New headers, new headaches
 

I replaced the rusted and warped headers on my truck with new ones a few weeks ago. The new headers went in easy, and seemed to clear everything just fine, except for one spot at the passenger motor mount.

There is a tiny gap between the #2 primary tube and the motor mount, hard to see, but I can slide a credit card between the two, so it's not making contact (with the engine off). After driving around for a few minutes, I started to hear what sounded like metal vibrating on metal. I think it is the header rubbing on the motor mount (maybe it expands with the heat?)

I've read that shimming the transmission (TH350) at the crossmember can help move the header away from the motor mount. Is this true?

I know it is not the ideal solution, but I'd like to avoid getting another pair of headers (exhaust is already fabricated to fit these). I'd also like to avoid dimpling the headers, out of fear of ruining the ceramic coating.

Re: New headers, new headaches
 

What did you buy for headers?

Re: New headers, new headaches
 

I bought the Summit Racing brand ceramic coated headers SUM-G9006-9

Re: New headers, new headaches
 

Maybe adding a few washers under the motor mount studs(assuming you have the stock motor mounts) that should keep them clear without doing too much "over-Engineering"
Ben
:metal:

Re: New headers, new headaches
 

I have these headers without clearance issues. My motor must be in a dif location than yours.

Re: New headers, new headaches
 

I was thinking about that last night. I don't have a hoist to lift the engine, would I be able to do it with a floor jack without too much trouble? I think shimming the trans would be much simpler, but I'm not positive it would work, hence my question in the first post.

I bought them because of all the good reviews on Summit Racing about the clearance. Aside from this one spot, everything else about the fit of the headers is great. Easy access to spark plugs and flange bolts, cleared the frame and starter without any trouble.

I don't know if my motor mounts are stock, but they are as far forward as they can go. Here is a pic of the problem spot. http://s32.postimg.org/4oerqopg5/20160429_121859.jpg

Re: New headers, new headaches
 

I've used fender shims on engine mount bolts (they're shaped like Us) so that you don't have to get the whole bolt out to shim it. If you use washers you have to take it all the way apart.

Give yourself a few extra 16ths because the motor will rotate and torque down in that direction under load.

Re: New headers, new headaches
 

I had the exact same problem with mine....

Re: New headers, new headaches
 

I chose to grind on and hammer my problem spot, which wasn't that bad and was more frame than motor mount... you may not want to do that, but since we're on the topic of header clearance.

https://www.youtube.com/watch?v=azPK...t5dIHutSOu7srE

Re: New headers, new headaches
 

Since the front mount would be the center of rotation. Adding shims under the trans mount would take far more shim to achieve clearance at the aft edge of the front engine mount stand than up fron where you need it.

BTW: What kind of condition are your mounts in?

Re: New headers, new headaches
 

put a block of wood under the pan, and gently lift the engine off the mounts and use the alignment shims as mentioned earlier, never thought about those clever!
Ben
:metal:

Re: New headers, new headaches
 

The fender shims sounds like it would make the job much easier. Thanks.

Grinding the mount crossed my mind as well, I only need a little bit more clearance, but ultimately I'd like to avoid removing material from the mount. That video was great, maybe I should buy a sledge hammer :lol:

The motor mounts seem to be in good condition. It's hard to tell just by looking at them, but the engine doesn't move around too much while under load. I don't know the details about them, they were on the truck when I bought it.

Re: New headers, new headaches
 

X2 - Check condition of motor mounts.

Re: New headers, new headaches
 

Boy do I know about motor mounts.....had a '64 Plymouth Fury once, rebuilt the engine and transmission in auto shop, one day I was showing off and brake torqued the tires, broke the left mount and ate my radiator for lunch...ouch, not to mention had to walk a few blocks afterwards...:lol:
Ben
:metal:

Re: New headers, new headaches
 

I'd be surprised if raising the rear of the trans does much good. I mean the header tube is right at the pivot point. It would be like lifting up one end of a see-saw and expecting the center to move up.

I've used thick, hardened flat washers between motor mounts and block, but in your case, I think it would be easier to relieve the spot where the tube is touching the bracket. That way there is zero chance of causing a new problem like shift linkage misalignment, fan hitting the shroud, hose or hard line getting stretched, etc.

https://encrypted-tbn1.gstatic.com/i...Ha2EhGvdGPlKkA

http://i.ebayimg.com/00/s/MTIwMFgxMj..._id=880000500F

Re: New headers, new headaches
 

Why not put new mounts in? You can't tell by looking, they were on when you bought it, and if shims are enough to make it clear it's very possible that is to make up for lost thickness in mount cushion. What are we talking, 1/8-1/4"? The headers should be made to clear better than that, though.

Re: New headers, new headaches
 

Very good point.

Re: New headers, new headaches
 

Dude this post just helped me solve my "mystery noise" that I've been chasing for a week now lol couldn't for the life of me figure out where the intermittent squeak/tick was coming from. Here's an easy solution for ya. Get a flat screw driver or old chisel and tap it in between until there's a gap big enough to clear :) the ding will make literally no difference in performance, it's been dyno proven

Re: New headers, new headaches
 

It makes sense to replace the mounts, they are cheap enough and I'll be lifting the motor anyways. I have a box of shims on hand, as well... If the new mounts don't do enough to resolve the issue, I'll shim them. I'll report back when it's complete and post the results.

Thanks for the info, fellas.

Re: New headers, new headaches
 

I've been struggling trying to get the new motor mounts in, maybe somebody has some tips that can help me out?

The passenger side of the engine is done, everything is bolted in place, but the driver side is giving me a hard time.
-There are three bolts that hold the mount to the block, I got the top two bolts in, but I can't get a wrench or socket around the bottom bolt. The perch gets in the way and I can't get any tools in the small gap to start tightening the bolt.
-There is one bolt that holds the mount to the perch, and I can't get the hole to line up so I can thread the bolt in.

At the moment, it seems like it would be easier to remove the perch from the frame, bolt the perch to the block/engine mount, then try to align the holes on the perch/frame and bolt that back in. It doesn't help that I'm doing this work alone in my driveway, it's pretty difficult to nudge the engine around from underneath the truck to try and get the holes to line up.

Any suggestions?

Re: New headers, new headaches
 

Loosen the perch...the holes are elongated. I had the same issue when I changed mine to the poly mounts. Loosen both sides. It just take some finess, patients and a few choice words. I drove it awhile with the drivers side unbolted for a period thinking it would settle....not. Just had to keep at it. Even loosened the tranny mount.

Re: New headers, new headaches
 

That's an idea that hadn't crossed my mind. I was worried that once I removed the bolts holding the perches down I would have the same trouble getting them to line up. You loosened the perches on both sides? I'll give that a try. A few choice words (and some pushing and shoving) is what finally got the passenger side mount to line up perfectly :lol: