Broken motor mounts.....here's the fix

[firefighter3931]

Tired of busted engine mounts....well there's an easy fix. I've been doing them this way for several years and never had a falure. 

The driverside mount is the one that will seperate as the engine torques over and if there's a shroud on the radiator....then the fan will be taking it out which can be expensive and messy ! 

This mod is required only on the driverside because the passenger side biscuit gets compressed during hard acceleration....so there's no need to work it. 

Basicly, what you'll be doing is drilling a few holes through the mount and rubber biscuit and installing grade 8 hardware. There are no torque straps or chains needed and the mount looks perfectly stock.    I use a conical head bolt along with a flat washer and nylock nut to keep everything in place. The nylock will not back off or need to be retightened once it's installed. The idea is to just snug up the bolt so that there is:

(a) no compression on the rubber biscuit
(b) protection from seperation due to engine torqueing

You'll need some hardware ;

(1) a pair of 3/8 x 21/2 in grade 8 flathead bolts
(2) a pair of 3/8in "nylock" nuts and matching flat washers
(3) a good drill and 3/8in steel bit


Ron


Here's a few pics of the D/S modified mount :

[8WHEELER]

That looks like the Schumacher mount I had, had one for awhile, can't remember how much he charges.

Dan

[Rocky]

That's a great tip.  Thanks.  I love simple fixes that really work.

[steves66]

Great tip Ron! Luckily when I was putting my motor back in I read a post a while back where someone was talking about motor mounts and I ran across this mod. Very easy to do.

[Todd Wilson]

Great idea! My 318 breaks a mount about every 2-3 years.  Its getting about time! 


Todd

[firefighter3931]

That looks like the Schumacher mount I had, had one for awhile, can't remember how much he charges.

Dan

Ya Dan....i like to call it the "poor man's" Schumacher mount  An old drag racer showed me this trick many years ago and i've done it several times for myself and friends. The grade 8 hardware gives it the strength of a solid mount while the rubber continues to absorb drivetrain vibration. It's a win-win situation, inmo.

Steve, if anybody needed this fix....you do !  Can't imagine a  stock rubber mount lasting too long with that stroker ! 


Ron

[70kracken]

i have solid mounts, that fixes everything......no drilling, no buying bolts, just buy em and slap em in

[deputycrawford]

I hate to say it but I had a Schumaker mount in my 69 and ripped both bolts trough the mount. The engine rolled over under the hood and left a big gouge in my hood. I remember launching a 1.80 60 Ft. in a 4000lb car and hearing the driveshaft hitting the drag loop. I let off and realized what happened. I went solid Moroso and solved the problem. The bolts you use look bigger than the Schumakers. I probably should have made one myself. Looks stronger.

[8WHEELER]

I hate to say it but I had a Schumaker mount in my 69 and ripped both bolts trough the mount. The engine rolled over under the hood and left a big gouge in my hood. I remember launching a 1.80 60 Ft. in a 4000lb car and hearing the driveshaft hitting the drag loop. I let off and realized what happened. I went solid Moroso and solved the problem. The bolts you use look bigger than the Schumakers. I probably should have made one myself. Looks stronger.

There you go, I took out my Schumaker mount because it only had one bolt, I put 3 larger bolts in one of mine 

Dan

[firefighter3931]

I hate to say it but I had a Schumaker mount in my 69 and ripped both bolts trough the mount. The engine rolled over under the hood and left a big gouge in my hood. I remember launching a 1.80 60 Ft. in a 4000lb car and hearing the driveshaft hitting the drag loop. I let off and realized what happened. I went solid Moroso and solved the problem. The bolts you use look bigger than the Schumakers. I probably should have made one myself. Looks stronger.

I guess my "poor man's" design is stronger than the schumaucher mount.  A pair of grade 8 3/8 in bolts has lotsa shear strength : not sure of the exact number but i know it's large. I would think the ear would tear off the block before one of those bolts snapped. If you're  making that kind of power an engine plate is a better option anyway.

Ron

[Rolling_Thunder]

I just run solid mounts....       cures all problems...     Schumacher rubbed me the wrong way with my old mounts so I figured i would end all these broken motor mount problems...     

[kamkuda]

Nice set-up Ron.  I have to do that some time soon.

[firefighter3931]

I have to do that some time soon.

[Blakcharger440]

i have solid mounts, that fixes everything......no drilling, no buying bolts, just buy em and slap em in

Me too!   Althought it is a great tip for those running rubber mounts.

[71440charger]

fixed my buddys that way the other day just like new kind of hard to drill just right though

[firefighter3931]

fixed my buddys that way the other day just like new kind of hard to drill just right though

Yep, those mounts are tough. I use a 1/2in Hammer Drill with a high grade steel bit and it works pretty good. 

Ron

[Duey]

I hate to say it but I had a Schumaker mount in my 69 and ripped both bolts trough the mount. The engine rolled over under the hood and left a big gouge in my hood. I remember launching a 1.80 60 Ft. in a 4000lb car and hearing the driveshaft hitting the drag loop. I let off and realized what happened. I went solid Moroso and solved the problem. The bolts you use look bigger than the Schumakers. I probably should have made one myself. Looks stronger.

