Missing Header Bolt Size? - ZR-1 Net Registry Forums

BlackZR1 · 09-19-2015

Good Evening guys,
What size is my missing header bolt? Looks like an M8 x 1.0 (fine thread) but I tried a coarse and fine thread and neither wants to start.

I also notice that the bolt below has a collar (like a 3/4" long spacer) on it. What is the purpose of the collar? Is this a special bolt?

For extra credit, what size is the small bolt that secures the aluminum cover over the throttle cables at the throttle body? The 2 nuts on the side are 4mm. My missing small bolt in front seems like it should be a 4 mm, but I tried a 4 mm and it didn't want to go.

Thanks,
Roger

Dynomite · 09-19-2015

Quote:

Originally Posted by BlackZR1

Good Evening guys,
What size is my missing header bolt? Looks like an M8 x 1.0 (fine thread) but I tried a coarse and fine thread and neither wants to start.

I also notice that the bolt below has a collar (like a 3/4" long spacer) on it. What is the purpose of the collar? Is this a special bolt?

For extra credit, what size is the small bolt that secures the aluminum cover over the throttle cables at the throttle body? The 2 nuts on the side are 4mm. My missing small bolt in front seems like it should be a 4 mm, but I tried a 4 mm and it didn't want to go.

Thanks,
Roger

Header Bolt is 8mm x 1.25

Exhaust Headers Locking Bolt Tricks

I think the original accelerator cable clip screw....is a screw thread.....I think I just tapped those for a couple SS Allen Head bolts (I think 4 mm with a pitch of .70 same as TB Coolant Cover).
accelerator cable clip screw

WVZR-1 · 09-20-2015

Cliff is correct the accelerator cover fastener isn't a machine screw but a self-tapping M4.2-1.4X8 fastener. It is the same as the cable conduit retainers on the plenum if you needed a sample or wanted to confirm.

A26B · 09-20-2015

Roger,
If you have any difficulty finding the bolts you are looking for, we have a large inventory of LT5 OEM bolts.

Throttle Quadrant Cover Screw
http://www.jerrysgaskets.com/screw-a...ew-90-95-6-5b/

Exhaust Manifold Bolts

The actual specification for the bolt is inclusive of the spacer you noted. I have always thought the spacer is to make getting a socket on the bolt head easier where the header tube is close to the hole. The M8x1.25 bolt can be sized to 25mm length if you use a socket head cap screw (allen head) of a reduced hex head header bolt. Not all exhaust manifold bolt holes actually had bolts installed at the factory, even though the holes are tapped. I think only 5 or 6 per side actually had bolts installed.

Dynomite · 09-20-2015

Quote:

Originally Posted by A26B

Roger,
If you have any difficulty finding the bolts you are looking for, we have a large inventory of LT5 OEM bolts.

Throttle Quadrant Cover Screw
http://www.jerrysgaskets.com/screw-a...ew-90-95-6-5b/

No Jerry......it is called a accelerator cable clip screw (Left Click on the Underlined)

And I have to teach you Descriptive Links sometime (Left Click Links like in my Signature)

Oh....Jerry is the best on parts AND Packaging AND Delivery of parts no matter if I am in SD or CA it is always two days delivery with SUPER Packaging.

mike100 · 09-20-2015

You aren't missing any hardware. The factory only used 7 (out of 16) mounting flange holes. Notice the rusty texture and no evidence of a washer, spacer, or bolt head flange ever being mounted there.

RussMcB · 09-20-2015

Roger, if it bothers you, and you think there is room enough to put one in, I can send you one. I just installed headers and used new bolts, so I have some old (original) bolts laying around.

But, like others have said, you don't really need a bolt there.

BlackZR1 · 09-20-2015

Quote:

Originally Posted by RussMcB

Roger, if it bothers you, and you think there is room enough to put one in, I can send you one. I just installed headers and used new bolts, so I have some old (original) bolts laying around.

But, like others have said, you don't really need a bolt there.

Thanks Jerry, Cliff, Mike and Russ.
I have a big order coming for you Jerry, the little cover screw among them.
In checking that header bolt, I tried an 8mm x 1.25 like Cliff said then mistakenly dropped it into the header head shield. Arggghhhh!! I used a SS bolt so a magnet would not help retrieve it even if I could get contact with it.
Well if it is not necessary I won't worry about it.

Thanks again guys,
Roger

09-20-2015	#3
WVZR-1 Join Date: Oct 2004 Posts: 1,889	Re: Missing Header Bolt Size? Cliff is correct the accelerator cover fastener isn't a machine screw but a self-tapping M4.2-1.4X8 fastener. It is the same as the cable conduit retainers on the plenum if you needed a sample or wanted to confirm. Last edited by WVZR-1; 09-20-2015 at 04:55 AM.

09-20-2015	#4
A26B Join Date: Dec 2003 Location: Arcadia,OK Posts: 3,372	Re: Missing Header Bolt Size? Roger, If you have any difficulty finding the bolts you are looking for, we have a large inventory of LT5 OEM bolts. Throttle Quadrant Cover Screw http://www.jerrysgaskets.com/screw-a...ew-90-95-6-5b/ Exhaust Manifold Bolts The actual specification for the bolt is inclusive of the spacer you noted. I have always thought the spacer is to make getting a socket on the bolt head easier where the header tube is close to the hole. The M8x1.25 bolt can be sized to 25mm length if you use a socket head cap screw (allen head) of a reduced hex head header bolt. Not all exhaust manifold bolt holes actually had bolts installed at the factory, even though the holes are tapped. I think only 5 or 6 per side actually had bolts installed. __________________ Jerry Downey JERRYS LT5 GASKETS & PARTS http://www.jerrysgaskets.com 1994 *ZR-1, Black/Black, Lingenfelter Aerobody, 416cu in, 3.91 gears, coil-over susp, Brembo brakes, etc. 2016 Black-Red, 3LT-Z51 Auto 8-speed. Last edited by A26B; 09-20-2015 at 10:34 AM.*

09-20-2015	#6
mike100 Join Date: Feb 2011 Location: San Marcos CA Posts: 1,802	Re: Missing Header Bolt Size? You aren't missing any hardware. The factory only used 7 (out of 16) mounting flange holes. Notice the rusty texture and no evidence of a washer, spacer, or bolt head flange ever being mounted there.

09-20-2015	#7
RussMcB Join Date: Jan 2015 Location: Marietta, GA USA Posts: 1,160	Re: Missing Header Bolt Size? Roger, if it bothers you, and you think there is room enough to put one in, I can send you one. I just installed headers and used new bolts, so I have some old (original) bolts laying around. But, like others have said, you don't really need a bolt there.