Plum 95 engine project

[98blackbeauty]

Thanks for all the input guys, everyone has some good points and It really helps. So I jacked up the bird and crawled under her this afternoon. here are the Problems and in reading the posts probable fixes.

1. Drivers side is not collector but the 3" y pipe past the collector. It is 1/4" away from body brace and floor board. Fix would be to remove y pipe and flatten the top of the y in that area. I marked it so when I remove it I'll know where.

2. The y crosses over towards the passenger side and is 1/8 to 1/4" from trans mount cross brace. Probably the easiest to fix. the trans brace is u shaped then has edge rolled up. Taking a cutoff wheel I can trip part of the rolled edge for about 1.5 to 2 inches and increase the gap. I don't think this would hurt to integrety of the trans mount brace.

3. the heat shield on the passenger side is 1/8 to1/4 away. Fix remove heat shield, Joel your point was great "drivers side doesn't have a heat shield" Made me stop and realize that the heat shield was for cat.

My neighbor suggested heat wrap tape to see if that silences it aswell. I might try that so I don't have to remove y pipe. I realize that eventually this would rub through and noise would be back. But then I would know if it is the correct area before removing y pipe.

Last would be the motor mounts, there is no doubt that they are weak. But could aggravate the problem.

[Derek]

thats not necessarily the case either. Pacesetters on LT1s are very very well known for having that issue. I smacked my floorboard up with a hammer an inch or so and forgot about it. When i do install new motormounts ill make sure to measure if there was any difference, but the way the driver-side header sits i doubt new motor mounts would fix the problem for long.

its not about measuring anything joel, its what the engine does when it torques. I could rev the crap out of mine and ZERO rattles, but when the engine torqued while going down the road at a certain throttle level.. is when it hit. Not sure what larry was experiencing, but if it didnt rattle at idle, motor mounts would probably solve the issues.

and larry. Just put some spacers above the tunnel brace. That is what I did on my friend's formula. I have spacers AND a custom driveshaft saftey loop/tunnel brace on my car just to clear my ypipe lol.

A quarter of an inch is on the small side but with poly motor mounts I bet your problems would be DRASTICALLY minimized if not gone alltogether. My engine doesnt move one bit now.

Your y-pipe wasn't flattened on top already? I thought all of them had some sort of a dent in them around that floorboard/crossbrace area that is always close.

[c0ncEpT]

Like Derek said Poly mounts will cure your problem as long as its not resting on the floor and rattling at idle. Everything else is a bandaid.

[Derek]

The headers fit very well in the engine bay and around the K frame. the issue is the collectors are only 1/4" from the floor boards. the passenger side is better but is hitting the heat shield. I don't think looking at the geometry of the motor mounts new poly mounts would help, infact they could make it worse by slightly raising the engine.
The added performance of the headers are not worth the rattling and clunking noise. I have decided to play with them for a week and if I can't resolve the noise then off they come. lucky I save the old exhaust manifolds and y pipe. If New motor mounts would resolve the issue I would put them in.

your mounts wont raise the car at all. at least mine didnt. they are way bigger than the factory ones, but that is because they acctually fill up the whole clamshell instead of just part of it like the factory ones. If you don't have anything resting on the car itself, with no movement of the motor I really think all your problems will be solved.. If you are still hitting that tunnel brace then you could just put a spacer in there like I said.. Don't go removing the headers just yet.. To put the mounts in just jack the car up and then lift the motor up to get each mount out. My dad and I did mine easily in a couple hours at our shop.. easier said than done when we have all the tools and a lift though..

