Motorsports Village

Any suggestions on possible causes or things to check as to why my car slowed??? Here are the details ...

Went racing the week before going to EMC and car was running normal for the weather (5.18-5.19 @ 130.xx)) and in the 3rd round it ran a 5.205@129, 4th round a 5.25@128, 5th round 5.32@125 so I was done. I didn't notice anything unusual as I was driving the car. ... no surging, missing, no strange noises etc.

Times seemed to slow all the way down the track. Times shown below as they, and the problem, progressed. Maybe just a little more loss at top end.




What I've checked so far ...
wheels were not hot after runs ... (not a brake hanging up)
it rolls easy and no noises from rear end
drained engine oil ... looks normal, no metal flakes, cut open filter and looks clean ... no metal at all
fuel pressure ... normal sitting in garage
throttle cable ... nothing loose at either end of cable
plugs ... look normal and the same on all cylinders
valve lash ... all within a couple thou of where I set them
valve springs ... all read about the same seat pressure with on engine tester.
leak down ... all cylinders read 10% or less cold
No problem found in engine so I pulled trans ...
torque converter ... fins look fine, nothing bent or broken inside, bearings/bushings look and feel good. Sprag feels normal rotates by hand in one direction freely and I can't rotate it backward when slid on stator support trying to turn by hand.
Trans ... pulled planetaries, nothing wrong, bearings look fine.

I haven't looked at all the trans, but for the car to slow down that much I expect to find something obvious whether its engine, trans or whatever.

Rick

Did you check the timing to make sure it wasn't moving?
Anything different with the fuel run to run?

_________________
Donee

Have you welded on the car lately, is the ignition ok. just a thought.

Ty

I didn't check the timing but it is a crank trigger and the dist is tight and the pickup is tight. Rotor and cap don't look too bad. It also idled normal. Fuel was all from the same jug which I had used previously and had to use quite a bit to fill to normal level at the beginning of that day. I ran it quite a while to warm that morning.

I haven't done any welding on the car. The ignition "sounded" ok. I didn't hear anything wrong like missing etc. It would be unusual for electronics to go wrong in this manner ... slower each run rather than works ok now then is dead now.

Rick

Rick is this day time or night time racing? Reason I ask is that this time if the year we're gonna have really good air and the later it gets the better it gets and you might be going lean. How was the DA from start to finish and does that difference correlate to the ET and MPH changes?

_________________
Big Boyz Toyz!



Necessity is the plea for every infringement of human freedom. It is the argument of tyrants; it is the creed of slaves.

William Pitt, British Prime-Minister (1759-1806)

Ken,
It was all daytime. Rnd 1 was 12:42PM and rnd 5 was 4:43PM. I forgot my weather station that day so I don't have weather data, but I can tell you my morning TT runs were cooler and ran teens. Rnd 3 or 4 were probably the warmest times. I'm sure the morning was better DA. I've had same jets all year and ran 5.25/5.26 when the DA was ~3500. The DA would have been ~1500 from what I remember. Good Fall air but not great.

The 5.18 to 5.32 ET suggests about 50HP loss and the 130 to 125 mph suggests closer to 75HP down.

Rick

Do you have an air activated starting line controller? If so, how was the bottle pressure?

_________________
Mark Slayton
Rochester, NY
Quick Rod 130C
Super Comp 130C

Don't think he h as air operated anything from past comments on my CO2 problems.

_________________
Big Boyz Toyz!



Necessity is the plea for every infringement of human freedom. It is the argument of tyrants; it is the creed of slaves.

William Pitt, British Prime-Minister (1759-1806)

Ken is right ... nothing air operated.

I looked at both clutch packs and the band and they all look fine. Took trans pan off and no metal pieces or anything unusual. Starting to think the problems not in the tranny like I was convinced it was.

Also had the wife push throttle pedal so I could check carb for full throttle... it's full open.

Checked the dot on the cam gear to make sure the belt hadn't slipped, and trying to find original Jesel indicating position to make sure it hadn't slipped. Just found it and it is still where it was when dyno'd 2 yrs ago.

Anybody ever seen a bearing seizing without metal in the oil and filter? I don't really want to pull the pan cause it's a bitch and I don't have a PB like Ken to do those jobs.

Tomorrow I plan to run some fuel out the lines to see that it pumps enough volume although I would expect something different as far as symptoms if it was a fuel delivery problem.

May put oil back in it and run it to check timing.

Any other ideas??? I'm about out of them.

Rick

Never seen a bearing spin without something showing up in the oil or filter and as maticulous are you were with that engine setup I seriously doubt that there's a bearing problem. That and you're not making that much power considering what you put in that bottom end, ie, it's probably good for 300+ more HP than you are making with it.

Dunno Rick but if it was me and I'd done all that, I do think I'd have it back at the track for a T&T to see if it's still slow. If it keeps on slowing down, sooner or later the problem will manifest itself in the form of some kind of failure. I know that may not be what most would do but as you said, you're running out of options.

As far as pulling the pan goes, it's really not that hard to do on one of these cars since there's not much stuff in the way. I would loan you Pit Bitch but it's kinda costly for him to travel from Lynchburg to you there in Missouri. That and I don't let him do much of anything when the pan is off. He's real good for grunt work and that's about it.

_________________
Big Boyz Toyz!



Necessity is the plea for every infringement of human freedom. It is the argument of tyrants; it is the creed of slaves.

William Pitt, British Prime-Minister (1759-1806)

Got a spare crank trigger pickup to try?

Converter?

_________________
6.11@110 Gas
1.3718 Sixty Foot with the rear wheels Gas

6.07@110 on Alcohol Injection with a 4-link 4-6-12
Best 60' 1.2537 Alcohol Injection 4-29-11
Thru the Mufflers!!

I'm kinda with Jody on a possible convertor problem but I noticed in your 1st post you said it looked ok. Is that a bolt together? It looks like the time between all the incrementals is falling off about the same so it does sound like the power is falling off.

_________________
Chuck Woloch

Chuck's Automotive
Full line Computech dealer
chucksautomotive@yahoo.com

Yes Chuck it is a bolt together converter and as far as I can tell it is ok. I took it apart and the pump and turbine fins are all perfect, bearings are fine and the sprag feels good. I was thinking if it was converter it would be off in 60' more if the sprag is slipping or off at the top only if the sprag is stuck.

If the fuel pump test doesn't find anything I'm thinking I'll start putting it back together and fire it back up to check on the ignition related posibilities. Like checking timing trying a different pickup like jmark mentioned.

Thanks for the ideas... this has been a real head scratcher.

Rick

Were you topping the tank off after every round? Maybe your latest batch of fuel is bad?