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Join Date: Mar 2005 Location: Nairn
Posts: 5,658 Thanks: 289 Trader Rating: 0 ![]() | Retorqueing cylinder head nuts. Haynes or one of my other manuals says you have to do this after the engine has been run for a while following rebuild. I assume you perfectionists out there have also done that...or have you found it unnecessary? To retighten I think you're supposed to slacken them a little first , but is that done one by one or slacken the lot and start from scratch?
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Last edited by fiat500; 20-10-2014 at 21:39. | ||
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Join Date: Feb 2013 Location: Christchurch, New Zealand
Posts: 141 Thanks: 8 Trader Rating: 0 ![]() | Re: Retorqueing cylinder head nuts. Having just recently put my engine back together, I noticed that more than half of the nuts were surprisingly loose after only running the car a couple times while setting the timing and tuning. So, I did re-tighten. Once it's run in, I'll check again. I did install a new head gasket (and cylinder base gaskets), so this could explain why things were slightly loose. I loosened them all a little because, as I understand it, having them all loose and one tight puts an inordinate amount of pressure on the head in the area of the one tight nut. Being super anal, I tightened in 4 passes versus the two suggested by Haynes. But, you pose an interesting question that if all the nuts are tight, is loosening only one at a time and retighten it OK? I'll look forward to posts by others.
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Join Date: Mar 2014 Location: Herne Bay
Posts: 1,619 Thanks: 141 Trader Rating: 0 ![]() | Re: Retorqueing cylinder head nuts. If my memory serves me correctly, depending on what the manual says. First off the manual tells you to re torque the nuts either hot or cold. It makes a difference so do what it says. No you don't need to loosen them as the whole point is the head gasket usually compresses more once it has been through a heat cycle. So if you checked the torque on each one you should find they are slightly less than when you set them first off. So just go through the sequence & torque them to the correct setting. ![]()
__________________ Regards Sean "con grande sacrificio, coraggio, pazienza, determinazione e qualche chilo e il sogno si avvera" |
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Join Date: Apr 2010 Location: Sydney & Verona
Posts: 165 Thanks: 3 Trader Rating: 0 ![]() | Re: Retorqueing cylinder head nuts. Tighten bolts to recommended torque and follow the sequence. Do this in 3 stages. For 650engine: 1st stage: 15ftlbs 2nd stage: 20ftlbs 3rd stage: 29-30 lbfts set tappets roughly as you'll need to remove again. Don't bolt up the tin ware to the block - as this will prevent the head from "settling" and remove the 2 banjo bolts (bolts with holes in them) Start engine and run it until hot (20 mins at least). Let it cool down and the following day WHEN ENGINE IS STONE COLD retorque and you'll be surprised at the results! The head will come loose as I was told. Retorque again at approx. 1000kms (600 miles). I didn't do this first time and had to buy a new head. Live and learn.
__________________ OO==/////==OO 124CS, 500F, PUNTO T-JET, BRAVO T-JET Last edited by 124spiderman; 06-11-2014 at 23:53. Reason: er |
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Join Date: Jun 2008
Posts: 280 Thanks: 28 Trader Rating: 0 ![]() | Re: Retorqueing cylinder head nuts. Haynes or one of my other manuals says you have to do this after the engine has been run for a while following rebuild. I assume you perfectionists out there have also done that...or have you found it unnecessary? To retighten I think you're supposed to slacken them a little first , but is that done one by one or slacken the lot and start from scratch? If you keep the head tight on a 500 it should never need a head gasket replacement, I have never had one fail in any of my cars over the last 20 years but have seen plenty of them fail. How many miles have you done since your rebuild?
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Join Date: Mar 2005 Location: Nairn
Posts: 5,658 Thanks: 289 Trader Rating: 0 ![]() | Re: Retorqueing cylinder head nuts. Yikes! All makes sense but that's quite hard work. On the same line of thinking you could argue that the exhaust systen will brace the head against accurate torqueing to some extent. Must get round to that. Still got time because the Authorities are still messing me about with registering the car. At least it's not a 126 Bis. The head on that seemed genetically designed to fail.
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Last edited by fiat500; 07-11-2014 at 17:43. | ||
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Join Date: Apr 2010 Location: Sydney & Verona
Posts: 165 Thanks: 3 Trader Rating: 0 ![]() | Re: Retorqueing cylinder head nuts. Yes, forgot to add that you should loosen the exhaust from the engine block brackets also.
__________________ OO==/////==OO 124CS, 500F, PUNTO T-JET, BRAVO T-JET Last edited by 124spiderman; 09-11-2014 at 00:50. |
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