There has been a lot of talk lately on cams and converters lately and I'd like to through this out. The last race of this session which is close to me will be taking place this weekend and after that it will be time to pull the motor and trans for some exploration and freshen up. The exploration part I am looking forward to is finding out what is really inside the motor in the Maverick and trying to determine what the heads are. My question is if I stick with the same cam or try something different. A little history of what I have been told the motor is; 408ci 351w Ross pistons @15.1cr.....which is a little hard to believe but have borescoped them and they do have a big dome SCAT rods SCAT steel crank the heads are Twisted Wedge R heads, but the serial number does not correspond with anything that TFS has ever produced. I was told that these heads came from Roush/Yates and was on one of their race cars, so I will try and determine what they are when I take them off. It has Super Victor Jr. MSD 85805 distributor MSD 7AL 3 box Dawson long tube headers made for the car CSR electric water pump Carb Shop 850 that I was told is worked on to flow 1020cfm???? Last but not least is the cam, I have the cam card which is; http://www.crower.com/index.php/search-results/ It has a 9" with spool and I assume 4:56 gears The transmission is a Powerglide w/TB and was built by Mike's in SoCal with a 4500 stall converter. So, you guys with stroked 351w's.................what do you think about the cam choice...................understanding I haven't torn the motor apart yet. OK, the car currently weighs 3125 without me............add another 200lbs and it goes up just a little. The best time with it currently is 9.8 @133 with a 1.410 RT. It does have 31x13 MT's in the rear. This year I have only taken the motor to 7000rpm once and most of the time I have been short shifting at 6500/6700rmp. Also keeping in mind that the car was an old B/SM car back in the late 70's and early 80's and I don't want to change too much on the car except go to disc brakes in the front................yes, it still has the drums which makes it a pain to stop on short strips. Assuming I can get the chassis cert'd for sub 10sec times I want to get my comp license next year and start pushing the car a little harder once I know exactly what the motor can handle.
How about getting a bit more weight off. When I hit the scales at the track they read just over 2600 pounds without me in it. I have a 6 point in mine. Not sure how much more your bars weigh than mine, but it shouldn't be that much.
Don, When the car was built it was tubbed............and because of the B/SM rules they had to use steel, not aluminum. The car right now is pretty close to 50/50 with about 100lbs of lead in the rear crossmember that I doubt anyone except me or the original owner knows. The inside if fully carpeted as it was back when it was built..................I guess I can take that out and probably save 30/40lbs, the windows are fixed in place with no rolldown hardware, no wiper motor or heater and I think the cage is probably mild steel. Right now the car is pretty quite inside probably because of the carpet. So.....................I am sure taking the front drums off will save a little weight but how much...................not sure.
When I clicked the crower cam link it came up with a 4.0 V6 camshaft card? Without knowing the head flow characteristics, it's really a "crap shoot" (so to speak) as far as cams. With that much compression, it should probably be in the neighborhood of 268-275 duration (at .050). About the brakes. Discs are slightly heavier than drums are. How about Aerospace or Wilwood? I wonder if one of them makes a kit to bolt onto the spindles. Mine is mustang 2 front so it was a bolt-on deal. Between front brakes, rear brakes, and the aluminum 9" center section, the car lost 149 lbs and picked up .15 in the 1/8. Stops better too.
MavMan, Really strange because I copied it from the Crower webpage. Anyway, the cam is an E-20104, Advertised Cam Specs; Intake Duration is 307 Lift is .704 Clearance Hot is .026 Exhaust " 311 Lift is .704 " " is .028 Specs are with 1.6 rocker arms of which are on the motor Specs @ .050 lift are; Intake Opens @ 33 BTDC Intake Closes @ 61 ABDC Exhaust Opens @ 71 BBDC Exhaust Closes @ 27 ATDC Lobe Seperation is 108 Duration and Lift @ .050 is; Intake @ 274 Exhaust @ 277 Lobe Lift @ .440 for both exhaust and intake The one thing I really need to know is that if the motor really has this much compression. Looking at the type of plugs and how they burn I just can't believe the 15.1 although the guy that put the motor together did at one time run Alcohol.................don't know. When I get the motor apart I guess I'll find out. When we used the boreascope and looked at the tops of the pistons they looked like the motor was running fat, but the plugs suggest otherwise. If the motor does have that kind of compression I think I'll bring it down a little............we will see. Wilwood did say they make a kit for the spindles but I don't want to have to buy new front wheels..................the Wilwood calipers are a little on the fat side. The other thing I want to change is the brake master cylinder, I have a Ford Ranger unit that is smaller and then I can run some better valve covers...............ie Bigger. Thanks for the advice..............when I get it torn down I will post some pictures.
