23 replies to this topic

[Kerrin]

Sorry guys but Altzheimers has set in, and a case of asking too many people.

should I re-tourque my cylinder head again once it has been run.

Next door neighbour who owns 3 cooper s' and a few more besides says no. My mate who owns an autotest mini says yes.

I think the mini films 1380 build also says yes

[Southy]

Yes you should, let it get upto temp and turn it off and re-torque the head. Let it cool back down and then reset the tappets and jobs a goodun

[Dan]

Definitely yes. Almost every time someone has started a thread here saying they'd replaced a head gasket and it had failed within a week it was because it hadn't been re-torqued.

[Kam]

Check it after around 500 miles aswell

[Sprocket]

I dont re torque the head gasket on the 16 valver. Have you seen what you have to do to re torque Had no problems

I think its more to do with older gaskets. These modern BK450 gaskets dont have much to compress to start with.

Some say you have to, some say you dont. I have done it both ways and not suffered any failures

[tony kenobi]

I would say yes, only last week i had gasket failure on my rebuilt engine, i hadn't re-torqued.
Like said above, let it warm well up, then cool and check them, no harm in it anyway.

[Prawn]

When I fitted my new head I bolted it up with a payern copper gasket and standard studs to 45lbft, and forgot to retorque it after running the engine.

Unrelated I think, but it ended up having 2 valves stick in the guides and bend on the rolling road, and at the same time the gasket blew between 2-3 and across the waterways to the back of the block.

I refitted it all with a bk450 and ARP studs, and retorqued it 4 times once I had it running to 60lbft just to be sure. after the first 'retorque' after running it they didn't turn any further.

[mini7boy]

When I fitted my new head I bolted it up with a payern copper gasket and standard studs to 45lbft, and forgot to retorque it after running the engine.

Unrelated I think, but it ended up having 2 valves stick in the guides and bend on the rolling road, and at the same time the gasket blew between 2-3 and across the waterways to the back of the block.

I refitted it all with a bk450 and ARP studs, and retorqued it 4 times once I had it running to 60lbft just to be sure. after the first 'retorque' after running it they didn't turn any further.

Prawn,

your stuck valves are most likely not caused by the head gasket issues, but you are definitely making a big mistake torquing the head to 60 pounds. By doing so, you are merely increasing the likelihood of fire ring failure and the burning you observed between 2-3. The fire ring is the metal ring around each cylinder.

Don't take my word for it.

Read what Keith Calver recommends: http://www.minimania...27/ArticleV.cfm

Edited by mini7boy, 09 March 2009 - 07:41 PM.

[Adcuz]

When you say re torque. Does that mean take the head off and do the whole lot again, or just double check the torque is correct after running? I'm replacing my head this weekend so would like to know.

[Ouster]

I would have thought just double checking the torque setting.

[Guess-Works.com]

When you say re torque. Does that mean take the head off and do the whole lot again, or just double check the torque is correct after running? I'm replacing my head this weekend so would like to know.

No, it just means going around the head with the torque wrench again ( set to the correct setting, slaps prawns wrist ) in a spiral starting from the front centre stud.

and then as above, checking the tappet clearances.

[ianpettifer]

what is the setting?

cheers

[Prawn]

Prawn,

your stuck valves are most likely not caused by the head gasket issues, but you are definitely making a big mistake torquing the head to 60 pounds. By doing so, you are merely increasing the likelihood of fire ring failure and the burning you observed between 2-3. The fire ring is the metal ring around each cylinder.

Don't take my word for it.

Read what Keith Calver recommends: http://www.minimania...27/ArticleV.cfm

Very interesting! I know why the valves picked up in the guides, the guides fitted were not remead out before the head was assembled, and as a result, the valves were far too tight in the guides.

I'm a little worried now about the head stud issue though! I torqued them up to 60lbft on the recommendation of the guy who's rolling road it initially broke on. this 60lbft figure was confirmed by the ARP head stud set instructions too. Which clearly stated they should be torqued to 60lbft when lubed with engine oil.

It's only done a few hundred miles since refitting the head, and no problems as of yet, but I'll definately bare that in mind if I start to get problems!

[Pauly]

For high performance engines I would say yes, but for a standard engine I would just torque it down the once, done it on my blue mini and its been ok *touch wood*. You shouldn't torque it down more than twice really as the gasket seal will weaken.

