matt69olds

I just received my newest issue of JWO. I read the FrontWheeling article, it mentions the 66 Toronado carb fire issues. I have heard of this before reading the article, but never heard what the issue actually was. Why is it a Toronado thing? The Rochester carb was used on other car lines, was something unique to the Toro carb?

Most myths have their start in fact, so what’s the facts to this story? Just curious

rocketraider

The first year QuadraJet had some teething issues, notably a staked plug on the 90° fuel inlet where RP drilled the fuel inlet passage. That plug was prone to leaking, right onto the intake manifold. It also had an unusual diaphram type needle and seat that was prone to flooding the carbs.

Combine that with the Toronado's high underhood temperatures and low profile intake manifold design and it was a recipe for disaster.

Other issues included shallow threads in the carb's filter inlet fitting. Combine that with some owners and service techs were clumsy servicing fuel filters, and would strip out the potmetal filter fitting or twist the steel fuel line.

Then you got into the myriad fuel inlet thread saver gizmos which usually made things worse.

QuadraJet got a lot of upgrades and running changes until Oldsmobile finally had their fuel inlet reengineered to eliminate the 90° bend and leak-prone plug, in 1968. The diaphram needle and seat was also phased out and kits released to change it to a conventional needle and seat.

joe_padavano

The first year Qjets had a recall to retrofit a band-aid to try to prevent the plug from coming out.

matt69olds

Ok, I do remember seeing the “fix” for the plug. I’m guessing the plug coming out affected all Q-Jets, regardless of application? Same with the first design needle/seat?

rocketraider

Yes. Seemed to be worse on Toronado due to their unique underhood conditions.

To GM/Rochester Products credit, they made a fix and kept upgrading the QJet till it became one of the finest carbs made. They were every bit as tunable as a Holley, just didn't enjoy the support Holleys did. And were way more efficient.

ourkid2000

I wonder why you never see that bracket gizmo installed on any of the early carbs? No one ever has them on their carbs (quality rebuilds, etc), as far as I've seen anyway.

rocketraider

Probably because the rebuilder doesn't know what it's for and tosses it in the junk pile.

A QUALITY QJet rebuilder like Kalkhoff would more than likely make a permanent fix to eliminate it, and he got his start on Toronado carbs.

Rocketguy

The '66 Quadrajet also had a press in seat for the float needle with an O ring. It was prone to working it's way out and was later replaced with a screw in seat. I spent some frustrating time on the road's shoulder figuring this out back in the 90s.