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96 LX 1.9L - Head replacement
06-10-2010, 05:19 PM
My wifes 96 LX 1.9L had some rough idle issues and eng. light came on. Retrieved codes and vacuum/egr related. Changed out egr and light turned off and ran good for two weeks. then one day as she was pulling into the garage, engine started knocking very loud and stalled. codes pulled and says cyl #4 misfire. I suspected the worst, knowing this engines history of dropping valve seats in #4 cyl. So, I did a compression test and alas, no compression cyl #4. So, removed the head and sure enough, valve seat dropped and mashed up the head and gouged piston surface. Luckily, damage occurred as she was pulling into garage and thus only ran for a few seconds on damage. Cylinder walls were not damaged, not even a trace of scoring. Old head, too damaged for machine shop repair so I bought a remanufactured assembly for a good price. The piston was actually still serviceable, so I resurfaced it and polished it (and the other three as well). Luckily, the shrapnel didn't get sucked into any of the other cylinders. So, big job to replace head, but I am able to do it and I am now in the process of placing the new head gasket and new head onto the block. So, straight-forward right? but I also have some questions that maybe someone can provide some insight into. Could this damage have been induced by a vacuum related (EGR) incident? perhaps make it lean out, or offset the timing? I really do not want to put it all back together, just for the same thing to happen again in two weeks. also, for anyone who has replaced an aluminum head for this engine, do you have any tips for me? I removed the head with the intake and exhaust manifolds still attached, so should I then place them on the new head before reattaching to the block or will this just make it harder to reinstall and perhaps damage the new head gasket? If I put the head on without the manifolds attached, how hard is it to reassemble after head is bolted to the block? and lastly what is the best way to clean out the exhaust and intake manifolds before reassembly (in case any shrapnel is still inside), keeping in mind that I do not own an air compressor? also, should I then replace the spark plugs? as some of the old gasket material (as well as some aluminum dust from resurfacing and polishing pistons)inevitably fell into cooling ports, should I then do a block coolant flush?
Please, any advice you can give me is well appreciated! Its funny you know, I have replaced heads and head gaskets on all sorts of V8 engines with little difficulty, but it seems that this little four banger has been the most complex so far! Thank you in advance!
06-12-2010, 05:41 AM
I don't think the valve seat failure was due to a faulty EGR related problem. Escorts have been plagued with faulty #4 intake seats on all years. It's a design problem and new heads or remanufactured heads should have the new improved seats that will stand up.
As far as replacing the manifolds before putting the head back on is a call you will have to make. It can be done either way. I'd put the old manifolds on the head before replacing it and the head gasket. btw, it's reccomended that new head bolts be used instead of the used ones. When I do a head I always take the bolts off the exhaust manifold and leave it in the engine compartment. That way, once the new head has been put on everything is lined up and easy to get started. Since, you took the old head off with the manifolds attatched that would be the best way to put it back together.
Since you don't have an air gun you could rinse any of the shrapnel out with a high pressure water hose or you could take the intake manifold to a tire shop and have them blow it out. Tell them what you are doing.
It's sounds like you know what you are doing. Since you have the manifolds off be sure to clear any debris out of them, so it doesn't get sucked back in to the head. Since you took the old head off with the manifolds attatched, that would be the easiest way to put it back together.
To flush the gasket and metal particles out of the cooling jackets of the block could be done by placing a hose into the neck of the radiator with a towel wrapped around it to get a good seal. Back flush it with the head off. That would be the easiest and best way to do it I think. You could flush it after you get it put back together, but I fear that some particles would bet into the cooling jackets of the head.
I would rather do a a head on a V8 any day of the week. Escorts don't have as much room to work on them. I don't think you'll have a bit of trouble. You'll be all right. It'll be a piece of cake.
06-12-2010, 12:00 PM
Hey thank you very much Davescort97! You have given me alot of valuable info and advice and I really appreciate it! Yes, I think I will place the manifolds on the head before reassembly, as it was the way I took it apart. That is a great idea about taking the manifolds to a shop to have them blown out, I will also do this. I have purchased all new head bolts and gaskets , so I should be Okay! Thanks for taking the time to respond to my questions. I can do alot of different mechanic jobs, but I am far from knowing everything and sometimes even the most obvious things I don't know about, so I appreciate any advice I receive.
A couple of additional questions though. After re-installing the camshaft into the new head I needed to install the new cup plug into the borehole. All Haynes manual says is to install it without additional info. So using a rubber mallet and a large socket I carefully pounded it into place (making sure not to damage the lip surface), and it went in, piece of cake right? Now, what I need to know is do I (or should I have before installation) need to apply a coating of some type of sealant, or is this flange type of plug only supposed pressure fitted/seated? I was thinking of placing a dab of aluminum based epoxy weld (sort of like plumbers epoxy, but made for engine blocks) at the base of the lip to seal it in, but I don't know if it is even called for or what? is the oil; filled cam chamber pressurized while engine running, and if don't do something to lock it into place will it eventually pop-out?
And last question: When pulling off the old head, the head/head-gasket locating dowels stayed inside the old head, but I removed them. Now, haynes instructions works from the point of view that the dowels are still in the block, so don't give any advice on how they are supposed to be put back into the block. Do I need to also apply some type of sealant or adhesive to the dowels before insertion? or do I just clean out the ports and tap them in until they are seated?
