*help* overheating issues

[jza80king]

*edit* pics/update below

Hello everyone my name is Edward, as you can see I'm new to this forums but I'm not actually new to cars in general so I hope someone can provide some help. I have been part of 240sx.org and 240sxforums.com for several years and unfortunately I have not received much advice from those forums so I'm hoping zilvia.net can help.

Where do I begin? I have a 92 Ka24DE with lots and lots of miles. It is my dd, It reads 145k but the odometer stopped working like 10 years ago so this fucker is old/tired, but it's my DD and I love it. Anyway, I've been through a lot with this car lately and it's been overheating on me. At first i thought my radiator but it doesn't leak as it was replaced about 3 years ago and seems fine after thoroughly checking it out. I notice my radiator cap was getting stuck when I tried to open it so I replaced the radiator cap thinking this was the issue and no still overheating. Was thinking maybe water pump since when I did run it without the cap I couldn't really see water moving in the radiator so I started to think maybe the pump isn't moving water at all? I dunno? I did replace the thermostat with an OEM one about 2 weeks ago cuz I figured this might be it, even after removing the old thermostat I put both the new and old thermostat in 200 degree water and the old one barely opened while the OEM new one immediately opened. I thought this was the fix so I refilled with coolant added some water wetter, raised the front end up off the ground and THOUGHT I had bled all the air out of the system. I know how notorious for air in the system these motors are known for so i took my time with raising the front opening the cap and letting it run with the heater full blast for at least 30 mins. Well, it overheated again 2 nights ago when it was probably 85 degrees outside. Got home and I used a laser thermometer and got readings from about 145-240 degrees on different parts of the thermostat housing, radiator hoses, side of the heads, near the temp sensor etc so at this point i'm thinking the worse with a BHG, 240 degrees is way too damn hot. I went and rented 2 compression tools from autozone (got 2 to get a more accurate reading using both tools) I ran a compression test about 2 hours ago, followed the steps as per the repair manual I got, warmed it up removed the ignition wires, made sure oil and battery are good. I removed the 1st spark plug and put the compression thread in and tightened and had my brother help press the gas completely down and let it crank for 7-10 seconds....I get 130 compression. I repeat this for the other 3 and I get 130, 130, 130, 125. This is very low compression obviously. My car is also showing whitish smoke when I accelerated it in my drive way. My oil is perfect, my coolant is not black or any different color than normal either. I'm thinking the early BHG stages? Maybe water is leaking slightly and being burned up (hence the smoke) then when too much water is burnt up the car is low on coolant thus it overheats? anyway, I wanted to see what you all think and I am open to any suggestions or advice. I'm uncertain about buying a new head online somewhere reputable or if I should take my heads and have them rebuilt. Also how likely is it that the block needs machining or do you guys think a new rebuilt head with new head gasket should be ok? Do I need new studs also or is that not necessary? I did some brief google searches and found ebay stuff which i'm uncertain of but I found a company called Cylinder Heads International which seem pretty good and offer a 12 month unlimited mileage warranty and require me to send them my head with valves, cams, etc as a core. I'm unsure if anyone might suggest something else? Anyone know of someone reputable in Utah they might lead me towards? Anyway sorry for the long post, I appreciate any advice/suggestions/feedback. still trying to pick myself up from this kick in the nuts I just received.

[Sileighty_85]

its possible for a HG to leak right at a coolant passage. does your coolant have little black flakes in it?But if you decide to replace the HG :If you pull the head, just have it machined flat and while your at it have the machinist replace the Valve seals too.Ask Nissan where they send their Machine work to.Block should be fine, its cast iron so its not really gonna warp, just clean the block mating surface good but be mindful if debris falling down the passages.but a new NISSAN OEM gasket and buy new head studs, dont reuse the old one.

[jza80king]

its possible for a HG to leak right at a coolant passage. does your coolant have little black flakes in it?But if you decide to replace the HG :If you pull the head, just have it machined flat and while your at it have the machinist replace the Valve seals too.Ask Nissan where they send their Machine work to.Block should be fine, its cast iron so its not really gonna warp, just clean the block mating surface good but be mindful if debris falling down the passages.but a new NISSAN OEM gasket and buy new head studs, dont reuse the old one.

No black flakes that i could see. And what you suggest is kind of my thoughts too. Get the head off and have rebuilt with new valves, 3 angle valve job have the surfaced inspected and machined if needed, vacuumed/pressure test the heads etc. New OEM studs with an OEM head gasket or would something like a comedic and ARP be overkill? As for the block I also thought the same with it being cast iron but would there be a way to check it without removing the whole block? Do you think leaving the bottom end as is and just working on the surfaces of the head/block I would be OK?

[Sileighty_85]

No black flakes that i could see. And what you suggest is kind of my thoughts too. Get the head off and have rebuilt with new valves, 3 angle valve job have the surfaced inspected and machined if needed, vacuumed/pressure test the heads etc. New OEM studs with an OEM head gasket or would something like a comedic and ARP be overkill? As for the block I also thought the same with it being cast iron but would there be a way to check it without removing the whole block? Do you think leaving the bottom end as is and just working on the surfaces of the head/block I would be OK?

