Author	[Modern View]
Britcheflee 08-05-2012 08:22:04 67.187.170.181 Report to Moderator	think I have at last worked out what the problem is with my 8N - misfiring and popping under load - not so bad cold but as soon as it warms up starts running bad. No smoke as such but when the engine was revved up a small cloud of white smoke. Checked valve gaps ok. Checked compression From back to front 100, 100, 60 100. Was going to use a block seal product that I was told works well and in process of draining and flushing cooling system saw oil in the water - not a lot but its there. I think I may have made an error when I replaced the head last time - I used the lower torque settings for the head nuts rather than the higher settings for the head bolts - I did torque it down later at the higher setting but I have a feeling in the meantime might have blown the head gasket again. I have some help so will take off hood and remove head again. Couple of questions: 1. If I take it to a machine shop to check for warping and it is warped should I just get a new head or can I have it skimmed? If so what is the amount they can take off safely? 2. If it is not warped and I cannot see any cracks I will get a new gasket and replace it - is it of any help to put any sealant on and if so what make and how? 3. Finally, on the head bolts when replacing I have read to us 'pucky' - what actually is this and what the the proceedure for using. It was very tempting just to use the K&W block sealant but decided to do this - it might work but then it might not. Lee [Reply]   [No Email]
Jimps 08-06-2012 09:08:05 216.166.222.115 Report to Moderator	Re: Off with his head! Head gasket questions. in reply to jon4020, 08-05-2012 08:22:04   Quoting Removed, click Modern View to see I use the Felpro 7277B gasket, and it has a stamp (hard to read) that tells you which side is which. I think it indicates the block side. Other gaskets may not indicate the orientation. So, yes, it matters, if you use the Felpro 7277B. I just went through a similar issue with a bad head. Mine was obviously bad, rotted, warped and cracked. New head was the remedy for my issue. Jimps in GA. [Reply]  [No Email]
Royse 08-05-2012 18:24:14 69.36.49.151 Report to Moderator	Re: Off with his head! Head gasket questions. in reply to Britcheflee, 08-05-2012 08:22:04   The version in my FO-4 also varies from the ones I've seen posted here. I'd have to go get it and look to be sure, but it seems like somewhere in the middle of the sequence it wants you to torque one of the bolts on the end of the head. [Reply]  [No Email]
JMOR 08-05-2012 17:21:47 99.105.24.57 Report to Moderator	Re: Off with his head! Head gasket questions. in reply to jackinok, 08-05-2012 08:22:04   Quoting Removed, click Modern View to seeMy arly FO-4 doesn't even show a dwg/picture, rather just words, "tighten alternately, from center out to each end". [Reply]  [No Email]
Paul in MN 08-05-2012 13:23:30 174.20.115.113 Report to Moderator	Re: Off with his head! Head gasket questions. in reply to Britcheflee, 08-05-2012 08:22:04   Lee, As to which torque value to use on the head bolts, there is a lot of confusion on this issue. Here is the scoop.... If you are using head studs (which I definitely prefer in these older blocks), and the studs have one end with coarse threads (block side), and the other end with fine threads (for the 7/16" N.F. nuts), then you use the lower torque setting (55 ft lbs IIRC). Basically the studs are threaded into the block with some water proofing thread sealer (Dell calls it pucky) with very little torque... maybe just finger tight. You can easily feel if you hit bottom of a blind hole or if the thread is full of garp. Do not force the stud further than it wants to go, especially on the hole at the most right rear corner of the block. Stressing that bolt hole can cause the corner of the block to be broken off. With all the studs in place, place the head gasket (I use copper gasket sealer on both sides of the gasket), and slide the head onto the studs. The fine thread 7/16" nuts should have clean threads and go onto the clean threads of the studs without oil. Follow the torque sequence as shown in the FO-4, but do it in steps of about 20 ft lbs each time you go around the pattern. If your #3 cylinder is showing 60 psi, I really doubt the head gasket has failed. The common head gasket failures are between cylinders 1 & 2 or between #3 & #4, and then you see nearly 0 psi on the 2 adjoining cylinders. I suspect