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Senior Contributor
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Discussion Starter · #1 ·
Exploding Cannons see pic's

This causes what is known as vacuum leak.


I have been having a hunting problem at idle (that is where the idle jumps around for all the folks like me who aren’t up on jargon). Well I found out the hard way what it was after trying several different expensive and time consuming linkage set-ups, (not to mention decimating one of the Webers to see if the shaft was straight)


The machine shop tut tutted but says they can fix it.. More $$$$ out the window but they will also port match it to the 48ies instead of the 40ies so hopefully a slight performance improvement here to. They are also going to add more material to strengthen them as much as possible.


Lots of fun when this kind of thing brings the car to a halt (in the middle of
nowhere of course). Nowhere in this case being the area between the on and off ramps of the cloverleaf intersection of the two busiest HWY's in the St Louis area (270 and 44) where there is no #^%@* shoulder and you are miles from a phone.

Only took two ½ hours to rig something that finally worked to limp it out of there.... The fuel pump coming unwired did n’t help this. (Don’t ask…. just remember if you put a bigger motor in a Manta once a year retighten every bolt especially the one you can’t see and all the ones that are hard to get to).

Since it was so noisy with all the cars going by I drained the battery trying to start the car cause I couldn't hear that the fuel pump was not going and I thought my rag intake was letting in too much air. Yes an aluminum foil wrapped wadded rag and some huge washers will serve as an intake long enough to get you off the hwy and 11 miles home when one of your intake manifolds splits open and breaks in two pieces. I would of added pictures but the rag and foil did not leave enough pieces that weren’t cremated to photograph.

On the bright side for a change I was totally ignored by the police who were to busy driving by back and forth writing tickets to mess with a stranded motorist with a car on jackstands in the left lane blocking hwy traffic.
 

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Super Moderator
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Calvin, you never cease to amaze me! Most people are content to have the same old problems over and over again, and you have to go and make up your own new ones! I've never seen anything like that before on a non-nitroused engine.....
 

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Pathologic Opeler
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1,960 Posts
why would that break

the intake is just supporting the carbs, so how can solid Alum. break like that?
I dont think a moderate hit with an average hammer would break that :confused:
 

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If I remeber the Cannons the right way they are a bit thicker than a stock exhaust. This puts especially the inner mount at a high stress level. To contact and seal the exhaust you can crank on them or mill them to match the shorter exhausts. Not seeing it all I'm relying on an old memory of the Cannons.
 

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Senior Contributor
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Aluminum is funny stuff. Transititions from cold to hot can cause micro fractures. If there are enough of them, they join forces to really screw up your day. Calvin, do you still have the other piece? A GOOD welder/machinist can weld that back together and check for true. Unless you got a spare handy.
It's also very nice that RallyBob thinks so highly of you! :rolleyes:
(Sorry, just trying to lighten your "in touch with nature" groove) :D
 

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Looks Like Your Troubles Are Just Starting

Looks like your troubles are just starting - from the photos, it looks like you've set your dirty auto parts on your wife's (girlfriend's) glass-topped sofa table. Good Luck - you're going to be wishing you were back out there stuck on the freeway again.
 

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I don't mean to hurt your feelings but I had to laugh. Then my better half wanted to see what was so funny. I told her this is the same guy who took the pictures of his speedo buried past the numbers. :)
 

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Discussion Starter · #8 ·
well what was worse it happened as I was passing a parade of 7 mustangs, mach I's, Cobra's, a 65 with the lead car a very very cherry mustang II driven by at least a 75 year old blue haired lady.

I do have the piece which is good. The pic's are from the speed shop (which is far better than the couch).

I am sure that the prob was poor wrenching on my part somehow but I am having them match the the sides of the cannons to make them flush with the Rohnret header by making them thicker. As is I had half washer made of alu on the intake sides to flush them out and I see that the pieces of alu compressed at least a mm which then cause things to vibrate and my problem.

I will say with the new header there is far less lower end and it really seems that there are only two speeds with the car carbs all the way open or all the way closed.

If I get rid of the hunting prob I can finally dial in the carbs and see what difference the 2ft longer collector makes at top end. After that it will be some sort of cold air set-up added and maybe, after I get it all going, I will tear it apart and go for the roller cam.

The speed shop is saying put a little 50 nitrous system in to deal with the loss of lower end. They say since you won't use it till the car is rolling the rear end will survive.. I am not so sure if that is a good idea. Of course I am a whiz at not so good idea's

c
 

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Well it could have been worse... it could have been raining. The positive side to it is that it was aluminum and can be fixed. I hit something like a tree stump in a manta and fractured the oil pan pretty good. I got it heli arced on the car after the oil was gone. after the impact it was kinda done for me anyway. I like aluminum parts to this day for that reason. If that pan were steel it would have been gone. Just looking at the bright side
 

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Detritus Maximus
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Calvin-

I have a feeling you tried to reach me.....I left my cell at my parents house (phone, that is, I moved out a long time ago!) on Sunday.

I agree it may have been a bolts tightened more on one side than the other, placing more stress on one side of the manifold.

Call me at my house, tonight, after 8:30.
 
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