bent valve(motor) or front pump(trans.) causing truck to shake?

[benoit454]

Guys my dad has this weird vibration/shake in the whole truck now, aafter a motor swap. Here's the info....

shakes in park and neutral and he says it also does it in drive sitting still, once moving it usually stops or blends fades away kinda.

Now here's more details on the swap, it's a 4 bolt 350 I had in my monte carlo, the motor never shook or anything in my car except on idle with the cam loping it makes the car wiggle a lil bit.

The 2000 stall was in my car also and is now in his truck.

My trans. was short tail and his long tail so he had to reuse his th350, and it never had that problem when it was a 305 in front of his trans.

Now we did find out when we pulled the motors and trans' apart that his torque convertor had a broke snout, probably something we done when seperately them, because it had NO problems before. There were pieces of it in the front pump, you could see by looking down past the front seal, we took it to a guy and had him replace the front pump, it was probably a used one.

We also installed a b&m shift improver kit at the same time, this was my 2nd shift improver in a th350 and I had no problems doing the first so it shouldn't be that.

So would it be the front pump causing this?

2nd....

when we pulled the 350 we had the valve covers off to avoid bending them, at one point the chain for the cherry picker was laying on the number 8 inake valve and had tension on it. So is there a chance the valve got bent? It doesn't miss or pop or anything.

However when that motor was in my car you could turn the distributor(advance it) and get the rough idle to smooth out, in his truck now you can't, it won't smooth out, you'll turn it too far and it'll kill the motor out.

everything is the same as it was before really, we didn't change anything other that was mentioned. My motor and stall in his truck with his trans. The 305 out of his truck and my trans. are back in the monte carlo and they run meaner then ever LOL. I switched them because the 350 was really mean in my monte carlo, plus it was the first motor my dad and I ever built together and I was selling the monte carlo. My bro-in-law has the car now, I just couldn't stand to let the motor go with it.

[chicklin]

Sure it's not a vacuum leak?

[benoit454]

I don't hear it sucking any air, and the idle hasn't pickup or anything.

[chicklin]

Originally Posted by benoit454

I don't hear it sucking any air, and the idle hasn't pickup or anything.

I didn't notice if it was carb'd or TBI. If it's TBI, you're right, the idle would bump up noticeably. If it's carb'd, a vacuum leak can cause it to stumble and shudder at idle. It usually goes away with a little throttle because the extra air becomes negligible with the throttle plate open.

I just spent a ton of time and money troubleshooting a couple vacuum leaks on mine. I may be way off but it's at least something to check.

[benoit454]

it's carb'd but it usually doesn't go away with light throttle, it just smoothes out a lil bit, usually you don't see it go away until you are going 10-20 or so I guess. I haven't been in it for a few months so I'm fuzy on it all now, but he's in it a couple times a week.

[chicklin]

Originally Posted by benoit454

it's carb'd but it usually doesn't go away with light throttle, it just smoothes out a lil bit, usually you don't see it go away until you are going 10-20 or so I guess. I haven't been in it for a few months so I'm fuzy on it all now, but he's in it a couple times a week.

So, if it changes with wheel speed, not RPM's then you've probably got a mechanical problem not a carb issue (like you originally suspected). Just a guess on the vacuum leak but it sounds like you've probably already ruled that out. Good luck.

[benoit454]

well it also will go away with rpm's if it's sitting still in park but it's not like 100-200 rpm improvment makes it stop it's more like 500-1000 rpm makes improvment I'd guess.

It be nice if it was a carb issue, lol simple fix.

[chicklin]

Originally Posted by benoit454

well it also will go away with rpm's if it's sitting still in park but it's not like 100-200 rpm improvment makes it stop it's more like 500-1000 rpm makes improvment I'd guess.

It be nice if it was a carb issue, lol simple fix.

hmmm....motor mounts, then? Your original guesses might be right, too, I just don't know enough about them to say one way or the other.

[benoit454]

talked to dad he said yea for sure they go away when you hit the gas, in any gear park reverse drive anything.