FrontEngineDragsters.Org Forum
Drag Racing Discussions => Front Engine Dragsters => Topic started by: digster on March 19, 2016, 10:57:17 AM
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My old Dart block used torque limiting struts from holes where std. motor mounts would be angling up to a chassis tube. My new Brodix Alum. Block has the std motor mount pad milled off. I do run a 1/4 in. Alum mid plate. How have you quys limited engine fore and aft movement when you couldn't
bolt to the side of the block?
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You could use the front of the block, back of the trans or even the back of the block if you could come up with some brackets that shared the trans bolt pattern. Some clutch cans have tabs just for that purpose if you're running a clutch.
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We, as every other FED with SBC that I see use the front water pump bolt holes for front motor mounts, that are clamped unto the chassis. And the rear motor plate bolted to the chassis, but some guys also clamp the rear motor plate to the chassis. It is a good idea to have the front motor mounts line-up with a chassis upright.
1'st photo is our front mounts, 2'nd photo is the rear motorplate, including our rear support mounted to the motor plate that helped cut down our tire shake, that with the rear trans mount keeps the chassis from flexing between the motor and rear end.
I'm surprized you would have a problem with it moving forward and rearward if the rear motorplate is bolted to the chassis.
Jon
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Jon,I think he's looking for ideas just like that top link you have from the rear motor plate to the steering cross member. Motor plates will flex and eventually break without something to limit engine movement on launch. It's not as much of a problem on less frequently run cars like a lot of nostalgia cars, but on something like a bracket RED that gets run a couple days a week every week it can really take a toll. It can also help the trans live a happy life on the off chance that the coupler was bottoming out when the motor plate flexed.
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^^^^^ Yep, he is looking for something to stop the inertia of the motor (usually the heaviest part of the car) from having it try to move backwards (or actually stay where it is relative to the track) when the car launches. Although the link in Jon's car probably helps it would be a better idea to tie the trans mounts to the upper frame rails with an triangulated bracket. In Jon's car any severe fore and aft load will have a tendency to to flex the steering cross member.
Roo
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Much to do about nothing
On a clutch can those are blow back struts to keep the can in place during an explosion. The fit is rather loose to be able to get the can off
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Thanks for all the replies. The second part of the question was also touched on. Are torque limiters really needed? A wide chassis car with a .100 steel mid plate would much more "Needy" than a narrow chassis car with a 1/4 in alum plate bolted in. My front mount is the same as Jon's wing and clamp style. Johns car has allot more "Good Business" going on up front though! ;D
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It took about a 100 passes at 1.24 60 foot times to crack my aluminum mid plate and also wreck the trans driving the coupler into the back of it.
It had a filled stock small block and its 19in. wide at the plate.
I wish I had put limiters in. Live and learn.
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Torque is a rotational movement , if you was to stop rearword movement at the hit, then weld a strip of material to the motor plate uprite so that it backs up the aluminum motor plate and limits rear movment
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Torque is a rotational movement , if you was to stop rearword movement at the hit, then weld a strip of material to the motor plate uprite so that it backs up the aluminum motor plate and limits rear movment
This helps, especially on cars with narrow motor plates. I've seen motor plate's broken around the outline of the block as well, mostly on wider motor plates. I also radius every hole and edge on the motor plate, makes it a lot more friendly on skin if you slip a wrench near it and kills the stress risers as well.
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I agree with most everything said. I broke a motor plate on a soft leaving 1.25 60' RED after a couple hundred passes with no Limiters. I use the bars to my clutch can on our BA/D but I designed them to be very tight and solid.( Maybe I even need more support) A big yes to removing all edges on the block and trans/bell and buff all the rough edges on all of your aluminum parts.