Motor plate GoodVSBad

Who mounts their engine with a motor plate? The car I bought has the K-member modified minus the motor mounting brackets and used a motor plate to set the engine back 2 inches looks fine but I'm wondering the effect of driving the car on the street. Motor plates work well for drag racing but what is the good vs bad for the street? The car is a 64 plymouth with a 4 inch altered wheelbase (moved forward) in the rear and has the frame tied so body twist should not be an issue I think.

 

You feel every vibration from the engine. With time stuff will start to crack remember dragsters only drive 1320 ft at a time max and only on weekends.

Solution build yourself the equivalent of a HURST style of motor mount and mount it on biscuits. Loose the mid motor plate and put a proper rubber mount under the tranny.

 

That is what I am concerned about, the car has no midplate it uses the production tranny mount. Here is the motor and plate that was in the car.

 

Well let me preface what I'm going to say with this disclaimer. I'm a go fast junky and always have been. Lighter and faster has been a specific goal of mine as long as I can remember.

That said that particular mount mount needs a mid mount plate and a solid tranny mount to be proper. I don't think that I would run that particular setup in a driver myself. But you will find some that will say go for it.

You could duplicate that with a little stiffening and a little tube with a bushing in it on the ends and make yourself a good street setup. Give me a minute and I'll see if I can come up with a drawing for you to show you what I'm thinking.

Edit: Ok I'm a little rusty and I can't remember how to turn a CAD drawing into a jpeg that is easy to see so I'll have to mess with it tonight when I have more time. But I'll get you a legit drawing that you can see. I promise.

It does look good under the hood BTW. Someone was into clean and I am all for that.

 

The motor plate with a std tranny mount made me wonder also. If you are eliminating torque loss you need ridgit mount for engine and trans. When you research motor plates they stress they are eliminating distortion on the engine block and cylinder bores by using the plates as well as putting the torque to the rear wheels with less loss. The higher dollar plates have bushings so you think that would be more for the street than ridgit mounts. The plates do make it easier to swap out the engine and trans.

 

The type of plate you are talking about will wrap under the crank. You have to be putting a lot of torque to the ground to make that type of block stabilization necessary.

With the setup that you have it would be a pretty simple step to drill the end of the plate nearest the sub frame and weld a tube in it to accept a bushing say big enough for a spring bushing. Then weld a piece of flat to the bottom endge of the plate to stiffen it. A second ear welded to the sub frame and a bolt slid through the bushing and both ears and you have a very streetable mount that still looks the part.

If you need it rigid just chain it down on the drivers side or put a torque stay on it and then remove it or loosen the chain when you want to go cruisin'.

I just can't see your setup holding it for any length of time without a mid-motor plate.

 

Those 'ears' were popular way back on drag cars, but as noted drag cars were not DD's.
There is a real basic reason why manufacturers have spend large piles of money developing and using rubber cushions...


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forget the concerns That is not called a motor plate. They are called Elephant Ears. It was a very common way Mopar BB were mounted back in the day. All the bla bla bla about vibrations is nonsense. You will be surpised at how little there is. We used to add a triangulated Turnbuckle to the left front just to ensure it wouldnt move but not always. (usually only on 4 speed cars with a real heavy clutch pedal.Although it wouldnt hurtto always do it. ) The sixty nine Dart I had used these Mounts for both a 426 hemi and later a 440. Never had a seconds bit of trouble. Also used them in A body Street cars when installing a BB . Never had anyone complain about vibration. It is just a non issue. Probably because of the length of the ears. It is a wonderful set up and is really nice when you need to work on the motor. Early ones I saw used 1/2 inch to 3/4 inch aluminum. I made them in my shop out of 3/16 steel . We used to make up ten sets at a time so we had them on hand on the shelf. With the steel you could put the water pump in the press and move the fan blade hub back 3/16ths on the shaft so the pulleys would even line up. Some of the newer pumps had a thicker boss on the backside of the pump fan blade hub and we moved it a prudent amount then fabbed a steel shim for the bottom pullley as well to complete the job. In those cases we had to shim the alternator forward the thicknes of the pulley shim so we made new spacer sleeves up in the lathe. On race cars we didnt (and still dont) run an alternator so es macht nichts)
Don

 

If the motor plate is the sole support of the front of the motor it is a bitch to mess with a cam change. You have to remove the motor plate and jack up the motor to remove the timing cover. Then if you have to move the car in the process you have to put the plate on or do something to support the motor unless you just let the pan ride on the crossmember. Just my 2 cents.

Mike

 

I drag race. There is no other way to put it. I have worked on cars that look like they drag race, but it is different. so here is the .02 that I will give you.