[98blackbeauty]

your mounts wont raise the car at all. at least mine didnt. they are way bigger than the factory ones, but that is because they acctually fill up the whole clamshell instead of just part of it like the factory ones. If you don't have anything resting on the car itself, with no movement of the motor I really think all your problems will be solved.. If you are still hitting that tunnel brace then you could just put a spacer in there like I said.. Don't go removing the headers just yet.. To put the mounts in just jack the car up and then lift the motor up to get each mount out. My dad and I did mine easily in a couple hours at our shop.. easier said than done when we have all the tools and a lift though..

the mounts I think will raise the motor a slight amount, when you raise the motor the headers raise to. When I did B's his, engine sits a little higher. Spacers won't help it is the trans mount bracket not the tunnel bracket. I put spacers on B's car to stop header rattle.

[meissen]

I don't think the motor mounts will help at all - it's rattling at idle and like dad said - the geometry with new motor mounts instead will angle the engine to cause less clearance.

If you draw a line from the center of the transmission to the tailshaft. With the bad motor mounts, it's allowing the engine and transmission to angle back towards the end of the car. Dad's worried with new motor mounts it will straighten that angle and thus bringing the merge and y-pipe closer to the floorboards.

[JoeliusZ28]

its not about measuring anything joel, its what the engine does when it torques.

again this is a very specific issue with pacesetter LT1 headers. It is not the same problem you had. an LT1 pacesetter header will often not clear the floorboard (engine not even running) unless you have no exhaust after the collector, or route your exhaust at an extreme downward angle.

The problem is fixed by flattening the pipe like larry said, or clearancing the floor board like i did. I didnt use the pacesetter y-pipe but i am 90% sure it is not flattened. If you had a flattened y-pipe your issue was with torqing as you said, not a lack of clearance in the first place.

With my 3" exhaust i have a clearanced floorboard and my exhaust runs at a mild downward angle before it turns inside. And i still barely have enough clearance. I plan on flattening the pipe some this winter.

Also I would have to agree with new mounts making the problem worse, i hadnt even taken that angle into consideration.

--Double post auto merged--

Like Derek said Poly mounts will cure your problem as long as its not resting on the floor and rattling at idle. Everything else is a bandaid.

I disagree in this situation because mounts do not solve a clearance issue that exists in the design of the header itself. Other headers hang low enough to clear the brace in the floor board. (and if pacesetter had a flattened y-pipe in mind, they wouldnt have included a regular one).

[DETROITMUSCLE]

damn these headers are ****ed.

[JoeliusZ28]

for what you pay you cant beat em though. They have hands down best plug clearance of anything ive seen so far, give great gains and seem to hold up well.

[98blackbeauty]

damn these headers are ****ed.

keep in mind Jeff we are talking lt1 not ls1. I am winning the battle on the noise, like Joel said they do have some great plus's in the engine bay area.
Now I am down to rattly noise on acceleration, so thats driven by torque. I am doing 1 thing at a time because you can't tell where its coming from when your driving.
Most of you guys would not even bother with it now. But I am a nut when it comes to rattles and noises.

[my1994z28]

I am running pacesetter lts,with their y-pipe on my 94 z28,the y does have a flat spot that is under the driver side.Before you give up I would try and hammer up the floor board.

[JoeliusZ28]

I am running pacesetter lts,with their y-pipe on my 94 z28,the y does have a flat spot that is under the driver side.Before you give up I would try and hammer up the floor board.

Guess i was wrong about that then but i have definitely read of the supplied y-pipe hitting regardless. I made my own right from the start though

Larry if its at the point that its very minor you can press the floor board up gently with a floor jack. I have a small bump in the foot area now but I sacrificed there being just like you --- I hate rattles and vibrations with a passion

[98blackbeauty]

My y pipe does not have a flat spot so that will def. help when I do that.
Next I am going to try and remove the heat sheild, not sure if I can do that without removing the y pipe. I don't think I'm going to do anything till this weekend.

[DETROITMUSCLE]

I understand guys, I have pacesetters myself and the LT1 and LS1 seem to be completely different animals. I have never had a single problem with the fitment of mine at all and they were a hell for a deal for what you get.

[mcssmostwanted]

larry give me a call when you get a chance.....