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Discussion Starter · #1 ·
I've bought a chassis car with strut front end.
this is all new ground to me, so hopefully I'm not asking ignorant questions..

going over it with tooth and nail, I found the strut lower arms had different turns on the heims.
wondering if there is a starting point to take everything back to square one, like as if this was the original build,
or leave it alone and see what the first pass holds in store, as for safe driveability ?
(it has Hoosier front runners, in fairly decent condition,, but the tread on both seems to have a "scrubbed" appearance, which is what actually led me to check the front end.)
it has been a race car for a longggg time, and both prior owners say it's safe and drives easily; no bump steer or "pull".
here's some comparitive pics of the arms and calipers, noting the difference in the camber of the LH caliper as compared to the RH is straight up.. (frame is level on the lift).

this bottom heim is screwed out from the chassis mount


this bottom heim is flush with the mount


zero degree camber


half a bubble positive camber (didn't calculate the degree)


to add, it will have a BBC and I weigh ~190#.
it's always had a BBC and both drivers were same size as me.
just wondering if the degree of camber in the driver side being more prominent than the passenger side (at this point in time, static) was to compensate for the weight of a driver,
or perhaps the passenger side needs the same degree of camber ??
can front end alignment folks figure this out, or do most racers just have a rule of thumb they go by ??

thanks
 

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With the car on stands, I wouldn't be too concerned about it. You will need to see where everything is once the weight is added to the car. Get it aligned once its loaded.
 

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With the car on stands, I wouldn't be too concerned about it. You will need to see where everything is once the weight is added to the car. Get it aligned once its loaded.
Agree with Mark Dude! Mark & Pro3148 Merry X-Mas to you & yours Dude! :cool:
 

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Discussion Starter · #5 ·
thanks guys, and Merry Christmas back to ya's !

what has me concerned ( I tend to overthink the box) is the positive camber on the LH..
that heim would need to be significantly screwed "out" more than it is, to have zero camber like the RH side.... if it was screwed in, it would be severely positive.. correct ?
and if the RH side was screwed "out", that would give negative camber to that side....
by measuring, everything seems to be square to itself..
but whether that is "square-correct" is my doubt..
or maybe it doesn't even need to be ?
like I said: I tend to overthink.

we're doing some chassis updates to the roll cage bars, to meet today's 8.50 cert specs: 3 bars were too thin-walled...
and if I need to make changes or repairs, this would be the opportune time to do it, as opposed to when the car is assembled.. even though I do understand what you're saying about the assembled weight affecting measurements and etc.
we don't have access to any jigs or alignment devices; it's all strictly dimensional measurements and level/square.

I'm seeing some indicators which leads me to believe the car was either crashed at some point in time, or came down really hard from a wheelie; i/e the dash bar (which the steering shaft is anchored to) is slightly bent "upwards", and the accelerator mount which is attached to that same bar has been broken off and cobble-welded back on.. (both are on the repairs list).
the chassis/frame all measures level and square.
has me puzzled.
the car was a late 1980s home-shop-build, not anything near a pro-shop job, but is quality work, and both owners swear the car is safe.

don't ponder on this too much for me guys, as it is Christmas and I'm not gonna be working back on it until tomorrow.
but any help or suggestions are greatly appreciated, if you ponder the pictures and see something in that structure I'm missing.
 

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If you are concerned about adjustability, you can always cut and lengthen or shorten the one tube on the controll arm. I don't think the longer threads on one side indicated the chassis is bent or has been wrecked.

Use whatever tools you have to check square. Even a plum bob. Check the length of the controll arms, maybe one is shorter.

It does look like you have a good sense about things. Just keep checking.

IMO, I wouldn't be worried about what you have posted.

I saw a professional NASCAR team string checking their car once. Nothing wrong with a string and level! :)
 

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What I would do with a new (to me) car is; Weight it up to race weight, then check everything (without changing anything); squareness, front end alignment, wheelbase(s), corner weights, preloads, ride heights, bump steer, link lengths, etc, etc. When you do that, you may find the reason for any adjustments that look oddball at first glance; on the other hand, you may find something totally out in left field.

Once you start changing things, it's hard to return to a baseline if you don't have one.
 