I guess my "poor man's" design is stronger than the schumaucher mount.  A pair of grade 8 3/8 in bolts has lotsa shear strength : not sure of the exact number but i know it's large. I would think the ear would tear off the block before one of those bolts snapped. If you're  making that kind of power an engine plate is a better option anyway.

Ron

3/8" Grade 8 (150,000 mpsi Tensile/130,000 mpsi yield) will deform starting at 10,800 lbs and fail at 12,500 lbs.  Proof load is based on 120,000 mpsi which means 10,000 lbs is max design load for a 3/8" bolt.  Clamping loads (assumed at 75% of design load) would be 7,500 lbs. 

Two of those bad boys per Ron's design give a 20,000 lb design load, with failure at 25,000 lbs......they aren't going to break. 

You're good to go! 

Cheers,
Duey

[firefighter3931]

3/8" Grade 8 (150,000 mpsi Tensile/130,000 mpsi yield) will deform starting at 10,800 lbs and fail at 12,500 lbs.  Proof load is based on 120,000 mpsi which means 10,000 lbs is max design load for a 3/8" bolt.  Clamping loads (assumed at 75% of design load) would be 7,500 lbs. 

Two of those bad boys per Ron's design give a 20,000 lb design load, with failure at 25,000 lbs......they aren't going to break. 

You're good to go! 

Cheers,
Duey

Thanks for the technical info Duey ! 

How's the engine project coming along ?


Ron

[Duey]

3/8" Grade 8 (150,000 mpsi Tensile/130,000 mpsi yield) will deform starting at 10,800 lbs and fail at 12,500 lbs.  Proof load is based on 120,000 mpsi which means 10,000 lbs is max design load for a 3/8" bolt.  Clamping loads (assumed at 75% of design load) would be 7,500 lbs. 

Two of those bad boys per Ron's design give a 20,000 lb design load, with failure at 25,000 lbs......they aren't going to break. 

You're good to go! 

Cheers,
Duey

Thanks for the technical info Duey ! 

How's the engine project coming along ?


Ron

Ron, I'll likely not get to it till I'm doing weeks up in Pet with Paul.  I still have a heap of "mission critical" projects (i.e. CINC House's project list) that have to get done before I get in to the motor again.  That, however, did no stop me from assembling the Proform 850, spacer, AN-fitting dual feed and pressure guage on my Holly SD manifold and making "vroom, vroom" noises in the garage.

Hey, off-topic Q, bro...what's the deal with the apparently very reasonable price for BB roller rockers at 440source.com?  Is it really $215 for an entire set? (p/n 113-1007)  What's the hitch?

Thanks,
Duey

[firefighter3931]

Hey, off-topic Q, bro...what's the deal with the apparently very reasonable price for BB roller rockers at 440source.com?  Is it really $215 for an entire set? (p/n 113-1007)  What's the hitch?

Thanks,
Duey

Hi Duey, not sure on those rockers. They look very similar to the CAT rockers some people were haveing problems with in the past. I can't imagine they'd be descent quality for that price. If you really want a fully rollerized rocker arm, Harland Sharp is your best bet. I went with those so i'd have the option of upgrading to a roller cam in the future. The crane golds and ductile iron are fine for flat tappet spring pressures if that's what you're thinking. If you're planning to only run a solid flat tappet with less than .600 lift ; the ductlie iron setup will serve you well.

Ron

Ps. Vroom-Vroom noises huh....sounds like fun  Post a pic up of the induction setup when you get a chance 

[Steve P.]

We did this on VegasMike's drivers side mount in March. After riding in the car with solid mounts and having my teeth rattled, we pulled both mounts and replaced them with stockers. We drilled and bolted the drivers mount and put it in. I was completely blind sided by the difference.   Still have all my teeth.. 

On my 65' I had to chamfer the K-Member side and use bugle headed bolts. I was able to get (3) 3/8s bolts in it. Probably overkill, but I tend to do things that way.. 

This is another one of those techno things we need to sticky.. Works great..

[Tarzan]

Hi Ron,

Did you use you old mount when you put on the 2 bolts or did you get a new one?
What kind of mount did you buy and where?

I am thinking about doing the same thing on my 69 charger.

[Steve P.]

I have allways used new mounts. They are not very expensive and come out of the box nice and clean.

No brand loyalty here on mounts.  I just pick them up at the local auto parts store..

[Tarzan]

The thing is that here in Norway (where I live) everything is much more expencive than in the us.

The schumaker mounts cost 277 dollars and that toooooo much for some mounts.

Thats why Im asking. So I would like to know where I could buy these cheap mounts and then out the 2 bolts on and the torque strap.

[Tarzan]

I actually just need the rubber and not the mounts. They look good but I know that it is smart to change them but not at 300 dollars.

Where can I buy this rubber for the mount???