PapaSmurf Posted July 24, 2010 Share Posted July 24, 2010 (edited) Hey guys, well when I went through my "new" (f54 block) engine I installed an old (never used) head gasket left over from my n42 block. I forgot the f54 had an extra water jacket and the gasket died after about 3 miles worth of driving. So I ordered and installed a new head gasket specifically for the 81zx engine. When I installed it I noticed it had the extra hole but was missing quite a few holes that were on the block and cylinder head. So I figured the hell with it I've never had an issue with these gaskets before they must know what they're doing right? Well this head gasket is seemingly bad too now - after only driving it a mile to the gas station and back! So either the gasket was the wrong one or the cylinder head is warped. I saw no evidence of water damage or corosion when I disasembled the engine the first time so I've got to believe that this is a gasket and not warp (Gasket is a cheaper fix too and I'm optimistic) So what's the deal with the missing holes in the f54 felpro gaskets? I'm confused as hell here. I can post a part number if it would be helpful, I still have the box. I just went out there and ran the engine for a bit and the oil pressure is HELLA low! But the water seems to be gone from the exhaust. I'm loosing it here I also adjusted the timing chain when I replaced the gasket, I seem to be off a notch because it's running like ****, stumbling and misfiring here and there, which is odd because the marks all line up the cam mark was off to the left before the adjustment which is what I thought was correct but reading my possibly lying chiltons manual it said it should be to the right - closest I could get it on the #3 mark was just about dead center which is better than nothing for now - but it's not running right and it was running great before. another annoying issue is I'm burning oil still, I just replaced the valve stem seals, but when I got the head off 5 out of 6 combustion chambers were fouled with oil. I think I payed too much for this engine! The last tid bit is - I just replaced the crank pully, the crankshaft was warped underneath it, I'm wondering if it's warped further back into the engine and may have killed some bearings causing the low oil pressure scenario? I'm thinking of just honing my n42 block, buying some rings, and plugging in the flat tops I just cant afford the rings, bearings, etc and I've never taken apart the lower end of these things before. *sigh* another summer without my Z Edited July 24, 2010 by PapaSmurf Quote Link to comment Share on other sites More sharing options...
woldson Posted July 24, 2010 Share Posted July 24, 2010 Gotta search one this one, I remember a couple threads one this. One might be that fantastic thread one head cooling..................... When you blew the first so soon my first thought was......now the second. Check the head and the block for true. Also cracks. Don't hurry. Quote Link to comment Share on other sites More sharing options...
PapaSmurf Posted July 24, 2010 Author Share Posted July 24, 2010 yeah when I get time to tear it back down I'll be checking both the head and block making sure they're flat, I'll take the head down and get it magnafluxed and have the machine shop make damned sure it's true. I was thinking a leak down test would be a good idea though before I tear it down. The cheapest machine shop in town that I've found will charge me 400 bucks for a valve job and new guides + the cost of parts :S so I was really putting it off. The cost of rings for the 81-83 n/a blocks is almost twice that of rings for the n42 blocks so I've been putting that off too. When I initially installed the engine I checked the cylinder walls and could still see the honing marks quite clearly, when I removed the head to change the gasket I could still see them, I saw no scoring or anything to tell me that the rings were in fact bad. So I'm at a loss as far as the oil burning goes. I'll do some more searching on that gasket though maybe I'll find something. Quote Link to comment Share on other sites More sharing options...
PapaSmurf Posted July 24, 2010 Author Share Posted July 24, 2010 I did another search and found this thread The blocked passages are just for coolant - so shouldn't be contributing to my low oil pressure issue. However I was confused as hell when he said that his f54 block didn't have those blocked passages. Mine does. I thought all f54s were the same cast? Both my p79 and my f54block have those coolant passages. My gasket ignores them. I'm going to try trading the oil pump from my old n42 with the f54 and see if that helps the oil pressure issue and I'm going to do a wet/dry compression test to test the rings. If I do need new rings I'll just swap crank shafts with the n42 while I'm at it and have the new one checked out. I really don't have time for this I just want to drive the thing already. Quote Link to comment Share on other sites More sharing options...
woldson Posted July 24, 2010 Share Posted July 24, 2010 Gauges can be wrong, as well as sending units. Anyhow if the bores look good visually, look to the head. Make sure the block is flat. Good straight edge should give you a general idea. Quote Link to comment Share on other sites More sharing options...
woldson Posted July 24, 2010 Share Posted July 24, 2010 I just can not remember that thread and the pics. Mostly what I saw on mine and others is the amount of passages blocked by the gasket. Quote Link to comment Share on other sites More sharing options...
Tony D Posted July 25, 2010 Share Posted July 25, 2010 Did I read that right? Two head gaskets in less than 5 miles? And you're optimistic...indeed you truly are! What kind of torque wrench are you using on the head bolts? When it blows in that short a distance, either insufficient torque (wrong make up or bad wrench) or excessive warpage is where I'd look, costs be damned. Hoping a head gasket will fix a 0.020" warp won't make it so! Good Luck. Quote Link to comment Share on other sites More sharing options...
randy 77zt Posted July 28, 2010 Share Posted July 28, 2010 check both the block and the head with a straight edge.i clean out the head bolt threads in the block with a tap,brake cleaner and compressed air.use NEW head bolts.i use a felpro on l28et with no problems Quote Link to comment Share on other sites More sharing options...
PapaSmurf Posted July 30, 2010 Author Share Posted July 30, 2010 I used a brand new torque wrench, not the most expensive wrench but I believe it to be acurate I torqued it to the highest option according to the book by the pattern in three stages ie to 35 to 45 to 65 I dont remember the exact numbers but I took them from the book. It doesnt seem to be burning water as much any more mostly oil. I havent had time to get it apart to check the head with a straight edge but that is the plan. It smokes most on acceleration which makes me worry its rings too. I may take it in for a leak down test before dissasembly to save some trouble. If the rings are bad Ill just have to find an engine stand and learn how to hone it out and change them. Quote Link to comment Share on other sites More sharing options...
-eric Posted July 30, 2010 Share Posted July 30, 2010 Torque specs I have off hand for 73-83 are..... 1-30ft lbs 2-44 ft lbs 3-54-61ft lbs Tighten from the middle, then outwards alternating sets. If that helps Im not sure, sounds like its warped tho. Quote Link to comment Share on other sites More sharing options...
PapaSmurf Posted August 1, 2010 Author Share Posted August 1, 2010 Torque specs I have off hand for 73-83 are..... 1-30ft lbs 2-44 ft lbs 3-54-61ft lbs Tighten from the middle, then outwards alternating sets. If that helps Im not sure, sounds like its warped tho. yep that's right that's what I did. It doesn't seem to be burning water at all anymore so I wonder if this head gasket ordeal is over. It's burning oil on acceleration though so I expect that to be rings, I'm going to get it to the shop and ask them to do a leak down test as part of a qoute - then kindly decline their offer to fix it for 4-5 thousand dollars and do it myself. One day I'll have some free time to pull it apart and get it figured out, My son is turning 1 year old on Tuesday and I've got another on the way so it's hard to find time for the Z these days. What I really need to do is get a 6x4 sheet of plywood and a few 3x4s and build a few baby gates. This kid has torn down every gate I've put up, he ripped the latest one out of the wall - I didn't know 1 year olds were supposed to be able to climb, maybe mine's just some sort of evil genius. Quote Link to comment Share on other sites More sharing options...
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