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Yea I got a tube chassis strut front end and actually am wondering about some things in the picture you posted.


The two pieced I highlighted are they some kind of engine limiter and strut extension limiter? I've been around a few strut cars and haven't seen anything like what you have.


Bickle chassis IHRA Pro Stock Car. Lamb strut.


My car Strange struts, 2115 Lbs fully loaded at the line. Iron factory SBC, two Optima batteries, some of the original steel body, a bit of aluminum, fiberglass, and lexan though.




An older Pro Mod Car




Before you try to do any alignment adjustments you need to have the car at it's ride height as if it is just about to line up, with driver and full fuel tank.

Castor - On strut cars 8-10 Degrees is normal.
Camber - Very little 1/4 Degree - 0 Degree
Toe In - 1/32" Each Side

If those are things I circled earlier are travel limiters they mean one of two things. First they could be to limit bump steer. Second it could be to improve reaction time for pro tree racing.

I can't tell for sure from the picture but as long as the Lower Control Arm and tie rod connection to the steering rack are parallel at normal ride high and have the same pivot lengths then there shouldn't be any horrible bump steer.

There is a book that I like from Dave Morgan, Door Slammers. I like the book and have set up cars with the understanding that I got from the book and they have run perfectly straight down different tracks.
 

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Discussion Starter · #9 ·
noice:
the yellow hi-lighted item is travel limiter for controlling extension;
the blue item is an alternator bracket, folded backwards from the engine compartment.
 

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Discussion Starter · #11 ·
it is a full square tube chassis with a 4-link.
am being told (by both owners) that it weighs 2145# in full race trim & 180s-ish lb driver.
chassis is certified to 8.50 - 1/4 mi., Advanced ET.
car was set-up to run Super Pro and Super Gas.
my game is S/P - 1/8th mile.
as a roller, I can push it (straight) on level ground with one hand.
2 of us can pick the front end up to waist-high with little effort.
it's light.

my buddy that's helping me with the roll cage updates says like you guys:
leave the front alone until I get it all assembled, because there is nothing apparent that is out of place or been damaged.
 

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Discussion Starter · #12 ·
{Before you try to do any alignment adjustments you need to have the car at it's ride height as if it is just about to line up, with driver and full fuel tank.

Castor - On strut cars 8-10 Degrees is normal.
Camber - Very little 1/4 Degree - 0 Degree
Toe In - 1/32" Each Side

If those are things I circled earlier are travel limiters they mean one of two things. First they could be to limit bump steer. Second it could be to improve reaction time for pro tree racing.

I can't tell for sure from the picture but as long as the Lower Control Arm and tie rod connection to the steering rack are parallel at normal ride high and have the same pivot lengths then there shouldn't be any horrible bump steer.}

..thanks for this info noice.
 

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it is a full square tube chassis with a 4-link.
That is a pretty light car for having square tube.

2 of us can pick the front end up to waist-high with little effort.
it's light.
It amazes me when people brag about carrying the front wheels really high in a car that could be adjusted to avoid that. I like having such a light car that barely puts the front left 1/2 inch off the ground.

I've had two people lift the front of the car a few inches with the front clip off and a SBC in the car just to show them how light it is.
 

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Discussion Starter · #17 ·
making the steering "safe" was one of the projects on my rebuild list.
this pic isn't too clear, but the mid U-joint was completely worn out.







as was the quick release wheel hub





I want safe...
the car is an older build, but needs very few actual updates.
just some old fashioned TLC and attention-to-detail..
 

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That is not the steering shaft angle is it? Looks very binding to me. Also is there another mount near the mid joint? Appears to be a long run with a very sharp angle to me.


Nice delay box. I love my K&R pro cube!
 

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Discussion Starter · #19 ·
yes. that mid-joint is the only twist in the steering assembly,
other-than the U-joint on the rack..
seems to me also to be extreme, but it apparently has worked since the original build in the mid-80s ?
that degree is within tolerances of the replacement joint I bought..
we have to re-configure the mount, but no issue there ..
it's to allow for the headers that pass underneath the steering shaft.

I have been studying the K & R box literature..

thinking I'm gonna like it.
especially the "Flinch Protection" feature..
;)
 
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