Ian Vincent Posted April 28, 2021 Report Share Posted April 28, 2021 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: The WSM says check them hot Another poster said do them cold Several posters said stick with the 105lbs ft recommended in the WSM and ignore the ARP figure of 110lbs ft, and 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 Quote Link to post Share on other sites
ntc Posted April 28, 2021 Report Share Posted April 28, 2021 (edited) 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: The WSM says check them hot Another poster said do them cold Several posters said stick with the 105lbs ft recommended in the WSM and ignore the ARP figure of 110lbs ft, and 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 April 28, 2021 by ntc Quote Link to post Share on other sites
Lebro Posted April 28, 2021 Report Share Posted April 28, 2021 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. Quote Link to post Share on other sites
Motorsport Mickey Posted April 28, 2021 Report Share Posted April 28, 2021 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 Quote Link to post Share on other sites
ntc Posted April 28, 2021 Report Share Posted April 28, 2021 But not ARP ? Quote Link to post Share on other sites
signalredshaker Posted April 28, 2021 Report Share Posted April 28, 2021 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 Quote Link to post Share on other sites
Ian Vincent Posted April 28, 2021 Author Report Share Posted April 28, 2021 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 Quote Link to post Share on other sites
ntc Posted April 28, 2021 Report Share Posted April 28, 2021 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 Quote Link to post Share on other sites
Motorsport Mickey Posted April 28, 2021 Report Share Posted April 28, 2021 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 Quote Link to post Share on other sites
Lebro Posted May 3, 2021 Report Share Posted May 3, 2021 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. Quote Link to post Share on other sites
ntc Posted May 3, 2021 Report Share Posted May 3, 2021 That’s high Quote Link to post Share on other sites
Motorsport Mickey Posted May 3, 2021 Report Share Posted May 3, 2021 Tighter piston deck settings, better gas movement across the head, better compression. Mick Richards Quote Link to post Share on other sites
ntc Posted May 3, 2021 Report Share Posted May 3, 2021 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 Quote Link to post Share on other sites
Ian Vincent Posted May 3, 2021 Author Report Share Posted May 3, 2021 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 Quote Link to post Share on other sites
Lebro Posted May 4, 2021 Report Share Posted May 4, 2021 Only logical reason I can think for 4 being richer than 3 is a possible manifold leak on 3, will check, & tighten. Bob. Quote Link to post Share on other sites
RogerH Posted May 4, 2021 Report Share Posted May 4, 2021 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 Quote Link to post Share on other sites
Lebro Posted May 4, 2021 Report Share Posted May 4, 2021 New valves & guides, so I would hope not. Bob. Quote Link to post Share on other sites
tim hunt Posted May 4, 2021 Report Share Posted May 4, 2021 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 Quote Link to post Share on other sites
Ian Vincent Posted May 4, 2021 Author Report Share Posted May 4, 2021 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 Quote Link to post Share on other sites
Lebro Posted May 4, 2021 Report Share Posted May 4, 2021 As the nuts are slackened 1 at a time I don't think anything is going to move. Bob Quote Link to post Share on other sites
Motorsport Mickey Posted May 4, 2021 Report Share Posted May 4, 2021 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 Quote Link to post Share on other sites
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