BigBlack620 Posted April 13, 2013 Report Share Posted April 13, 2013 So my first L16 w/ U67 head rebuild might be short lived ... Yesterday I decided to just go ahead and crack it open because there was zero compression on the #3 and #4 (which is very odd it it's self) so low and behold the camshaft was cracked between the #2 and #3 ... So now today it's time to pop the pan check for frags and flush it ... Get new gaskets, filter, and overpriced and overkilled oil to get her running so I can finish up my other project (that I've been too lazy to start build threads for) upload foto upload foto Quote Link to comment
Jayden71 Posted April 13, 2013 Report Share Posted April 13, 2013 OUCH! :o . How the hell does one snap a cam?? 10,000 rpms?? Quote Link to comment
DanielC Posted April 13, 2013 Report Share Posted April 13, 2013 My guess, the head was warped, and only the bottom was machined. The top surface of the head is still banana shaped. This forces the camshaft to constantly flex, or bend in the middle, and eventually the metal fatigues, and breaks. 1 Quote Link to comment
TENDRIL Posted April 13, 2013 Report Share Posted April 13, 2013 which cyl. did you start the compression test on #1? Quote Link to comment
datzenmike Posted April 13, 2013 Report Share Posted April 13, 2013 U-67 on an L16 only gives a compression of 6.72. Get rid of it and get a stock 210 head. Not the first snapped cam I've seen. Daniel, warped is a good call.... metal fatigue. When milling a head always torque it down and see if the cam will spin by hand before installing the rockers. The head has to come off anyway so time to get a 210 on it. 2 Quote Link to comment
Z-train Posted April 14, 2013 Report Share Posted April 14, 2013 Disagree on the head cause.The head would have to look like a rainbow for that to be the cause.More than likely the cam stands were removed and not replace the way they should have been. Quote Link to comment
Stoffregen Motorsports Posted April 14, 2013 Report Share Posted April 14, 2013 Maybe we can get the OP to shed some light on that for us. Was the head warped and milled? I have seen heads that were so warped that the cam would not spin, but I myself have never broken (or cracked, as the OP put it) a cam before. The only certain fix for this is replacing the head, and as Mike suggested, with a 210 head to bring the compression back up. I think Model T's had more compression than that! 1 Quote Link to comment
BigBlack620 Posted April 14, 2013 Author Report Share Posted April 14, 2013 Yesterday I pulled the pan, that was just raped with Orange noob spread, took forever!!! The tie rod was no problem, I found a way to just take one side off (so hopefully I don't have to realign it ... Scrapped that crap all off, cleaned out the pan put it back dry with the gasket I picked up from down the street (thanks NAPA), was thinking about painting or chroming the pan ... But it was getting late and I'm doing all this on the public street in front my house (asshole cops, who love writing tickets) ... Now I'm up bright and early about to pull the head ... But still waiting for my N58 head from Oregon, but it needs valve seals ... Got a buddy willing to let me borrow a head so I can make it to the Moreno Valley meet (where I hope to find a 219 head for my L20b block coming soon, that I want to build for my 74 620 also coming soon from OR ... So before I pull the head, any advice? Quote Link to comment
BigBlack620 Posted April 14, 2013 Author Report Share Posted April 14, 2013 windows 7 screen shot After I got all the noob orange off (which I found a bunch in the bottom of the pan) Quote Link to comment
BigBlack620 Posted April 14, 2013 Author Report Share Posted April 14, 2013 upload foto Look at all the peanut butter ... Keep in my I'm NOT the one who did this (only had this engine for about a month) 1 Quote Link to comment
BigBlack620 Posted April 14, 2013 Author Report Share Posted April 14, 2013 upload foto Tie rods look pretty new and JDM Quote Link to comment
BigBlack620 Posted April 14, 2013 Author Report Share Posted April 14, 2013 upload foto Daddy's little helper :-) 1 Quote Link to comment
BigBlack620 Posted April 14, 2013 Author Report Share Posted April 14, 2013 windows 7 screen shot I put her to work!! Free labor, lol 1 Quote Link to comment
DanielC Posted April 14, 2013 Report Share Posted April 14, 2013 The bolt holes on the oil pan are probably distorted. Take a small ball pien hammer, and center it on the top side of the hole. (engine block side) tap the face of the ball pien hammer, and make all 22 of the oil pan bolt holes very slightly below the sealing surface of the oil pan. It does not matter if the head was warped, or the can towers misaligned, the problem is the camshaft bores were not in line, and that was making the cam bend with every revolution. Most metals, if you bend them enough times, even a very little bit, will fatigue, and break. Like it was pointed out, make sure the camshaft will turn freely, without rocker arms on the head, when the head is torqued down on the block. If is does not, find out why. Quote Link to comment
BigBlack620 Posted April 14, 2013 Author Report Share Posted April 14, 2013 which cyl. did you start the compression test on #1? Yeah I started on the #1 which read 120 ... #2 a little over 90 ... And ofcourse #3 and #4 was 0 Quote Link to comment
