Jump to content

Recommended Posts

Having done about 250 miles since I rebuilt my engine during the most recent lockdown, and it being a wet afternoon, I thought I would retorque the head on my TR3a.

I have ARP head studs so I did a quick check on the forum before I started to see what the collective wisdom was on whether it should be done hot or cold and what was the recommended torque.

So I found a variety of conflicting advice:

  1. The WSM says check them hot
  2. Another poster said do them cold
  3. Several posters said stick with the 105lbs ft recommended in the WSM and ignore the ARP figure of 110lbs ft, and
  4. One poster (who shall remain nameless) said there is no need to re-torque ARP studs, end of.

So I went with the WSM figure of 105lbs-ft and did them hot.  I also backed them off the recommended 60 deg. (approx. recognising that ARPs don't have flats!).  The result was that I gathered up at least 1/2 a turn of additional turn on most of the studs with a couple of them turning even more and those two studs had almost felt loose when I backed them off.  So it was definitely a worthwhile exercise because I had been pretty careful doing them up in first place and wouldn't have missed two of the studs out.  And I use two torque wrenches, I pull them up initially with a bendy bar one and then check with a 'click' one.

Needless to say, after the re-torque, the valve clearances were too tight and needed adjustment.

Rgds Ian

Link to post
Share on other sites
16 minutes ago, Ian Vincent said:

Having done about 250 miles since I rebuilt my engine during the most recent lockdown, and it being a wet afternoon, I thought I would retorque the head on my TR3a.

I have ARP head studs so I did a quick check on the forum before I started to see what the collective wisdom was on whether it should be done hot or cold and what was the recommended torque.

So I found a variety of conflicting advice:

  1. The WSM says check them hot
  2. Another poster said do them cold
  3. Several posters said stick with the 105lbs ft recommended in the WSM and ignore the ARP figure of 110lbs ft, and
  4. One poster (who shall remain nameless) said there is no need to re-torque ARP studs, end of.

So I went with the WSM figure of 105lbs-ft and did them hot.  I also backed them off the recommended 60 deg. (approx. recognising that ARPs don't have flats!).  The result was that I gathered up at least 1/2 a turn of additional turn on most of the studs with a couple of them turning even more and those two studs had almost felt loose when I backed them off.  So it was definitely a worthwhile exercise because I had been pretty careful doing them up in first place and wouldn't have missed two of the studs out.  And I use two torque wrenches, I pull them up initially with a bendy bar one and then check with a 'click' one.

Needless to say, after the re-torque, the valve clearances were too tight and needed adjustment.

Rgds Ian

The Official ARP Web Site | FAQ (arp-bolts.com)

Do I need to re-torque my head bolts or studs?

If you follow the ARP installation instructions, there should be no need to do a re-torque. However, it may be necessary under certain circumstances if the gasket manufacturer’s instructions require it, particularly if a fire ring has been installed. ARP recommends not doing a re-torque on a hot engine.

Edited by ntc
Link to post
Share on other sites

My engine has now done 250 miles since re-build, given what Ian found perhaps I should do the same, although I did not use ARP studs, but re-used the originals.

Bob.

Link to post
Share on other sites
1 hour ago, Lebro said:

My engine has now done 250 miles since re-build, given what Ian found perhaps I should do the same, although I did not use ARP studs, but re-used the originals.

Bob.

At 250 miles after rebuild I'm happy to release the original studs 1 flat and then retorque up to 105 lb ft.

Mick Richards

Link to post
Share on other sites

Hey! I'm another TR (4) owner who has done 250 miles since my engine rebuild last March and who hasn't yet tightened down the cylinder head.

When I get moving with my car I'll do as the workshop manual says- but am I too late? No, I don't think so. Mind you 250 miles in just over a year isn't much is it!

James

Link to post
Share on other sites

Following Neil’s comment above I emailed ARP and asked why they don’t recommend tightening the studs hot. This is their reply.

“Hi Ian,

Our lubricant changes friction co-efficiancy around 120 degrees which can lead to either the stud yielding or breaking when re-torquing. 

Best regards, 
Zac Kimball”

 I got away with it and didn’t break anything but then I stepped back from their recommended 110ft-lbs. 

Rgds Ian

Link to post
Share on other sites
23 minutes ago, Ian Vincent said:

Following Neil’s comment above I emailed ARP and asked why they don’t recommend tightening the studs hot. This is their reply.

