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23-05-2018, 09:44 PM
(This post was last modified: 24-05-2018, 12:03 AM by John Newell.)
Hi all
I'm at that point in my engine rebuild where I need to torque up the starter dog bolt and the flywheel nut.
Tomorrow I will be tightening up the big end bolts
I'm using a Phoenix pressure fed crank, and Renault 4 rods.
Can anyone please help me with the required torque settings for these fasteners?
Google has suggested between 25 and 30 ft-lbs for the rods.
Phoenix has come back saying he thinks 100 ft-lbs may be correct for the flywheel nut.
I have no answers for the starter dog bolt, nor any idea if the above figures are correct.
Its been a while since I have been A7 Friends and its great to see the more modern forum bulletin board in use.
Looking forward to some informed replies
Regards
John
Christchurch
New Zealand
Joined: Aug 2017 Posts: 1,715 Threads: 47
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Location: Auckland NZ
Car type: 36 Nippy, 31 RM, 38 Special, 24 Works Rep
I do Phoenix rods to 35 ft lbs and flywheels to at least 125 ft lbs no washer
Black Art Enthusiast
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24-05-2018, 09:14 AM
(This post was last modified: 24-05-2018, 09:18 AM by Tom the Blacksmith.)
I too tighten Phoenix rods to 35 ft lb and the flywheel to 150 ft lb. The 150 figure was reached by incrementally going up and checking with slips til the flywheel stopped creeping up (no tab washer but 243 instead).
Tom
Joined: Aug 2017 Posts: 2,748 Threads: 31
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In light of the small recip weight with Seven, and that 5/16 bolts are used on much larger engines, and that 35 lbft on 5/16 or 8mm produces more tension than same on 3/8 then 35 lb ft seems a formidable tension, more suited to 3/8 very HT. Cars with heavy rods and pistons which run beyond 5000 rpm manage with 20 lbs ft on 5/16. With the vagaries of torque is there not a big risk of snapping on assembly ?
Joined: Aug 2017 Posts: 1,715 Threads: 47
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Location: Auckland NZ
Car type: 36 Nippy, 31 RM, 38 Special, 24 Works Rep
None whatsoever with ARP bolts Bob, it is the recommended torque for them, I would not suggest anyone tries this with std 5/16" bolts on Austin rods.
Black Art Enthusiast
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Great news re the 150 ft-lbs measured against slips. Useful real data.
I usually fit tapered joints with hot, with the female piece not only lapped on, but also heated. This way the joint really locks on. When I removed the flywheel 2 months ago it took lots of force to pull off , and then really came off with a bang. I do the same with halfshafts, and although I push hard with driving tests and trials, have not had an issue since 1993 and an Edinburg Trial.
As said above, my rods are Renault 4.
Any idea on the factory spec torque for their big end bolts? They are not ARP bolts.
Cheers John
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Location: Bristol
24-05-2018, 12:31 PM
(This post was last modified: 24-05-2018, 01:00 PM by Terrytuned.
Edit Reason: add bolts
)
Factory spec torque for R4 big end bolts 26 ft-lbs. As they were frequently over tightened it wise to replace them Renault P/no 7700509393 sold as single bolts.
Terry.
