Drag Racing Discussions > Front Engine Dragsters

Initial engine install:

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DNCMOTORS:
I'm installing the engine for the first time in a new 200"frame.  The motor is hanging and the rear of the engine is snugged up to the rear motor plate.  I'm fabricating the front motor supports to rest on the frame.  My question is should I have zero flex on the frame from the engine weight, or do I want some pre flex?  The motor is hanging level in the car as it sits on the tires.  Is this where I need to get my measurements for the front supports of the motor?
Thanks   

Supercat:
I did not preload my frame. Set engine to motor plate and made sure there was no distortion on the motor plate. Think balanced here. Measure for front mounts and tack together.  Before final finish on front mounts set trans in place with complete driveline in place to make sure of alignment.
Hope this helps

THE FRENCHTOWN FLYER:
I never ran a rail, but my gut feeling is most of the chassis flex will be ahead of the front motor plate. Not much will be at the engine bay.
Having said that, it is still best to mount the front plate on saddles with clamps. "Not much" bend is still not zero, and twisting of the chassis due to the engine torque will put some stress in the block if the front mounts are not "saddled up".
Some builders use a bolted engine mount in double shear taps on the left side where torque tends to pull the plate up and a saddle on the right side where torque tends to push the saddle mount down on the frame rail.

fuel749:
When I build a car the weight of the block is supported by the alignment bar and the bar is supported by the jig so naturally this  leaves no preload on the chassis.  As mentioned, if you're not using an alignment bar you'll probably come out way ahead to get all your driveline parts in place and make sure the coupler slides free through the whole process. 

JEFF/21C:
on the feds sbc with long glide  with a alignment bar set the motor then added saddle mounts on the top rail that had a tab welded to it and a grade 8 5/16" thru bolt then added a trans mount with insulator  never  broke a stock case even when doing a wheel stand high enough drag the rear of the frame (no wheelie bars) flattened both front rims.

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