lookforjoe Posted April 24, 2011 Author Report Share Posted April 24, 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. That's a very good idea 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. Yes the head was shaved .015" to true it. The Enem makes no mention of only working with a brand new head, that would be quite impractical, I would imagine. They also sell cams with significantly greater lift. Only requirement mentioned is the use of heavier springs when using their cams with over 10mm lift. Quote Link to comment Share on other sites More sharing options...
flaco Posted April 25, 2011 Report Share Posted April 25, 2011 Can you post a pic of the head of the failed bolts? Curious what grade they were... Quote Link to comment Share on other sites More sharing options...
lookforjoe Posted April 25, 2011 Author Report Share Posted April 25, 2011 Can you post a pic of the head of the failed bolts? Curious what grade they were... The threads stripped in the hub, not off the bolts. you know we're talking about the M6 small bolts, not the large 55 torx heads that hold the hub to the cam, right? - I'll double check, but I don't recall any grade markings on the bolts. I ordered all new cam/hub bolts to play it safe. EDIT: M6 flanged head bolts are grade 8.8 Cam hub bolts are 10.9 Quote Link to comment Share on other sites More sharing options...
lookforjoe Posted April 25, 2011 Author Report Share Posted April 25, 2011 Hussein, I figure you might like to see the difference between an 02 (and older) and R block (maybe newer 2.5t aswell) PCV vent on the block. The entire PCV box seems to be larger. I wonder how much of difference this makes. 04 B5254T4 What is not clear in the above pic, is that the box is MUCH larger than earlier versions! Also the cam vent is moved to the outer port. Since I have everything apart while I'm waiting for the head to be repaired, I ordered the later box, and the revised cam breather hose to go with it. I'll add an additional drain port for my secondary can drain back. Quote Link to comment Share on other sites More sharing options...
Captain Bondo Posted April 25, 2011 Report Share Posted April 25, 2011 It seems there are quite a few assumptions being made in terms of cam timing, how the lash is being set, how much the head has been cut, etc. I would definitely do a "clay test" as mentioned earlier in the thread when you reassemble it. Really, that's all you can do at this point. Do the test with the intake cam fully advanced and the exhaust cam fully retarded, and just see what you get. Quote Link to comment Share on other sites More sharing options...
Johann Posted April 25, 2011 Report Share Posted April 25, 2011 Valves have plenty of space when set in the correct position. Why not order non VVT style cams and use the non VVT gears? much more solid and also better fixed construction... 1 Quote Link to comment Share on other sites More sharing options...
lookforjoe Posted April 26, 2011 Author Report Share Posted April 26, 2011 It seems there are quite a few assumptions being made in terms of cam timing, how the lash is being set, how much the head has been cut, etc. I would definitely do a "clay test" as mentioned earlier in the thread when you reassemble it. Really, that's all you can do at this point. Do the test with the intake cam fully advanced and the exhaust cam fully retarded, and just see what you get. Valves have plenty of space when set in the correct position. Why not order non VVT style cams and use the non VVT gears? much more solid and also better fixed construction... ^ This. I did not know that Enem sold non-VVT cams that fit the VVT head. I can't read anything on their website, so I went with what was designed for the head... Head was previously cut at least .015" to true it. Valve lash was/is set to Volvo spec - .20mm INT, .40mm EXH I got the head back this afternoon ($250 for machine work/adjusting valves), and refitted the cams & rechecked the reference markers I made - because the slots had spun - the lift was actually .090" INT & .086" EXH. - So that explains the situation, I would imagine. Valves must have been kissing the pistons on the downward stroke, just not enough to feel it when turned by hand, I guess. Set the lift back to .059" INT (opening) & .046" EXH (closing), and remarked the reference plates accordingly. Hubs are repaired & ready Head back on the car. I borrowed a Snap-On Boroscope, so I tomorrow when I install the cams, I can look in at the valves while I turn the crank & check clearances @ TDC & the given lift. I plan on setting the centered gear adjustment so that max advance in the slots will not cause valve/piston contact, if it is possible. Quote Link to comment Share on other sites More sharing options...
