Is it possible to re-use the fasteners, or should I get new ones. If the latter, what size do I need? Summit's webpage does not guide me to the right ones.
I decided to get new bolts from ARP. Unfortunately I was to stupid to order the right ones (in spite of the good information from Hugger and Larry). Fortunately I got bolts which are not to short, but to long. So instead of mounting the flexplate to the crank I did spend the time today with shortening the bolts. Oh well, **** happens. Also have one question: ARP states 85ftlbs, whereas the Buick manual states 58ftlbs of torque for the flexplate fasteners. I tend to 58ftlbs because I am concerned about the crank. What do you recommend?
Why use higher-tensile-strength fasteners if you're not going to tighten them to the manufacturer's spec? Might as well use GM bolts. The high-tensile bolts won't be properly stretched at the lower torque spec.
Does the length of the bolt affect anything? Probably not, but I thought I’d ask. Interesting that ARP would specify a torque, I always figured it varied according to the application. I used red locktite on mine.
Do you know what is funny?My car just ran 9.04 and 148 mph,never used anything but stock bolts in it,that's for 30 odd years. My GS also has the same bolts,which has a estimated HP of over 600 hp.No problem here also.Never used anything also all of the years I've been racing.Not saying that ARP are not good,and that's your preference,go for it,but for a fairly stock car..And like Briz,just used the gun,never any problems with that.Bruno.
same here as Bruno, I use Loctite red and away we go. I do verify with torque wrench. To the OP, I do recommend follow what ARP says. Find out is that 85 dry or with a lubricant.
This is from the ARP Catalog, The bolts I used were the 200-2903, https://www.summitracing.com/parts/arp-200-2903 The fastener yield strength for these is 200,000 psi
I did not go with ARP for additional strenght. The old bolts are probably as old as the car and the hex shape of the heads is bad. I went with ARP for convinience, as I ordered other stuff @ summit. Please keep in mind that I do not have the convinient situation that I have several auto stores carrying parts for US cars within 5 miles or so, nor do I have a junkyard to go to for used parts. The bolts I got are not for Buick, but for Chevy (arp-200-2902) and ARP specifys 85ft/lbs with lubricant underneath the head and loctite 232 on the thread. I do not know what the material of the Chevy crank compared to the Buick crank is (might be stronger material), so I rather stick with the torque spec given in the Buick manual. The clamp force at a given torque is independent ot the tensile strenght of the bolt. It depends on the friction underneath the head and in the threads, the thread geometrie (diameter, shape, pitch). Those parameters are the same, so the clamp force at stock torque will be equal. As this is a relative short bolt (diameter/length) it is difficult anyway to reach a stretch so that it will not become loose. Thats why the use of loctite is a good idea.
Locktite 242 is the blue, medium strength. I used the Red. I don't remember what the paper in my package stated. Probably didn't pay any attention as the bolts were for the Mopar 6 and 8 cylinder engines.
