Not same head gasket questions...

[Axoure Dragonkin]

Ok, here is the deal, doing a new head gasket, used the search button, and have some more questions... 1. Head gasket blew from lack of matainence (did not overheat, temp needle stayed at normal level all the way home) and had to drive it ~2 miles to get home. Wasn't racing when it blew either. Do I have to get the head checked for warping and cracking? If so, can I check it myself with the right tools (I have access to a pretty standard set of mechanics tools)? What tool would I use to check for warpage?

2. How do I prepare the surfaces for the new gaskets? Do I just scrape or use some brake cleaner, etc...?

3. What types of liquid gasket am I going to need to buy?

4. I bought a Fel-pro head gasket set and head bolts, anything else i need to get beside the different types of liquid gasket?

Thanks a bunch.

[guyaverage]

Head gasket blew from lack of maintenance? Not sure what you mean by that, once they are installed, not much to do to them. What are the symptoms that make you believe it is bad? Are you getting steam out the exhaust, antifreeze in the oil, oil in the antifreeze, etc?

Assuming it really is bad, yes do check both the head and block for warpage. Use feeler gauges (cheap, available anywhere you buy tools) and a flat edge. I use a thick steel ruler.

To clean the head and block surface, I've used brake cleaner, carb cleaner, acetone, scotchbrite pads, and hard plastic scrapers if necessary. No failures so far. Make sure you clean out whatever crud falls into the cylinders. Stuff a clean rag into each one to minimize the mess. I stuff big chunks of newspaper or small pieces of rag into the coolant and oil passages so nothing gets in them too.

As for liquid gasket, you know NOT to use sealer on a head gasket, right? Head gaskets go on dry, as is. No sealant. As for liquid sealant for the other gaskets (timing cover, etc) I use the Permatex red liquid sealer. It comes in a small white can, I get mine at Autozone. I use it on everything automotive, and I have never had anything leak that I have used it on. Nothing. Good stuff, use it once you will never use RTV again. A very thin layer on each surface is plenty. Dont use so much that it oozes out when you tighten bolts, thats too much.

I have had no problems will Felpro head gaskets before, just make sure you torque the bolts properly (in proper order and proper torque steps).

Since the head will be off, might be a good time to do the timing chain while you are in there. Definitely more work and more time involved, but at least you wont have to worry about that again for a long time, if ever.

[Axoure Dragonkin]

I guess what I mean is, that the HG didn't blow because of overheating.

Yeah, i had coolant in the oil and steam was shooting out the breather on the valve cover, and other places.

[Neil]

the headgasket doesnt blow necessarily because of overheating, it's overheating that is a symptom of a blown head gasket.

The head gasket itself doesn't need any gasket sealer. Nor do the intake/exhaust gaskets. the front timing covers and oil pan get gasket sealer, maybe a thin bead around the cam cover gasket too.

You shouldnt need to use new head bolts. If you use the original ones you don't need to re-torque them because theyre already stretched. With your new head bolts you need to torque them down, loosen them and then re-torque. Which i guess isnt that big a bother but i re-used mine without any problems on both my 240's.

The first thing I ever tried to do to a KA24DE was remove the head with the block in the car. I had to use my dremel to shave some casting off the intake manifold so I could pull it up and off, also had to double-nut a couple studs to get them out cuz the manifold wouldnt lift off of them, etc. You'll encounter these things as you do your work.

also its difficult to see but on the back of the head is a plate with some vaccuum capilaries attached to it. That plate is held on with 3 bolts. Thats the only thing that gave me any snags since i couldnt see it and didnt know it was there the first time around.

Also check for a hose connecting to the EGR valve. the past two 240's ive owned have had a small rubber elbow attached to the EGR that was rotted out, venting exhaust gasses to atmosphere.

Do you have an S13 or KA24DE manual? Torque specs and removal/tightning orders for the head and cams are very important things to know.

edit: The best tool for removing leftover gasket from the heads surface is with a fresh razor blade. It IS aluminum however, and the blade CAN finely gouge the surface so be careful. I do not reccomend a wire brush. Brakleen may help to soften some of the harder bits.

[robertwb70]

have the head surfaced -IME aluminum heads ALWAYS need surfacing if they've been torqued and run and most definitely after a head gasket failure-trust me I've tried to get away with not surfacing a few times and they never last

is it going to be worth the $50 you saved by not getting the head done when you have to tear it all down 2 weeks later and do it again(and THEN pay for the surface job anyway)?--you see what I'm saying

[Newcastle82]

Whoa whoa whoa!! Back up the truck!!

I'm sure Neil means no harm by suggesting that new head bolts are not a necessity, but please be warned that it is very much a necessary part of a head job. If you've got 175k miles on a stock 240sx head and you remove it for ANY reason, you absolutely need new head bolts. Those bolts that have been heated and cooled and expanded and contracted over the years have definitely stretched themselves to fit that exact torque setting and position. I've never done a head job or a gasket job without using new bolts, not once, and subsequently I've never had to do one a second time. Just some friendly advice. Think about it. It's 55 bucks for the guarantee of knowing that you did the job right.

[Neil]

^^ that IS a good point. maybe i've just had abnormally good luck with re-using the originals on my mgb, volvo 740, and on my nissans.

On both the S13's that ive owned, the head gasket didnt fail because the head warped from overheating... it simply was old and deteriorated enough to let combustion gasses into the water jackets. After replacing the head gasket with a FelPro at 170,000 miles, I drove my last S13 for 9 months without previously having the head resurfaced. I did check the head for tolerance with an aluminum ruler and feeler gauge and any gaps were well within tolerance as per my service manual. Ive put about 4500 miles on my new '92 Coupe after replacing the head gasket and not resurfacing and reusing the original head bolts and everything's still fine. Except for my rod bearing problem ( http://www.recordedmemory.com/240/badbearing.jpg ) which should be remedied this thursday.
Modified by Neil at 7:31 PM 2/24/2005

[Axoure Dragonkin]

i've learned the hard way not to re-use bolts that need to be replaced on a previous car

i guess i'm going to buy a polishing tool for my dremel since i don't own a compressor yet. just take me longer to get shiny mating surfaces