that some carbon has broke loose and is keeping the exhaust valve from closing to make a tight seal. If that is the case, you will hear air hissing at the exhaust pipe when you do the blow down test. The usually successful solution to that problem is to put the tractor to work and work it hard at about 3/4 throttle. Good heat and good exhaust flow will usually loosen the junk from the valve or seat. An hour with the brush hog is the prescription I'd use. The head can be checked for flat with a good carpenter square and a feeler gauge. The flat head is flexible enough that .010" warp over the length of the head is acceptable, but no more than .003" across the head at the narrow point between #1 & #2 or at the narrows between #3 & #4. I doubt that these specs show up in any book, but it is what I have found works with the N engine. In some cases, I have found the block to be warped and in need of a trip to the machine shop for a "deck" pass in the Bridgeport mill. The block can be checked with a good carpenter square (long side as straight edge) and the feeler gauge. The aftermarket heads I have seen have a lower compression than a good used original head. I'd rather repair the original head (unless it is cracked). Put her to work and the problem may solve itself, and the rest of this stuff is just academic (but learned in the school of hard knocks ... 42 years of N tractor fixing on my own N and many customer's N's). Best wishes! Paul in MN [Reply]  [No Email]
Gaspump 08-05-2012 14:00:57 72.40.147.47 Report to Moderator	Re: Off with his head! Head gasket questions. in reply to Paul in MN, 08-05-2012 13:23:30   Interesting, I just looked at the sequence for tightening on page of 26 of my FO-4 and it is incorrect. The one shown is the early version and has been superceded by the later 8N version and that one is applicable to both studs and bolts. The correct version has been posted here on several occasions. [Reply]  [No Email]
ZANE 08-05-2012 12:30:55 98.83.99.84 Report to Moderator	Re: Off with his head! Head gasket questions. in reply to Britcheflee, 08-05-2012 08:22:04   I can almost guarentee you that an automotive machine shop is going to find the head "warped" I have never seen an N head that has been used that will not have a "warp" end to end. In my opinion that is not a problem. If however you find a low place side to side that could be a problem. The slight end to end warp is not a problem because the bolts will pull the head down flat with the deck when properly torqued down. Iron does bend you know if only slightly. If you let a machine shop mill it you may then run into that old problem of the pistons hitting the head when they go up to the top. I have been building N engines for well over 50 years and have yet to see the necessity to mill a head and I've never had one give a problem I use "Copper Coat" spray on gasket sealer on both sides of an N head gasket. Lots of automible head gaskets now days have a sealant incorporated into the head gasket material and it works great but I've not seen it on N head gaskets. Zane [Reply]  [No Email]
NoNewParts 08-05-2012 11:20:33 67.240.145.25 Report to Moderator	Re: Off with his head! Head gasket questions. in reply to Britcheflee, 08-05-2012 08:22:04   I also use my compression testers hose for a poor mans leakdown tester. (its fitting even matches my air line) If tests reveal a bad head gasket, when you have it apart, check the block deck carefully for cracks too. Common for them to crack between a bolt hole and water jacket hole. be sure to tighten around and around the pattern gradually bringing the torque up to help prevent this. On your routine check of the valves with the head off, look carefully for a burnt valve or any damage to the valves or their seats. on non-runners I'm resurrecting, while working in there, after cleaning, I rotate the valves closed (on a N) and pour some solvent on them and leave it to check for leaks. [Reply]  [No Email]
JMOR 08-05-2012 08:59:11 99.105.24.57 Report to Moderator	Re: Off with his head! Head gasket questions. in reply to soundguy, 08-05-2012 08:22:04   Quoting Removed, click Modern View to seetake schrader valve out of hose first. it needs to be able to flow [Reply]  [No Email]