EricF Posted April 26, 2011 Report Share Posted April 26, 2011 Jeez Hussein, I admire your work ethic. Seriously. You jump hurdles like an olympian :) Quote Link to comment Share on other sites More sharing options...
sconeman Posted April 26, 2011 Report Share Posted April 26, 2011 Jeez Hussein, I admire your work ethic. Seriously. You jump hurdles like an olympian +1 Hussein, Maybe I missed it... how did the holes strip on the hub? Quote Link to comment Share on other sites More sharing options...
lookforjoe Posted April 27, 2011 Author Report Share Posted April 27, 2011 Jeez Hussein, I admire your work ethic. Seriously. You jump hurdles like an olympian Well, thank you +1 Hussein, Maybe I missed it... how did the holes strip on the hub? Don't know, Kristian. 2 of the three on the hub were not good - they were also not perpendicular to the flange, maybe that didn't help. Quote Link to comment Share on other sites More sharing options...
lookforjoe Posted April 27, 2011 Author Report Share Posted April 27, 2011 Put the cams back in - aligned the reference markers, set & torqued the cam hubs/gears so that the slots are straight up with the timing as Enem spec'd @ TDC on #1 With the piston @ TDC, I rotated the intake cam (looking in the chamber with the boroscope) until the valve contacted the piston. It took about a tooth of advance to get there Using a boroscope, I looked at the clearance @ 1.5mm lift, then opened the intake valves - here's three stages viewed with the boroscope clearance @ 1.5mm lift clearance @ 1/2 tooth advance valve/piston contact @ approx 1 tooth advance I advanced the cam gear (not the cam!) in the slots so that there is less than 1 tooth advance left, then installed the belt. Difference between early & late breather box - outlet is in the same spot, cam vent is moved outward & cam vent hose is revised to accommodate the change Added my drain back port & installed Somehow I put my longer intake manifold bolts (m7x40) somewhere very safe, now I can't find them - so I took some longer bolts & threaded them further down the shank & shortened them to 40mm. Tomorrow I just have to put the intake & plumbing back on & it'll be ready to roll. Quote Link to comment Share on other sites More sharing options...
mdlimy Posted April 27, 2011 Report Share Posted April 27, 2011 wow one tooth to make contact, scary. pretty safe to say the cam gear just moved and caused the contact eh? a bit off topic but what is your coolant temp at full operating temp after the RN head swap? Quote Link to comment Share on other sites More sharing options...
lookforjoe Posted April 27, 2011 Author Report Share Posted April 27, 2011 wow one tooth to make contact, scary. pretty safe to say the cam gear just moved and caused the contact eh? a bit off topic but what is your coolant temp at full operating temp after the RN head swap? No, I think it's more likely I had too much advance - the intake cam was @ .090" @ TDC (due to the moved slot), and then to get the belt on it is possible I pushed it even more because I had left the cam gear centered on the hub. This time around I moved the cam gear to get the belt on when pulling it up from the crank without pulling the cam forward. Chances are that the valve was either touching or so close that when running it made contact. I think the hub threads was an incidental - can't see how it could have caused the damage, as pointed out, when it spun, it retarded the cam, which increased clearance. Quote Link to comment Share on other sites More sharing options...
sconeman Posted April 27, 2011 Report Share Posted April 27, 2011 Hussein I don't think those bigger breather boxes fit under 93-98 manifolds. Quote Link to comment Share on other sites More sharing options...
EricF Posted April 27, 2011 Report Share Posted April 27, 2011 I've been running an 82ºc t/stat. Do the later heads have the same t-stat housing as the older? Or are the t-stats interchangeable? Reason I ask, where'd you get an 82C t-stat?? That would make me very happy I have a 92C, and by the time I finish third gear the coolant temps are at 98 sometimes if it's very hot out. That is not so good considering many of the failures on these engines point back towards cooling inefficiency at the tops of the cylinders. Quote Link to comment Share on other sites More sharing options...
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