Rallye hood shakes at speeds over 60 mph

[shebacat]

Hello again; I have a 1974 Challenger with the rallye hood. Problem is, it starts to shake at the cowl end when I go over 60 mph to the point I'm worried it's gonna chip the paint. The scoops have the factory block off plates installed. What I have done so far is, replaced the hinges and cranked up the hood bumpers at the front, this helped a little but sometimes I'll hit a gust of wind and the hood starts to shake violently. Question, will hood pins help? I'm really not crazy about drilling holes in a good hood. Thanks for any ideas..Shebacat

 

[terrywalker]

I assume you have the plastic hood wedges installed on the fenders at the rear of the hood?
Terry W.

 

[shebacat]

Yes, they are there and the wedges are spring loaded. I also looked at the hood where it should contact the wedges and the paint is undisturbed, like it's not even touching the wedge. Maybe I'll shim the wedge closer to the hood.

 

[terrywalker]

The new reproduction wedges are slightly different than originals. I've compared them and there is a difference. As you said, maybe shimming them up slightly will allow contact and help with the shaking problem.
Terry W.

 

[shebacat]

Hi Terry; how about rolling two 1/4" balls of putty and place them on the wedge then close the hood to check how much the hood contacts the wedge.Question is, how much contact should there be? Completely compressed or partially ? Thanks again. Shebacat

 

[terrywalker]

Look at my photo and you can see where the hood contacts the wedge and you can see where the dirt is wiped off in back of wedge slot. About 1-1/2 coils down from top of spring. I'd guess wedge should be at least down 1/8 to 1/4".
Terry W.

 

[shebacat]

Terry; thank you for the info. I'm sure this will help. Shebacat

 

[70chall440]

So you have the rear rubber bumpers and are the front rubber stops adjusted so that the hood when closed in resting on them? It would not hurt to check all of the mounting bolts both on the inner fender and hood itself as well.

 

[sdcbowler]

Shebacat,
You may also want to check your hood hinges. It could be that when the hood is fully closed, the springs may not have as much tension as they should, or once did. The speed of the wind when you drive 60+ mph may be enough to cause the spring to expand, retract, stretch.....etc.

 

[DetMatt1]

Maybe if the cowl didn’t shake to begin with? This seems to be a symptom.

 

[Chryco Psycho]

what tires are you using ?
I have seen BFGarbage 3/8 of an inch out of round causing the whole front end to shake at speed .

 

[shebacat]

Hi everyone; problem solved. I shimmed up the rear spring loaded bumpers until they contacted the hood by about 3/16". The hood is fairly stable now at 60mph, I can even remove the block off plates in the scoops now. Thank-you everyone for your help. Shebacat.

 

[Chryco Psycho]

Ok but what is causing the shake ?

 

[AUSTA]

Good info mine shakes at the same speed had the BF's balanced twice looking for a better type we have a Gripmax tyre here in 15" haven't heard any feedback on them