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Engine Specific Info and Questions => IDI Engine => Topic started by: Ohiobenz on February 07, 2022, 04:05:49 pm
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ARP paperwork states a retorque after initial warmup is not necessary.
I'm reading posts on other non VW forums indicating issues if not retorqued.
When I ran the studs in I took them all the way to the bottom, then backed off a couple turns, then hand tightened them.
I used the provided lube on the studs and washers when torqueing the head down.
The engine has now run through a full heat cycle and I'm debating whether to follow the ARP or other forum advice?
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On my rebuilt 1981 11mm block i retorqued the ARP head studs. But that was 150,000 miles ago with a couple more loosening and retorquing cycles since they were installed. Seems to be holding pretty well, no jinx intended.
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With the K14 turbo it gets into boost pretty quick.
I've run 2 heat/cool cycles just in the shop so far without driving it.
When you did the retorque did you back off then retorque or just tightened?
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I backed off a 1/4 turn and then retightened, doing one headbolt at a time following the manuals tightening sequence IIRC
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follow the arp directions, these are completely different fasteners from stock.
my horror story is with an 11mm block. i did a hot retorque and it cracked the block. the stud just spun and when i removed it and looked down into the threads i could it see it filling with coolant.
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That's weird.
The stud isn't supposed to spin.
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It will if you break it or strip it out. Which is my guess of what happened. Hot aluminum is not real strong.
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It's not screwed into aluminum.
I'm wondering if people are following the advice to send the studs all the way to the bottom.
I think the metal in the studs expands at a different rate than the cast in the block.
That can exert a tremendous force on the block and threads.
I also think that if the stud is all the way against the bottom of the hole
and you turn that stud in farther, even a little bit as you torque it down
it will also exert an enormous amount of force pushing up on the stud
while the nut is pulling it upward exerting more force in the same direction.
I always bottom the stud them back off a turn.
Then make sure it doesn't turn more as the nut is snugged up before torquing.
Oh and on topic:
I don't think I ever retorqued the studs I've used and have never had a problem with the head gasket letting loose.
But I don't see a problem with backing them off a little and retorquing if I had the valve cover off.
I read another thread on here where the person decided it was better to torque them more than the manufacturer
suggested. Don't do that.
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Geez another duh moment for me. Aluminum head, not block, Not thinking real clearly these days. Too many of life's troubles going on around me. My head hurts all day as I bumble from one calamity to another. But I come here to try and help. I just don't always get it right.
I am not even sure what ARP recommends for a torque limit on their product. I recently had suspected blowby and retightened the whole set to what was in the Bentley. I am now wondering if I should have gone more than that.
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It's a crazy world right now.
I'm not sure what the torque is supposed to be for the ARP stuff.
Might be 80.
I think 11mm studs are 95ftlbs.
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I think I will go look as I don't think I was much over 70 lbs with the wrench. I will check the dial on it as I put it away set to what I used. That would be good to go to 95 if i can. That might stop my blowby, being low might have been the problem.
Edit for numbers: This is what I got for a 1.9 turbo diesel engine. 125 ft/lbs
https://tech.arp-bolts.com/instructions/204-4706.pdf (https://tech.arp-bolts.com/instructions/204-4706.pdf)
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On the 11mm started out at 80 ft/lb. The last time went to 95.
They have held but I am losing a little coolant between oil changes now and might go up to 100 this next time, or the coolant tank cap is failing.
It is all an experiment :), caution advised. Good point about a cold engine block-have always retorqued when cold.
There should be more information on this board or it might have been on the Vortex; those posts would be at least 12 years old by now.
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I wouldn't go higher than 95 on the 11mm heads.
ORCoaster: Is the torque sequence on the ARP link wrong?
I think it's mirror image of what's in the bentley but,..
was going to say my bentley was outside but the truth was too lazy too look, ha.
Yep wrong.
According to my MK2, 1.6 Bentley official factory repair manual,.. that is still in the house.
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I was going to say that the link was for the newer 1.9 L engines but I see that it covers the 1.6 as well so yeah. A guy could have 11 mm heads on a block.
But are the ARP studs better-made steel than an 11 mm bolt? Thereby being able to take more torque? I really don't know about that. I was thinking of doing another sequence of tightening on my head gasket now that I see I have more potential to get it right and tight.
As for the sequence of bolts to tighten I thought it was correct. You just need to bounce back and forth on that process so you don't get one side too tight. I think the sequence allows for one to get the middle down and works it out toward the ends. Possibly to remove any warpage.
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Again, this is from old memories but IIRC when folks were using the AAZ metal head gasket on 1.6 hydraulic blocks (MF certainly) ARP 204-4706 studs were going up to 125 ft/lbs. With a fiber gasket it seemed like that much compression wasn't needed though? There is something about being able to go a certain spec over manufactures recommendations; what comes to mind is that Raceware studs were recommended at 50-55 ft/lbs but could go up to 70-80. The difference was the studs failing vs the block failing.
But i defer to you guys on all things VW diesel.
The point about not going to 100ft/lbs is well taken on my 11mm block. Can't remember the ARP part number for 11mm blocks for sure but may have ended with 4701 and were made for a Cosworth?
Originally the motor had the 1.5 head on a 1.6 block combo so it needed to be well clamped down. Started incredibly easy on cold days.
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The cosworth is the 12mm stuff.
11mm work in the gas VW engines of the time.
Something to concider with stud torque is the threads on the nuts isn't the same as the threads in the block.
Course threads get torqued higher.
Raceware has fine threads on the nut and a special lube so the torque is lower.
The problem with the stock 11mm headbolts is they are too short.
They probably only have 1/2" into the block.
Lots of stress in a small area.
The studs go deeper and grab more threads,.. not sure if the metal is better.
Also since the studs hold still and don't turn and grind on the threads as they are tightened
they aren't as likely to break the threads.
ARP part numbers: 204-4706 is 12mm
204-4701 is for the 11mm block
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The ARP Cosworth studs are 12mm and should not be used now that ARP has released VW diesel specific 12mm studs. The part # that Fatmobile posted (204-4706) for the 12mm studs are for the correct VW studs.
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I'm pretty sure the ARP headstuds were 12mm.
I torqued to the 125 ft/lbs using the ARP provided lube.
It's got a fiber gasket, plus .030" copper O-Rings in the block.
At this point I'm going to run it....
If it starts to leak I'll be surprised. I was more worried about blowing the headgasket running 20-25psi boost.
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That seems a little high @ 125.
What did ARP recommend?
You get 25psi out of your K14?
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I just retorqued the ARP studs I have on my Pickup to 90 ft/lbs. Seems to have helped the injection of air into the coolant system at the 10 psi boost mark.
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The installation instructions included in the box of 204-4706 ARP head studs i have in the garage say to go up to 125lbs on the third step so all should be good.
There isn't any mention of fiber or metal head gaskets but the application sheet specifies both 1.6 and 1.9 liter VW/Audi diesels motors.
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I torqued mine to the 125 ft/lbs ARP recommends on mine (12mm studs). I also retorqued them after a number of heat cycles and got up to an 8th turn on some of the nuts, so I would highly recommend retorquing. I am running a stock replacement head gasket.
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An update for those that might like to know. I put 90 ft-lbs on the nuts and that seems to have stopped my overheating issue. IF it comes back again I may jump it up to 100 but after that, I think it would be better to get a different HG and start over. Once those things blow it is hard to get them tight enough.
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That's great!. If I end up going to 100 ft/lbs (on the 11mm studs) before you do will post about success/failure.
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Sure will, But I really don't want to be doing that. I have the body work to get done and fooling around with the engine keeps me from sanding and painting.