Solid engine mounts
- Thread starter Johnny
- Start date
Wild Mango
Member
Why would you do that?. Solid mounts vibrate. Ask anyone who has driven a solid mount dirt car, especially a four banger midget with an intrinsically out-of-balance engine. Wonder why the crew go all over the car with a handful of spanners between heats? For a small block the standard Chevy mounts are plenty rigid, if you making grunt deluxe, a torque stay is good insurance against mount rubber tearing in tension. Hard mounts you get all the high frequency vibes you and the rest of the car can do without. JM2CW
Johnny
Member
Well, my reasoning on this is due to my brake master cylinder is so close to the transmission. I'm worried that the engine could move enough to hit the line coming out of the M/C.
How much will the engine move with the rubber biscuits?? I will leave the mounts alone and see what happens.
Thanks for the info.
How much will the engine move with the rubber biscuits?? I will leave the mounts alone and see what happens.
Thanks for the info.
donsrods
Member
It has been done and although some people say they have one and it isn't too bad, I would still want rubber insulators in there. The factories do it for a reason. That being said, we are building a Capri Drag/sometimes street car for my Son and it is going to have a 460 Ford with engine plates solidly mounted to the subframe. Since it will be getting limited street use it will probably be bearable, but I sure wouldn't want to drive one like this often.
If your brake line is that close to the transmission you have other issues that are more serious (heat) I would redo that part instead.
Don
If your brake line is that close to the transmission you have other issues that are more serious (heat) I would redo that part instead.
Don
Keeper
Active Member
I have a similar situation with the master cylinder. While I did get the lines coming out to bend/clear the transmission its still pretty damn close.
The plan I have to fix it is to use some 90 degree adapters that come right off the master cylinder. They use the same style connector as the calipers, with the banjo/washers.
If I could find them again I would show you what I am talking about but I seem to have misplaced the link!
The plan I have to fix it is to use some 90 degree adapters that come right off the master cylinder. They use the same style connector as the calipers, with the banjo/washers.
If I could find them again I would show you what I am talking about but I seem to have misplaced the link!
Keeper
Active Member
Found them:
http://www.purechoicemotorsports.com/index.cfm?ptype=results_w&mode=zoom&image=prd_zm_107.jpg
You could always make some 1/2 inch metal biscuits then put a smaller 1/4 rubber biscuit on top, would limit the movement of the engine and still keep the vibes down.
I would be more worried about the rubber trans mount moving over the engine.
http://www.purechoicemotorsports.com/index.cfm?ptype=results_w&mode=zoom&image=prd_zm_107.jpg
You could always make some 1/2 inch metal biscuits then put a smaller 1/4 rubber biscuit on top, would limit the movement of the engine and still keep the vibes down.
I would be more worried about the rubber trans mount moving over the engine.
Wild Mango
Member
Good to be cautious wherever brakes are concerned. A torque stay on the back of the trans will make sure the brake parts are safe - the trans mounts are usually softer and bigger in section than the fronts, as someone has already pointed out. Torque reaction on an SBC tends to lift the front drivers side and push the trans rear to the passenger side if the front is restrained. The stock Chevy mounts don't move much at all, having said that, and most people fit torque stays as insurance against the driver side mount failing in tension, albeit unusual.
Keeper, Lamb Industries sells a 1/2 x 20 banjo fitting that i used on my Wilwood master cylinder
Wild Mango
Member
A torque stay is a solid linkage, often with a rod end on each end, used to limit the movement of the engine under load conditions. A front torque stay might run from the front of the engine, bolted to one of the accessory mount holes and down to the frame. This steadies the engine when it reacts under load and twists against the driveshaft torque, it also takes the tensile load off the drivers side mount. Inevitably a bit of smoothness is lost through the stays rigidity, so there is a trade off. The rear stay usually stops the trans movement in a horizontal plane.
donsrods
Member
We used to run a turnbuckle or a piece of chain from the drivers side of the engine down to the frame on our cars to keep the engine from breaking motor mounts.
Some people say you are not supposed to mix polyurethane trans mounts with regular motor mounts because it can cause cracking of the trans tailshaft. I don't say that, but was taken to task on another forum because I have that setup on the rpu I am building.
Don
Some people say you are not supposed to mix polyurethane trans mounts with regular motor mounts because it can cause cracking of the trans tailshaft. I don't say that, but was taken to task on another forum because I have that setup on the rpu I am building.
Don
Isn't that simply a matter of whether or not the engine mounts allow it to twist more than the trans mount does?
Back in the day we ran solid engine mounts and a rubber trans mount, on automatic trans cars. If you ran 3 solid mounts then more than likely the trans case would break right behind where it bolted to the engine. The theory was if it was all solid, when the car left the line and it hooked up good the chassis would twist from the torque of the engine. With 3 solid mounts the trans did not twist but broke. With a manual trans and a scattersheild, you did not have that problem.
Wild Mango
Member
In all my years I have only ever seen one bucket engine tear a LHS mount. Back in the thankfully short lived era of clutch flytes, when a two plate clutch locks over 200lbs of 7000rpm rotating mass to a drive train it results in a lot of energy to dispose of, and in this case it disposed of the left and right front mounts in that order, the rear never stood a chance, and this big heavy hot roaring thing leapt over the right hand side of the car in a cloud of steam and busted fiberglass, smashed the trans case open in a spray of dexron, rolled over a few times and lay still. No injuries, happy days.
Front stay, cheap insurance.
Front stay, cheap insurance.
Screaming Metal
Active Member
Back in the day we ran solid engine mounts and a rubber trans mount, on automatic trans cars. If you ran 3 solid mounts then more than likely the trans case would break right behind where it bolted to the engine. The theory was if it was all solid, when the car left the line and it hooked up good the chassis would twist from the torque of the engine. With 3 solid mounts the trans did not twist but broke. With a manual trans and a scattersheild, you did not have that problem.
I killed several Transmissions just as Ron said, with 2-400 cu.in. Poncho's in Firebirds. Then, it happened with the 455 SuperDuty in the Firebird. Was learning, and learned my lesson well. My pride and joy was a Factory 421 SuperDuty Drag Catalina, it came from the factory with solids, and I never messed with them, I kept the car as it was, until I sold it.
If your gonna run solid, your in for alot of vibration. Otherwise, run the torquestay or torquebar on the one side of the motor to keep it in place. They also keep the motors from ripping the rubber mounts loose. All the Hi-Perf. cars less than 450 horses usually had factory rubber mounts.
A cable, as Mike mentioned, works very well as it "gives" just a bit when it goes tight. a chain is a bit more violent, and a solid link transmits vibration to the drivers seat at all times. I find it a bit more challenging to make a neat appearing end on a cable, but it's worth the little extra effort IMHO. I couldn't fit a restraint in on the "correct" side of my [off topic car], so was forced to use a solid link. It's a free massage (woman love it), but it would get old on longer drives.
If you have a shop that does cable ends (like a logging supply company for example) you can have them put loops in the ends by using nico-press fitting. slip a piece of heat shrink tubing on over the nicos and the ragged ends of the cable, and it will look as nice as it works.
Russ
If you have a shop that does cable ends (like a logging supply company for example) you can have them put loops in the ends by using nico-press fitting. slip a piece of heat shrink tubing on over the nicos and the ragged ends of the cable, and it will look as nice as it works.
Russ
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