Hello all,

I have a 1972 Dart Custom that I cannot get to go over 55pmh. I was on a long drive and blew a manifold gasket and lost pressure. I replaced it and everything seemed ok, but. a couple hours later I started loosing a lot of power. Topping out at 25/30mph up hill and 55mph on flat land. Its been sitting for some months and starts right up. It idles fine but drops when put into drive. I have to rev it to keep it from dying and it will eventually get there. Does just fine in all other gears. Havent been able to pressure test it as my tester just bit the dust. Waiting on another I'm in a VERY remote small town so everything takes quite a while. I've been told by a couple people that it sounds like the timing is off. Any ideas?

If it idles smoothly then I wouldn't suspect a burned valve. Have you checked and reset the valve lash? I would also check for excessive exhaust back pressure, but this requires a back pressure gauge and drilling a small hole in the exhaust pipe ahead of the muffler. Also, before you do anything make sure the throttle is opening all the way, with the engine off of course. Report back with your findings.

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63 Plymouth Valiant Wagon

This could be a ton of different things. You might try replacing the fuel filter and/or blowing out the fuel line from the back of the fuel pump back to the gas tank. Good idea to check the ignition timing. Pull out 2-3 of the spark plugs too and look for dark and sooty appearance or speckled with dots of aluminum. Can you post pics? Start taking some "measurements" and give us more data on the engine.

Best wishes,
Lou

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Home of Slant6-powered fun machines since 1988

Thank you so much for the suggestions! I will start trying these out and hopefully one of em works.

Remember to go simple and cheap first, Willsy. Things I would look at include:

Blocked exhaust/muffler--you can do a fair amount of diagnosis just holding your hand over the tail pipe. If you blew an exhaust gasket, there could well be something causing too much back pressure.

Check your head gasket--is their water in the oil? You can do a lot with a rubber hose to listen through around the head as well. I thought I had an exhaust gasket problem but it turned out to me a head gasket blown out under one of the manifold studs.

Make certain there aren't any vacuum leaks or leaks around your carburetor throttle shaft. Vacuum leaks and throttle shaft leaks can sometimes let your car idle okay, but then when it needs more fuel, it isn't able to get the correct mixture.

Best of luck,
Joe

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Joe Hoppe

71 D100 225 Super Six 727 AT on 2008 Crown Vic CopCar frame

64 Valiant Wagon 225 904 AT 3:23 8.75"

"blew a manifold gasket and lost pressure" the engine produces vacuum not pressure. Is this a boosted application?

How's it going, Willsy? Any progress or insights?

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Joe Hoppe

71 D100 225 Super Six 727 AT on 2008 Crown Vic CopCar frame

64 Valiant Wagon 225 904 AT 3:23 8.75"

Got another one for ya
Little bit of a story, bear with me please

I just got done working on one of my kid's cars a 2004 VW POS.(Passat )
I had to weld in new exhaust flex couplers as they cracked in the bellows portion, and only because I just happened to see something else while I was under there (and no more reason for this next part) I seen the front brake hoses were cracked and the cotton mid layer was showing. So I told him it wasn't leaving without new ones. And I had to drill out the locking lugs because the key he gave me was stripped. So I had to pull the rotor off to get the remnants of the lug studs out (brakes otherwise worked fine to this point, he had replaced pads and rotors not long ago)
I saw that the outer 1/3 of the rotor surface was like chipped/peeling chrome plating and there were huge pits part way around the circumference where chunks were missing.
This was all on the "back side" of the rotor. Pads are still like brand new. So I replaced the front brake hoses and the front rotors and had my wife sit inside and pump it so I could bleed the brakes. Which were working fine to this point.
As she pumped and id tell her to let off, (and she said she did) I could see the reflection of the brake lights bouncing off of my garage door and she was having to pull the pedal up. Weird.
We got it bled, pedal went back to feeling high and hard.
I took it down the road and the brakes were dragging BAD. I put it in 4th then 5th and with the gas pedal floored I couldn't go over about 50-55
I couldn't run 5th, could barely get 4th gear.
When I turned around to head home I had to wait for the brakes to cool as they were smoking. I got it home, got out and the brake lights were still on. I went out of town for a couple of days (nobody touched the car while I was gone, blocked it in so it couldn't be moved) I drove it again the day we got home and it was as if nothing ever happened. Drove how I remember it from the previous time I drove it. Which was alright for what it is.

Could your brakes be hanging up?

We also had a problem when we put a fresh brake booster on his 72 fury wagon. ( Sent original one in for rebuild, sent it back for redo and the rebuilder place found his mistake on that one, took care of it) that one acted strangely like this VW did on me last week. Though we've never had the master/booster off of the VW