Blowback bar solution?

We're breaking the blowback bars on our fuel altered. Chromoly bars are bolted rigidly to the firewall and frame with clevis ends. A good hard run or any amount of tire shake at all and we end up breaking the tabs off the frame or firewall.

What's your setup? Anyone using heim joints and or bushings of any kind to absorb vibration?

 

Do not tighten the bolts as they pass through the connections -- use a locking nut and just tighten them enough to keep them on --- there's alot of movement going on there and when you tighten it all up you will break something ---

 

blow back tubes

Machine the bolt down and drill for a hairpin this should solve the problem

 

blow back bars

Mine have slots in the ends on the bell housing, can move about 3/8". clevises on the chassis, have pins with a locking bail on both end, never had a failure

 

Had the same problem, broke all kinds of heims. I have a Clevis on the motor plate side and a heim at the can. Use a 3/8 bolt drilled for a hair pin on the can. On the motor plate side with the clevis ....use a 3/8 hole in chassis tab and clevis and a 5/16 bolt drilled for hair pin....I bet it fixes it. Make sure that nothing is in a bind and do not use nuts on either side.
Darren

 

Here is the instructions from McKinney for his blow back tubes:

http://www.darkside.ca/TF-BlowBack-Instructions.pdf

Note he includes 2 (for both ends) 1" rubber hoses to be inserted in moly tubing as bushings.
the rubber tubing is the type you use for heater hoses