Motorplates - Where to buy?

96speed
03-01-2004, 09:03 PM
Where are you guys buying your motorplates from? Does Billingsley offer one? Looking for options over Madman'$ piece.

Anyone have pics of where the plate mounts to the frame - would like to get a better idea...

TIA,
Ryan

Stephen 87 IROC
03-01-2004, 11:35 PM
I made my own from some 3/8" thick sheet aluminum.

You can buy motor plates from Jegs and Summit. You'll also need at least one engine limiter.

96speed
03-04-2004, 11:44 PM
Stephen: Thanks for the info. Where do you mount the engine limiter?

Does anyone have a pic of the motorplate/frame rail junction?

Ryan

Stephen 87 IROC
03-05-2004, 12:45 AM
I only use one limiter. One end is bolted to one of the old motor mount holes on the driver's side of the block. The other end is attached to a bracket I welded to the underside of the frame by the steering box. I think it's about 18" long and is made from 1/2" tubing and some 3/8" heim joints. All the limiter does is keeps the engine and tranny from moving forward and backward. A motor plate has a lot of flex in it. Don't use a solid tranny mount. It will break the tranny tailshaft housing.

I left the original engine mounts on the engine when I installed my motor plate. When I positioned the plate on the front of the engine, I fabricated it to sit on top of the frame rails. Once it was bolted onto the engine I fabricated and welded some brackets on top of the frame rails behind the plate (easier to pull engine forward away from than up over the brackets). Once everything was bolted in, I removed the original motor mounts.

A proper motor plate bolts to the lower front bolt holes in the block. These are the original front mount holes GM used back in the 50's and 60's and still kept them in the newer castings. The motor plate also sits behind the water pump so the water pump and fan if used, will sit the thickness of the motor plate closer to the rad. I made mine as 2 pieces but many of the aftermarket ones are a single piece. All the aftermarket motor plates need to be trimmed to fit in whatever vehicle you decide to use it in.

I think I have some pics on my web site of the engine but I don't know if any of them show good shots of the motor plate or engine limiter.

96speed
03-05-2004, 07:24 AM
Stephen: I'm following you. Thanks for the info man - Much appreciated.

Ryan

T/A lt1
03-09-2004, 02:14 PM
Does this help traction any?

Stephen 87 IROC
03-09-2004, 09:23 PM
No, not really. It solid mounts the engine directly to the frame instead of the regular engine mounts sitting on the crossmember.

I installed a motor plate because it's easier to pull the engine plus it gives more room beside the block with no mounts bolted to the side of the block. I run oil lines down the driver side of the block to a remote mounted filter on the motor plate. If I had the room I'd install a mid plate also. Right now when I pull the tranny I have to support the rear of the engine or it'll fall over backwards.

As I mentioned above, an engine will walk back and forth on a motor plate because it flexes. Engine limiters need to be used to keep the engine in place. It doesn't move very much but an 1/8" is enough to break a tranny tailshaft housing even if a rubber mount is used. If a mid plate is used then the engine is supported at the front and rear. A tranny can then just be bolted to the bellhousing and doesn't need the rear mount.

RacinLT1
03-09-2004, 10:48 PM
so it's OK to run just a front plate. i was trying to figure out what to do with my future setup.
Stephen,what trans mount are you using?

Just to get this through my thick skull,if you run a front plate,you definately have to run some sort of limiter off the side,but if you use a midplate you dont?

Stephen 87 IROC
03-10-2004, 12:57 AM
You need a limiter no matter what. It won't flex as much with front and rear plates but it will still flex. Some people use a front plate and still use solid motor mounts on the side of the engine instead of using a limiter. The motor plate still attaches to the frame so the engine torque is better controlled through the frame mounts.

I use a polyurathane tranny mount. I haven't broken a tranny case yet. I use a powerglide tranny.

One of the biggest problems with using a motor plate is mounting accessories. Because of how it's positioned at the front of the engine things that need to bolt onto the front of the engine won't usually clear the plates. The only real accessory I have is the alternator and I have it high mounted over on the passenger side. In the stock position bolted to the head, the back of the alternator hits the plate so I moved it outward and higher from the original location. I fabricated some new support brackets to keep it in place. The thickness of the plate will also change the belt position of the accessories depending on where they're mounted. I threw a few belts before I finally got the alternator directly inline and square with the crank pulley. I'd still like to install an idler just to shorten the distance between the 2 pulleys so the belt doesn't flop so much at high rpms. My water pump has an electric drive motor so my alternator belts just goes around 2 pulleys. The alternator and the crankshaft. The ideal setup would be to have a low mounted alternator with a real short belt but with the BBC I just don't have the room unless I converted to a rack and pinion steering system which would remove the steering box and idler arm from the inside of the frame rails. Even converting to rack and pinion wouldn't be easy because of how much room I have past the headers for the relocated steering shaft.

Steely
03-11-2004, 01:33 AM
Stephen a few things you could do with the K member is modifiy it like a Quay super-stocker or even better a tubular K-member with the rack mounts ton more room everywere.And while Ive got ya what is the crank centerline on your car(from ride height)and second do you like the Koni struts. I'm building a 85 with Quay componets,just trying too pick peoples brains

Stephen 87 IROC
03-11-2004, 08:22 AM
I want the PAracing tubular crossmember but right now the exchange rate puts it financially out of reach for me. I'd want the crossmember, tubular control arms with rod ends and the coil over kit.

I've never measured the crank height.

The SPA1 shocks are nice but I've never adjusted them to see if 60' times improve.