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 Post subject: Engine Mounts
PostPosted: Thu Dec 02, 2021 12:26 pm 
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3 Deuce Webber

Joined: Thu Jun 04, 2020 11:40 am
Posts: 73
Location: Owasso OK
Car Model: SDRA Dragster
Who is using front and rear (mid plate) type mounts? I'm using the factory mounting points of the two mounts to the block and one transmission tail shaft mount. I have my reasons, but was wondering if anyone is using the "front and back of block" type mounting and what advantages it has.

Most dragsters use the mid plate type mounting, but I chose to keep the factory mount points. I have received some comments on how that won't work in a dragster. Yet its working just fine.


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 Post subject: Re: Engine Mounts
PostPosted: Thu Dec 02, 2021 2:00 pm 
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Turbo EFI
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Location: Brightwood, VA
Car Model: 1965 Plymouth Belvedere I
Considering how well you are running, I'd say youare doing something right.
Jus sayin.....

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 Post subject: Re: Engine Mounts
PostPosted: Thu Dec 02, 2021 2:14 pm 
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3 Deuce Webber

Joined: Thu Jun 04, 2020 11:40 am
Posts: 73
Location: Owasso OK
Car Model: SDRA Dragster
The front mounts are solid. The tail shaft mount is a pivot mount. This is a trick I learned from dirt track stock cars that used to break the ears off the three speed manual transmissions. They used to mount the tail solid. Once they used a soft rubber mount, they quit breaking housing.
I took it a little bit further and just allowed the tail to "twist" or Pivot on a bolt. That takes care of any chassis flex. And I'm sure I have chassis flex.
Funny thing is the guy that told me it wont work broke the ears off his Chevy/PG setup. Hmmmm.

But, there is no doubt the mid plate setup is widely used in dragsters. I just can't figure the advantage until you get above say 500 HP. Maybe the mid plate is more for chassis strength than mounting the engine.

I just thought three points of connection was a good idea. That way nothing is in a bind.


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 Post subject: Re: Engine Mounts
PostPosted: Thu Dec 02, 2021 5:12 pm 
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Board Sponsor & SL6 Racer

Joined: Wed Oct 23, 2002 7:57 pm
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Ryan's race car has Front engine plate and then bolt on "Mid Plate" ears that bolt to the belhousing and then bolt to the frame. No sure of the advantage though. :D :D

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 Post subject: Re: Engine Mounts
PostPosted: Thu Dec 02, 2021 7:09 pm 
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Supercharged
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Joined: Sat Nov 27, 2004 8:03 pm
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Location: IRWIN PA
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I have a front plate in ruster with no midplate and a poly trans mount for the tail shaft on the 904.


I would surmise that you are getting those comments possibly because some rail cars... ( I cant remember on yours) have no rear suspension except the tires so it shocks the drivetrain pretyy hard at launch?

That's all just conjecture on my part.. so take it for what it worth.

Greg

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 Post subject: Re: Engine Mounts
PostPosted: Fri Dec 03, 2021 4:59 am 
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Turbo EFI
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Location: Brightwood, VA
Car Model: 1965 Plymouth Belvedere I
The pics of the #43 car that I have seen show it launching straight and true. Wheels up, the chassis looks straight, no twisting or flexing. I'd say you are doing pretty good.

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 Post subject: Re: Engine Mounts
PostPosted: Fri Dec 03, 2021 5:44 am 
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If you're worried about fore/aft movement with a front plate, you can always make a pair of torque limiter bars that go from the front of the block to the chassis back toward the bellhousing area.

My car has a plate and rear mount like Greg's. Mike used to go pretty fast with it that way.

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 Post subject: Re: Engine Mounts
PostPosted: Fri Dec 03, 2021 9:08 am 
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Supercharged
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slantzilla wrote:
If you're worried about fore/aft movement with a front plate, you can always make a pair of torque limiter bars that go from the front of the block to the chassis back toward the bellhousing area.

My car has a plate and rear mount like Greg's. Mike used to go pretty fast with it that way.



Yes and our cars are quite a bit more heavy and girthy then not2slow's #43



:D :D

Greg

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 Post subject: Re: Engine Mounts
PostPosted: Fri Dec 03, 2021 12:04 pm 
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"Girthy" :lol:

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 Post subject: Re: Engine Mounts
PostPosted: Fri Dec 03, 2021 12:21 pm 
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slantzilla wrote:
"Girthy" :lol:


Girthy bucket pizza... :lol:

The Challenger has a front plate and rigid trans mount in the stock location. It's a tube frame car though.