Nissan OEM parts for a KA are cheap, Id go that route. For an N/A KA i dont see a need for ARP.But with a many miles that are on it and comp #'s Id do a leak down check to see how bad the rings are.the FSM can show you how to check the block, It'd be like a straight edge and feeler gauges.Ive done multiple head gaskets without decking the block no issues

[Primo's Silvia]

This is great info! im planning to send my head to get rebuilt as well due to leaky valve seals. Is it worth upgrading valves and springs? For a N/A ka? I dont really ever bring it up higher then 5k, i occasionally do spirited driving and would like to know if it will b safer? Thanks!

[jza80king]

Nissan OEM parts for a KA are cheap, Id go that route. For an N/A KA i dont see a need for ARP.But with a many miles that are on it and comp #'s Id do a leak down check to see how bad the rings are.the FSM can show you how to check the block, It'd be like a straight edge and feeler gauges.Ive done multiple head gaskets without decking the block no issues

So I just did another compression test and added a cap of oil this time and got slightly higher numbers 165, 155, 152, 160 which would mean rings are toast no? Not really burning any oil so what would happen if say I was to just rebuild the head, replace valves, machine the head surfaces, new gasket and OEM studs.... Would it last another 2 years maybe? I'm gonna need another car probably in 2 years or so, so I'm not sure building the bottom end would be all worth it for me.

[jza80king]

This is great info! im planning to send my head to get rebuilt as well due to leaky valve seals. Is it worth upgrading valves and springs? For a N/A ka? I dont really ever bring it up higher then 5k, i occasionally do spirited driving and would like to know if it will b safer? Thanks!

If you are not revving higher than the stock rev limiter you really wouldn't need to 'reinforce' the head like that. Just my opinion.

[Primo's Silvia]

If you are not revving higher than the stock rev limiter you really wouldn't need to 'reinforce' the head like that. Just my opinion.

Yea thts true thats what i was thinking thanks for the feedback!

And for the oil increasing I due believe that the piston rings are wearing, but not sure dont take my word for it :confused:

[Sileighty_85]

This is great info! im planning to send my head to get rebuilt as well due to leaky valve seals. Is it worth upgrading valves and springs? For a N/A ka? I dont really ever bring it up higher then 5k, i occasionally do spirited driving and would like to know if it will b safer? Thanks!ahhh not really, you can probably have the springs checked to make sure they are still within specs (Check the FSM) if they still check out good id reuse those.So I just did another compression test and added a cap of oil this time and got slightly higher numbers 165, 155, 152, 160 which would mean rings are toast no? Not really burning any oil so what would happen if say I was to just rebuild the head, replace valves, machine the head surfaces, new gasket and OEM studs.... Would it last another 2 years maybe? I'm gonna need another car probably in 2 years or so, so I'm not sure building the bottom end would be all worth it for me.Another thing i forgot to say is, when doing a comp test you need to pull all the plugs at the same time and hold the throttle fully open while cranking. might help the numbers if you did not.but yeah adding oil to the cylinder and the number rising usually point to worn rings. well if you are not burning oil and drives fine you might be ok for a while. Cant really give you a time frame though.

[jza80king]

Another thing i forgot to say is, when doing a comp test you need to pull all the plugs at the same time and hold the throttle fully open while cranking. might help the numbers if you did not.but yeah adding oil to the cylinder and the number rising usually point to worn rings. well if you are not burning oil and drives fine you might be ok for a while. Cant really give you a time frame though.

Ah damn, that's what I wasn't sure so I would do 1 cylinder at a time. I would do the first cylinder then put the plug back in, do the 2nd cylinder then put that pkg back, etc etc..... How much of a difference would you say it would read doing it my way? Sileigthy, is there somewhere online you might recommend for rebuilt KA motors or anything like that?

[Primo's Silvia]

ahhh not really, you can probably have the springs checked to make sure they are still within specs (Check the FSM) if they still check out good id reuse those.




Thanks! Jus gnna save up now, ive heard of a place called K&A head masters in fullerton CA, ive been wanting to call to check thier prices.

[jza80king]

Nissan OEM parts for a KA are cheap, Id go that route.

So I was looking at a couple of options and online via courtesyparts.com i have been able to find the parts needed for the rebuild. For example the full gasket kit for the DOHC motor part number 10101-S13002 for GASKET KIT-ENGINE REPAIR is about $170. I also found the Valves, (intake/exhaust) springs, springs seats, etc....my question however, is there anywhere else you might suggest to search? Exhaust valves are showing $14.70 and intake valves $9.13 each? that's more than the valves for my brother's 7m-GTE Supra motor we rebuilt.

[fliprayzin240sx]

130 is low compression for a KA. Drop a cap full of oil in each cylinder and re-do your compression test. If it jumps up to 160-180 psi, headgasket is the least of your worries.

