Performance Q&A Questions - Performance Q&A

Kevin McClelland Feb 1, 2009 0 Comment(s)
0902chp_01_z Performance_qa_questions Hand_drawn_carb 2/2

Keep Track Of Your Washers!
I really enjoy when you guys come up to me at events and comment on the topics I've written about over the years. What I find very surprising is that when I've written about making a mistake, like hurting an engine on the dyno or installing the upper control arms backwards on my wagon, it seems many of you guys can't believe I would write about it. Well, none of us are perfect.

So here I go again. If this keeps one of you from making a similar mistake, I'll take one for the team. About a month ago, Daniel and I were at a Summit ET Points race at Infineon Raceway (big surprise). During Daniel's final time trial, the engine bogged at the hit of the throttle. It was a slight bog and really didn't affect the run that much except for his reaction time. To correct this, I have from time to time run various sizes of stainless safety wire in the idle air bleeds to richen the transfer circuit of the carburetor. If I had replaceable air bleeds, naturally, I would just change their size. When I do this, I capture the wire between two flat washers under a Nylock nut on the air cleaner stud. This works very well to retain the wire for testing and semipermanent running. I knew I didn't have any wire in the bleeds when the engine bogged this time. I had run down the wire I needed and went to remove the air cleaner. The wing nut jammed on the carb stud and pulled the air cleaner stud out of the carb, even though I was using a jamb nut to secure it. After I got the lid off, I immediately turned my attention to the wing nut, trying to get it off the stud. That was my first mistake. Next, I installed the wire and noticed that I needed a washer to capture the wire properly. After rounding one up, I installed the stud, jamb nut, and washer and tested the stall in the pits. Everything sounded and looked good, so Daniel was off for first round.

By now I think you all know what's coming next. Daniel was at the head of the lanes and was next to pull into the water. I was off to the starting line to watch his race, and there was no Daniel. I turned around and there he was, pushing the car away. I ran back to the car. He said the engine was running funny, like it was loaded up, and he gave the engine a rev. Well, the rev opened the carb blades enough to let the washers through the carb and down into the No. 6 and No. 7 cylinders! As soon as he said that, the engine started knocking, and he shut it off. I knew what I had done, and I was sick to my stomach.

I'm far from proud to share these escapades with you guys, but again, if it saves you dollars and time, it's worth it to me. All I know is that I'll never run washers under the air cleaner carb stud again. I'm putting the engine back together this weekend with new pistons and rings. Luckily the washers stayed flat and never turned on end, otherwise it would have killed the cylinder heads and really hurt my wallet. My pride is already beyond repair.

Rock And Roll
I have a '55 Chevy two-door hardtop. I recently purchased a 12-bolt Moser rearend and installed it with a triangulated four-link setup from Air Ride with coilover shocks. When the old rearend was still in with the leaf springs, I had the same Budnik 17x10 rims with BFGoodrich KDW 255/45/ZR17 tires as I do now, with plenty of clearance in and out and no rubbing. The problem I'm encountering now is with the four-link. When the rearend articulates up and down, such as when entering driveways, with one wheel high and one low, there is enough lateral movement in the four-link to allow the tires to rub (inner body on one side and inner fender on the other). It's been suggested that I attach a Panhard bar from the frame on one side to the shock mount on the other side. This would require changing the gas tank for added clearance, eliminating the spare tire well, and fabricating mounts for the new Panhard bar. Do you think this would work, or is there another way to fix this? Thanks for your help.
Mike Genovese
San Jose, CA

What you've done to your Tri-5 is a very nice upgrade to the rear suspension and the power capacity of your driveline. The Air Ride triangulated four-link system uses the same geometry that many GM cars have used through the years. They have never used a Panhard bar, and you don't need to either. The triangulated link system locates the rearend by putting the bars into compression and tension from their differing angles. If you had a racing-type four-link with parallel links, you'd need some type of rearend locater, either a diagonal bar between the lower links or a Panhard bar.

The problem you are having is not the lateral movement; it's the free articulation of the rearend that causes your tires to come into contact with your wheelwells from the body roll. The only thing that will reduce this body roll is an antiroll bar on the rear suspension. Air Ride offers a very nice Musclebar front sway bar, but not a rear bar. Check with Hellwig Products for a very nice adjustable 1-inch rear sway-bar kit that mounts under the rearend for improved exhaust clearance. The bar is constructed from 4140 alloy steel and has three attachment points for the sway-bar endlinks to adjust the roll stiffness to suit your driving style. The kit (PN 5822) is supplied with all the hardware and high-durometer Polyurethane bushings.

You'll need to check out the mounting of your four-link and coilovers to see if there will be interference with the bar. Take some measurements and contact Hellwig. If you find that the bar won't get in there, check out Chris Alston's Chassisworks and pick up the universal rear antiroll bar kit, PN 6266. This kit is designed for drag cars to help control high-torque launches and will require fabrication skills to be welded into the chassis.





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