BigBlack620 Posted April 14, 2013 Author Report Share Posted April 14, 2013 The bolt holes on the oil pan are probably distorted. Take a small ball pien hammer, and center it on the top side of the hole. (engine block side) tap the face of the ball pien hammer, and make all 22 of the oil pan bolt holes very slightly below the sealing surface of the oil pan. It does not matter if the head was warped, or the can towers misaligned, the problem is the camshaft bores were not in line, and that was making the cam bend with every revolution. Most metals, if you bend them enough times, even a very little bit, will fatigue, and break. Like it was pointed out, make sure the camshaft will turn freely, without rocker arms on the head, when the head is torqued down on the block. If is does not, find out why. I checked for that, they all looked good ... Do you know the torque for the oil pan bolts off the top of your head (I can look it up, but was lazy, lol) or is it too low to measure? Quote Link to comment
datzenmike Posted April 14, 2013 Report Share Posted April 14, 2013 Yeah I started on the #1 which read 120 ... #2 a little over 90 ... This is likely the 6.7 compression ... So before I pull the head, any advice? Yes make sure you loosen the cam sprocket bolt first but don't remove. Set motor carefully to TDC #1. ...and block the timing chain carefully and securely. If you don't know about blocking the chain don't assume... make sure you ask for directions. Failure to block the chain will result in the tensioner falling out and a 3-4 hour job this weekend will sit all week till next weekend for gaskets and time to take the front off the motor and fix it.. Quote Link to comment
Stoffregen Motorsports Posted April 14, 2013 Report Share Posted April 14, 2013 Do you know the torque for the oil pan bolts off the top of your head (I can look it up, but was lazy, lol) or is it too low to measure? 6 to 7 foot lbs, but probably too low for a normal torgue wrench. I use a 1/4" drive inch pound torque wrench, but it's not exactly crucial. What type of gasket did you get? If it is solid cork, I would use a bit of grey or black RTV, if it is rubber impregnated, I wouldn't use any, except maybe around the two rear main cap seals. Quote Link to comment
BigBlack620 Posted April 14, 2013 Author Report Share Posted April 14, 2013 6 to 7 foot lbs, but probably too low for a normal torgue wrench. I use a 1/4" drive inch pound torque wrench, but it's not exactly crucial. What type of gasket did you get? If it is solid cork, I would use a bit of grey or black RTV, if it is rubber impregnated, I wouldn't use any, except maybe around the two rear main cap seals. It's a cork gasket from NAPA Quote Link to comment
datzenmike Posted April 14, 2013 Report Share Posted April 14, 2013 Without a torque wrench just wrist tight. Quote Link to comment
BigBlack620 Posted April 14, 2013 Author Report Share Posted April 14, 2013 upload foto All ready for the new head, should have been here yesterday but the shipping company is lagging it. Does anyone have a 219 they'd like to part with? Quote Link to comment
BigBlack620 Posted April 14, 2013 Author Report Share Posted April 14, 2013 windows 7 screen shot Is this right? Sorry so many pictures ... I'm a bit of a picture whore (but in a good way, lol) Quote Link to comment
datzenmike Posted April 14, 2013 Report Share Posted April 14, 2013 Best to loosen (not take off yet) the cam sprocket bolt before setting TDC. It's hard to loosen without upsetting the blocked chain. Turn the crank in a clockwise direction only to bring the timing notch up to the timing scale (zero) If you overshoot back well before and try as many times as needed to get it. Backing up to TDC will move the cam but not the crank and add slack to the tension side. The reason for turning only clockwise is so you can inspect your chain for wear or stretch. If slightly stretched you can adjust this while the sprocket is off. Quote Link to comment
datzenmike Posted April 14, 2013 Report Share Posted April 14, 2013 Once you have a perfect TDC look through the top hole in the sprocket. On the back side of the sprocket is a small notch. (could be U or V shaped) Just above the notch is a tiny horizontal etch mark on the cam thrust/retainer plate. The notch on the sprocket must be below or just slightly to the tight of the horizontal etch mark. This cam is perfectly timed. If by chance your chain is stretched you can move the sprocket to the #2 cam alignment pin hole. This will advance the cam by 4 degrees and move the notch to the right. . Quote Link to comment
BigBlack620 Posted April 20, 2013 Author Report Share Posted April 20, 2013 Update! Sent out the N58 head I got from Oregon to get resurfaced, got it back yesterday ... Would have had it on but the PO but a shit load of sealant on EVERYTHiNG!!!!!!! So it took just about the entire day removing it! I'm sitting in my living room right now with my valve cover removing it watching a movie ... I hate the last dumbass to own my truck!!!! Should be done and installed and cranked up within an hour Quote Link to comment
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