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 Post subject: Re: Engine Mounts
PostPosted: Fri Dec 03, 2021 1:07 pm 
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3 Deuce Webber

Joined: Thu Jun 04, 2020 11:40 am
Posts: 73
Location: Owasso OK
Car Model: SDRA Dragster
I am happy (and surprised) with how well the 43 launches. However, at three tracks this year, including Jeffers, I had severe bouncing. These three tracks were very sticky. I tried going up in air pressure to no avail. That's what a solid mount diff will do for you. Everyone I asked about it said soften the shocks. :roll:

Slow motion video showed the tires wadding up and then releasing the energy, starting a bouncing ball effect. It seems to start the second the front end comes back down. In fact, one racer advised me to "plant" the front end, then work on the traction. Slick tracks allow slight wheel spin and off she goes, pulling the fronts up. :shock:

I have talked to several hard tail dragster guys, and they say stiff side wall tires cured it for them. Stiff sidewall tires are intended for heavy cars, but with no suspension, the tire sees the dragster as a heavy car. At least that's what the dragster guys say. Now, I'm running a 9" MT on 8" wheels. They don't make stiff sidewalls in a 9". I'd have to go up to a 10.5 tire. Or....maybe a drag radial.
Anyone have experience with drag radials?

When at Jeffers, I mentioned to Dallas that the track was WAY too sticky for slant six cars. It was just as sticky at the 1/8 mile as it was at the starting line. Peal your shoes off kind of sticky. He said I was the only drag racer he ever heard of that said the track was too sticky. I guarantee you if they would glue the track to the 60ft and taper it out to nothing over 30 feet, all the cars there that day would have been faster. Seriously, we don't have enough power to break the tires loose 60ft and on. The cars were just glued to the track.

This picture is of the very first pass the car ever made. Notice the even tire pattern at launch. Amazes me seeing that the car is heavily loaded to the right side.

All this to say I am happy with the engine/transmission stock mounting configuration. Maybe more power and shock will reveal system weaknesses.

Speaking of that, I tore down the engine this week. Everything looks new. I'm surprised since I thought I was pushing the limits of the engine, especially at 6500, and launching at 3200

BTW: I appreciate everyone's comments and methods of engine/trans mounts. Keep in mind guys, that's what makes this groups special. Everyone has or has seen many different ways of doing the same thing. Not one car at the Jeffers race was the same, or even used the same approach to getting down the track. Yet the slant was common in all of them.


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 Post subject: Re: Engine Mounts
PostPosted: Fri Dec 03, 2021 9:58 pm 
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Joined: Thu Oct 17, 2002 7:27 pm
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Location: Park Forest, Illinoisy
Car Model: 68 Valiant
A drag radial will either dead hook or spin, they won't slip like a bias ply will.

How much air do you run? I have 9X30 radial slicks 9n a 10" wheel and I run 25. I could probably go up a couple pounds yet.

A 9" tire will work better on a 10" wheel too.

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 Post subject: Re: Engine Mounts
PostPosted: Sun Dec 05, 2021 12:04 pm 
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3 Deuce Webber

Joined: Thu Jun 04, 2020 11:40 am
Posts: 73
Location: Owasso OK
Car Model: SDRA Dragster
slantzilla wrote:
A drag radial will either dead hook or spin, they won't slip like a bias ply will.

How much air do you run? I have 9X30 radial slicks 9n a 10" wheel and I run 25. I could probably go up a couple pounds yet.

A 9" tire will work better on a 10" wheel too.



Thanks for that info. I've been as high a 20 psi, guess I can just keep going. I used the 8" wheel because I like the old Craigar ST and that's all I could find.
Plus SDRA used to limit rear wheel to 8". The rules have changed to allow 10" wheels.


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 Post subject: Re: Engine Mounts
PostPosted: Sun Dec 05, 2021 1:24 pm 
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Board Sponsor & SL6 Racer

Joined: Wed Oct 23, 2002 7:57 pm
Posts: 7393
Location: Waynesboro, Pa.
Car Model: 65 Valiant 2Dr Post
I run Drag radials on my race car at 19-20# and have never had any problem hooking up. My car is a lot heavier than yours at 2775#

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 Post subject: Re: Engine Mounts
PostPosted: Sun Dec 05, 2021 6:29 pm 
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Supercharged
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Location: IRWIN PA
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1000 + Pounds... that's one girthy bucket there...

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