964 head Stud Question

[colingreene]

Guys,

I am putting together a motor that is twin plug.
This would be my second motor I have built being twin plugged.
One of the problems I have is clearance is tight between the socket/spark plug and the barrel nut that holds the head on with the existing combo.
So seeking to avoid that problem on this motor I was planning on using a 964 Head stud nut. (P/N: 964 104 382 01)
From what I have been able to glean from the PET Diagrams, No washer is used under these nuts. (Image Attached.)
The part in question is #18 in the diagram.
However I am suspect that is the case. So before I do something colossally stupid.
Does anyone have any first hand info as to how this is assembled?
Taking that into account if in fact a washer is not needed would that potentially change the install height of the stud into the case?

Thanks for any available help



Motor break down for people wondering because why not share, everyone likes motor specs right?

The motor is a 2.8 Twin Plug
2.7 7R case fully machined
Ported heads
Twin plug JB Racing distributor
AASCO springs and retainers
10.5:1 CP coated pistons
DC60 cams
964 Oil pump
Everything balanced
Stock rods with ARP Hardware
Headers to suit
and I have a choice of 40 and 46 carbs to test.

[winders]

twin plug ignition: 12mm or 14mm spark plugs

[HaroldMHedge]

I'm using Henry Schmidt's Supertec Performance Cylinder Head Stud Kit, SPTC-HSK-1, in my 87 3.2L to 3.4L twin plug build.

From twin plug ignition: 12mm or 14mm spark plugs

Originally Posted by Henry Schmidt

14mm work fine. I have never seen a failure based on this modification.
The compression loss is minimal but accurately dimensioning your engine will allow you to order your pistons to compensate for the chamber volume change.

One cure for head stud nut clearance is Supertec head studs. They offer improved head to cylinder stability,greatly improve engine assembly and the nuts offer clearance for lower spark plugs.

https://www.pelicanparts.com/More_Info/SPTCHSK1.htm?pn=SPTC-HSK-1&bt=Y&fs=0&SVSVSI=911M

Edit
Scott and I are refencing the same thread.

[colingreene]

Thanks for the links, however it does not really answer the question that I asked.

[Ollies930]

The 964 nut will probably be no help with clearance, it is pretty tall. Why not get a set of ARP 12 point head nuts and use the existing washers (or replace with ARP washer)?

[blue911rsr]

964 nut will not fit early head without turning the washer part
Down a little to fit the head otherwise they are better than nut and
Washer
Use a plug with a 5/8 head and you won’t have issues

[colingreene]

Originally Posted by blue911rsr

964 nut will not fit early head without turning the washer part
Down a little to fit the head otherwise they are better than nut and
Washer
Use a plug with a 5/8 head and you won’t have issues

So Is that to say the 964 nut does not use a separate washer?
Thats the only question I wanted answered here.

[safe]

I use spark plugs with 16mm, about 5/8, hex in my engines. Zero problems fitting a standard spark plug socket down in the heads.
Best "upgrade" ever, right after a high torque starter.
I have no idea why someone would use the original big hex spark plugs....

[blue911rsr]

Yes washer is part of nut

[colingreene]

Originally Posted by blue911rsr

Yes washer is part of nut

Thank you.

[colingreene]

Originally Posted by Ollies930

The 964 nut will probably be no help with clearance, it is pretty tall. Why not get a set of ARP 12 point head nuts and use the existing washers (or replace with ARP washer)?

Just updating this to say this is what i did and it worked perfectly.
thank you for the idea.