torque for plenum cover

[teigan]

a stupid but easy question: what's the recommended tightness for the plenum cover bolts? i don't have my notes with me, and it isn't easily locatable in the service manual. thanks.

[toyroom]

Is this a V8 turtle question ??
Intake plenum (no further specification) is listed as 20Nm (15 lbft)

or do you mean the 4 cylinder ? ; 4 cylinder inlet manifold to cylinder head is 19 to 22 Nm (14 to 16 lbft)

[teigan]

yeah i did mean the 4 cyl. thanks.

[Esprit2]

A torque spec for it isn't listed in the manual. However, the plenum is secured with M8 bolts, so the appropriate torque would be...

14-16 Lb-Ft = 1.93-2.21 Kg-m = 19-21.7 N-m

>> Edited by Esprit2 on Saturday 4th March 21:31

[victormeldrew]

Esprit2 said:

The plenum isn't listed in the manual, but the plenum is secured with M8 Bolts. So the appropriate torque would be... 14-16 Lb-Ft = 1.93-2.21 Kg-m = 19-21.7 N-m

Just out of interest, how did you derive the torque from the bolt size - or did you just *know* that was the right figure?

[toyroom]

I think he might be going on the general comment in the manual in the list of the torque settings which says: "All other M6 nuts or bolts - 9-11 Nm " and: "All other non-specified M8 studs - 16 Nm" and stuff like that, ... maybe...?

>> Edited by toyroom on Wednesday 1st March 20:34

[toyroom]

Going on what I just said, if it is secured by M8 studs then 16 Nm would seem to be correct.

[bojangles]

almost all M8 bolts are torqued to 20Nm as a standard. If you need more clamping force you need a larger bolt.. if you need less you use a smaller bolt.

I base this on being a parts supplier to the auto world for 12 years....
And in every case that i have seen when the drawing for a parts specifies a given torque the assemebly line ALWAYS has the gun set about 10% higher. THis drives suppliers nuts because when there is a failure.. they refuse to reduce the torque.. they just say the part is no good.

[Esprit2]

victormeldrew said:

Esprit2 said: The plenum isn't listed in the manual, but the plenum is secured with M8 Bolts. So the appropriate torque would be... 14-16 Lb-Ft = 1.93-2.21 Kg-m = 19-21.7 N-m Just out of interest, how did you derive the torque from the bolt size - or did you just *know* that was the right figure?

In part, experience:
... as a mechanical engineer for the last 36 years.
... wrenching on Lotus engines for the last 30 years.

And in part by observing Lotus' torque recommendations for other 8mm fasteners used in the engine, transaxle and chassis.

Inlet Manifold to Cyl Head ........... 14-16 Lb-Ft
Exhaust Manifold to Cyl Head ...... 14-16 Lb-Ft
Camshaft Housings to Cyl Head .... 14-16 Lb-Ft
Main Bearing Housing Perimeter .... 14-16 Lb-Ft
Engine Mount Legs to Cyl Block .... 14-15 Lb-Ft
Transaxle Rubber Mount/Chassis ... 14-15 Lb-Ft
Renault Translator Clamp Bolt ....... 14-15 Lb-Ft
S-Turbo Exhaust Mount to Cradle . 14-15 Lb-Ft
Pedal box to body ...................... 14-15 Lb-Ft

Tim

>> Edited by Esprit2 on Saturday 4th March 22:04

[victormeldrew]

Esprit2 said:

And in part by observing Lotus' torque recommendations for other 8mm fasteners used in the engine, transaxle and chassis.

Yes, there does seem to be a pattern there!