Putting It Back Together - Nuts, Bolts & Clamps assembly tips

[ArchHibb]

After a backfire cracked my SC airbox last Fall, I waded into the repair last month. Just for reference, I know my way around auto and boat mechanicals and have a strong shop incl. air tools and a welder, but this is my first venture into the 911's engine bay.

The engine/trans came out just fine and I am in the cleaning & disassembly phase. As I bag 'n tag various parts, I have some questions about reassembly.

1. There are numerous band clamps. Is there a good rule of thumb as to how tight these should be? "Firm handshake" kind-of-grip on the screwdriver tight or Tight-as-you-can?
   
2. For nuts & bolts without a listed torque spec., is a little blue (or red) loctite a good idea or just the usual tighten as appropriate to the application?

Given the total lack of access to some of these fasteners once the engine is reinstalled, I want to get it right the first time!

[RWebb]

1. clamps around rubber hoses should not damage the hose - snug is as good a word as any; be sure the hose will not come off; Loctite makes a sealant that some people use on their hoses

2. do NOT use Red; I often use Purple (low strength) but that is partly from a history of thrashing a VW Bus all over the Oregon desert and consequent vibration - a low strength dab of Purple Loctit can prevent viration caused loosening, and can also prevent corrosion, galvanic action and, along with a regular program of prefessional car, tooth decay

- if no torque spec. is given you can use a general spec. for that size bolt (if you care)

[Pazuzu]

*technically* you're supposed to replace all of those nuts and washers, since they won't torque back to spec properly the second time (the nylon inserts are deformed, the washers are warped, etc).

Most of us don't bother for normal day to day stuff, but it's pretty easy to replace everything if you have the engine apart. 99% of what you'll come across is M6 and M6 nylock nuts, M8 steel washers and M6 aluminum washers. If you go into the engine at all (maybe changing stuff under the valve covers, or timing chain covers) then you'll find M8 oval/prevailing torque nuts and M8 wave washers.

I just bought a collection of everything from McMasterCarr, cost about $60 for enough hardware to last the next few years of maintenance.

[DrkJstc]

Pazuzu,
What parts did you get? Is there a list or did you get random parts to create your kit?

[Pazuzu]

I can get order numbers tomorrow, but basically got a box each of:
M6 nylock nuts
M8 nylock nuts
M6 and M8 steel washers
M8 oval nuts
M8 single wave washers.


That will cover all but about 30 nuts in the entire engine (those would be the M8 barrel nuts and headstud nuts).

They're not yellow plated, and they're not "concours", but they work just fine.

[winders]

Originally Posted by Pazuzu

I can get order numbers tomorrow, but basically got a box each of:
M6 nylock nuts
M8 nylock nuts
M6 and M8 steel washers
M8 oval nuts
M8 single wave washers.


That will cover all but about 30 nuts in the entire engine (those would be the M8 barrel nuts and headstud nuts).

They're not yellow plated, and they're not "concours", but they work just fine.

Order from here and get them with yellow zinc plating:

https://www.belmetric.com/

Scott

[ArchHibb]

Thanks guys! Good tip about adding purple loctite to my toolkit - right next to the Neverseize. I'll be sure to inspect closely for "single use" fasteners and replace them appropriately. Would the nuts & washers for the intake runners (at the engine) fall into that group? Other than those, I'm dealing mainly with the CIS and engine tin, which might have torque spec. nuts & bolts, but I haven't researched yet.

[Pazuzu]

Originally Posted by ArchHibb

Would the nuts & washers for the intake runners (at the engine) fall into that group?

"Technically", yes. Realistically? No. If the nylock nuts seem to bite well before they're threaded all down (do you need a wrench to get the last 5 turns in, or just the last 1 turn?) then they're probably good. You can feel when a nylock is gone too far, you can finger tighten them almost completely down, and that means that they're not biting any more.

My McMaster Carr order:

90576A117 Metric Zinc-Plated Steel Nylon-Insert Locknut, Class 8, M8 Screw Size, 1.25MM Pitch, 13MM W, 8MM H, Packs of 100 $9.64

90576A115 Metric Zinc-Plated Steel Nylon-Insert Locknut, Class 8, M6 Size, 1MM Pitch, 10MM Width, 6MM Height, Packs of 100 $4.45

93795A230 Zinc-Plated Class 8 Steel Conical-Top Hex Locknut, M8 Screw Size, 1.25MM Pitch, 13MM Width, 8MM Height, Packs of 50 $5.60

90965A190 Metric DIN 125 Type 316 Stainless Steel Flat Washer, M8 Screw Size, 16MM OD, 1.4MM-1.8MM Thick, Packs of 100 $10.80

92168A109 Metric 18-8 Stainless Steel Single-Wave Washer, M8 Screw Size, 15MM OD, 0.8MM Thick, Packs of 50 $4.90

6 90965A170 Metric DIN 125 Type 316 Stainless Steel Flat Washer, M6 Screw Size, 12MM OD, 1.4MM-1.8MM Thick, Packs of 100 $6.86

Just about $50 shipped. The conical head nuts and the wave washers are NOT needed if you don't go into the "oily areas" of the engine, they're only in places where nylon shavings cannot be risked. The nylocks are all outside of the "oily areas".

Now, another option is our host's hardware kit, which is EXPENSIVE but contains basically every nut, washer, screw, etc in the engine engine. I picked one up when I did my rebuild last year, and it contained everything plus extras.
Pelican Parts - Product Information: PEL-REBKT-06

[RWebb]

steel nuts are fine for re-use unless damaged or "gittin' rusty"

spring washers are fine if still.... wait for it... "springy"

I should always use new Nyloc nuts, but...

I should always use new crush washers for the oil drain plug, but...

There are very few stretch bolts or single use fasteners on a 911 - besides Nylockery, the only ones that come to mind are the Schnorr washers on the CVs and rod bolts; maybe the typ 911 tranny simplified diff. bolts too but I forgit...


OTOH - you can buy safety for cheap by just replacing fasteners - the only risk you run by replacement with a new QUALITY part is that you might hurt your fist when you punch out some concours guy who paints at your car and yells out "Not Correct" since your older car will not be Nut Correct