Sidepipe mount fastener issue

[davids2toys]

I have done many searches on this subject, also talked to someone at Unique( can't remember who) a couple of years ago who told me to just sock them down tight. This to me would make sense if the motor mount was a solid mount, then the engine, frame, and side-pipe would all be vibrating/moving in unyson creating no stress points.
My motor mount is not however, it has rubber in it to provide flex.
What worries me is that that motor is moving separately from the frame, so if you sock down on the fastener you would now be creating a hard point at the side-pipe mounts.
My present situation (the way I bought the car) is 5/16 bolt with a washer under the head, then a spring followed by another washer. The spring is similar to a brake shoe spring. I have lost a few of these bolts already, must have vibrated out, maybe I should have install the bolts with locktight? I also cut some radiator hose into 1x1 squares and put them between the frame and the side-pipe mount.
I'm really sick of all the make shift rigs and would really like to have the correct set-up I just don't want to crack out the the headers anywhere.
I was actually considering a solid motor mount then socking up on the sidepipe mount fasteners.
any thoughts on this fellas, anybody running solid motor mounts or have some sound advice?
Thanks...Dave

[dmswann]

I installed a heavy duty truck bed mat in a 1978 Chevy Suburban a few year back and had to cut it to size. That left me with some heavy-rubber, fiber re-inforced strips that are about 1/4" thick. I used a 2" hole saw and fabricated some washers from the material. I put one between the mount and the frame at each sidepipe support location. They worked great. Compressibe enough to keep bolts tight and also provided some cushion preventing the metal-to-metal contact point. I have some of this material and can make you 4-washers if you would like. Just send me your address!

[davids2toys]

Hey Dennis,
That is very nice of you, sounds like a better material than what i am using for sure. i will PM you my address.
did you tighten up on the fastener? Did you use locktight?

This will be a nice addition to what i have, however, eventually I would like have the whole situatuion corrected the proper way instead of work-arounds.

[RJacobsen]

The problem is how do you rubber mount the exhaust and leave the bolt loose enough for it to allow movement but tight enough to not fall out? What I did was eliminate the bolt and install a stud instead. You can use all thread or cut the end off of a bolt with enough threads on it and screw that in where the bolt goes, use a jam nut to lock it into place. Make some rubber washers out of what ever you have, floor mat, mud flap, or bed liner and use them on both sides of the side pipe flanges. Use a large enough metal washer to cover the rubber washer and a locking nut to hold it all together.

[mkassab]

The problem is how do you rubber mount the exhaust and leave the bolt loose enough for it to allow movement but tight enough to not fall out? What I did was eliminate the bolt and install a stud instead. You can use all thread or cut the end off of a bolt with enough threads on it and screw that in where the bolt goes, use a jam nut to lock it into place. Make some rubber washers out of what ever you have, floor mat, mud flap, or bed liner and use them on both sides of the side pipe flanges. Use a large enough metal washer to cover the rubber washer and a locking nut to hold it all together.

This is a good way to do it..... But I'll offer another suggestion. From a auto parts store, buy a cheap exhaust pipe hanger... one with a rubber fiber donut... something like http://www.amazon.com/Walker-Exhaust.../dp/B000CQBGEQ or like this http://www.autoanything.com/exhausts.../201A1753.aspx or this http://www.discountexhaustsystems.co...tegory:Exhaust)

see attached picture for my choice. then you'd fasten top to frame and bottom to side pipe mount.

My $0.02
Mark

[Aggressor]

Bolt it up tight as it comes from Unique. No insultators should ever be used. Verify this statement with Unique. As most of you know my engine is capable of extreme torque/horsepower and is doing well with stock engine mounts and hard mounted sidepipes as per original.

The 1st 13,000 miles with 500 HP on tap - No Problems
The last 7,000 miles with Dual Superchargers added - No Problems
The next 20,000 miles - No problems anticipated due to track record to date.

With Unique being intimately associated with these vehicles since 1977 check with them.

I did.

-Geary

[Stan]

I used a couple of rubber upper shock bushings and tightened the brackets down with no problems.

[Aggressor]

Stan - There have been recent broken sidepipe mount events listed on this forum.
Search and read comments by Eliminator and GeorgiaSnake on this topic.

Give Maurice a call.

- Geary

[davids2toys]

The problem is how do you rubber mount the exhaust and leave the bolt loose enough for it to allow movement but tight enough to not fall out? What I did was eliminate the bolt and install a stud instead. You can use all thread or cut the end off of a bolt with enough threads on it and screw that in where the bolt goes, use a jam nut to lock it into place. Make some rubber washers out of what ever you have, floor mat, mud flap, or bed liner and use them on both sides of the side pipe flanges. Use a large enough metal washer to cover the rubber washer and a locking nut to hold it all together.