Anyways, thanks again for the advice and info, I hope that I can someday repay in the way of giving similar worthwhile advice! cheers,
06-13-2010, 06:10 AM
You have gotten good advice. I have rebuilt 3 lx 1.9l engines, which may be the same as your 96, anyway my info applies to the 2nd gen. Escorts, which all I know about.
I always put the manifolds back on the head after the head is on the block and torqued down. I do it this way because it makes the head lighter/easier to set down -gently- onto the block; no hoist or helper needed. I also like to take a couple of the old head bolts, saw the hex heads off as close to the top of the bolt as I can, and put them into a couple of the head-bolt holes, just a turn or two. This gives me a pair of guides when I lower the head down.
When taking the exhaust manifold off, I find that the three long studs often come out of the head when taking the nuts off; and that makes it possible to put the exh. manifold back on - with the engine accessory bracket already bolted to the front of the block. Otherwise the a.c. low pressure tube and the side of the accessory bracket are in the way.
I always put the locating dowels into the block, making sure they arent distorted or have burrs on them from being pulled out of the head with vise grips. Im sure it doesnt make any difference whether you put them into the head or the block, .... but the dowels being in the block ensure the head gasket is lined up just right. And I just put them in 'dry'. In fact I expect to have to gently tap them down into the hole.
I put the lower radiator hose on with the accessory bracket removed, and preferrably with the block out of the car. I use the original 'spring clamp', and with the block out of the car its easy to re-install. If I had to do it with a block that was in the car, I would use a screw type hose clamp. I did that with my first 1.9l rebuild. It means you need to re-tighten the clamp a couple of times afterward though, and getting to the clamp means removing the tensioner for the serpentine belt, and having the screw of the screw clamp positioned 'just right' to reach it. The screw clamps in that size usually have a 5/16" hex head, which makes it easy to re-snug them with a 8mm or 5/16" socket. I re-snugged the clamp after 3 or 4 days, and again about 2 weeks later. And it hasnt leaked in the 4 years since. Both times I did it when the coolant was still warm, and the hose nice and soft.
Another scheme to ensure you dont damage the bottom surface of the head when you put it down, is to have a couple of wooden strips, slightly thicker than the 'height' of the two steel dowels, to lay the head on, until you are sure the head is lined up correctly. Then you can slide the wooden strips out carefully, tilting the head up slightly to take the weight off the wood strip.
This isnt necessary if using the old head bolts as guides. Dont thread the old head bolts into the block more than a couple of turns, or you wont have enough of the bolt sticking up through the head to be able to unscrew them. Maybe I should saw a slot in the top of my homemade 'head guides' for the next time I need to do this.
The wooden strips I used were once slats from a baby crib.
With the head in place but the intake manifold not yet installed, it is easier to reach stuff behind the motor. When rebuilding an engine I have to torque up the bell housing bolts, put the starter back, the rear heater hose to the water pump (another spring clamp), the crankshaft position sensor connection, etc. Much easier with the int. manifold not in the way.
I like to sand down the diameter of the dipstick end a little bit, so it fits into the block without damage, then use RTV gasket maker (ultrablack) as a sealant on it when I shove it back into the block.
Be sure to install the cam position sensor before you put the intake manifold back on. Wont fit otherwise.
I have had to use more of the RTV gasket maker to stop oil from seeping out past the valve cover gasket.
When removing or re-installing the alternator, I find it comes out through the hole where the passenger side headlamp was. Thats what is easiest for me anyway.
06-13-2010, 04:18 PM
I don't see that anyone really addressed the possible cause of this issue. The EGR was not the cause, but was likely a symptom of the pending trouble.
The dropped seat is typically a result of overheating.
If you have not regularly maintained the radiator, check to make sure you have adequate flow. If the car has started to run hot and you do not address that possible issue, then you could be headed down the same path before long.
The only other significant issue I can think of has already been addressed... and that is to be sure you clean out the intake manifold, because there more than likely is something in there that will get sucked right back into the engine as soon as you fire it up.
06-20-2010, 09:08 AM
See the heading "why valve seats fail"...
With help, I placed the head with the exhaust and intake manifolds already attached. It was easier for me to get everything perfectly mounted and torqued while it sat on the bench, versus being mounted in the confines of the engine bay. Also, there won't be any additional contortional changes on the head, and shifts in weight distribution after the torquing process. Hopefully that may reduce some of the stresses on the head by some infinitesimal amount. It was repaired for cracking between the exhaust valves and coolant passage for the 2nd and 3rd cylinders, and possibly forward head bolt well near 4th cyl; which could've been headgasket failure. The metal sleeves/dowels/seals/whatever already setting in the block for the oil feed holes made sure that our descent was perfectly aligned. The original headseat from Ford dealership was for an earlier year, possibly 1.8L engine. (slight differences) So I had to go back again and get the correct one. (their mistake) Re timing belt, give the tensioner some assist before locking it into place. The belt will stretch and make the timing a little sloppy. Also clean the MAF+ACT/IAT everytime that air filter is removed. MAF cleaner in parts stores.
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