Sprint head tension, advice please.

[Sundowner]

I'm looking for advice on what tension a Sprint head should/could be torqued down to......and I understand 55lbs/ft is the recommended tension.

Before you answer, I need to tell you that three weeks ago, this car had an overheating issue due to an electric fan failing, in slow moving traffic, while climbing a mountain.
After eventually finding a spot to pull over and upon stopping the engine, it boiled, and left traces of coolant that had escaped between the head and block, directly under the inlet manifold and around the area of cylinders 2 & 3. There is no water in the oil, nor oil in the coolant.

The electric cooling fan has been repaired and works as it should and the car is still running fine. But on one run since then, there was just the slightest/tiniest evidence of a coolant seep in that area.

In an effort to stop any further leak without going to the trouble and expense of removing the head, I'm about to re-tension it and would like to know if there's a safe maximum, beyond the 55lbs ft.
Should this fail to stop any further seepage of coolant, then I'll have to bite the bullet and import all the necessary gaskets, machine the head, etc, etc.

Thanks & Cheers,
Rob

[gmsclassics]

Don't know the history of your car, but you MAY find this is simpler to fix than you think.

Yes I would try retorquing first. I've never gone beyond 58ft lb, even on the racecar with an overskimmed head, and use the standard sequence in the manual. I lightly oil the threads or use copper grease if necessary, never dry. However how accurate is your torque wrench, especially if it hasn't been checked recently?

If it is just coolant to the outside, there is always the chance a 'stop leak' type product might work.

If that doesn't work make sure you order a Payen gasket set (I get mine from Rimmers and order a couple so I always have a spare, just in case!). Unless the head is warped, and I doubt it is from what you say, I suspect if you clean the surfaces up, especially where the leak is, you'll be alright with just a gasket change. I also spray the gasket lightly with VHT high temperature Copper Gasket Cement on both faces before assembling (I would have got that from either Repco or Supercheap).

There is only so many times a Sprint head can be skimmed and there are no more new ones, so I would only do that if there was no alternative. The minimum head height from the factory is supposed to be 120.5mm, measured from the cam journal to main face. If you measure yours when/if you take if off, you'll get an idea of how much has been skimmed off to date.

Let us know how you get on.

Geoff

[sprint95m]

The torque figures quoted in the BL manual are for the threads oiled.
(If you use copper grease then you will over tighten.....)


If it was me, I would take the head off and replace the gasket.




Ian.

[Mad Mart]

I torque them to 60 lbs ft. 58 is the minimum I would use.

[tony g]

58 to 60 lb/ft here too. re-torque studs first one undone and redone etc. Middle then outer then outer then outer. Then the bolts in the same sequence. Typically I have seen the nuts and bolts rotate just shy of 30 degrees each (from an initial torque as stated above). Good luck.

Tony

[xvivalve]

On the basis all you have to lose by re-torquing is time (if it is unsuccessful) then I would try this procedure first, even if you do so whilst awaiting for gaskets to arrive.

If it is successful, then I'm sure having some gaskets ready on continent will be no inconvenience to you, or others, in the future!

[Sundowner]

Gentlemen,
Thank you all for your advice.
We have some bad weather here at present, so we'll get onto the task sometime during the week.
I'll report back as we progress.
Thanks again,
Rob

Edit,
PS; Knowing that......
1) "Coolant" will find a way between surfaces where "water" wont.
2) I live in an area with only a few light frosts each winter.
3) Apart from this problem, the cooling system in the Sprint is in A1 top condition......
I am prepared to change the Anti boil, anti freeze, anti corrosion "coolant" to a decent corrosion inhibitor only. Should you feel that this might be a good option, what do you think of this, locally available product ?...... https://www.penriteoil.com.au/assets/pi ... OOLANT.pdf

[cleverusername]

Gentlemen,
Thank you all for your advice.
We have some bad weather here at present, so we'll get onto the task sometime during the week.
I'll report back as we progress.
Thanks again,
Rob

Edit,
PS; Knowing that......
1) "Coolant" will find a way between surfaces where "water" wont.
2) I live in an area with only a few light frosts each winter.
3) Apart from this problem, the cooling system in the Sprint is in A1 top condition......
I am prepared to change the Anti boil, anti freeze, anti corrosion "coolant" to a decent corrosion inhibitor only. Should you feel that this might be a good option, what do you think of this, locally available product ?...... https://www.penriteoil.com.au/assets/pi ... OOLANT.pdf

That only thing that gives me pause is it compatible with an alloy head? Alloy head without an aluminium friendly inhibitor will dissolve if left long enough.

[Sundowner]

OK, here are 2 others from the same manufacturer, for your comments please......
https://www.penriteoil.com.au/assets/pi ... NTRATE.pdf
https://www.penriteoil.com.au/assets/pi ... IBITOR.pdf
Rob

[gmsclassics]

Sounds like a good option to me, given that is what I have done in the Auckland climate.

I would ring or email Penrite Technical and Cutomer Service Centre up and ask them direct. I have found them very helpful when I've contacted them about product (oil) suitability. Otherwise there is the RedLine's 'WaterWetter' and that I can vouch for. You may have to order that though (GL Lubricants Pty Ltd., 4/364 Park Road, Regents Park, NSW, 2143, +61 02 9645 1806)

Geoff

[Sundowner]

Today we re-tensioned the head.
It appears that when the head was replaced last time, it hadn't been re-tensioned after its initial install.
One by one, we noted the tension of each and the location of the wrench, then cracked the bolts undone. They were all around 45-50lbs/ft, but are now evenly re-torqued down to 60lbs/ft.

And that reminds me of a question I've been meaning to ask for several years.....
What's with the angled head studs and bolts? I assume there's a reason for it, but I haven't got a clue as to why its designed this way. Someone, please enlighten me.

Again, Thanks to all of you who answered this thread with advice. Its very much appreciated.

Cheers,
Rob