I have a set of Hedman Elite headers on my 89. There is not much space (only about 1/4 inch) between the number 2 cylinder tube and the upper control arm. When the go pedal is mashed the tube contacts the upper control arm and causes a false knock. Anybody else have this issue? What was your solution? How much clearance should I have? The motor mounts are new replacements changed when the engine was out last year.

 

Mikky i have those hedman elites on my 87 , but no problems at all ....can you post pictures please ?

 

I will try to get a picture up today. Thanks

 

Mark the spot on the header, remove the header and dimple the area slightly using a long 5/8" socket and hammer. It won't take much. Sometimes you can do it on the car with a tire iron, but I wouldn't try prying against an aluminum control arm.

 

Here is the picture, hard to get a camera shot in that tight space

 

I have a fast investment for you.

This SPC UCA is smaller, and will give your headers plenty of room.

 

This may seem like a dumb post but have you checked the shims are the same on both sides , the bolts holding the shims etc are tight and that your wheel alignment is good?

If the shims are all there and there is no obvious difference from one side of the car to the other and the wheel alignment is not of it may be the jig they used to make the headers is of?

There are dumb *** wheel alignment techs out there so hope that is what it is, they may have been trying to achieve a strange caster or negative camber setting at some time in the past.

PLRX I LOVE YOUR STYLE

 

Great ideas guys, I did look at the alignment shims and everything is in place and tight. I don't believe the PO ever raced the car and it does drive straight down the road, so I don't think there is anything weird going on with the suspension. I was looking at the TPIS headers and I see the #2 tube bends down quickly before going back, similar to PRLX above. That may be the answer.

 

i had very tight clearances when i installed headers on my 91 (different brand headers, clearance issues not in the same place tho), so had to resort to polyurethane inserts on the motor mounts to limit movement.

 

Can you provide more info on the motor mounts you used? Source?

 

Here is what I did.

You will need two of these:
http://www.summitracing.com/parts/ENS-3-1127R/

And follow this thread:
http://forums.corvetteforum.com/c4-t...yurethane.html

 

I had the Headman Elites on my 91 and did not have this issue. I would go with the mounts Kubs suggested if I were you.

 

for securing the clamshell halves together after inserting the polyurethane insert, i bought some 7/16 dia bolts instead of using the smaller Energy Suspension supplied bolts. i'm sure the ES bolts are adequate, just my OCD. i figure that since the rivet holes were 7/16" dia, might as well use 7/16" bolts. the bolts have to be really short due to the limited clearance between the engine block and the clamshell bolt. red loctite on the bolts.

I think i ended up having the bolts all facing inwards, nut towards the engine block, i recall there was something about that was the only way i could jam the damn assembly into place since i didn't have the motor out of the car, something about the lower bolts, my memory fails me.

also, one important thing, AFTER the whole assembly is aligned as good as you can, and then bolted together, run a 7/16" drill through the other 3 bolt holes for where the assembly bolts to the engine block. you will be very thankful when you're under the car, contorting your hand in very unnatural positions, trying to get a stubborn bolt to thread into a hole that you can't see at some weird angle. always the last of the 3. believe me, it makes a HUGE difference.

of course, if you have the engine out of the car, so simple, even your GF could do it blindfolded with one hand tied behind her back.

 

I had the same problem on my 93 when long tubes were installed from exotic muscle. Just as 383vett said, mark it, pull it off and dimple it with a hammer. A little heat will help too.

 

Thanks guys, I appreciate the help.