DeLorean Posted November 25, 2015 Share Posted November 25, 2015 I have searched for help on this topic, but I've only turned up articles that address some of my problems. I'm wondering if someone here can help me make sense of this all. I am replacing the head gasket on my 240z. The head has been removed and taken to a shop, where it was determined that the valve seats are damaged. Fortunately, I had a replacement E88 head. The issue that I am running into is setting the proper timing on the head before I put it back on the car. The motor is at TDC, but the head is way off. I know that the front two lobes should be pointing up, that tells you the head is at TDC, but I am unsure how to get it there. Do I need to install the cam gear? Sorry if this is a real rookie question, but I am completely lost and would really like to get my car back together. Any advice would be greatly appreciated, thank you. Quote Link to comment Share on other sites More sharing options...
NewZed Posted November 25, 2015 Share Posted November 25, 2015 How to tell that it's at TDC or how to turn the camshaft? You can use a wrench on the flat sections of the cam shaft, or some pliers. You can just hold the sprocket up to where it would go and check orientation of the sprocket notch. You can also measure how far the valves stick from the bottom of the head and compare to the holes they go in. Quote Link to comment Share on other sites More sharing options...
DeLorean Posted November 25, 2015 Author Share Posted November 25, 2015 That's helpful, thanks. I guess I am still confused what to look for to make sure the head is TDC. Quote Link to comment Share on other sites More sharing options...
NewZed Posted November 25, 2015 Share Posted November 25, 2015 There's a notch and a groove. Picture in the manual. The factory one. EM. Quote Link to comment Share on other sites More sharing options...
HuD 91gt Posted November 25, 2015 Share Posted November 25, 2015 (edited) Don't take this as gospel, as i've never even taken the head off my vehicle. (That's a lie, i've taken a couple off, but yet to re-install). But wouldn't it be easiest to install the head without valve springs. Align the cam/sprocket with the timing chain where it needs to be. Then put in the valve springs? The small amount of fiddling i've down with my head, i've always found spinning the cam with that flat notch to be a bit of B*&ch. Opinions? Edited November 25, 2015 by HuD 91gt Quote Link to comment Share on other sites More sharing options...
1969honda Posted November 25, 2015 Share Posted November 25, 2015 (edited) I have searched for help on this topic, but I've only turned up articles that address some of my problems. I'm wondering if someone here can help me make sense of this all. I am replacing the head gasket on my 240z. The head has been removed and taken to a shop, where it was determined that the valve seats are damaged. Fortunately, I had a replacement E88 head. The issue that I am running into is setting the proper timing on the head before I put it back on the car. The motor is at TDC, but the head is way off. I know that the front two lobes should be pointing up, that tells you the head is at TDC, but I am unsure how to get it there. Do I need to install the cam gear? Sorry if this is a real rookie question, but I am completely lost and would really like to get my car back together. Any advice would be greatly appreciated, thank you. Install the gears, usually your timing marks will correspond with the gear to ensure the camshaft rotation is in the right spot with the crankshaft rotation. You might be 180* out on your timing if the marks are not lining up. Here's a link that should help show and explain things for you: http://www.xenonzcar.com/s30/reference.html Don't take this as gospel, as i've never even taken the head off my vehicle. (That's a lie, i've taken a couple off, but yet to re-install). But wouldn't it be easiest to install the head without valve springs. Align the cam/sprocket with the timing chain where it needs to be. Then put in the valve springs? The small amount of fiddling i've down with my head, i've always found spinning the cam with that flat notch to be a bit of B*&ch. Opinions? If you put the heads on without springs what are you going to hold the valves in place with? The spring pressure holds the retainer locks in the upper spring retainer to the valve stem and if you use compressed air that will only work on the cylinders the the valves closed, not all the others that are partially open on their exhaust/intake strokes. Edited November 25, 2015 by 1969honda Quote Link to comment Share on other sites More sharing options...
NewZed Posted November 25, 2015 Share Posted November 25, 2015 Grab the gear and stick it on, with the camshaft dowel in the gear hole. Turn the gear and the shaft until the notch and groove line up. Remove the gear. Install the head. Don't make it complicated. The riskiest part is letting the head slip off of whatever you're working on and landing on a valve head. Let your eyes tell you if it's right. If there's a valve sticking out and about to go in to a hole with the piston at the top, that's wrong. If you need leverage on the head because it's free, take a piece of steel or wood and drill a hole or two in it. Bolt it to the bottom of the head as a handle. If you can't move the gear, put the bolt in and use a wrench on the bolt. But you'll have to shock the bolt head loose to remove since it will have tightened and will want to turn the shaft when you try to get it back out. A dead blow hammer, hammer, sledge, piece of 2x4, tapped on the wrench handle should do it. Go slow and look at how the parts fit together. Quote Link to comment Share on other sites More sharing options...
NewZed Posted November 25, 2015 Share Posted November 25, 2015 He's probably past this already and trying to figure out how to get the gear back on, because the chain seems too tight. Quote Link to comment Share on other sites More sharing options...
DeLorean Posted November 25, 2015 Author Share Posted November 25, 2015 I cannot spin the cam to save my life. I appreciate the suggestions about using a piece of metal or wood as leverage, I will try and give that a shot. I have the tensioner wedged, while I am hopelessly under qualified to be doing this job, I did try and do some homework before I started. Quote Link to comment Share on other sites More sharing options...
1969honda Posted November 25, 2015 Share Posted November 25, 2015 Everyone has to learn sometime, just do as NewZed stated and take your time, biggest novice mistake is to rush things. Quote Link to comment Share on other sites More sharing options...
TimZ Posted November 26, 2015 Share Posted November 26, 2015 (edited) Everyone has to learn sometime, just do as NewZed stated and take your time, biggest novice mistake is to rush things. You can omit the word "novice" from that sentence and it will still be accurate. Edited November 26, 2015 by TimZ Quote Link to comment Share on other sites More sharing options...
HuD 91gt Posted November 26, 2015 Share Posted November 26, 2015 If you put the heads on without springs what are you going to hold the valves in place with? The spring pressure holds the retainer locks in the upper spring retainer to the valve stem and if you use compressed air that will only work on the cylinders the the valves closed, not all the others that are partially open on their exhaust/intake strokes. And this is exactly the reason why I warned everyone that I had never done it! Haha. I did it with compressed air, but I guess that's pretty tough when the heads not bolted down yet. Quote Link to comment Share on other sites More sharing options...
TimZ Posted November 26, 2015 Share Posted November 26, 2015 And this is exactly the reason why I warned everyone that I had never done it! Haha. I did it with compressed air, but I guess that's pretty tough when the heads not bolted down yet. Actually your idea was sound, but you still need the springs. You could install the head with just the rockers missing and achieve what you were thinking of. Quote Link to comment Share on other sites More sharing options...
DeLorean Posted December 1, 2015 Author Share Posted December 1, 2015 Turned the cam to TDC, worked great. Thanks again to everyone for their advice. Quote Link to comment Share on other sites More sharing options...
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