“Hi Ian,

Our lubricant changes friction co-efficiancy around 120 degrees which can lead to either the stud yielding or breaking when re-torquing. 

Best regards, 
Zac Kimball”

 I got away with it and didn’t break anything but then I stepped back from their recommended 110ft-lbs. 

Rgds Ian

Ian 

I do hope you have got away with it only time and contraction will tell 

Link to post
Share on other sites
4 hours ago, ntc said:

But not ARP ? 

Hi Neil, the ARP fastenings are fitted lubricated which increases the actual clamping force applied to the head and block against the Triumph original 105 lb ft torque figures.

I torque ARP at 90 lb ft which allowing for a 15% increase in clamping force for the lubrication comes out at 103.5 lb ft as close as I can estimate. 

Mick Richards

Link to post
Share on other sites

Following Ian's lead I re-torqued my head nuts today. after slackening off  ½ a flat or so most went another flat and ½ before clicking at 105 ft lb. Re set valve clearances, some needed tightening, some loosening. Then, after a spin or two round the block, went on to check tick over mixture using 4 X colourtune plugs.

interestingly No. 4 runs richer than No.3 so some compromise had to be reached on tuning the rear carb. Finished off by checking compression's:

213  200  204  210  PSI   Nos 1 & 4  4 PSI higher than before running in started.  Yet to get a feel for MPG !

Bob.

Link to post
Share on other sites

Tighter piston deck settings, better gas movement across the head, better compression.

Mick Richards

Link to post
Share on other sites
1 minute ago, Motorsport Mickey said:

Tighter piston deck settings, better gas movement across the head, better compression.

Mick Richards

Hope the rest of the engine can cope with it 

Link to post
Share on other sites

I thought these engines were pretty much indestructable once they were properly sorted.

Rgds Ian

1 hour ago, Lebro said:

interestingly No. 4 runs richer than No.3 so some compromise had to be reached on tuning the rear carb.

I only have two colourtunes so I use them in nos. 2 & 3.  I then go for a 20 or 30 mile drive trying to keep the engine up around 2,500 rpm minimum and afterwards pull the plugs to check their colour.  I always find that the outer two cylinders run marginally leaner than the inners.

Rgds Ian

Link to post
Share on other sites

Only logical reason I can think for 4 being richer than 3 is a possible manifold leak on 3, will check, & tighten.

Bob.

Link to post
Share on other sites
8 minutes ago, Lebro said:

Only logical reason I can think for 4 being richer than 3 is a possible manifold leak on 3, will check, & tighten.

Bob.

Possible a very subtle oil leak down the valve guide !!

 

Roger

Link to post
Share on other sites
On 4/28/2021 at 6:21 PM, Motorsport Mickey said:

At 250 miles after rebuild I'm happy to release the original studs 1 flat and then retorque up to 105 lb ft.

Mick Richards

Is it a good idea to drain some coolant before slackening the head nuts? It is very 'seaching' and is there not a chance some might enter the cylinders by capillary action?

Tim

Link to post
Share on other sites
20 minutes ago, tim hunt said:

Is it a good idea to drain some coolant before slackening the head nuts? It is very 'seaching' and is there not a chance some might enter the cylinders by capillary action?

Tim

If it does, wouldn’t it be burnt off the moment you fired the engine up?

 Rgds Ian

Link to post
Share on other sites

As the nuts are slackened 1 at a time I don't think anything is going to move.

Bob

Link to post
Share on other sites
43 minutes ago, Lebro said:

As the nuts are slackened 1 at a time I don't think anything is going to move.

Bob

Aaahhh, answering both questions

I’mn not bothered about a minuscule amount of seepage between head- gasket- block. But  I always worry that NOT dropping the water level might allow a pathway to be formed through the Wellseal to a chamber, and trapped moisture giving a future weakness to gasket integrity. So I do drop the water level down below the head join, sorry I hadn’t posted that this time but have done previously.

Also, I do unmdo ALL the headnuts first by the one flat, after dropping the coolant level to try and avoid any stressing of the head. Then just carry out the retorque in the normal manner. Although this is just my practice, whether an individual fastening release and retorque could cause a problem...I don’t know.

Mick Richards

Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Restore formatting

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
×
×
  • Create New...

Important Information

Please familiarise yourself with our Terms and Conditions. By using this site, you agree to the following: Terms of Use.