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#1
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Any Helicoil pros out there ?? Help
OK, getting ready for some A/C install action and I went to swap out the heads from my Sanden 508. I believe I have amassed every part and item and I was very pumped. I also got ROLLGUYS kit, very nice !
Took a bit of mojo to get the old head off. This is a NOS Japan original, not a Chinese clone knock off. I got the pump, et cet from Secondaries over a month ago. Now, it's too hot for any more delays. Then, per the spec's, 24-27 ft pounds, I went to the install. Guess what ? threads pulled right out ... poop. So, I am thinking my only hope is to helicoli the 5 bolts. Right now, I removed the thin metal star-like plate too. I am down to the pistons, so I am good for the clean up and re-install. Need to order the gaskets tonight. So, any ideas or caution about helicoiling this? If it's a loser from the beginning, please let me know so I don't waste my evening or tomorrow in the early AM before Mr. Sun rises. Thanks in advance. |
#2
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If the are 8mm and grade 8.8, then it should be only 18 ft/lbs or more accurately 225 in/lbs. Smaller bolts would be less torque. Also make sure your torque wrench is accurate. At these low torques I prefer a beam type, as the click type has too soft of a click at the lower end. Also, if it has been left set for more than a few hours it will not be accurate, and the further you are from the center of the wrench's range the less accurate it will be as well.
Using a helicoil or similar will be a good fix, just make sure you drill straight, tap straight and keep chips out of the moving parts. |
#3
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I can't really see which bit you are planning to fix - but so long as there is enough metal a helicoil will probably do just fine. You have to oversize the hole anyway before running the specially made tap (can be bought in a kit - drill, tap, inserts and insert tool) and fitting the insert. Very simple process - try to drill the hole straight!
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1992 W201 190E 1.8 171,000 km - Daily driver 1981 W123 300D ~ 100,000 miles / 160,000 km - project car stripped to the bone 1965 Land Rover Series 2a Station Wagon CIS recovery therapy! 1961 Volvo PV544 Bare metal rat rod-ish thing I'm here to chat about cars and to help others - I'm not here "to always be right" like an internet warrior Don't leave that there - I'll take it to bits! |
#4
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Quote:
An 8mm can to to 30-35 lb.-ft. before it fails. I routinely run the 5/16 screws to 28 lb.-ft. with plenty of room above (by feel). |
#5
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Are we talking the bolt or the threads in the aluminum? I am sure the threads in the aluminum will give out before the bolt will break. Also, are both heads the same thickness? If the new head is thicker, longer bolts will be needed. A short bolt ( only a few threads in the aluminum) will surely pull a few threads out.
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All Diesel Fleet 1985 R107 300SLD TURBODIESEL 2005 E320 CDI (daily) LOTS of parts for sale! EGR block kit http://www.peachparts.com/shopforum/diesel-discussion/355250-sale-egr-delete-block-off-plate-kit.html 1985 CA emissions 617 owners- You Need This! Sanden style A/C Compressor Mounting Kit for your 616/ 617 For Sale + Install Inst. Sanden Instalation Guide (post 11): http://www.peachparts.com/shopforum/diesel-discussion/367883-sanden-retrofit-installation-guide.html |
#6
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Quote:
Metric Bolt Torque Table - CNCexpo.com Do you have a reference to qualify your statement, or is it just the calibrated elbow? |
#7
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I would recommend Time Sert insted of Heli coil.
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76 240 D. Bought in 1998 for $25. 85 300D. Got it for free with a bad engine. ( Sold ) 60 Unimog 404. What was left of it, was given to me. Now powerd by 617A. 88 560 SEL. Bought without engine and trans. Now powerd by 617A. 67 250 SE. Cuope. For resto or sale. 64 220SE. For resto. |
#8
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I also only torque in steel with sufficient length (1.5X diameter), so my figures are going to be higher than any other charts. You're probably much closer to the mark in aluminum. |
#9
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Quote:
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#10
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Aren't Time Serts quite a bit larger in diameter? They are great for something that gets put together and taken apart fairly often, but I couldn't see the expense on something that would just be put together once. You are looking at nearly three times the cost of a Helicoil-
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#11
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Well, I totally chickened out because the pistons in the pump looked a little too close for me. I drilled them out and re-tapped 9mm x 1.25, which took out very, very little aluminum.
Any ideas on whether the torque will remain the same, e.g., 24-27 ft pounds. That is, with new bolts which are 9mmx1.25x40mm? |
#12
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I'd use the rated torque, or less and loctite. The alum threads are the limiting factor, not the bolts.
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$60 OM617 Blank Exhaust Flanges $110 OM606 Blank Exhaust Flanges No merc at the moment |
#13
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OK ... news at 11.
No such thing as a 9mm bolt. So, need to go up another hair in sized bolt. Why in the world would you have a 9mm tap and die and NO bolt on the market. This is turning into a royal PITA ! |
#14
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Quote:
Make sure you pick the "right" pitch for a 10MM bolt. One is really common and the other is rare (I *think* it's 1.5)
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$60 OM617 Blank Exhaust Flanges $110 OM606 Blank Exhaust Flanges No merc at the moment |
#15
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No, it's M9 x 1.25. I am not the only dufus to have done this. It's all over the forums for different cars. There are options, e.g., a Polaris speciality bolt, et cet. I am lucky because I removed so little material, that I am going the helicoil route tonight. Keep in mind that I have to keep the bolt shaft size down since the head has pre-bored holes and I am not messing with those no matter what. Worst case scenario is that I am forced to buy a Chinese clone 508SD compressor for my a/c. My gaskets should be here by Wednesday or Thursday, just in time for the 4th weekend. Poop !
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