TimZ Posted December 8, 2009 Share Posted December 8, 2009 That last pic is exactly what my failed BHJ dampner looked like in the keyway. Just out of curiosity, were you guys using the Nissan Comp special bolt and extra thick crank pulley washer by any chance? It has a step in it that is supposed to register the washer in the bore of the damper. Problem is they made the stepped section a bit to deep and it bottoms on the crank snout a few thou before the shoulder of the washer grounds to the damper. While the washer keeps the damper captive, this make it impossible for the washer to apply any clamping force on the damper at all. The damper can thus walk on the snout and eventually fails. I ruined two stock dampers before figuring this one out - milled the step down on the washer and have not had a problem since. I was pretty sure I'd posted on this before, but I couldn't find it when I searched - sorry if this was your issue.. Here's a pic of the bolt/washer: Link to comment Share on other sites More sharing options...
eec564 Posted December 8, 2009 Share Posted December 8, 2009 How many pounds is your pressure plate? Would you have a suggestion for a safe maximum to use? Link to comment Share on other sites More sharing options...
JohnH Posted December 9, 2009 Share Posted December 9, 2009 No TimZ I did not use the Nissan comp stepped washer. Regular dampner washer. Bryan not a very encouraging response back from BHJ. What I read from Chris's reply is that essentialy people who bought these when they first came out were test mules. A part essentially designed for a race application that cannot be taken on or off on a regular basis on engine that may go through a few builds a year is just poor design. I don't think weight was a factor over the dampner not coming apart at high RPM's when compared to stock dampners. So another $225 plus shipping & duty to get this fixed. NO THANK YOU BHJ. I will take my money & my word of mouth to another company that actually engineers a dampner that does not fail because you have taken the dampner off the engine to do some work. Link to comment Share on other sites More sharing options...
Tony D Posted December 11, 2009 Share Posted December 11, 2009 It's well known the stock washer is unacceptable as it bows. JeffP's usage of the Volvo washer (similar thickness as the one photo'd by TimZ) along with the KA Damper bolt (longer for the increased thickness) will keep it from bottoming and securely clamp it. If you don't like Chris's answer, go get one from ATI. The design is dictated by the OEM limitations and requirements. More than likely it's inadequate clamping that let yours move (from the stock washer) than from repeated removals. That is only one thought to why it's moving. The washer is critical, and it likely more at fault in your case than any number of removals and reinstallations. It's only an issue of longevity in two instances: Improper Securing of the unti to the crank, and peroper securing, but with ultra extreme usage (high torque, high revs). If you're not in the 300+ RWHP N/A range, or like Bryan & JeffP/TimZ, chances are it's improper installation. Welcome to the world of high performance racing parts where you take your parts out the door with no warranty, express or implied... Like I said, there's always ATI. Link to comment Share on other sites More sharing options...
1 fast z Posted December 12, 2009 Author Share Posted December 12, 2009 Read first post about the situation.. 17-4 PH washer, which is CUSTOM! Washer nor bolt was the problem. The problem is an alluminum hub. Link to comment Share on other sites More sharing options...
Kanzen Posted December 12, 2009 Share Posted December 12, 2009 I have no two cents on the matter, but that engine is just absolute car-porn. Seriously, I'll know that I'll never be able to put that sort of engine together. Man, just epic, truly, Fast Z. Curious mate, I know the work youve done with it has been a co-op with your old man but, how old are you man? Link to comment Share on other sites More sharing options...
jeffp Posted December 12, 2009 Share Posted December 12, 2009 I have never seen one of those dampers break like your part did. I did have the first damper made and I did end up replacing that part with the steel part mentioned. I had that damper installed and removed at least 5 times. I noticed how loose the damper was and started checking cranks out. I measured 5 cranks and came up with an Id for the part. I had the part made in steel. I havent installed the damper yet, but we will see how it goes. The crack on your part, if you look is right at the 90 degree angle in the slot. Notice there is no relief radious. The strength of the aluminum part was compromised because of the sharp corner. Then when the damper moved it cracked. How do you install all of the components on the snout? Do you use the oil flinger washer? I have had nothing but trouble with one installed. Like Tony said, I use a standard Volvo washer. I turn down the OD and use the KA bolt, or the 81 Turbo bolt. You do have to shorten the bolt 6mm or so. sorry to see that happen to your bottom end. Link to comment Share on other sites More sharing options...
Tony D Posted December 12, 2009 Share Posted December 12, 2009 What more people have to look at is Bryan's Quote: "It also looks like that with 600 ft lbs of torque and 700 plus RWHP, that the cylinder bores are not staying round, even with an extra thick block. I have sonic tested this block to be an average of .125" walls with an 89mm bore. I am now going with an 87mm bore with another extra thick block, to maintain more cylinder wall thickness for my HP and TQ numbers. " Remember my standard: Electramotive making 1000HP on a max 0.040" L28 Overbore. Making horsepower means flow and boost, in that order on an L-Series. Leave the big bores to the N/A guys. They are making over 400HP N/A in Japan on 8000+ rpm 3.2L strokers. For N/A and what you're going to get out of it, you can bore away. For the serious power you can make with the Turbo, keep the meat, leave the bores alone. You will see your HP will not suffer as much as you think, and it will be able to be recovered with more flow/boost. Link to comment Share on other sites More sharing options...
