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Hi to everybody , I have been a "Lurker" on these pages for quit a while now , and am in the process of rebuilding a BJ7 for the last few months. I would never have undertaken this task if it was not for the amount of information online , and in particular , the huge amount of knowledge , that is shared on these pages. A big Thank you from Me to You. One particular item that I have come up against , and I cant find an answer to is --- When removing my Carbs (Twin 2" SUs) , I noticed that the Air intake gap on the heat shield for the Front Carb was restricted to 1and a half inches. This would (I imagine) unbalance the Air/Fuel mixture between the Carbs. I intend to increase this gap to 2" before refitting the Carbs. I just wondered if anyone else had come up against this?. BTW I'm based in Southern Ireland , where Healeys are as scarce as Hens Teeth. If any of you Guys ever visit Ireland , you will get a 100,000 Welcomes and a Guinness or Coffee should you wish to contact me.
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A Mighty Forum
- Thread starter PCullen
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Welcome to posting! The standard carb on a BJ7 is an 1 3/4" HS6. The 2" HD8 was introduced on the BJ8. You can Google the numbers on the tags on the float bowls to ascertain what you have. If they are HD8s, perhaps there's been some more modding in the motor, like a camshaft to bump up the power a bit, or maybe a prior owner just used something handy as a replacement. What's the diameter of the throat opening on the intake manifold?
Thanks for the quick response. I believe that the Engine was subject to a rebuild , as it was bored out +20 and a high lift cam as well as a Dennis Welch oil pump were fitted. Hardened valve seats were also fitted. The measurement of the opening is definitely 2" . I don't understand why , after going to so much trouble , that the heat shield difference was overlooked. Would this difference in intake capacity between the Carbs?
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If you were to open up the heat shield to 2" would the bore of the intake manifold still restrict the airfow? In other words, is the intake bore 1 3/4" or 2"?
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I'd just open up the heat shield to 2". You're right, strange they missed that.
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Hi PCullen, I also have 2" HD8 Carbs on my BJ7. It was a fairly common upgrade back in the day when someone was hopping up the engine. Mine also has an uprated cam. The whole system works great. The only bear about it is that the bottom fastening nuts on the rear carb are really tough to reach. Welcome to the Forum.
Dave.
Dave.