Shocks upside down? Torque of the cyl.head bolts?

[pwissel]

Hi all,

Have board new AVO shocks - Does anyone know if its possible (and does it make sense) to mount them upside down to have less unsprung mass?

By the way - Does anyone have the torque figures of the cylinder head bolts 4.0 Rover V8 engine? Havent´t found them in the bible...

Thanks!
Peter

[GreenV8S]

Steve's books are excellent owners guides but are not (and don't pretend to me) workshop manuals. You need a proper workshop manual if you are stripping and rebuilding engines.

I've only got a Haynes comic, but it has enough info for this sort of thing:

The head torques are 65-70 lb-ft for the long and medium bolts. I assume you know not to use the outer line of bolts, but if you do use them the torque is 40-50 lb-ft. You can reuse the head bolts (up to four times) as long as they have not stretched or elongated. They need to be tightened in sequence, diagonally starting in the middle of each head and working out to the ends.

Hope this helps.

[GreenV8S]

Most dampers are designed to work with the rods at the top. You can sometimes get away with fitting them upside down if they have been bled exceptionally carefully or if they have been specifically design to work upside down. Unless you are absolutely certain, put them the conventional way up. The unsprung weight gains are insignificant compared to the problems it can cause.

[keithyboy]

Pete, you sure about those figs for the head? I did mine at 40nm then 90 degrees and 90 degrees - 3 stage process. Obviously working centre outwards on opposite sides - if that makes sense?

[GreenV8S]

Not particularly sure, but that's how Mr. Haynes does it. Your system sounds like it is intended for stretch bolts?

[19560]

pwissel said:

Have board new AVO shocks - Does anyone know if its possible (and does it make sense) to mount them upside down to have less unsprung mass?

Yes and yes. Joospeed man used to recommend this for some cars but there were caveats that I can't remember. (Doh!) Race use only seems to be the most likely recommendation. Do you really need that level of dynamic weight saving? Do you have lightweight wheels?

[pwissel]

Is it right that pound-feet (lb-ft) x 1.35582 = Newtonmeter (Nm)? So i have to tighten the bolts with 88-95Nm? lb-ft unfortuetly is not on my tourqe spanner...
the bolts have to be tighten from center crossover to the outside - Found a picture on

www.gomog.com/headgaskets.html



to 19560:
Was just an idea - Actually I have "very dynamic lightweight" spoke weels...

[19560]

pwissel said:

Is it right that pound-feet (lb-ft) x 1.35582 = Newtonmeter (Nm)? So i have to tighten the bolts with 88-95Nm? Yes and yes for the long and medium length bolts 54 to 68 Nm for the short ones, according to Haynes again. to 19560: Was just an idea - Actually I have "very dynamic lightweight" spoke weels...

Interesting site. Sounds like you have some great wheels, any details and photos? Jonathan

[GreenV8S]

1 ft lb = 1.356 Nm

All the conversion formulae you could ever be interested in, and more, here:

www.engineeringtoolbox.com/unit-converter-19_185.html

[HarryW]

19560 said:

Interesting site. ....

regulary use it to help in the understanding of RV8's myself too.

Harry

[pwissel]

19560 said:

Interesting site. Sounds like you have some great wheels, any details and photos? Jonathan

Hope you have understood the irony in my statement?!
There is a photo from older postings at:
www.pistonheads.com/uploads/galleries/9-345.jpg

My one is called the "alien S" because it confused some of the guys due to the aircondition and the round backlights. First time they told me i own a corvette and mocked me - after sending the photo it was very quiet. That was my first experience with the forum and its British homor...

[pwissel]

GreenV8S said:

1 ft lb = 1.356 Nm All the conversion formulae you could ever be interested in, and more, here: www.engineeringtoolbox.com/unit-converter-19_185.html

So 88 to 95 Nm ist the right tourque for the bolt 1-10...
What do you think is the best for bolt 11-14? Not to use the or tighten with 25-40 lb-ft (or 34-55 Nm))

[GreenV8S]

pwissel said:

So 88 to 95 Nm ist the right tourque for the bolt 1-10... What do you think is the best for bolt 11-14? Not to use the or tighten with 25-40 lb-ft (or 34-55 Nm))

Yes.

The outer line of bolts do no good and some harm. They are left out completely on later engines. Personally I would leave them out. If you don't like to see the empty holes and prefer to fit them, don't torque them up fully. 25 lb-ft is low enough to stop them doing any harm.

In case you're interested, the problem occurs because the original head that the RV8 was based on had six bolts evenly spaced round each cylinder, but on the RV8 they designed out the inner line of bolts. With only five bolts per cylinder the clamping load is asymetrical and tends to lift the inner edge where the bolts are missing. By removing the outer bolts, it makes the clamping load symmetrical and removes the problem.