what all should i do when i change my headgaskets? <-- Advice, more than info

[daeron]

i just typed alot, and realized i never started right: 87, spfi, non turbo EA82, 3AT, 139K (yesterday)

 

Well, I am 99.9% certain I need new head gaskets. I first had a stuck thermostat, then a LONG time later, blew a radiator hose and a water pump together, then the other radiator hose, then replaced the radiator, then removed the thermostat, and just blew another heater hose. Im still losing coolant, not into oil, no puddles or drips, no detectable water being dried up by heat before the ground... no smoke from the exhaust, to my knowledge.. i havent verified that with an assistant intent on ruling it out yet. I have bubbled into my overflow without overheating the whole time (practically) and its gotten more and more regular. I dont lose too much coolant as long as i top it off every day, which is about 100 miles. if i miss a day it deteriorates more rapidly. (think less than a quart in a day and half a gallon in two) Ive had an oil leak forever, and already replaced the water pump. I put timing belts on 30K ago, but didnt do any seals because i had no cash.

 

I am going to do the headgaskets. I never got around to checking compression. Im convinced its the spot on the head gasket between combustion chamber and coolant passage, letting compression into the coolant system. the water always looks almost muddy, and its more than just engine contamination and rust.... so i should just pull the motor from the car right? i have access to a good nonpro shop with a big compressor, engine hoist, etc so i have the tools and facility that its not too big a deal..

 

the other big question is, what all should i reseal? im not certain where my oil leak is coming from, i am thinking rear main, but it doesnt seem to be the heads... but its all over. not too major a leak, but steady enough that if i dont check it (and add) often enough i may get the TOD to remind me... so should i get cam seals, and front and rear crank seals, and an oil pump seal too? since the Tbelts are 30K should i go ahead and replace those too, and keep em for spares? i think that might be a tad excessive, as i think i could put new t-belts on easily enough in the future.. but the seals, i mean some of them are no brainers. should i reseal the oil pump too? oilpan gasket? intake manifold? exhaust? i dont think i should need the intake or exhaust, but how wise would it be to be prudent on which of these? heck, if i can replace the motor mounts i suppose that would only help too, huh? what of this is included in the fel-pro headgasket kit? im trying not to break the bank here, and i honestly have decided that i NEED to buy the headgaskets ASAP even if i wait to put them on.. I am afraid of blowing them on the road one day to a point of non-drivability, and if i do that on the wrong day then i _might_ be broke (happened with my tierods) and since i drive pizzas, it would make life hard.. so i want to be prepared for that eventuality. However, i also want to get everything i can get done, done when i do this. am i missing anything? anyone have any advice?

im planning on fel pro gaskets because theres no need to retorque.. good idea, right? any cons to that one?

 

 

thanks for reading another chapter in the book of shawn....Im sorry i talk so much, but i default to using stream-of-consciousness when im fixing on and thinking and talking about cars, and im NOT good at summarizing. I really would like some feedback on this even though i know alot has been covered in the past..

[Syonyk]

What's your oil pressure look like? If it's 45 or so when running after warmed up, your oil pump is fine. If it's much below that, look at replacing the oil pump while you're in there.

 

Personally, if *I* had the engine out of my car, I'd reseal everything I could get my paws on. Front seals, cam cover o-rings (you'll have those off to do the heads anyway), rear main, make sure the crankcase plugs (for punching out the wrist pins) are well sealed, etc.

 

I agree with you on the timing belts as well. If the engine is out of the car, I want to do EVERYTHING when it's out, so I don't have to think about it for another 50k miles.

 

-=Russ=-

[DasWaff]

Might want to pull the oil pan off and clean the bottom where you may have some goo from the oil/water mix. Make sure the oil passages behind the seals aren't sludgy. The oil pump rebuild is cheap and easy. Basically flush all the things that are easy to get at while the engine is out... That's one mutant's opinion anyway. DW

[daeron]

well since my original post i managed to do some research, and i think im set on the fel-pro headgasket kit that includes the intake/exhaust manifolds, and a whole bunch of other stuff including i think everything that was recommended..

 

I haven't checked the price of the timing belts yet, but i think ill give that one a pass. Like I said, i did them 30K miles ago, which was just under two years. If I can get a pair for cheap, then maybe.. but this is already getting expensive. Im pretty well set on doing the camshaft seals, and the front and rear crank seals.. as well as an oil pump rebuild. I have the digidash, with no oil pressure gauge.. only a light that ive never seen come on, even though i know ive let it get over a quart low.. but I get the TOD on occasion, and it seemed pointless not to do anything.. but how likely is it that with no _particular_ problem i should need to replace the pump?? i was anticipating replacing some sort of impeller or seal or something, havent looked into the specifics beyond vague references on the board to "resealing" it..and i dont think i have ever had an oil pump issue on any car ive worked on.. seen em in my uncle's and dad's cars, etc.. just never had to deal with mine.

