billbranch Posted September 12, 2012 Report Share Posted September 12, 2012 Now that the V6 is mechanically pretty good, I need more punishment in the form of piston rings. I also read one of the threads here where some have used Volvo pistons, Saab con rods, I guess the possibilities are endless. The HG was blown, so the head has been pulled and a new/used one with valve job is ready. Leak-down test was atrocious. I have a broken ring although it does not appear any broken pistons. The boost was set very low, only overboosted once when the hose to the actuator tore. What are the recommendations here? We used Deves last time. Thanks for any tips. Bill Quote Link to comment Share on other sites More sharing options...
Bean Posted September 12, 2012 Report Share Posted September 12, 2012 Do you know the the piston ring gap was set correctly in the piston bores? Were the ring in piston grove clearances in spec? I've heard of ring issues when either gap wasn't set right or there was too much play in the groove - but no actual experience. I did over boost my 89' WAY more than I should have diagnosing my overboost issue (very stupid I know) - but the car is running awesome so I'm happy to say I didn't cause any damage as the car still runs great. I doubt one indescretion should have caused an issue - but never know. Not sure if anyone has used different rings in stock pistons - I would think the chances of finding ones that worked well were pretty much slim to none. Deves have a good rep, and as far as I know - I thought they were pretty much the only option. Using another piston would require a bottom end rebuild so I would assume that's off the table. Curious to hear if you find any other solutions. Quote Link to comment Share on other sites More sharing options...
Bean Posted September 12, 2012 Report Share Posted September 12, 2012 BTW - did the removed head have no sign of cracking between the middle exhaust valve seats and the coolant passages? Which HG are you going to use? And have you thought of doing ARP head studs? Rabin Quote Link to comment Share on other sites More sharing options...
billbranch Posted September 12, 2012 Author Report Share Posted September 12, 2012 Hi, Rabin, This head had been welded and had had a lot of cracks. I was extremely disappointed (euphemism) because I should have gone with a different head last time, but someone else made the call. This time yes, there was at least one crack at the number two or number three exhaust valve. We are using OEM gaskets. Not sure about the studs. What are they? What do they do? How does using them make a better job? Bill Quote Link to comment Share on other sites More sharing options...
Bean Posted September 12, 2012 Report Share Posted September 12, 2012 Mechanical strength is much stronger if you use a stud threaded into the block with a nut on top to secure the head than using a bolt for the same job. More accurate torque and even pressure for each stud as well. It's a common for race motors to run head studs, and it's a common upgrade for turbo cars to run head studs instead of bolts. I think Nick is running them, Koll was looking at spec'ing some out for his head rebuild, and I will definitely use them. It's a must have IMHO for a turbo motor. If I was a wealthy man I'd see if Raceware (http://www.raceware-fasteners.com/photo.htm)had something - but last I checked it'd be a $400 touch if they had anything in stock that would work. Very high end race motor stuff - and I doubt any of us would even push the ARP stud strength and they're way cheaper. Rabin Quote Link to comment Share on other sites More sharing options...
nick@nite Posted September 13, 2012 Report Share Posted September 13, 2012 I think I still have a set of Deeves rings around. I have to ask if the old man if he wants to part way if in fact we do have them... 91.7mm rings do not exist anymore... 92mm are 92.5 are, like the Volvo and WRX Quote Link to comment Share on other sites More sharing options...
billbranch Posted September 13, 2012 Author Report Share Posted September 13, 2012 Tomorrow I will have a very good idea where we're headed: the pistons are in the sink, and tomorrow they'll be thoroughly examined for cracks. My fingers are crossed. Roger wants to have the pistons knurled; I am concerned about fragility. Nick: let me know about the availability of the rings. Roger says he can get them directly from a supplier. Anyone: is there a kit or parts number for the ARP head studs? Bill Quote Link to comment Share on other sites More sharing options...
Bean Posted September 13, 2012 Report Share Posted September 13, 2012 I've heard of pistons being knurled to tighten up the bore clearances, but I've only ever seen them knurled and finish machined after the block has been bored just enough to true up the cylinders. Pistons were then knurled, and finished so that bore clearance was within spec. Not sure how knurling and then fitting them into the untouched bores would be good however since the bores will be slightly out of round. (I'd be shocked if the bores were perfect - but it's not impossible) They can knurl valve guides for the same reason - but in both cases it's not really the "proper" way to do it - but it's better than not doing anything. Rabin Quote Link to comment Share on other sites More sharing options...
billbranch Posted September 13, 2012 Author Report Share Posted September 13, 2012 Roger is concerned about a sloppy fit in the cylinder and the chances of the piston, as he put it, wobbling on the compression stroke. Tomorrow, as I said, I'll have a great idea of how I am to proceed when the pistons are examined for cracks. Quote Link to comment Share on other sites More sharing options...