Sound a little better than what I have presently
First off, where do you put the first jam nut for the rear mount, it is a closed box tube with no access to the threads.
I do like the stud idea better than the bolts which I am using washers for adjustment.
Thanks

[davids2toys]

This is a good way to do it..... But I'll offer another suggestion. From a auto parts store, buy a cheap exhaust pipe hanger... one with a rubber fiber donut... something like http://www.amazon.com/Walker-Exhaust.../dp/B000CQBGEQ or like this http://www.autoanything.com/exhausts.../201A1753.aspx or this http://www.discountexhaustsystems.com/shop/?PN=2490&N=0&Nr=AND(category:Exhaust)

see attached picture for my choice. then you'd fasten top to frame and bottom to side pipe mount.

My $0.02
Mark

Thanks Mark,
I do like your choice in mount, do you have a link for it? Also, it looks pretty big, how in the world would you get that between the frame and the side-pipe mount???
Am I missing something here?

[davids2toys]

Bolt it up tight as it comes from Unique. No insultators should ever be used. Verify this statement with Unique. As most of you know my engine is capable of extreme torque/horsepower and is doing well with stock engine mounts and hard mounted sidepipes as per original.

The 1st 13,000 miles with 500 HP on tap - No Problems
The last 7,000 miles with Dual Superchargers added - No Problems
The next 20,000 miles - No problems anticipated due to track record to date.

With Unique being intimately associated with these vehicles since 1977 check with them.

I did.

-Geary

Wow, I am amazed, just does not sound possible without a solid motor mount, but i may take a chance and just try it down the road. What you are saying is what Unique told me also! Just does not make sense to me.

[Aggressor]

Dave - I went through the same rationallizing back in the day. We all do.

I do a few other things that other owners take exception to but I have a 20,000 mile success rating so far. I don't have heat shielding on my master cylinders and did not use thermoshield under the front fenders. To date the fiberglass above my headers is smooth and the paint is good. I did replace a clutch master at around 8000 miles (as I recall) but I have had no other exceptions and chalk it up to randon early mortality. Maurice looked over my car and we discussed these items at the Carlisle replica/import show 3 weeks ago.

- Geary

[RJacobsen]

Sound a little better than what I have presently
First off, where do you put the first jam nut for the rear mount, it is a closed box tube with no access to the threads.
I do like the stud idea better than the bolts which I am using washers for adjustment.
Thanks

I have the jam nut for front and rear on the bottom and drilled the hole in the side pipe flange out to clear it.

[mkassab]

Thanks Mark,
I do like your choice in mount, do you have a link for it? Also, it looks pretty big, how in the world would you get that between the frame and the side-pipe mount???
Am I missing something here?

the last link takes you to the mount I like.... they have many to choose from. As far as mounting, you'll have to be creative and do some modifications. The rubber ring may have to go around vs between... or add your own bracket to side of frame.... But at the end of the day.... i think the best advice I've seen is call Maurice.... if there is an issue, he'd be aware.

Mark

[davids2toys]

Dave - I went through the same rationallizing back in the day. We all do.

I do a few other things that other owners take exception to but I have a 20,000 mile success rating so far. I don't have heat shielding on my master cylinders and did not use thermoshield under the front fenders. To date the fiberglass above my headers is smooth and the paint is good. I did replace a clutch master at around 8000 miles (as I recall) but I have had no other exceptions and chalk it up to randon early mortality. Maurice looked over my car and we discussed these items at the Carlisle replica/import show 3 weeks ago.

- Geary

Thanks Geary,
I do respect what you and Unique are saying but I just can't wrap my brain around it, it just sounds like asking for trouble, I also see there are many schools of thought on this subject. I am going to be stubborn for now and go the flex route again. For now anyway!

[davids2toys]

I have the jam nut for front and rear on the bottom and drilled the hole in the side pipe flange out to clear it.

I was looking at mine today and the holes are already large enough for a jam nut. I also bought some allen headed studs. I am thinking that the shoulders on the bolts if sized correctly will bottom out , along with lock-tight should hold fine. I am going to go with the rubber between the flange and the frame, but I am going to use the springs on the bottom, between the bolt head and the flange along with washers I bought some new springs today.
I also measured the gaps and will sizes the rubber to the gaps in the unloaded position. i have 1./4 inch on the drivers side and barely a 1/16 on the pass side, I will add this gap is not even at all, very tapered
I also made some rubber bushings for the hole in the flange, worked great, I made them from fuel line, fits aound the bolt perfect...now I am cushioned both ways!
I will watch this set-up for a while as I run the car, if it starts loosening up I will go the jam nut route as you did.
Thanks you everyone for all the input.
If anybody wants me to take some pics, let me know.
Thanks again...Dave

[mkassab]

Well, I for one want pictures..... !!

Thanks Mark

[Slither]

Well, I for one want pictures..... !!

Thanks Mark

Yah, pics!

[davids2toys]

Ok, it will be a few days, but I will get to it

[davebetts]

I've been running for six years now. Had to remove once or twice. Street drive and raced. Big block - 500 + HP.
Never had any issues - bolt it down and drive. Especially if that's what the Weavers have already said.
That's my 2 cents.