 

I haven't gotten any water in the oil, the water dissappears (and some bubbles out of the overflow) so i think its a leak from coolant passage into combustion chamber. could i confirm this by compression checks with the radiator cap on and off??? i would think so, but i wouldnt rule it out if it "failed" the test.. and of course, ultimately, pulling this engine and doing all this resealing (<$140US) is only going to be a good thing, and increase viability, reliability, and overall worth of the car. The biggest reason Im going to pass on the timing belts (probably, unless i manage to put this off longer than i fear) is that I have another car that i have failed to start working on for almost two years (in october now) and i HAVE to get going on my Z before it winds up getting hauled away... my datsun is really my baby and I want to make this headgasket project my last one on the soob until i get some visible progress in on the Z.

 

Anyhow, if in the future i pop a timing belt, its something i have done before. I will know immediately what it is, and i wont take too much time to replace them. timing belts on a geo turned me from a kid (who helped his dad alot) into a full fledged shadetree mechanic.. and this soob has finished taking me to amateur technician status. so timing belts and me go waaaay back :cool:

 

thanks for the feedback.

[idosubaru]

do not pull the motor just to change the head gaskets. if you have air tools headgaskets in these little 4 cylinders are a cake walk (as far as head gaskets go). even without air tools i'd still do it in the car. i bust out headgaskets in no time on both EA82's and 6 cylinder XT6's. the bottom line is that there is nothing hard about doing a headgasket in the car. pulling the engine only makes it take longer.

 

the only trick to doing it in the car (no jokes please!!!) is removing the valve cover bolt, mostly on the drivers side. just have a wratcheting 10mm wrench on hand and it's easy. then you'll need grease (who doesn't have that?) to hang the rocker arms on when you reassemble.

 

i would look into those perma-torque fel-pro gaskets that don't require retorquing the head bolts.

 

also - plan on it taking awhile and having the car down. large jobs like this typically run into a quirk here or there that may take longer than you expected. cost being an issue you probably won't want to do this, but i like to have a set of heads ready to go so i can swap right away and not worry about taking the set off the car in and waiting on the shop.

[daeron]

do not pull the motor just to change the head gaskets.

 

i would look into those perma-torque fel-pro gaskets that don't require retorquing the head bolts.

 

also - plan on it taking awhile and having the car down. large jobs like this typically run into a quirk here or there that may take longer than you expected. cost being an issue you probably won't want to do this, but i like to have a set of heads ready to go so i can swap right away and not worry about taking the set off the car in and waiting on the shop.

 

okay, GREAT tip on the spare heads.... i may have to check into the cost of a pair of junkyard heads, because as soon as you mentioned it (especially on the tail of the comment about the likelihood of a snag or six) the logic and wisdom was apparent. besides, i already know im gambling in assuming that the heads on the car will be reusable...not a SIGNIFICANT gamble, but ive got those irish leprechaun demons chewing on my neck all the time anyhow... it doesnt take a high likelihood to happen to me beyond maybe having them checked and milled if needs be, is there any real work that i would want to have done to a set of junkyard heads? i personally would not necessarily be able, alone to do a thorough look-over to make sure theyre A-OK but i know i have family members who can show me what to be looking for. this is a job in a region that im still unexperienced in, never having had head problems on _my_ car. life was different when i was just helping.

 

there IS a decent chance that i could pull heads off a car in the boneyard and have them OK to slap onto my motor, right?

 

also, the perma torque fel pro gasket, would that be the ones included in the head gasket set??

 

as for pulling the motor, i was planning on doing all the seals, too.. wouldnt the rear crank seal require me either pulling the motor or dropping the trans? ive read all about doing the headgaskets only with engine in car, but the seals were really what prompted me to think pull the engine.

 

continued dialogue is appreciated, since i want to do the best job in the least time possible here... I know its not going to be cheap, just the gaskets and seals already amount to as much money as ive spent on the car at one time!

 

what would i want to look for in a cylinder head? would a later model, or an XT head provide me with any better flowing? ive read a few vague references to different generation heads, but no real specifics (i know my datsun heads pretty well, tour P-90s, you N-42s, the p-79s.. lol) so i dont know if its even a subject worthy of a search. I guess I will go do so now, but thanks for the remarks.

