Vibration

[gary peed]

I just picked up a 70 swinger 318 auto there is a slight vibration in park when the engine is reved up and on acceleration when going down the road, I have checked everything I could think of and still cant seem to pin point the problem any ideas on what it could be will be very helpfull.
Thanks

 

[3404speed]

Misfire
Flex plate problem
Ignition
Fuel
Torque convertor
Could be a lot of things
Need to narrow it down

 

[tekslk]

Mine did that I figured out what rpms it was happening, turned out my engine builder didnt rebalance after changing pistons, so I live with it for now and stay away from certain rpms.

 

[gary peed]

I checked the flex plate and torque converter bolts they seem to be ok. the car still has points so I was going to convert it to electronic and see if that helps I dont think the engine has been into so I dont think there is a balance issue. I will let you know if the electronic switch over helps.
Thanks for your input

 

[magnumdart]

Maybe it is just on the verge of needing a tune-up, if the vibration is very slight. After this the possibilities are endless.

 

[hemi446]

If the vibration is all the time and seems to increase with RPM's then it could be a mechanical problem. If you know the timing is correct then put a timing light on it and see if the timings marks line up. If they do then the balancer is still good but if you can't see the marks pull the pulleys off and look at the rubber ring on the balancer and see if it's damaged or coming out in places. if the timing marks are good then get a piece of vacuum hose and cut 8 pieces about an 1" long. Put them between each plug wire and the cap. With the engine idling take a piece of regular wire and hook one end to the NEG. battery terminal and touch the other end to each piece of vacuum hose one at a time and see if the engine idles rougher or stays the same. The cylinder that stays the same is not making any power and that is your vibration or we would call it a misfire. By using the vacuum hose trick it keeps you from getting shocked or burning out and other electronic components. If neither one of these ideas help you PM me and we can come up with other things to check.

 

[gary peed]

Update I pulled the trans cross member and the trans mount came out in 3 pieces I replaced it and the vibration is gone, Thanks everyone for the input

 

[magnumdart]

Update I pulled the trans cross member and the trans mount came out in 3 pieces I replaced it and the vibration is gone, Thanks everyone for the input

Interesting. I would have had to search for that. Probably wouldn't have guessed.