lookforjoe Posted April 22, 2011 Author Report Share Posted April 22, 2011 Wtf how does a steel hub like that strip, is it pretty thin? So the enem cams worked ok tho? the problem area didn't give any issues? No - as long as you don't try to lock the cams from the back, it's fine. Quote Link to comment Share on other sites More sharing options...
lookforjoe Posted April 22, 2011 Author Report Share Posted April 22, 2011 Ah, I see what you were saying before. The threads that hold the cam gear slots stripped, releasing tension, and then the cams went to the most retarded position in the slot, but didn't actually spin freely? I don't see how the intake cam being at full retard would cause interference though. It'll open late and close late, in both cases, the piston isn't near TDC. So the cam gear was actually spinning freely? When the cam spun, it rotated clockwise (CC in the slots), which is full advance. Neither hub nor gear were spinning freely, it just advanced as far as it could. Here's the before pic advancing either cam will move the locater bolts CC - this is from my Fiat, but it's the same on the Volvo - not - the Fiat has the slots in the hub, instead of in the gear holy shiiiiiiiiiiitttttt. what a crappy design That is a bad luck. But no worries those pistons will work for another 150k Yeah, not worried about the pistons. The hub/gear relationship is the same design as the VVT setup, so it should be fine from a design perspective, it was just that the threads stripped in the hub - having captive nuts on the back should be sufficient insurance. Quote Link to comment Share on other sites More sharing options...
ozzimark Posted April 22, 2011 Report Share Posted April 22, 2011 That's backwards. If the pulley loosens and lets the cam slide, the cam will be moving CCW compared to the pulley, which means the opening and closing of the valves will occur later; the cam is retarded, not advanced. You're probably thinking of what the cam timing tool indicates, which is fixed to the cam, as you rotate the cam CW, the pulley is moving CCW compared to the cam to advance it. That said, I fail to see why retarding the intake cam will result in bent valves unless it was freely spinning between the hub and cam. :unsure: 1 Quote Link to comment Share on other sites More sharing options...
Volvo5.0 Posted April 22, 2011 Report Share Posted April 22, 2011 Since Aaron's hubs were a limited production I bought one in case the hub I'm currently using, My Hub, failed. In all fairness to Aaron, his hubs are actually about 1.5 times thicker than the OE hub.... So unless his steel is VERY soft, his unit should work fine as is. I know you have done alot of experimenting with cam timing, so I wonder if it's possible that the bolts are just worn out from being tightened so many times, and THEY stripped. As Ozzimark said, something seems very strange :unsure: Quote Link to comment Share on other sites More sharing options...
lookforjoe Posted April 22, 2011 Author Report Share Posted April 22, 2011 So unless his steel is VERY soft, his unit should work fine as is. I know you have done alot of experimenting with cam timing, so I wonder if it's possible that the bolts are just worn out from being tightened so many times, and THEY stripped. As Ozzimark said, something seems very strange I don't know what to say. I didn't ever tighten the cam gears on the hubs until I actually got to the point where I was ready to actually set the timing - which had not occurred prior to yesterday. All the times I played with the cams/hubs/gears when I was setting them up in the basement, I never tightened them. Locking the gears with an old belt vs. the rear locking tool should not cause any load on the threads, either - I would have expected the bolts to shear, if anything. I've ordered new cam gear bolts & cam hubs bolts to be safe. In any event, it is what it is, and I'm not asking Aaron for anything, it was more of an observation. The exhaust cam hub seems fine, but I'm still going to helicoil all six & tack nuts on the backside to increase overall thread mating surface. That's backwards. If the pulley loosens and lets the cam slide, the cam will be moving CCW compared to the pulley, which means the opening and closing of the valves will occur later; the cam is retarded, not advanced. You're probably thinking of what the cam timing tool indicates, which is fixed to the cam, as you rotate the cam CW, the pulley is moving CCW compared to the cam to advance it. That said, I fail to see why retarding the intake cam will result in bent valves unless it was freely spinning between the hub and cam. No, the cam moved clockwise in the gear, which is advanced Makes no sense, perhaps, but that is what happened. As you say, if it had retarded, no damage would have occurred. Quote Link to comment Share on other sites More sharing options...
Captain Bondo Posted April 22, 2011 Report Share Posted April 22, 2011 The cam retard if it slips on the gear. Retarding the intake cam INCREASES piston to valve clearance. The bolts slipping are not what caused the piston to valve contact. It is likely the other way around, the piston to valve contact caused the bolts to slip. Quote Link to comment Share on other sites More sharing options...
lookforjoe Posted April 22, 2011 Author Report Share Posted April 22, 2011 The cam retard if it slips on the gear. Retarding the intake cam INCREASES piston to valve clearance. The bolts slipping are not what caused the piston to valve contact. It is likely the other way around, the piston to valve contact caused the bolts to slip. Yeah, of course you & Mark are correct - not sure why I had it backwards in my head. (EDIT) I had my Fiat adjustable gear in mind - since that was the last one I adjusted - the hub is slotted on that, so the bolts go CC in the slots when the cam is advanced, the reverse of the Volvo hub/gear relationship) I hand cranked the motor 4 full revolutions before I even thought about starting it - I would have thought any contact would have been discernable? I can't imagine that the piston somehow increases it's travel when running? Quote Link to comment Share on other sites More sharing options...