with that camshaft intake closing @ 61 ABDC, it should crank around 270 psi on a compression gauge. That is of course at sea level (14.8 psi air pressure) and with 6.250 rods at a static compression ratio of 15:1...which is entirely believeable because with the longer stroke, it's super easy to get lots of compression with even a small dome. My 438 is close to 16:1 (15.7 actually). You could get out a compression gauge & pump it. If it pumps 260-270 psi, then yes it would be around 15:1. On mine I HAD to advance the cam 4 degrees. Exhaust valve would have hit the piston at -4 and that's really the way I wanted it to be installed (4 retarded)-just wouldn't work out that way. It was only about .030" exh valve to piston clearance when the cam was installed at zero. .070 now which is fine. My cam is similar just with a hair more duration. Good torquey camshaft and consistent on methanol but IMO, it just doesn't perform as I thought it should-especially considering methanol + nearly 16:1 compression ratio (12:1+ dynamic). I do know that it doesn't like a lot of timing as I had mentioned. More than 34 and it slows down considerably. Would have thought that with that much compression and the domes, I could have gotten away with 36. Actually I did have it at 38 and it was really responsive but the box pulled 4 deg by 4000 RPM (38 - 4 = 34)...and it worked GREAT that way but the timing was locked out and the starter saver wasn't doing a very good job (destroyed a flexplate and 2 starters....) so I modded the distributor to be "all in" by 1000 RPM (34°) and crank over at 14°. Even then once in a while while cranking hot with gasoline it will try to kick back-just not nearly as severe. Your cam looks nice. I'd guess a peak around 7200 (shift probably around 74) and a peak torque around 5500-5700. I think it could use a bit more converter stall speed but 4500 ain't bad. Mine is 5900 footbrake (datalogged) and on the TB chip out it's 6090. Works well. CCX stator 9.5" spragless. My other converter actually probably has another tenth in it. 8" C stator sprag 150+ vane angle. I tried it out but the builder missed the stall speed. 6400 is just too much and I drive through the converter BUT the 60' time was quite a bit better (1.29 vs the normal 1.34) so it does have potential. But I bracket race a lot and the spragless is a good consistent converter so it's stayed in. It's been a best 1.262 60' and 5.83/119-but that was some good air (DA 800'). Just a few random thoughts...perhaps there might be some good in them?
MavMan, Thanks for the reply, I appreciate it. When I first bought the car it had around 230 pretty close to sea level but the motor put together by CHP in 1999. Unfortunately I have no idea who the owner was that had CHP build the motor.............so they have no records. I know the cam was specially ground by Crower in 99 and sent to CHP, but no way to track a name either way. So, when I pull the motor apart I should have a better idea of what I have and certainly the pistons.............which are supposed to be Ross......and the TF heads are a big question mark. When I get the trans out I will have a better idea of what the converter really is. When I first got the car I tried to foot brake it at around 2500, then tried to flash it and never really had any 60' times better than 1.6. I used the trans brake and brought it to the rev limiter..........which is 5000......... and you could really feel the converter shake, and that was my best 60' of 1.41 The one thing about this motor is from about the 300' mark it just pulls like crazy and the front end is still in the air when I go through the traps at 6500rpm................this motor pulls extremely hard and it has been fun to run people down. Personally I would rather run someone down than have them run me down...............IMHO I am pretty sure it will go back to Mike's transmission for a freshen up.
Well..................since I haven't had any takers that want to help me pull the engine and trans........................I guess it's up to me to go it alone. I will start this weekend........................still time if anyone around Redding wants to come over and help/supervise..............cold beer or ??? available. John
Yes, I would rather be at the track today also.....................hey, its only a little over 14 ours away.................and I'd put you up in the "Don Graham" Suite. Send pictures and times...........................
Unfortunately in the first round last night the car started drifting toward the right wall. I corrected it and the rear started fishtailing. I was dialed a 12.45. My opponent was an 11.16. She said she saw my car almost sideways. I got out of it right after that and went back to the pits to clean my shorts.
