Changing head gasket Stuck on Timing chain

[Luvmy240]

I just got this 1989 Nissan 240sx as a gift. Only thing the car has a blown head gasket.Since I don’t have $ to hire a mechanic I decided to do the job my self. I started today and am already stuck.

How do I take off the timing chain? Does it need to come out if I am only changing the head gasket? I was thinking of replacing the chain since the car does have over 150k, but that money is for the machine shop. I want to make sure the Head doesn’t have any cracks.

Any advice or Tips on the removal or installation process would be greatly appreciated.

thanks

Modified by Luvmy240 at 9:29 AM 4/6/2005
Modified by Luvmy240 at 7:29 PM 4/6/2005

[slipnfall]

I'm sure someone here might be able to give you better advice, but to get you started:

I'd first set your crank to top-dead-center, just in case the lower chain slips off. I *think* the KA24E has a chain' holder/catch that engages if the chain is loosened, so when you unbolt that gear(you'll have to, no way arround it), the chain should stay relatively 'put. Don't quote me here, some fellow KA-E owners should confirm. Just in case, have someone keep tension on the chain, then use something to secure it while you ready the new gasket and head. Worst case you'll have to pull the lower cover to reset the chain/gear.

It's generally *not* recommended to use the chain/crank to back your wrench when unbolting the cam gear. They make a gear wrench(looks like a spanner wrench almost) that is used to hold the gear stationary while untightening. It's only there pretty tight, like 130-150ft-lbs, so you don't want to risk fudging your chain.

HTH, get yourself a factory service manual, it's all laid out there.

-Jamie

[Luvmy240]

Hey thanks,

I removed the head no problem although the head gasket didn't look blown. Now I've never actuallyseen a blown gasket, but was expecting it to be broken is some way.

I called the previous owner see why he thought it was a blown head gasket. He said the car started smoking at a stop sign but would disapper when ever he went over 1000 rpm. while on this same trip the car started to eat coolant, because the temp went up. He managed to keep from overheating by driving with the heater on. The next day he called a mechanic who told him he had a bad head gasket

I guess what I am try to find out is if not a blown gasket what else could it be?

I did notice that when I removed the head bolts for the fourth piston, there was a noticable burnt smell? Count this indicate another problem?

I plan on taking the head to have it cheaked tommorrow

[slipnfall]

Yeah by the look of those pistons you were certainly burning something other than fuel. Make sure they check the head well, it's very likely it warped if it overheated. If it is indeed, don't cheap out, have the block magnafluxed and planed too! You'v gotten this far, it's not much more hassle to remove the block.

[Luvmy240]

Hey someone told me that burning smell meant I blew they Engine? Can this be true? The car was still running when I picked it up.

I guess I just assumed the car had a blown head gasket based on what the mechcanic told the previous owner.

Can someone help me decided wheather I should continue to investigate what was caused the white smoke? Should I even take the head to have it checked for warping? Or should I just get a new engine?

I attached a pic the gasket, if it offers any help

Please help

[slipnfall]

Not necessarily. The white-ish parts of the head gasket are where the coolant seeped past the passages. Looks like the coolant surrounded the ::edit:: front, not rear ::edit:: two cylinders(that last picture was of the gasket upside down, right?), and probably burned off in those cylinder. Hang on to the gasket, bring it to the machine shop even. They can tell a lot from a gasket. As long as the coolant wasn't ever run low(just allowed to burn) and thus overheat, you can still get by w/out any cracking. Block cracks aren't as obvious, but you *may* be able to spot them on the head. The machine shop should give you an estimate for free.

Hope this helps, I don't want to say yes or no because I'm not all that experianced with blown headgaskets.
Modified by slipnfall at 8:49 AM 4/8/2005

[slipnfall]

Oh and on that note... an engine can still run with a blown headgasket, and with a cracked head/block. It'll just either leak like crazy, or leak internall(burn oil and/or coolant).

[NISTECH]

?

[petesleaf]

You might as well get the head rebuilt now that u have it out. Make sure the machine shop replaces all of the valve seals and shaves the head. Take a Flat steel ruler on edge and place it on top of the block. shine a light along the margin between the block and the rule edge and look for any warpage/ light comming through. You can do a peliminary check on the head as well using this age old mechanic's method.

[Luvmy240]

Thanks for all your help guys. Head is at shop. hopefully my baby will be back to boom in no time.

[Luvmy240]

Hey Guys I'm Back,

I got my head back and it looks great. I have a couple of questions.

The cam shaft was moved and from its TDC postion. If i just move it back to to the orginal postion it was when I removed the head will it be good to go? Should I apply any lube the the head ?

Also, anybody want to share some Tips on reinstallation to make this go smoother. This is my first time, so I need all the help I can get.

[Luvmy240]

I think I did a Boo Boo

When I removed the wooden block which was holding my timing chain in place, the tensioner on the passenger side came out a bit too much, actually alot, about an inch. Anyways is there a way to return it to its orginal postion?

[NISTECH]

Couple things I see wrong here, one dont lay your head on its mating surface ,you'll bend the valves ,its ok the way it is on your hatch cover in the picture but if you did that on concreate or on your work bench you could bend the valves. another thing if you tensioner came out as you say it did,did the chane fall down when it happened? if so front covers gonna have to come off for realignemt of your timing marks.

[Luvmy240]

no, the chain did not fall. Luckly I zipped tied the chain to the cam sprocket.

[NISTECH]

as long as the chain did not fall down off the crank pulley and none of the parts from the tensioner fell down you should be able to push it back into its bore without a problem.