mdlimy Posted April 22, 2011 Report Share Posted April 22, 2011 (edited) Not sure if you mentioned it but did you rev the motor high at all? Just wondering if maybe the new cams caused some valve float, that is something that could cause the pistons to hit valves but not when turning over by hand. Or something to that extent. I can understand that kenny would think the pistons hitting the valves occured first which then caused the cam gear to move but I really can't see it stripping out the bolts...if the cam gear just moved it would be a different story but the bolts stripping, that is just bizzar. Also are you running heavier valve springs? Edited April 22, 2011 by mdlimy Quote Link to comment Share on other sites More sharing options...
Captain Bondo Posted April 22, 2011 Report Share Posted April 22, 2011 My guess would be the cam gear spun on the cam. Youll be able to tell if it's still timed right. But who knows, no point in speculating via the internet. The seats will be fine- if anything in addition to the valves is damaged, it will be the guides. I have seen guides crack from bent valves on whiteblocks. You are assuming the pistons are fine... I have my doubts... I would be at least pulling the worst one to confirm side clearance on the top compression ring. ring side clearance is critical and the crown has taken a pretty hard hit. If it has deformed the ring groove at all you are humped.Also, no way valve float is gonna put huge dents in the pistons like that. The valves got RAMMED into the piston.Are these solid lifter cams (I assume so since the are VVT?)? Obvious question, but - valve lash was correct? Quote Link to comment Share on other sites More sharing options...
lookforjoe Posted April 22, 2011 Author Report Share Posted April 22, 2011 Thanks for the input. Stock valve springs, the 9.6 lift cams don't call for heavy springs. The pistons are recessed where the main valve markings are, if that makes any difference. I did not rev the motor much at all, I was literally driving around the block, 1st-2nd gear, taking it easy to see how it felt. I doubt I revved it over 3K, partly because the low end felt so different, and vacuum @ idle is vastly decreased, so I was going slow, kinda watching the vacuum gauge when it died. Valve lash was set by the machine shop when the head was overhauled. I have no reason to question his work. He'll look at the guides when the valves are out. He's also going to modify the cam cover so I can check the lift on #3 cylinder. I checked to see if Volvo sold the oil filler neck, but they don't, so something will have to be fabricated for the back port, the front I can just remove the oil filler baffle for access. I was able to negotiate a good price on new valves, $12 a piece, so the new valves, head gasket, intake gaskets, new head bolts, misc gaskets have come to about $240 all told. Hopefully the guides are good & he can just swap the valves & get me going. Quote Link to comment Share on other sites More sharing options...
B Mac Posted April 23, 2011 Report Share Posted April 23, 2011 You're certainly keeping a lot more calm than I would be if this happened to me H . But $240 to freshen up the head isn't too bad at all! Are you fixing all of this today? Let me know if you want or need a hand, my weekend is fairly opened aside from installing the new air compressor-zilla at dad's house for him. Quote Link to comment Share on other sites More sharing options...
lookforjoe Posted April 23, 2011 Author Report Share Posted April 23, 2011 You're certainly keeping a lot more calm than I would be if this happened to me H . But $240 to freshen up the head isn't too bad at all! Are you fixing all of this today? Let me know if you want or need a hand, my weekend is fairly opened aside from installing the new air compressor-zilla at dad's house for him. Don't know what the machine shop charges will amount to, but hopefully not too much. I can't do anything until later in the week & the head is revalved/adjusted. Thanks for the offer, though. Took the oil filler neck from another spare head ...and swapped out the existing baffled one for the plain one from my previous head silversoldered nuts on the back of the hubs these long bolts make it pretty clear that the threaded holes are not square to the hub flange Quote Link to comment Share on other sites More sharing options...
mdlimy Posted April 23, 2011 Report Share Posted April 23, 2011 You need to invest in a ac tig welder! With the ammount of soldering you do you would be great in no time ;) Quote Link to comment Share on other sites More sharing options...
Alan M Posted April 23, 2011 Report Share Posted April 23, 2011 Has the new VVT head been machined to get the block mating face true? If so do you know if the Enem Cams are designed for a head that is the correct size from the factory and not one that has been machined? With the extra lift the Enem cams provide any material removed from the head may be detrimental to their operation and cause a contact with piston situation should the head be too small. Quote Link to comment Share on other sites More sharing options...
Volvo5.0 Posted April 23, 2011 Report Share Posted April 23, 2011 Just a thought. With cams with that much lift, you may want to mock up the engine with clay on the pistons to verify piston to valve clearance. Use your old head gasket and head bolts, throw in the cams, install the belt, and then roll the motor over a couple times. Might be time well spent at this point. 1 Quote Link to comment Share on other sites More sharing options...
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