Exhaust Manifold bolts

[Banno 480]

Hi All,

Are the XE model exhaust manifold bolts  3/8 in size and where would be the best place to get them?

Cheers 

[XTREME KARTS XF 1,212]

From memory they are 3/8 UNC, try national nuts and bolts on fyans st in sth geelong.

[adrianphu123 73]

If you're using headers with a thinner flange compared to the stock manifold, make sure you use shorter bolts of they'll bottom out before clamping the header flange onto the head. I got a pack of header bolts from rarespares 

[slydog 7,873]

Nice looking car bro...

[adrianphu123 73]

sorry for the hijack, is it a bad idea to run spring washers? i just stripped a header bolt hole. 

[Banno 480]

From memory they are 3/8 UNC, try national nuts and bolts on fyans st in sth geelong.

 Thanks mate, Went in today and they helped with what I wanted. Extractors are in and done now. Cheers

 

sorry for the hijack, is it a bad idea to run spring washers? i just stripped a header bolt hole. 

 Don't know if its a bad idea. But a heli-coil be only thing now to fix a stripped hole

[bear351c 10,356]

 Auto shops usually sell the bolts behind the counter as "extractor bolts".

 

Spring washer will lose all its tension with the heating/cooling cycles of the engine. Don't reckon they ran them from the factory.

 

Mind you, Clevo's never came out with an exhaust manifold gasket, just metal to metal, so I could be wrong.

 

Also, I drink a lot...........

[Crazy2287 1,888]

Get some long bolts, wind them in till they bottom with some red high temp loctite then cut the heads off and now you have studs. Studs = 100x better then the bolts and it will cost a fraction of getting an actual stud kit.

 

Spring washer should be okay, What temperature does spring metal soften at? I do not think the flange of the manifold will get that hot?

 

Don't over tighten, Torque the bolts/studs. It's alloy it's soft and will expand at a different rate to the 8.8 grade steel bolts so it's best to obey the torque settings.

[adrianphu123 73]

the spring washers were all flat when i took them off so i guess they're useless anyway

 

I tightened them to 30 NM but it felt a little excessive, on the last bolt ripped the thread from the head. Next time im going to dial it back to 20-25NM

[scottly 475]

hey mate, call ron from kustom bitz  0407818511 he has bolt kits to suit lots of makes and models, they are cheap and cheap postage to, they also have a website hope this helps 

[Tyler06 266]

They might seem cheap but still double the price of the kits from the US delivered. Thats what I found.

[adrianphu123 73]

turns out rarespares sell em, you can do a crossflow for under $40. The studs appear to have a tapered thread on the part that goes into the head. Is this normal?

[Crazy2287 1,888]

should be able to make em up yourself useing set or socket screws/bolts for less than half that inc nuts and washers.... I'm just sayin' =P

[ando76 4,354]

3/8 unc threaded rod and a long (tube) nuts. problem solved and cheap as fek.  or just long threaded bolts like crazy said with the tube nuts. 

[gerg 10,875]

Those alloy heads had a habit of creeping the bolts out on both to he exhaust and inlet. Studs might be the go with brass nuts, will never seize that way.

[ando76 4,354]

never thought of the brass nuts - good idea. they use them on turbo stuff from memory.  mind you I've only ever used extractor bolts, cut to size, and never had an issue.  I ordered a set of ARP header studs for the roller cam motor just the other day but that was more for show than anything else. 

[slydog 7,873]

Holy fuck...Ando doing something for show...next Q will polish something all nice like and maybe even get some black fuckin leads!

[gerg 10,875]

Stock Clevo manifold to exhaust flange use brass nuts on studs from factory.

[ando76 4,354]

yeah must be better with the heat/ cool/ sweat cycle. 

 

Yes sly - it's hard to believe that I'm actually using stuff for form over function but you know I think THOR may draw a few looks so I might just make it look good as well as going like stink. 

[Guest Kode]

Does anyone no the sizes of the exhaust manifold bolts for a bf xr6?? Thans

[bear351c 10,356]

Hmmm.......good question,  reckon they'd be Metric. Anyone know?

[wagoon 2,429]

Sorry dont know about the later model stuff, but would be metric.

 

On a side note I used a 3/8 UNC tap to chase the thread out on my roller cam motor head and when I did it I actually removed metal from the holes. The only explaination for this is the head thread from standard is BSW and the bolt is UNC (I have used a thread pitch gauge to confirm bolt is UNC). If you look at a thread pitch chart the 3/8 UNC and BSW only has a 5 degree thread angle differenc. It has been mentioned else where on this site that by using the different pitch on 3/8 stuff it works as a mechanical lock, fitters that I have spoken to seem to agree with this thought.

[Campo 869]

Yeah barra is m10x1.25

 

Sent from my SM-G900I using Tapatalk

[Thom 6,694]

Sorry dont know about the later model stuff, but would be metric.

 

 

On a side note I used a 3/8 UNC tap to chase the thread out on my roller cam motor head and when I did it I actually removed metal from the holes. The only explaination for this is the head thread from standard is BSW and the bolt is UNC (I have used a thread pitch gauge to confirm bolt is UNC). If you look at a thread pitch chart the 3/8 UNC and BSW only has a 5 degree thread angle differenc. It has been mentioned else where on this site that by using the different pitch on 3/8 stuff it works as a mechanical lock, fitters that I have spoken to seem to agree with this thought.

 

That is actually a sound theory, but it could also change slightly during use due to heat

[wagoon 2,429]

It was actually due to heat that it works Thom, as the metals expand they mechanically lock especially with different metal like alloy head and steel bolt.