1 fast z Posted December 19, 2009 Author Share Posted December 19, 2009 Here are some photos of the new torque plate I made. It is 2" Thick Alloy Steel. Stress relieved after it was milled, then it was surface ground to ensure it was directly flat. Also shown is the new N42 Block I am going to use. Also is the new pistons. They are for a z32TT. Wiseco brand, 87mm bore. Link to comment Share on other sites More sharing options...
Xnke Posted December 19, 2009 Share Posted December 19, 2009 Awesome torque plate. I bet that sucker weighs 75lbs, maybe more. How did you determine that the bores were going out of round at high RPM? Increased blowby? PCV hoses blowing off? Really, I'm curious as to how that can be measured/determined, I can't think of a really good way to do it. Course, I haven't really looked, either. Link to comment Share on other sites More sharing options...
Overkill Z Posted December 19, 2009 Share Posted December 19, 2009 I know this doesn't add much to your build but i was just reading through it. I have come to the conclusion there is only one word that comes to mind. "nuts". LOL Amazing build and so much work i hope it works out big time. I wonder how youll do vs my z? Link to comment Share on other sites More sharing options...
garvice Posted December 19, 2009 Share Posted December 19, 2009 So is the block cut down by 2 inches? Also after all this machine work, you are going to get to the point where you have basically built the whole engine. HA. Link to comment Share on other sites More sharing options...
Tony D Posted December 19, 2009 Share Posted December 19, 2009 My bet on the blowby is that measurements of the bore reveal distortion during the freshening checks. It's one thing if the wals flex and you blow by, it's impending doom if the walls flex and don't return to round or straight afterward. Link to comment Share on other sites More sharing options...
Drax240z Posted December 19, 2009 Share Posted December 19, 2009 So is the block cut down by 2 inches?Also after all this machine work, you are going to get to the point where you have basically built the whole engine. HA. The torque plate is used when machining the bores, so that they can be fully clamped via head bolts while machining. (simulating the head in place) It's a jig, not part of the engine. Link to comment Share on other sites More sharing options...
Tony D Posted December 19, 2009 Share Posted December 19, 2009 Well, now if you want increased deck height there is a device that looks like that, used in conjunction with cylinder liners... Link to comment Share on other sites More sharing options...
garvice Posted December 19, 2009 Share Posted December 19, 2009 The torque plate is used when machining the bores, so that they can be fully clamped via head bolts while machining. (simulating the head in place) It's a jig, not part of the engine. Oh, my mistake. Thanks for pointing that out, I thought it was like one of those engine girdles but just ridiculously over-killed. Well, now if you want increased deck height there is a device that looks like that, used in conjunction with cylinder liners... I assume if you didn't use liners that there would be a problem with a step change in the cylinder bore if the pieces didn't heat evenly? Also, I should have known as there are no water passages etc to get water to the head. Link to comment Share on other sites More sharing options...
Tony D Posted December 19, 2009 Share Posted December 19, 2009 Step change is only going to affect you if the rings run over the gap... Outside the box, gentlemen, please! LOL Link to comment Share on other sites More sharing options...
Daeron Posted December 20, 2009 Share Posted December 20, 2009 Step change is only going to affect you if the rings run over the gap... Outside the box, gentlemen, please! LOL so the moral is, chop a 90 mm section off the top of one F54 block, then take another F54 block and knock the top 75mm off of it, so you can run a 3.1 liter stroker (or better) at 89mm bore or less with longer rods? Link to comment Share on other sites More sharing options...
Noddle Posted December 20, 2009 Share Posted December 20, 2009 Step change is only going to affect you if the rings run over the gap... Outside the box, gentlemen, please! LOL my guess, more boost via a larger piston / head clerance, crappy off boost, killer on boost ? do I win ??? Nigel Link to comment Share on other sites More sharing options...
NZeder Posted December 21, 2009 Share Posted December 21, 2009 Well, now if you want increased deck height there is a device that looks like that, used in conjunction with cylinder liners...Or run with the taller LD28 block but that requires a lot of work too to get a good bore again - so then you are running into the same issues with thin walls and blow by again unless some sleeves/cylinder liners are employed - either way cylinder liners required for a taller block setup. It is my understanding that large bores on the L6 blocks is best left to those of us that love NA and the turbo boys should limit the bore to 88mm and not go any larger due to the issues 1 Fast Z has found with his turbo 89mm DOHC 3.1 build. Link to comment Share on other sites More sharing options...
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