Bad first ride of season

[dotman]

Well finally got to take the cover off the GTX and wake up the bear from its winter hibernation. Checked fluid levels backed out of the garage and took a spin around the block to warm it up for its oil change and spring shake down. Car was running great. Suddenly about 3 miles from home I felt a slight miss that got worse:sad:. Limped the car home on what felt like 7 cylinders and parked it in the garage. Could hear a slight rattling noise that came and went away with no rhyme or reason. Even though hot as heck, I pulled the valve covers off and had my wife crane the car over as I inspected the valve train. Nothing found. Pulled the plugs and found #1,#7 and # 6 plugs mashed right over. Did a compression check and found all about 170 but # 7. It was 125. Ripped the head of and found as expected but not understood debris in the cylinders and bonded to the top of #7 piston. When I bought the car I planned on going through the engine but one thing lead to another and 2 years later here I am. The cylinders do have a nasty ridge at the top that I can catch my nail on with ease. I was hoping it would be salvageable with maybe a valve issue on the afflicted cylinder but I guess the car will have to sit this summer. The car is a 70 GTX with a 1968 440 engine, original 18 spline 4 speed and a Dana rear with 3.54 gears. Stock carb intake and exhaust manifolds but I did treat it to a 2 1/2 exhaust with X pipe and Flowmaster 2 chamber mufflers. Any thoughts on a direction on its now needed rebuild (Cam suggestions)? I would like to retain the stock manifolds and carb ( spent a lot finding and rebuilding the original carb) but would like it to have a slight lope at idle, but with enough vacuum operate the booster. Car is street driven. Thanks for all replies. PS: debris found- all I can think of is maybe they were in the used original manifold I bought. I cleaned the hell out of it but maybe I missed something. Why it broke loose now, who knows!!

 

[rumblefish360]

Well, as far as a cam goes, a slight lope is due to a tighter centerline. A 110 is a normal C-line ground in by most grinders. If your going to insist on exhaust manifolds, I would look into a Comp cam and there line of cams designed for exhaust manifold cars.

Good luck on the rebuild. Keep the compression reasonable for pump gas.

 

[69 Runner]

I'd run either this Summit cam
http://www.summitracing.com/parts/SUM-6401/

or Bob K's "blueprinted" six pack cam. (I'm putting one in a 383 right now)

DAMN good cam

 

[dotman]

Thanks for the replies. How do I get in touch with Bob K? Does he have a web site or contact number ? Any issues with low vacuum with one of his cams? I just don't want a car that turns heads with a nice idle but is not enjoyable to drive. I had a brand x with a big block that was one of those rides. Got rid of it when a tiny boper in a honda smoked me from a light because of the lack of bottom end! ;>) . I had a charger years ago that had a mopar 6 pack purple cam I put in it and if my memory serves me had a nice idle, but I think the vacuum was a little low in it. Rich

 

[69 Runner]

Nope. That cam pulled better than 18" at idle in my six pack. I'll send you a PM with my name and his number

 

[dotman]

Thanks for the name and number. I will give him a shout once I get the engine out and ready of assembly. Rich

 

[69 Runner]

No Prob:beavisnbutthead:

 

[dotman]

Finally found the culprit that caused the damage to the engine. I don't know how I missed it when I ripped the engine down. The linkage that attaches to the choke flap fell off got sucked into the engine. The link is missing along with the bracket that attaches to the flap itself. Now shape and sizes of the bits I pulled out of the cylinders make sense now. Doesn't fix the engine but at least the mystery has been solved. Luckily I have a parts AVS on the shelf with the missing pieces on it.

 

[65-440]

man that sucks .... sorry for the bad news ... time to dump that choke crap !!