building a back half car...got questions

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overdriv
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building a back half car...got questions

Postby overdriv » Tue Sep 06, 2011 5:48 pm

I'm in the process of building a 87 Camaro drag car. It has a S&W 4 link back half coil overs, etc.
I'm trying to decide what to use for a track locator. I have read and by just looking at it, I thought the wish bone type would be the best. But the guy that is going to install the roll cage says they are unsafe and the diagonal bar is the better choice. He said a friend had a wishbone and wreaked his car becauce the slip joint in it froze up and the bars broke, letting the rear end move around, causing the guy to over conpensate with the steering and well he wreaked it.

What say you guys?
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pro70z28
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Re: building a back half car...got questions

Postby pro70z28 » Tue Sep 06, 2011 7:57 pm

I've got a wishbone in mine. I've run the suspension through & past it's travel range. The wishbone joints are in the same plane as the 4 link joints so there's little or no movement of the slip joint. I went with a wishbone because I've heard bad things about diagonals, go figure.

Image

If you look at the pic. of mine (pay no attention to the surface rust :oops: ) a diagonal would be at a pretty bad angle to stop lateral movement. I was afraid at that angel there would be too much stress on a diagonal bar.
Yours may work out different, I don't have much room between the tires.

Anything, especially if it's put together with heim joints will need pretty regular maintenance to be safe.

Just my opinion. Ask 6 people, probably get 6 different answers

If you have the room, a watts link is a slick set-up.

I should mention, I plan to pack mine with wheel bearing grease. I built it with an aluminum cap (slip joint end - see in pic) machined to accept a pressed in seal to keep the junk out. The other cap on the front end is just a dust cover. I'm sort of annal about details that no one will ever see. :lol: :lol: :lol:
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overdriv
Posts: 44
Joined: Wed Sep 02, 2009 10:28 am
Location: Central IL

Re: building a back half car...got questions

Postby overdriv » Wed Sep 07, 2011 1:02 pm

My frame rails are 24" apart. The diagonal bar would be pretty short which would be good for strength, but would cause the rear end to move sideways a bit more than a longer one.

Now I've read and seem some are selling and using an "X" bar between the lower 4-link bars.

What is a Watts link, could you guide me to a picture of one?

Thanks.
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pro70z28
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Re: building a back half car...got questions

Postby pro70z28 » Wed Sep 07, 2011 1:41 pm

Here's one. If I were to build over I might go this way.

Image
nothing to say at this time.

overdriv
Posts: 44
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Location: Central IL

Re: building a back half car...got questions

Postby overdriv » Wed Sep 07, 2011 3:53 pm

ah, yeah, I've seem these before. I don't have enough room to do that. I think I'm going to do the wishbone for awhile and see how it works out. I'll just add that to my service procedure and go from there. Thanks for the help.
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overdriv
Posts: 44
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Location: Central IL

Re: building a back half car...got questions

Postby overdriv » Wed Sep 07, 2011 8:23 pm

OK, if you mods think I should start a new thread just say so and I will.

I will be using a front engine plate and a mid plate. The mid plate will be a hanger instead of bolting to the body on either side. Front plate will be 1/4" aluminum.

Do I still need the mount on the rear of the transmission?

Should I use some sort of limiters on the front of the engine?
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pro70z28
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Re: building a back half car...got questions

Postby pro70z28 » Wed Sep 07, 2011 8:49 pm

You'll get varying opinions about that too. I have bolted in motor & mid plates & a urethane tail shaft mount. Some will say they run all solid mounts (including tans) but it seems to me unless your chassis has 0 flex you run the risk of putting the trans in a bind, breaking the tail shaft housing or more likely the bell housing. No tans. mount at all sorta does the same thing. A lot of weight hanging off the mid plate + the torque of the engine. That's a lot to ask of the bell housing. An ultra bell would be stronger but I think I'd still put the trans mount on it just to be on the safe side.

Image
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overdriv
Posts: 44
Joined: Wed Sep 02, 2009 10:28 am
Location: Central IL

Re: building a back half car...got questions

Postby overdriv » Wed Sep 07, 2011 10:03 pm

Well that's my feelings too. So do you think I should still employ engine lateral limiters if I keep the trans mount. Seems to me it would limit the fore/aft movement of the engine/trans during acceleration and deceleration.
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pro70z28
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Re: building a back half car...got questions

Postby pro70z28 » Wed Sep 07, 2011 10:29 pm

I agree. I don't have them built yet but they are on the to do list.
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stimpy
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Re: building a back half car...got questions

Postby stimpy » Fri Sep 09, 2011 2:33 am

the wishbone is superior to the diagnol in strength and makes it easier to tune the rear end , but you must keep on top of greasing the slide tube ( and like pro said you must also check your heim joints on the diagnols and 4 links regularly too ) .also never run a x in the four links as it will bind the housing up as it needs to pivots or roll ,,only one side to the other you must have the roll rotation that the four links allow otherwise it would act like a ladder bar , 4 links allow the chassis to torque one direction the axle housing the other allowing you to tune the hit on the tires .
as for front and mid mounts . with a aluminum bellhousing thats not sfi aproved ( superbells ) I wouldn't chance it as if you have a small crack, the torquing action and weight bearing can lead to disasterous results as the factory housings can develop small cracks at the bottom where the bell housing joins the pan and around the bolt holes on the bell area , and a factory transmission bellhousing wasn't designed to bear all the weight of the transmission or the torquing action( the case is used as part of the locking mechanism for the planetarys thru the servos ) thats why they have the back mount , oems are very cost concous if they feel it don't need it they eliminate it as its $$$
as for engine limiters . a must with any motor plate car as the motor will stay still when the chassis launches and the chassis will move forward and then bend the plate and you can damage your driveline and start cracking the motor plates . even on some big block cars that use solid motor mounts a limiter is need if it launches hard . the car I used to work on we bent solid motor mounts and cracked the trans until I put a limiter on it and the car only pulled a 1.30 in the 60
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