Inlet manifold studs are NOT Whitworth

[ramiroflores]

Inlet manifold studs Whitworth? Two different lengths can anyone advise both proper lengths...
Gee have a hodge podge of studs!
77' Stag

[DJT]

All 5/16" UNC bolts (set screws). 4 x 3" & 8 x 1".

[mole42]

As Dave said, they are UNC not Whit threads. They should all be bolts, but most suppliers these days will sell you set screws for the shorter ones, it’s getting difficult to find UNC bolts less than a couple of inches.

[marshman]

What Richard said^^^^^

Most suppliers will also send the nearest length as well. Always check the length is correct as bolts (set screws!) that go into a blind hole, like on the inlet manifold, will bottom out if too long. Annoyingly some suppliers think it is OK to supply a specific bolt that is 1/" too long. At first glance it looks OK and you tighten it up without realising it has bottomed out and is not clamping the parts tightly together but it is close so there is no gap visible, i.e. it is not obvious.

I have given up buying bolt kits/sets form the likes of ANG etc. as far too many bolts/set screws are the wrong length and have to be cut down - or worse just too short. Some time ago I bought a large selection of both UNF and UNC nuts, bolts, set screws and washers from Spalding fasteners. I do have more than one classic car, far cheaper than buying them individually form the specialist suppliers. Westfield is also good. Spalding do "selection" boxes of UNF and UNC fasteners.

https://www.westfieldfasteners.co.uk/

https://www.spaldingfasteners.co.uk/

If your manifold has been attached with a "hotch potch" of fasteners I would carefully examine the threads in the heads and consider helicoiling them before refitting, nothing worse than getting to torque up the last bolt and the thread stripping ..... BTDT & got the T shirt.

[Wheelz]

I recommend my local supplier of bolts/screws which include UNF, UNC. They are old school and experienced guys who pick the parts personally. Quality Supplies:
Top-grade hex head bolts and more in Surrey (quality-suppliers.com)

[mole42]

I just changed the topic title so that any future searches don't gain the impression that the threads are Whit - they are not, as discussed.

[jbuckl]

I worked on a stag last year that had been ‘cough’ -‘repaired’ using u.n.f. Helicoils…. In some manifold to head threads…

Had assumed they were original unc before disassembly.

Don’t assume!!!!


had got new unc ready to use.

heads resisted removal , so plenty of time to get sorted.

[mole42]

The original heads on my car had some manifold bolts glued in with epoxy. As my American friend would say: "go figure!"

[jbuckl]

The original heads on my car had some manifold bolts glued in with epoxy. As my American friend would say: "go figure!"

My first stag relied on glue for the bolts and a folded carpet on the air cleaner (bonnet slammed down shut) to seal the manifold to heads….. however things improved and we stuck with it!