Bruce (VA) 08-05-2012 08:35:08 24.125.80.178 Report to Moderator	Re: Off with his head! Head gasket questions. in reply to Britcheflee, 08-05-2012 08:22:04   " I have some help so will take off hood and remove head again." Why? Because # 3 is at 60 lbs? First, check the plugs. Any of them look "steam cleaned"? Then, invest in a leak down gauge. Learn to use it to diagnose the problem before you just assume it's a head or head gasket problem. You wouldn't be the first guy to misdiagnose a problem & pull the head off only to make matters worse.....as breaking a bolt, etc. BTW, you are wise not to use "crap in the can". " saw oil in the water" While water in the oil is always a problem, oil in an N radiator is not usually a problem. Anti-freeze has water pump lubricant in it. That's oil. Because it's a flathead, no oil lines are above the head gasket. But, you could have a slight leak in the head gasket which will produce a sheen on the coolant thanks to combustion gases. 50 Tips [Reply]  [No Email]
JMOR 08-05-2012 08:33:50 99.105.24.57 Report to Moderator	Re: Off with his head! Head gasket questions. in reply to soundguy, 08-05-2012 08:22:04   Quoting Removed, click Modern View to seeYour tractor & your time, do what you want. Yes, bolts/studs go into water jacket & need sealer. Personally, I would plumb my air compressor into the suspect cylinder's spark plug hole, set that one to TDC-compression, apply air pressure & listen/look for escaping air at 1) bubbles in radiator, 2) air hiss at oil filler, 3) at exhaust, 4) at intake/carb. Might be doing a head gasket when you need piston/cylinder work or valve work instead........if procede blind with head gasket, then you may get to do it all over again if problem is else where. Just my 2 cents. [Reply]  [No Email]
Britcheflee 08-06-2012 09:02:36 67.187.170.181 Report to Moderator	Re: Off with his head! Head gasket questions. in reply to JMOR, 08-05-2012 08:33:50   I am getting equipment together today to do pressure test - however, as I see it, no matter what it might be - valves, rings (which I really doubt) or leak in head gasket the head has to come off to deal with any of these problems? I will of course do the pressure test first to verify for sure which of these might be the culprit - with the head off it might also be quite obvious. I asked this before but did not get advice - is there an up or down on the head gasket with installation? Would it make any difference one way or another? Just waiting for my buddy to come over and give me a hand lifting hood off - got a full tank of gas so it is heavy. Thankyou Lee [Reply]  [No Email]
Britcheflee 08-05-2012 09:36:34 67.187.170.181 Report to Moderator	Re: Off with his head! Head gasket questions. in reply to JMOR, 08-05-2012 08:33:50   OK planning to do that - I did replace pistons, rings, sleeves last year and I think the 100 psi for the other cylinders is not bad? Lee [Reply]  [No Email]
Bruce (VA) 08-05-2012 08:38:17 24.125.80.178 Report to Moderator	Re: Off with his head! Head gasket questions. in reply to JMOR, 08-05-2012 08:33:50   " I would plumb my air compressor into the suspect cylinder's spark plug hole, set that one to TDC-compression, apply air pressure & listen/look for escaping air " AKA a poor mans leak-down gauge! [Reply]  [No Email]
Britcheflee 08-05-2012 08:50:20 67.187.170.181 Report to Moderator	Re: Off with his head! Head gasket questions. in reply to Bruce (VA), 08-05-2012 08:38:17   OK I am going to harbour freight today so see if I can get one of those to attach to my air compressor. On the head gasket - is there an up and down side to them or does it not matter? [Reply]  [No Email]
Britcheflee 08-05-2012 08:51:12 67.187.170.181 Report to Moderator	Re: Off with his head! Head gasket questions. in reply to Britcheflee, 08-05-2012 08:50:20   Can I use the connector for the compression tester and find an adaptor to the air compressor hose? Thanks [Reply]  [No Email]
Den N Ms 08-05-2012 10:55:17 184.41.143.48 Report to Moderator	Re: Off with his head! Head gasket questions. in reply to Britcheflee, 08-05-2012 08:51:12   Britcheflee ,Yes you can use the hose and fitting for the compression gauge to pressurize the cylinders.You will just have to remove the schrader valve core from end that screws into the head to allow air pressure into the cylinder.(don't loose it as it is a special core).Be sure you have the cylinder to be checked on compression stroke wit the piston at top dead center,If its not TDC the engine will spin.Start with your air pressure regulator set at 40lbs,and take the radiator cap off,oil fill cap off.Hook up the air hose and watch for leaks in the radiator,Listen at the oil fill,carb intake,or exhaust pipe.Post back your findings. [Reply]  [No Email]