Solid Motor Mounts

mtpockets · #1 (**permalink**) 10-26-2010, 09:03 AM

Anyone running solid motor mounts out there?
I am, with a SBF - 408, 450 RWHP, LSD rearend.
I have a bit of problem with the passenger side motor support where it attaches to the frame, it is BENT

New name for the beast is TORQUE MONSTER. Just checking to see if anyone else has experienced this. Starting repairs this week. If you are running solid mounts, get under there and check out that motor support.

PS: I run my car pretty hard at the track, with sticky tires and have broken two half shafts. I live up to my signature line.

FredBMOC · #2 (**permalink**) 11-14-2010, 04:56 AM

What is the advantage provided by the solid mounts?

scottj · #3 (**permalink**) 11-14-2010, 05:48 AM

I've never run anything but solid mounts. I can run any motor height I want. Without the spacer is for the track when I run a button clutch and a LGC bellhousing. With the spacer is for a stock bellhousing.

vector1 · #4 (**permalink**) 11-14-2010, 06:25 AM

Quote:

Originally Posted by scottj

I've never run anything but solid mounts. I can run any motor height I want. Without the spacer is for the track when I run a button clutch and a LGC bellhousing. With the spacer is for a stock bellhousing.

be cool if you could offcenter it to get the side to side 50/50. looks like a lot of work to drop the engine an inch and a half. you drop the tranny also?

mtpockets--sounds like you're running too much hp, i have a 351 crate engine i'll swap out for your 408 if that helps

scottj · #5 (**permalink**) 11-14-2010, 06:42 AM

Quote:

Originally Posted by vector1

be cool if you could offcenter it to get the side to side 50/50. looks like a lot of work to drop the engine an inch and a half. you drop the tranny also?

The mounts allow for lateral adjustment. I'm about 1" to the right in the pic, which is the max I can go and not have the headers getting too close to the passenger foot box. I also have multiple trans crossmembers to choose from and 2 different locations on the chassis to bolt them to, depending on which trans I'm running.

This crossmember is 6" to the rear for a T56 Magnum.

FWB · #6 (**permalink**) 11-14-2010, 06:49 PM

Quote:

Originally Posted by vector1

be cool if you could offcenter it to get the side to side 50/50. looks like a lot of work to drop the engine an inch and a half. you drop the tranny also?

mtpockets--sounds like you're running too much hp, i have a 351 crate engine i'll swap out for your 408 if that helps

it looks like your trusting that one grade 5 bolt to handle all the motors torque.

scottj · #7 (**permalink**) 11-14-2010, 07:06 PM

Quote:

Originally Posted by FWB

it looks like your trusting that one grade 5 bolt to handle all the motors torque.

You quoted Vector, but I'm assuming you're referring to my one grade 5 bolt. Grade 5 was for mock up, which is when the pics were taken. Final assembly used Grade 8, but yes, I trust it.

Rwillia4 · #8 (**permalink**) 11-15-2010, 04:47 AM

I would expect that you get some flexing in those plates under torque. But it is a nice clean setup.

I like those headers.

scottj · #9 (**permalink**) 11-15-2010, 05:17 AM

With regard to engine torque; the loads on the bolts and frame mounts are in the direction compression and tension, so no problem there. There is a bending moment on the engine mounts, but not of sufficient force to cause a problem.

The real loads, I suspect, come from chassis twist on the track. I've experienced enough chassis flex to pinch a door in the opening and crack the door. I've never had a problem with motor mounts though.

Jerry Clayton · #10 (**permalink**) 11-15-2010, 09:49 AM

As to forces on motor mounts---engine torque probably has less effect than a hydraulic clutch with the slave cylinder frame mounted or even momentem from heavy braking--

many times I've installed fore and aft stablizer links and only seldom had to do a link to control the engine torque--

Many top fuelers/funny cars have only hose clamps around the top frame rail---

tcrist · #11 (**permalink**) 11-15-2010, 10:01 AM

I know that I would not trust that thin bracket to hold much. I would rather over engineer a bracket then take a chance. But what do I know, I've only been in the sheetmetal fabrication business for 40+ years.

Jerry Clayton · #12 (**permalink**) 11-15-2010, 10:12 AM

Terry

tell us about the thickness of your lower mount for your rear coil over

scottj · #13 (**permalink**) 11-15-2010, 10:33 AM

Quote:

Originally Posted by tcrist

I know that I would not trust that thin bracket to hold much. I would rather over engineer a bracket then take a chance. But what do I know, I've only been in the sheetmetal fabrication business for 40+ years.

I did over-engineer it... I bought the ones made of steel rather than the ones made of aluminum.

vector1 · #14 (**permalink**) 11-15-2010, 09:21 PM

had the same type motor mounts on a larry phillips late model, i don't think they are quite that unique, or pretty common imo so i wouldn't expect much trouble.

tcrist · #15 (**permalink**) 11-15-2010, 09:48 PM

Quote:

Originally Posted by Jerry Clayton

Terry

tell us about the thickness of your lower mount for your rear coil over

Lower coil over mount is 3/16 thick steel stamped plate with rolled edges for strength (stock 8.8 bracket) and another 3/16 thick plate welded to the inside.

Upper coil over mount is also 3/16 thick steel formed (stock CR frame) with welded in 3/16 steel gussets and plate for strength.

Motor mount bracket that bolts between the frame and the engine mount is stock CRII 3/16" or 1/4" steel plate fully welded and with 3/16 steel gussets welded in for strength.

Any other information you need Jerry?

tcrist · #16 (**permalink**) 11-15-2010, 09:51 PM

Quote:

Originally Posted by scottj

I did over-engineer it... I bought the ones made of steel rather than the ones made of aluminum.

I like that.

The brackets will probably work fine, just not my cup of tea, so to speak.
I guess that you have never had them work harden from flexing. That is good. Whod a thunk it?

scottj · #17 (**permalink**) 11-16-2010, 11:57 AM

To be fair, I’ll say that these mounts are for circle track applications designed to be used with a mid-plate or mid-mounts. In practice, they are often used in a 3-point mounting system by unbolting the mid-plate and adding a trans mount. The idea with a 3-point system is to eliminate the engine as a stressed member of the chassis… a way of tuning using chassis flex.

Below, on the left, is the same mount pictured (along with the grade 5 bolt) in the mock-up in a previous post. I ran this set for ten years in the circle track application previously described without a problem. On the right is a new mount that was installed in the Cobra for final assembly. It is identical to the set I’ve been running in the Cobra with previous engines and was chosen because of the additional cross-sectional area.
I actually posted these pics because my mounts look like they should bend or break, yet it’s the factory engineered cars with the problems. I can’t bend them in ten years of trying. Being the worrywart that I am though, I keep an extra set on the shelf and plan to change them out every 10 years.

ItBites · #18 (**permalink**) 11-16-2010, 12:10 PM

Terry,

With only 352 HP, I wouldn't worry about breaking solid motor mounts like Scott's... or any other design for that matter.

ItBites · #19 (**permalink**) 11-16-2010, 12:13 PM

Scott,

My Midstates is real similar to your EM, with the round tube frame and the C4 suspension. Where did you get your coil overs? I still run the transverse leafs, but they're not tunable... I'd really like to go to coilovers and have been looking at Penskes. Penske is pricey.

scottj · #20 (**permalink**) 11-16-2010, 12:29 PM

Quote:

Originally Posted by ItBites

Scott,

My Midstates is real similar to your EM, with the round tube frame and the C4 suspension. Where did you get your coil overs? I still run the transverse leafs, but they're not tunable... I'd really like to go to coilovers and have been looking at Penskes. Penske is pricey.

PM sent....