Paul.

[mini7boy]

Prawn,

your stuck valves are most likely not caused by the head gasket issues, but you are definitely making a big mistake torquing the head to 60 pounds. By doing so, you are merely increasing the likelihood of fire ring failure and the burning you observed between 2-3. The fire ring is the metal ring around each cylinder.

Don't take my word for it.

Read what Keith Calver recommends: http://www.minimania...27/ArticleV.cfm

Very interesting! I know why the valves picked up in the guides, the guides fitted were not remead out before the head was assembled, and as a result, the valves were far too tight in the guides.

I'm a little worried now about the head stud issue though! I torqued them up to 60lbft on the recommendation of the guy who's rolling road it initially broke on. this 60lbft figure was confirmed by the ARP head stud set instructions too. Which clearly stated they should be torqued to 60lbft when lubed with engine oil.

It's only done a few hundred miles since refitting the head, and no problems as of yet, but I'll definately bare that in mind if I start to get problems!

Prawn,

I was going to speculate about the failure to ream the guides after they were installed into the head, but I didn't only because I thought that everyone knew of the need to ream them. You're just lucky that the damage was not worse than it was.

I am sorry for confusing the issue because I failed to notice that you use motor oil with the ARP studs.

You are right about using 60 lbs/ft with MOTOR OIL. I always use the ARP moly lube and the correct figure for that is only 40 lbs/ft.

I was curious about your remark about the ARP instructions specifying 60 lbs/ft for the head studs. So curious that I called APT, one of the biggest A-series ARP bits sellers in the U.S. As I expected, he said that the ARP studs, using the ARP moly lube, should be torqued to no more than 40 lbs/ft and that the rocker studs and smaller ones should be torqued to 20. Since the ARP bits are really designed to be installed with their own lube, I would recommend that you use it in preference to anything else available. Just to be perfectly clear on this, these torque figures are for the nuts only. The studs are usually installed into the block using around 4 lbs.ft if I remember correctly.

Here's what the APT website says about using ARP bits:

‘A’ & ‘B’ series engines.

These studs are rated at 190,000 PSI (consider that Grade 8 is less than 150,000 PSI).
Included washers are hardened, and the 12 point type nuts are of the aircraft type.
The following head stud kits include rocker studs, nuts + washers: HSA9, HSA11, HSA11-B, HSB42
Always wash and inspect the product upon opening.
The oily coating on the parts is a rust preventive, and does not therefore have any lubricating properties.
30 cwt. engine oil, or the recommended ARP lube, part number L99 should always be used, and the different torque specifications for each type of lube followed.
The tension obtained in the fastener (which is what we need) is affected by how well the lubricant being used is coated evenly on the threads.

When using oil, and especially when using the ARP low friction lube, it is highly recommended that the following technique is followed:
- Coat the fastener with the lubricant, and especially with the lube, try and rub it into the threads as evenly as possible.
- Screw the nut down and pull up snugly with a wrench (spanner), repeat this three times.
- On the third go torque to the recommended torque setting.

All of the above might sound a little odd, but many carefully controlled tests have shown that this method distributes the lube evenly between the friction surfaces, so increasing the tension each time for a given torque.
The difference in tensile load between step #1 and step #3 can easily be well over 1000 pounds on a 3/8" stud or bolt… very significant!
Always run a tap down each threaded hole prior to installing the studs.
Use a bottom tap (called a plug or #3 tap in England).
Where possible we recommend using a 60 degree counter sink into the top of each stud hole. This will help stop the top threads being pulled up above the surface.
We don’t recommend using Loctite type compounds on studs or bolts, but if you feel you want to, then be sure to complete the job, including final torqueing before the compound 'sets up'.
Studs should not be screwed into the block very tightly, only about 4 ft lbs is all that is required (not much more than hand tight).
The torque figures we recommend will give a preload equal to 75% of the yield strength of the fastener.

If you have any questions, please contact us BEFORE proceeding.
ARP is a quality product, and like many other things in life, sometimes when you get into it a bit, you might find there is a little more involved than just "screwing it together"!

Thank you for considering the use of these great products,

David Anton Owner, Advanced Performance Technology