There is nothing wrong with a solid mount, but i would want to get a proper trans mount, as you are mismatched on the amount of drive train deflection that you can generate, and as such, it is not being spread in a even (well relatively) manner to the chassis attachment points. This can cause excessive vibration under acceleration.

With rubber engine/rubber trans you get a certain amount of flex, that is absorbed, same with poly, when you solid mount, it is a good Idea to do the whole thing. As you are set up now you are putting all of the stress (under torque) on just the front section of the frame, as the trans mount is not side loading due to the flex of the rubber. I think welding on the tubes, and rubberizing your plate is a good idea, or at least getting a solid trans mount.

I have run elephant ears on old cars, and newer cars with solid trans mounts and all is well, the amount of vibration is nominal at best, and as stated is a non issue. And this is with 550+ hp pump gas small blocks. Solid suspension parts are a whole different story.

If it is for looks, just get the solid tranny mount and be done with it.

Russ

 

Not all motor plates interfere with timing chain covers! I've run them on the track and street, they are just one way to mount an engine. You must also use a fore/aft travel limiter with a motor plate, as they don't have strength in the longitudinal direction.
They are not what I would consider "traditional" as this site sees tradition (with the exception of baggin, for some reason). There's lots of clean ways to mount an engine without motor plates, but if you like the look, or percieve it would be the simplest way to skin that cat, by all means have at it. Remember, a fore and aft limiter as well, or you'll be sorry!

 

OK,,, Not to piss anyone off, but you should never use a solid or hard urethene trans mount EVER!

With a solid rear mount any and all chassis or drivetrain flex is focused on the solid mount. The solid mount will transfer that twist onto the tailshaft housing of the transmission and it will snap.

Having built 100s of drag cars,, I use a solid rear mount for setup only. When final installation of the drivetrain is done I always use stock rubber mount.

This applies to every type of vehicle and every type of mounting arrangement.

It also doesnt matter what horsepower range. The laws of phsyics and leverage are the key components here, not horsepower and torque.

To further explain Storm King's comment on engine limiters,,, motor plates locate the mdrivetrain side to side and up and down but do little to keep it from moving front to back.

Without engine limiters teh fore/aft motion will work the mounting tabs for the plates to the point of failure.

to counteract this motion make a plate that will bolt in the stock motor mount location and add tabs so you can run a piece of tubing from that plate to the chassis, try and keep them as close to level as possible. Again this has nothing to do with horsepower level although more power will break them faster.

 

You have to remove the motor plate and jack up the motor to remove the timing cover.

No. On a mopar the motor plate or elephant ears do not cover the timing cover. You put six studs in the waterpump housing bolt holes at the front of the block, gaskets behind and a gaskets in front . Usually the mounts are two piece. One for each side although I have seen them and have made them with a connection between.
Don
This car ran them for many years (about 10 ) and then when it was sold they were used in the Duster with that motor that had been in my dart.
Originally i put a 426 Hemi in this and ran it till I flatout wore it out from old age. It used the same set of elephant ears that I am talking about now. Of course the plates fit both engines(Hemi and 440)(and B series motors as well) the same. The no chrome thing has been for me a lifelong thing BTW.
The plates are called Elephant ears because the 426 Hemi was known in its heyday as the Elephant so when these plates were first develpoed they were known as Elephant Ears.
The triangulated brace which is not a bad idea anyway can be installed right on the PS boss on the engine and on an angle to the K member or on up the frame rail. That stops any fore/ aft movement completely. . If you can find something wrong wth the setup you must have a vivid imagination. They were "Standard Mopar" equipment especially in A bodies and i dont recall in 40 odd years of racing and building hearing anyone having problems. Not once ever.
Don

 

Don is correct, I consider elephant ears to be motor plates, and of course, they really aren't. I think Elephant ears were first developed on the Hemi Pro Stock cars, and when SRD built the first tube chassis pro stock Vegas, they built the first motor plates, at least as we see them today. I've always used factory rubber mounts on the transmission, even with ears and a mid plate. I think that is wise...

 

Thanks for all the info, I needed to hear from people that actually ran the motor plates to get the good vs bad.

 

Yep, Don is right. On mopar it works that way. Had my head up my ...

 

If you end up using the motor plate, which is fine in my opinion then listen to King, fore/aft limiters are a must to keep the motor from wanting to "push" backwards when you nail it! Simple to make out of a couple of 1/2" heim joints and a few tabs.

 

I am going with the standard engine mounts since I'll be more on the street and some track time. I found a K-frame I need so replacing that will get me back to standard.