High Hydrocarbons / deq and idle issues!!

[dlb]

yes that is low. at that point, i would continue to drive it but find parts to rebuild it or a replacement engine for when the current one finally packs it in.

[duster97]

I was thinking about rebuilding the head anyway. You think it might need a lower end rebuild also? The leak down test appeared to indicate that the rings are still good

[dlb]

it's possible it might just be the head. the leak down test is an ok general indicator but it's not definitive. how many miles on the car? if it's high miles, i would bet the rings are pretty worn.

[duster97]

I bought it with 176k now it has 179k.

[irowiki]

If it wasn't taken care of at any point in the last 30 years, the rings are probably worn.

[Petros]

you might give it a heavy duty Seafoam treatment to try and clean any gunk off the rings, and than follow up with a Restore treatment (after an oil change), and try the compression test again. It will only cost about $20 to do a flush and Restore, plus the cost of new oil and filter. worth a try, will give you more time to plan for an overhaul if nothing else.

If your valves are pitted and not making a good seal a head rebuild would be good idea and may be most of the problem. a leak down test would tell you if the valves are bad, as well as doing the seafoam and than Restore treatment above. both a lot easier than pulling the engine apart.

Good luck.

[duster97]

Thanks for all the suggestions. After heavy duty seafoam treatment and restore the compression hasn't really changed much. After doing a dry then wet compression test I have come to the conclusion the the exhaust valves are probably shot, which is not suprising on an 85 with 180 miles. I plan on putting in a remanufactured head next weekend. I already have a fel pro gasket set for a top end rebuild, new dizzy cap and rotor,new spark plugs and wires, and a new pcv valves and grommet. I noticed my pcv valve was really Hard to draw air through from the manifold side when I would suck on it. I have been studying Petros guide on the head gasket job for a while to prepare myself for this weekend. It's a great guide. I'm not sure about the combustion chamber grooves and drilling two holes in the head gasket, not saying it doesn't make sense, just that I don't believe I'm quite as savvy as him to be making modifications like that. Hopefully all goes well and a rebuilt head will solve thos ordeal

Also tinkering around with the weber mixture. In order for the car to not sputter and run smooth I need to have the mixture screw out about 3 turns after being turned in all the way till it won't go in anymore. According to the weber paperwork it should be no more than 2 indicating I may have to go a half size up in the jets. Any suggestions on this? Not even sure what size the Jets are on my 32 36 progessive

[Petros]

do not be intimidated by altering the head gasket, I have lots of professional experiance with engine design, plus I experimented on it quite extensively. Just follow the instructions and it will improve the performance.

Of course you can always leave it stock, it worked before. The extra holes in the head gasket even out the cooling and make the head gasket more resistant to being compromised if it overheats. Many on this forum have been running it, as have I, with no ill effects after many years.

Good luck with the head swap, it should go well.

BTW, there is a Weber thread where everyone documents what size jets they run. On one of my project Tecel4wd the previous owner installed a weber, it had poor economy and fair performance. I swapped the jets to be similar to what others have found works, and it improved the drivablity and the fuel economy.

[duster97]

I was speaking to the rep at the machine shop I'm using about a remanufactured head, and he was telling me that they used 3 different types of combustion chambers on the 3ac cylinder head and he wouldn't be able to rebuild one until I took mine off to determine what style it was. This was news to me. Is there a way to determine this without ripping the head off mine?

My plan was to get the remanufactured head and swap it over the weekend since it's my only mode of transportation at the momment, but this kinda threw a wrench in thay plan

[Petros]

Sort of: all of the heads are interchangeable, all use the same valves, seats, seals, springs, rocker assembly and gaskets. There might be a difference in the cam shaft grind, but that is an easy swap over if you want keep the old one (though I suspect on the imported engines the JDM cams may have more HP), and there is some differences in the emission controls set up, but that would be of little consequence since you are keeping that from your old car. A different combustion chamber shape may affect the compression ratio a little, but I do not think I have seen different compression ratios ever listed for any USDM 3ac. Even if so, it will not harm a thing to change to different head. The imported "crate" engines have different emissions details, but no one has every had an issue swapping it into their USDM car, as long as they switch over all of their induction/emissions equipment.

I think he is being overly cautious, if you are in California it may be a violation of that states unique rules to change the head. As a practical matter it will not matter to either emission or performance, even if a technical violation. There is no enforcement process to inspect the detail differences on 30+ year old cars to determine it is not in compliance because you have a different part number head than the car came with. so if it were me I would not worry about it, you would not be violating the intent of the rules.

Just find a head and ask him to rebuilt it for you, he will not be doing any violation, if any, it would be you doing the actual swap. He is off the hook for it, though I suppose most of his customers are repair shops who would need to know this kind of information (it might cost them fines or even put them out of business). Not really relevant to you, but you can make that decision for yourself.

[duster97]

Well I pulled a 3ac head from a pick n pull out in sherwood oregon and the machine shop I took it too is telling me that the head has been resurfaced before and is past minimum thickness and won't rebuild it for me. I don't know whether to return that head to the junk yard, hunt another one down and have that one rebuilt, or just tear mine off this weekend and rebuild it. My issue is I'd have to have the job complete by the end of the weekend so I can get to work monay, and I've never rebuilt a head before. Any insight on this would be greatly appreciated. Thanks

[marlinh]

Is the head you bought flat? Does it need resurfacing?

[duster97]

All the shop told me was that it has been machines before and is past minimum thickness and pointless to use since the lack of proper thickness would mess with the came timing and gasket seal. I was going to pick it up later today and I could check it for flatness. I'm thinking I'm just going to get all the parts and tools I need and rebuild the one currently in my tercel this weekend

[marlinh]

That's too bad. I don't know what you paid for it, but I would return it to the wreckers if it is unusable.

[duster97]

Is it possible to have low compression due to a failed head gasket? I don't appear to be having the tell tale signs of a blown gasket however. I would just pull mine off to check it out, but the big issue is that it's my only mode of transportation, other wise I would see if it's just the gasket or the head needing rebuilt after pulling it off but then if the head needed rebuilt I would be without a car while it was at a machine shop, this is why I have been try to get a remanufactured head along with putting a new gasket it and do the swap over the weekend. If It's possible that it just might be the head gasket the screw rebuilding the head you know?