Exhaust manifold nuts

[Kev.O]

Does anyone know the size and pitch of the nuts that connect the manifold to the cylinder head via the studs. I have bought some from Mr T but some are fouling my new manifold so need to put separate washers and nuts on.

 

Also I need to know the size and pitch of the bolts and stud that connects a GT4088 turbo to a sound performance manifold. I have tried contacting SP but have yet to receive a reply

[matt k]

Does anyone know the size and pitch of the nuts that connect the manifold to the cylinder head via the studs. I have bought some from Mr T but some are fouling my new manifold so need to put separate washers and nuts on.

 

Also I need to know the size and pitch of the bolts and stud that connects a GT4088 turbo to a sound performance manifold. I have tried contacting SP but have yet to receive a reply

 

I used the originals Kev and the #6 cylinder was catching a bit but nipped up in the end, Mie's a HKs manifold waht make is yours?

[n boost]

Hello mate

 

I think the studs are M10 and have a 1.5 pitch. The standard ones did catch some of the branches on my xs manifold but i matched a few shorter one's up at my local car part's store.U could always grind them down slightly.

[Homer]

As mentioned before, I'm certain these are 1.5 pitch, but can't remember the size, either M10 or M12, but would guess M10.

 

Which manifold have you got? Most of them require at least one stud to be cut down, usually the lower stud on No4. If the weld is getting in the way, then just grind the washer area back and double bolt it if you're able (if you're concerned, maybe grind a the 2nd bolt to half the thickness and add it in when you start to thread the first one on - if you do it right it'll bolt up tighter than all the others)

[Kev.O]

Thanks guys. I've got a sound performance manifold. Surprisingly, none of the studs need grinding down, it's the weld itself that's in the way, and even then, it's marginal.

 

Does anyone know the size and pitch of the bolts and stud that go into the T4 flange on the SP manifold aswell? I've tried M10x1.25 but they don't fit.

[steb9780]

Thanks guys. I've got a sound performance manifold. Surprisingly, none of the studs need grinding down, it's the weld itself that's in the way, and even then, it's marginal.

 

Does anyone know the size and pitch of the bolts and stud that go into the T4 flange on the SP manifold aswell? I've tried M10x1.25 but they don't fit.

 

Does the thread look like M10, it could just be that the pitch is wrong. Usually if the pitch is wrong then it'll just start to go then stop. Where is the manifold from if it's from somewhere like the states it might be an imperial thread.

[Chris Wilson]

1.25 pitch on an M10 is metric fine, it's probably a 1.5 pitch thread. You need a set of thread gauges, get a metric and imperial set, only about a fiver each, they look like feeler gauges with teeth. You can roughly get the bolt / stud diameter with an open ended spanner as a gauge.

[Chris Wilson]

If you can get stainless steel nuts they are less likely to corrode on, BTW

[zap]

If it's M10 it will probably be 1.5 pitch as this is standard, fine pitch is not normally used where there are high temperatures because of expansion problems, if it is imperial it may be 3/8 inch.

[steb9780]

Best bet is to try and count threads over a fixed distance with pitch.

 

For example if it is 1.25 pitch then 10 threads should be 12.5mm long. If it's 15mm for 10 threads then the pitch is 1.5mm. Quite handy way of measuring pitches.

[Kev.O]

Thanks guys I'll have a look later

[Kev.O]

Best bet is to try and count threads over a fixed distance with pitch.

 

For example if it is 1.25 pitch then 10 threads should be 12.5mm long. If it's 15mm for 10 threads then the pitch is 1.5mm. Quite handy way of measuring pitches.

 

This is pretty much what you said, I found it on the web and thought I would put it here incase anyone reads this in the future:

 

Metric threads

Metric threads are measured by the diameter of the threaded portion and by how far apart the threads are. The common metric thread 10 x 1.00mm indicates a 10mm o.d. on the threaded portion and a thread pitch of 1.00mm, which is one thread every millimeter. Since there are 25.4 millimeters in 1 inch, that works out to 25.4 threads per inch. A 10 x 1.25mm is a course pitch. With the threads 1.25mm apart that works out to 20.3 threads per inch. A 1.5mm pitch is a courser pitch that works out to 16.9 threads per inch.

[steb9780]

This is pretty much what you said, I found it on the web and thought I would put it here incase anyone reads this in the future:

 

Metric threads

Metric threads are measured by the diameter of the threaded portion and by how far apart the threads are. The common metric thread 10 x 1.00mm indicates a 10mm o.d. on the threaded portion and a thread pitch of 1.00mm, which is one thread every millimeter. Since there are 25.4 millimeters in 1 inch, that works out to 25.4 threads per inch. A 10 x 1.25mm is a course pitch. With the threads 1.25mm apart that works out to 20.3 threads per inch. A 1.5mm pitch is a courser pitch that works out to 16.9 threads per inch.

 

Yeah that's fine but I'd always stick to measuring in metric for metric threads and imperial for those threads. That bit there is asking you to convert into imperial to measure a metric thread. I wouldn't do it that way as you can get mixed up etc.

 

Like I said for a metric thread we just tend to count the tops of the threads and if 10 threads is 15mm long its 1.5mm pitch and if 10 threads is 12.5mm long its 1.25mm pitch.

 

Chris's way is best with thread gauges, but if this is just a one off you may not want to buy some.

[Kev.O]

The nuts for the manifold to cylinder head are M10 x 1.25 pitch incase anyone wants to know

[Kev.O]

Are brass nuts ok to use like these?

[Kev.O]

I have found some stainless steel ones aswell. Are these better?

[Chris Wilson]

I'd go for stainless, but is there room for a 17 mm ring spanner on them? The stock ones are a 14 mm hex head. Can you grind the weld a bit to allow stock ones, with their floating washers, to fit?

[Kev.O]

I'd go for stainless, but is there room for a 17 mm ring spanner on them? The stock ones are a 14 mm hex head. Can you grind the weld a bit to allow stock ones, with their floating washers, to fit?

 

I've found some 14mm ones now. I'm abit concerned about grinding the welds down as I don't want to weaken the weld. I was thinking of getting a few seperate washers and grinding a little off one edge so it fits better.

[Chris Wilson]

Isn't all this FUN though? Multiply things like this many fold, and tell me you can do a proper single conversion for two and six

[Kev.O]

Isn't all this FUN though? Multiply things like this many fold, and tell me you can do a proper single conversion for two and six

 

I can think of plenty of things that are alot more fun I always knew this was going to cost a fortune and I'm more than happy to pay inorder to get the job done properly

[Kev.O]

A massive thanks to Snake for giving up a few hours of his Saturday to help me find out what size the SP manifold requires. For anyone who's interested it is 3/8 US thread

[snake]

:thumbs:your welcome kev, glad we manage to sort it

[Chris Wilson]

3/8 UNC is a common size on small and big block Chevrolet V8 engines, the likes of Moroso, ARP, et cetera will have various studs in that size.

[Kev.O]

3/8 UNC is a common size on small and big block Chevrolet V8 engines, the likes of Moroso, ARP, et cetera will have various studs in that size.

 

Luckily there was a shop just a minute down the road, which had just the right parts. Only cost me a pound aswell

[snake]

it would have been 30 seconds away if i could walk properly:p