Your cheaper option really is picking up a used running KA from somebody.

[jza80king]

130 is low compression for a KA. Drop a cap full of oil in each cylinder and re-do your compression test. If it jumps up to 160-180 psi, headgasket is the least of your worries.

Your cheaper option really is picking up a used running KA from somebody.

The oil in the cylinder for compression test was already done, see above....I am gonna do a leak down test to try to better pin point where air might be escaping. Any idea on the parts question though? Finding a running KA motor is difficult, at least it seems to be. I'm not getting many local results anyway.

[Sileighty_85]

So I was looking at a couple of options and online via courtesyparts.com i have been able to find the parts needed for the rebuild. For example the full gasket kit for the DOHC motor part number 10101-S13002 for GASKET KIT-ENGINE REPAIR is about $170. I also found the Valves, (intake/exhaust) springs, springs seats, etc....my question however, is there anywhere else you might suggest to search? Exhaust valves are showing $14.70 and intake valves $9.13 each? that's more than the valves for my brother's 7m-GTE Supra motor we rebuilt.

courtesyparts is a good site, shouldnt have to buy a whole gasket it, if you did they should come with Valve seals.You looking at Valves, or Valve seals? you shouldnt have to replace the Valves unless they are fucked up (leak down check will confirm or a machine shop can check) The Valve seals is what I recommmed to replace if the head is removed. http://www.nissanparts.cc/parts/1993/Nissan/240SX/SE/?siteid=218242&vehicleid=93292&section=ENGINE^^ Another great shop for OEM parts(Pardon the spacing, Gov computers fuck up the posts for some reason)

[jza80king]

Sweet thanks man. Yeah I need to do the leak down test this weekend. I'm hoping the valves aren't too bad that they have to be replaced. Valve seals would be replaced yes and I would be getting an OEM head gasket, and intake and exhaust Mani gaskets. I will check out that site should I need any parts.

[jza80king]

*update*

so i finally got time to post, long story short after completing the leak down test I was certain that I had a BHG. I have since torn the motor apart and I sent the head to a machine shop here in SLC Utah that my brother had his Supra Turbo head rebuild done. I lucked out, no valves needed replacing at all. I got a complete dissesemble, cleaning/hot tank, 3 angle valve job, dye checked, replaced the exhaust guides (intake were fine), all valve stem seals replaced, valve lash set and the surface was machined. The head looks great. I'm wondering if anyone (sileighty85 hope you can chime in) can provide tips on cleaning the head bolt threads on the block itself? I was thinking of using a thread chaser to clean out any gunk but are there any other ideas? I did use some permatex gasket remover and a razor blade to carefully remove any residue on the block itself, not sure if anyone can provide advice on that. I took my time scraping (carefully) old gasket residue, I have also purchased a plastic gasket remove that's just like a razor blade only plastic and worked the block clean. The tops of the pistons looked like shit, carbon everywhere but I have since cleaned the tops and they look brand new as well, I did not use any harsh brushes, I used a stiff plastic brush and some throttle body cleaner and rag. I moved the pistons from TDC slightly to be able to get to pistons 2 and 3 and cylinder walls look great also. Also, on the block there are 2 rings that i'm assuming help when putting on the new gasket to keep in place, my question is are there only 2? should there be more? I got new OEM studs (was going to go w/ARP but decided not to) I also bought the whole gasket kit for valve cover gaskets, head, intake and exhaust mani, etc. Here are some pictures of my project.

Here was the blow

http://i42.photobucket.com/albums/e349/jza80king/IMG_20140908_165014_637.jpg (http://s42.photobucket.com/user/jza80king/media/IMG_20140908_165014_637.jpg.html)

Before cleaning
http://i42.photobucket.com/albums/e349/jza80king/IMG_20140907_211315_486.jpg (http://s42.photobucket.com/user/jza80king/media/IMG_20140907_211315_486.jpg.html)

head after taken to shop
http://i42.photobucket.com/albums/e349/jza80king/IMG_20140926_084931_482.jpg (http://s42.photobucket.com/user/jza80king/media/IMG_20140926_084931_482.jpg.html)

http://i42.photobucket.com/albums/e349/jza80king/IMG_20140926_084940_821.jpg (http://s42.photobucket.com/user/jza80king/media/IMG_20140926_084940_821.jpg.html)

[jza80king]

Anyone with tips for cleaning the old gasket? Gasket remover and plastic razor blade to scrape it off? I have heard maybe a brass brush and sanding but I dunno if sanding is a good idea. Also, are there only 2 rings that hold the head gasket in place?

[jza80king]

Motor is done! Finished installing the water pump, thermostat, radiator. Installed the distributor and i had a grounding issue but once i got that figured out the car fired up beautifully. I have since added coolant and bled the system of any bubbles and set the timing. I'm so excited/relieved and that feeling of rebuilding a motor and hearing it start is just fantastic.