[idosubaru]

the only seal you can't get to without pulling the motor is the rear main seal. the thing with that seal is that they almost never leak. i don't know why, but they just don't. i know of TWO instances where a Subaru rear main seal leaked and both leaked shortly after being replaced (like almost immediately). by what i've seen, the chances are higher of having a rear main seal leak if you replace than if you don't! i've pulled some 200,000+ mile motors that i assume have the original rear main and i've yet to see one even seaping any oil. i know others (svxpert for one) that have done alot of engine work and have noticed the same thing, rear mains rarely need attention on EA and ER series engines.

 

all that to say, i still don't think pulling the engine gains you much of anything, but it certainly allows you to replace that seal, the oil pan gasket and the separator gasket. on a manul trans you're looking at clutch work. if it is manual i'd just wait until the clutch needs replaced to do the rear main and oil pan if you'd like. if it's an auto then you can replace the torque converter seal as well. be very careful with an auto and read about seating the last 1/4", it's an often missed point that ends up ruinning the trans oil pump (very bad) if you don't know about it.

 

subaru's typically have cracks between the valve seats, very common. most EA and ER series subarus driving around today probably have those cracks, they aren't all that big of a deal. (i'd be much more concerned with turbo's than non-turbo's) but i (almost) always have them repaired when the head is off. i take them to a shop and have a valve job done, cracks repaired and have them resurfaced. you could probably get away with slapping heads on there though, but it's risky of course. you can straight edge the heads and get a rough idea. there's information on this board on how to resurface the heads yourself using a flat machinist block and blah blah blah, you'll have to look it up if you'd like to do that yourself. i always take mine in to an aluminum head specialist they do excellent work.

 

if you pulled a set of heads off a known good motor they would likely perform fine. the valve stem seals are old and there will likely be cracks but cracks don't usually leak unless they get really deep. i forget what you have but if you're after performance, racing, turbo's...then going cheap on the heads is a terrible idea. if you want to stay non-turbo you'd likely be okay. the more i knew for certain they were never overheated the better i'd feel about doing it which brings the next point....

 

i've gasket-slapped two engines, pulled the heads and replaced the gaskets without any head work at all except cleaning the heads, head bolts, engine block and head bolt threads. both of those vehicles are still running great after a number of years. both had very minor external leaks and never overheated, so i assumed the heads were probably okay. i don't normally do that, but for various reasons sometimes i do if i'm confident the heads are likely okay. so far it hasn't come back to bite me yet.

 

one of the most important things about doing a headgasket on a motor this old is cleaning the mating surface between the head and engine. and cleaning the head bolts and head bolt holes. this is where air tools save a TON of time and make it much easier. you can zap a bolt and a bolt hole three times in a minute cleaning the threads up. by hand is a much more tedious process.

]

i've said enough.......good luck!

[daeron]

gary-

 

thanks a ton. im looking thru parts on the internet and im seeing both a rear crankshaft oil seal, and a rear main seal that seems to be associated with the rear main bearing?? but i assume when you say "rear main seal" you mean the seal just behind the flywheel :-)

 

its an auto, thanks for that point on searching for the re alignment... and given your advice, i suppose maybe i will NOT pull the motor. that was my original thought, but as i started leaning towards a complete re seal i began to assume that the extra work would make pulling the engine that much more of a good idea.. but since im failry sure i do have access to ratcheting box wrenches, and air tools (yay) i guess ill leave the engine in. it has been discussed lately that one could achieve the best of both worlds by unbolting the motor mounts and jacking the engine up from beneath.. and i may explore this avenue.

 

I'm torn on what to do for my heads. If i can pick up some cheap junkyard units, i think that may be the best way to go. this is an NA auto, NOT my sports car, i have a 280Z for that, thank you very much. However, i want this car to be as potent as i can make it, simply.. so i was basically wondering if there was any significant difference in ANY of the heads, as much to avoid thee wrong ones as to get the right ones. There is an older, carbureted EA-82 in the boneyard right now, and its crashed real bad. all the rest are just... dead???? so im thinking that the crashed car PROBABLY has the best chances of a running motor... of course, i noticed both the ECU test connectors connected on one of them (picture junked because of persistent CEL, maybe with accompanying "battery drain" from the parking lights lol)

 

anyhow, thanks again, that was great advice. ive been around motors for years, so i know the basics about cleaning etc... i just dont trust my knowledge base to render me an opinion i want to put the next 100K+ worth of confidence in, you know? im still learning, but this soob has made cars a new thing for me.