nick@nite Posted September 13, 2012 Report Share Posted September 13, 2012 double checked and I only have some 3 used ring set... So your most likely needing either the slightly larger B or C spec pistons... RARE! From my #45 thread page 13 "Finally the ARP headstuds came today... PN# are AU7.860-2LB for the studs 300-8376 nut, 200-8500 washer, 100-9908 ultra torque lube" Quote Link to comment Share on other sites More sharing options...
billbranch Posted September 15, 2012 Author Report Share Posted September 15, 2012 Thank you, Nick. Roger called me to say none of the pistons is broken. I had a cerebral orgasm. He said the piston he had in his hand was a "C." Are there any issues relating to the rings because of the classification? Quote Link to comment Share on other sites More sharing options...
billbranch Posted September 21, 2012 Author Report Share Posted September 21, 2012 OK, I believe we have assembled, except for excess cash, all of the things we need. Can anyone tell me if these ARP (excellent service, BTW) studs are simply torqued or if there are special procedures we should follow? Thank you, all, for your help with this. I love the V6 sedan, but I love the turbo wagon (MY SUV) even more. Quote Link to comment Share on other sites More sharing options...
Bean Posted September 21, 2012 Report Share Posted September 21, 2012 ARP should have specific instructions and torque specs for the studs they provided. Some say they don't need retorquing - other references online say you should. Rabin Quote Link to comment Share on other sites More sharing options...
bryancohnracing Posted September 23, 2012 Report Share Posted September 23, 2012 I'm a big believer in re-torqueing in general, regardless of what the specs say UNLESS the bolts are one time use stretch bolts. Then I throw them away and use good bolts, if possible! As for rings, it may take some work with a good parts guy or engine shop but they should be able to find rings that are damn close to the needed specs and you simply fit them via the end gaps as needed. As a weird example we used to use Harley Davidson rings in a Dodge Neon race car I ran back in 1995. This way we could get Deves (great product!) as they were not available for twin cam Neon's at the time. I ran a Ford Escort with similar odd ball rings at one time as well. Quote Link to comment Share on other sites More sharing options...
nick@nite Posted September 23, 2012 Report Share Posted September 23, 2012 80ftps you should be good, and I would retorque in 500 miles just to be sure. Quote Link to comment Share on other sites More sharing options...
billbranch Posted September 23, 2012 Author Report Share Posted September 23, 2012 Thanks, Rabin, Nick, Bryan, the retorque bolts and readjust valves is what Roger is doing. He's old-school, much like some of us. Quote Link to comment Share on other sites More sharing options...
N9TE Posted September 24, 2012 Report Share Posted September 24, 2012 Nick, could you install the studs after placing the head? I don't know if there's enough room to drop the head down over the studs. They're pretty long. What do you think? Quote Link to comment Share on other sites More sharing options...
Bean Posted September 24, 2012 Report Share Posted September 24, 2012 If the holes are prepped and ready for the studs it shouldn't be a problem as these heads are on dowels too correct? My question is what is recommended when threading the stud in. I've read guys say to thread it in all the way and then back off half a turn or so. This way when you torque the nut down the stud can turn a little and still not get bound up. Read a few threads of guys that couldn't get studs out as they snugged them into the block and then torqued the nuts down causing the studs to get super tight. I like the idea of half turn loose to ensure they don't rotate tight when it goes on. I need to get me as set - would someone mind posting the total cost for everything needed? (Or PM me if that is better for you) Rabin Quote Link to comment Share on other sites More sharing options...
billbranch Posted September 24, 2012 Author Report Share Posted September 24, 2012 Rabin, My set (minus the lube, which couldn't be shipped by air) was US $212.45 with second day air shipping. Bill Quote Link to comment Share on other sites More sharing options...
N9TE Posted September 25, 2012 Report Share Posted September 25, 2012 Thanks for the price. I'm going to order those up today! I've heard finger tight. The only remaining question I have is lube or no lube. Have you test fitted these Bill? If you look closely, the stud bosses at the top of the head have oil holes for the top end. The studs are the same thickness as the stock bolts? Quote Link to comment Share on other sites More sharing options...
N9TE Posted September 25, 2012 Report Share Posted September 25, 2012 Hey Bill, on those studs, I couldn't bring them up in the catalog. Is this a special order item or am I slow. Quote Link to comment Share on other sites More sharing options...
Bean Posted September 25, 2012 Report Share Posted September 25, 2012 Thanks for the price. I'm going to order those up today! I've heard finger tight. The only remaining question I have is lube or no lube. Have you test fitted these Bill? If you look closely, the stud bosses at the top of the head have oil holes for the top end. The studs are the same thickness as the stock bolts? I thought ARP bolt lube was manditory? I know Royal Purple assembly lube is highly recommended if you're looking for something. As for the oil holes in the bolt bosses - that would mean there would have to be holes bolt holes to drain oil into the block - doesn't seem to make sense so maybe they're casting vent holes for when they pour the cast? Quote Link to comment Share on other sites More sharing options...
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