GrandSportC3

About a week ago, Van Steel finished installing my new 32 spline axles and bearings etc. to go with my new 12-bolt rear (which I installed last week)... They did a awsome job (as always)....

I thought that the car would just be ready to race and perform as I was hoping... but it ended up a little different....
Went last weekend to Gainesville and made 3 passes there... I had several severe issues...
The tranny shifted at about 5000 RPM which is waaaaay too low (needs to shift at 6500). I was told that this can be fixed by changing springs in the tranny that controll the shift point...
The other, more severe problem was that the engine wouldn't REV past 5500 RPM... If felt like I was hitting the REV limiter at 5500 and the engine would hesitate even before hitting 5500 RPM...
Another issue was that the stall speed of the converter seems to be far from the necessary stall speed... The car doesn't launch by far as hard as expected... The stall speed feels more like 3000 RPM than 4500 RPM... My 60' times were only between high 1.70's and 1.90's because of that.. I didn't run the transbrake which should take about .2 - .35 off the 60' time. I was running 6 psi of fuel pressure and thought afterwards that this could've been the problem...
Even with all the problems, I was running in the 11.90 range at only 111 mph with a 7.50's 1/8 mile time (all that with the tranny shifting at 5000 RPM instead of 6500 RPM where I have about 100 HP more... Shortly after passing the 1/8 mile, the RPM stayed at 5500 until the finish line... (that's why the mph was only 111 mph). (With my old setup, I ran 11.67 with 7.50 1/8 mile time and a 1.640 60' time)

Went racing again tonight.. Went to Orlando to get a few passes in.. Jacked up the fuel pressure to 7.5 psi and made a pass... I still had the same problem... and the tranny also shifted into overdrive at 5500 RPM... Ran 11.91 @ 113 mph...
Made another pass and left the shifter in 3. This time the engine would rev up to 6000 RPM but would hesidate during accelerating several times . Got my mph up to 116 mph without improving the ET.. At the end of that pass, the coolant temperature went up to 250 degrees and the engine stalled... A few minutes later, I was able to re-start the engine but it stalled again shortly after... The engine ran ok again after letting it cool down for a while.... I decided not to make any more runs because I had no idea what this issue was and didn't want to cause any damage (if I didn't do damage already)... I'm suspecting either a fuel delivery/carburation problem or a issue with the ignition... Due to the high temperature at the end of the run, I might have run way too lean... .. Maybe I'm sucking air into the fuel lines somehow... I really don't know where to start troubleshooting.. The engine was on the dyno before it was installed and it performed flawless and reved well past 6000 RPM... so I'm pretty sure that it's not an engine internal problem.. However, it seems very difficult to pinpoint the problem...
It's gonna be a long road ahead... I hope that I'll be able to get the setup ready for the Cruise In.. but I'm not so sure about that...

BTW - checked the timing at both track visits and it was right on the money (36 degrees at 3000 RPM)

88'Cubka

Did you break in the motor before making the pass's? Havn't heard from ya in a while so you might have put a few hundred miles on the motor.


David

GrandSportC3

The engine was broken in on the dyno and dyno tuned.. It was ready to race when I received it.. I also drove about 100 miles on the street with the engine already...

GrandSportC3

Forgot to mention.. Also sliced one of my front skinnies in the pit area when loading the car ... Well - I needed a new set of front skinnies anyway...

88'Cubka

Got an air/fuel gauge in cab? Did you monitor it at all?

GrandSportC3

don't have a A/F gauge... Haven't even checked the plugs yet.. Will do that tomorrow... I'm pretty sure that they'll be white or even damaged from detonation ... I just hope that I didn't damage the engine...

88'Cubka

eeeep what kinda fuel you running? 103? (don't remember the specs on the motor, just that it has some pretty good lift hehe)

GrandSportC3

I'm running 110 leaded...

88'Cubka

and i don't really think you could hear the valvetrain while running with that exhaust... damn Hope the motor is okay....

GrandSportC3

The valvetrain sounded ok when I re-started the engine after cooling down... However - I'm concerned about damaging (melting) pistons...

88'Cubka

I'm POSITIVE you would know of you had piston problems. Yank the heads off and take a looksie

88'Cubka

If alum pistons, it takes about 1200º to melt them. So i really do think they would be okay....but i would yank the heads just for the sake of saving the motor incase there is something major.

GrandSportC3

Don't really wanna take off the heads.... I'll drive the '68 tomorrow around town and see if I notice anything unusual... I'll also check the plugs.. If the plugs are ok, the pistons should be ok too... They are forged pistons, so they should be able to take some abuse...

71coupe

What's the total timing set at? Are the secondaries opening all the way?

American Boy

When doing your road test, check for high rpm operation in first gear at part throttle. A fuel delivery problem will show more in second gear or third at full throttle. If you have problem in first gear, it will be most likely a problem from the ignition.

Don't worry too much about damage to your engine, it can take a lot of abuse before breaking.

Hope this help. It's not fun to have problem with a new engine... But in the end, it's all worth it.

Stephan

GrandSportC3

Total timing is at 36 degrees where it should be. Can't really do a road test with high rpm's because the car is too loud and I'll be caling the cops... I usualy keep the car below 3000 rpm around town not to draw too much attention of law enforcement..

Matt Gruber

it's darn fast for a guy without an A/F gauge

Schmucker

Call up CPT or whereever it was that built your transmission and ask them what RPM the governor is set at. The governor only affects WOT shift points, everything under WOT is controlled by the TV cable. A stock Grand National governor will upshift about 5500rpm. A normal car 200-4R governor upshifts around 4000rpm at WOT. If CPT built the transmission to what you wanted, a 6500rpm WOT upshift, then you did not set your TV cable up correctly and the transmission is not reaching WOT and you're damaging your transmission by driving it.

Who did you get your torque converter from? CPT? Did you give them all the specifications for your engine? It is possible that the converter was built too tight or for the wrong engine combination.

GrandSportC3

CPT said that they couldn't accurately set the shift point because they only have a V6 on the dyno and the tranny is going to shift differently if you have a engine which is pulling harder... I set up the TV cable to be fully pulled out at WOT... The converter is also from CPT and was built to my cam specs... If it was built to the cam specs (for 270 degrees @ .050 it has to be at least 4500 RPM but it feels only like 3000 RPM)..

Just checked my plugs and they are all black.. so I might have a ignition problem or a problem with the carb... There's no oil on any of the plugs, so I'm pretty sure that there's no engine internal problem.. Pulled off the valve covers and didn't notice anything wrong with the valvetrain either... . I'm pretty sure that the problem is electrical and/or ignition related...

GrandSportC3

I was surprised that I ran in the 11's with all the problems.. even though the car should be a full second faster without any problems and when running the transbrake... The transbrake alone should give me .3 at launch which usuallly translates to .5 at the 1/4 mile... When tuned in correctly, the car should also be at least additional .5 faster...