank

_________________
Scrapple: Because a mind is a terrible thing to waste.
73 Duster - Race Car
66 Dart Wagon - DD
178" FED
82 D150
All Slant powered

Lou, I have run 87 & 89 octane; no knock and difference in drivability between the two. That tells me my dynamic compression is still low. I wouldn’t mind feeding it 92 octane, if there were a noticeable boost in power from a few changes. This car is a tool box toy, not serious daily transportation.

[quote]If it were me, I'd get a true 2700-3000 RPM stall converter (for a Slant), degree the cam[/quote]

I agree with upping the stall speed if I keep this camshaft. At the time I purchased the 2600 unit, I thought it would be high enough to get to where this engine starts to make torque, and allow sitting in gear idling at a light with out trying to take off. I got this half right…

At that time the engine was not running very strong, the car wouldn’t sit still at a light in gear, the board & I were looking for vacuum leaks not radical camshafts, and the transmission was not shifting properly, those items I have been able to sort through. The converter I have now allows for docile in town running, and calm composed sitting in line at a light, but as you point out misses the torque sweet spot..

[quote]Balancing will not get you much until you are spinning high RPMS, unless you feel a big vibe right now while revving in neutral.[/quote]

As for a vibration, if I were to feel a vibration where in the rpm range would it manifest and how apparent would it be? Not having ever had a slant before, or driven a slant powered car in the last thirty years, (I recall driving a brown mid seventies Duster a few miles when I sold cars back in the day, that was a boat anchor, and thinking I couldn’t live with this pig for 10 seconds…) I have no feel for what level of vibration if any is acceptable. Additionally I don’t know how much I can rev this engine up, before it blows up, and don’t care to discover where that point is by trial & error; an other reason for a lower rpm cam I suppose.

[quote]13.6 sounds dreamish for that combo[/quote]

I agree, and figured he was leaving several “somethingsâ€￾ out of the equation, and I know the engine has been monkeyed with since he built it. I discovered it had a dead stock head, with heavy springs… I think someone cobbled it up for a quick sale.

_________________
67' Dart GT Convertible; the old Chrysler Corp.
82' LeBaron Convertible; the new Chrysler Corp
07' 300 C AWD; Now by Fiat, the old new Chrysler LLC

The 145 to 150 psi cranking is better then I expected so the DCR can't be that far off.

Get yourself a degree wheel, pull the valve cover, lash the intake at .075 (.050 lifter rise) and find the point in degrees (ABDC) where you start to feel the lash, that is where the intake is closed.
This number is needed for the DCR calculation.

Runner the DCR calc using some best guess info on your combo...
50 cc head chamber
.110 neg. deck height gives us a 9.47 static CR.

Using a intake closing value of 65 degrees (race cam) we get a 7.5 DCR
(I target DCR at 8 for street and 8.5 for track)
So I change numbers to a cam with a 45 degree closing point (Erson RV15/.295 RDP) and the DCR goes to 8.5

So from someone who has "been there"... put less cam in this engine and you will likely go "faster" getting the power (torque) into a more useable RPM area. (your 60 ft time will improve a bunch)

If you want to do a test... I will send you a good stock SL6 cam, swap that in and watch the cranking compression shoot-up to 175 to 185 psi and the idle vacuum go to 20 to 22 inches. Touch the throttle and the engine "jumps" off idle and into strong mid-range power. (then runs out at 4000 and will ping if given too much advance or crappy fuel)
DD

Again, I would not touch the bottom end unless it is burning oil. These engines generally had good balance from the factory, unless you want to spin 6000, which you won't. Save your time/effort/$$ for a stall converter and/or cam.

You will be doing quite well if you have a drivable 15 sec Slant that weighs 3400 with you and fuel, and not much more in the motor/car.

Lou

_________________
Home of Slant6-powered fun machines since 1988

Doc,

Numbers, I like numbers.
[quote]The 145 to 150 psi cranking is better then I expected so the DCR can't be that far off.[/quote]

When I first checked compression after head modifications I was disappointed with 150 psi. Than after reading about and understanding dynamic compression ratio, and how over-lap affects compression I took it for as good as it gets with this aggressive cam of mine..

[quote]Get yourself a degree wheel, pull the valve cover, lash the intake at .075 and find the point in degrees (ABDC) where you start to feel the lash, that is where the intake is closed.[/quote]

I’m sending for a degree wheel tomorrow. But, to make sure I understand your instructions I shall reiterate in my own vernacular your instructions.

I’m guessing that I have all ready zeroed the degree wheel at dead top center before measuring intake.

Back off lash to 0.075â€￾ on intake valve. While valve is open, and crank has past bottom dead center, watch for rocker to disengage the valve stem. At that point of disengagement, record reading on degree wheel.

Don’t I have to measure the exhaust event as well?

Do you have a favorite DCR calculator that you use?

I have measurements from when the head work was performed.

Cylinder head volume = 44 cc for all six
Piston is 0.153â€￾ down the hole
I have a Fel-Pro head gasket, and most likely use one of them again.

Thanks for the stock cam try out offer, but coast to coast shipping, winter coming real soon, this car ain’t moving much until next spring, so I’ll take a pass on it. I believe you that with a stock cam the static compression would take a big jump because of less over-lap.

Did I read somewhere that peanut heads have to be removed to pull the lifters?

Do you think with a little less cam, my so called 2600 rpm converter may work well enough so I don’t need to change it?


Is there an other part number for that RV 15 cam you are recomending. I can find its specs.

_________________
67' Dart GT Convertible; the old Chrysler Corp.
82' LeBaron Convertible; the new Chrysler Corp
07' 300 C AWD; Now by Fiat, the old new Chrysler LLC

Yep. Must pull head to replace lifters on a peanut. Grab a steel shim head gasket. Charlie had a couple last time I checked, see if he has any more.

I'll see if I can dig up my cam card. I run Doc's RV15M RDP grind straight up.
3200#, 15.02 quarter and a few cubic inches more than normal. 10.7:1, which is too much.

Your carb is going to need to be set up again with that cam.

CJ

_________________
Part of Tyrde-Browne Racing

CJ,

[quote]Grab a steel shim head gasket. Charlie had a couple last time I checked, see if he has any more.[/quote]

Is that the same as a Fel-Pro gasket with “No Retorqueâ€￾ in red printed on its bottom side, (don’t have a part number handy) that I used last time?

[quote]I'll see if I can dig up my cam card. I run Doc's RV15M RDP grind straight up.
3200#, 15.02 quarter and a few cubic inches more than normal. 10.7:1, which is too much.[/quote]

Low 15’s is getting acceptable. When dose the torque come on with that cam, and when does it drop off.

[quote]Your carb is going to need to be set up again with that cam.[/quote]

I can handle that. It should be a lot easer with better vacuum signal.

Bill

_________________
67' Dart GT Convertible; the old Chrysler Corp.
82' LeBaron Convertible; the new Chrysler Corp
07' 300 C AWD; Now by Fiat, the old new Chrysler LLC