High Hydrocarbons / deq and idle issues!!
- Petros
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- My tercel:: '84 Tercel4wd w/extensive mods
- Location: Arlington WA USA
Re: High Hydrocarbons / deq and idle issues!!
almost always if your head gasket is compromised you will have other symptoms besides low compression, in fact you can have a bad head gasket and the compression shows up okay (I have seen it), but the other symptoms are present. A bad head gasket will consum coolant, and typically will start up with white "smoke" (steam) in the exhaust. What is your compression numbers? do they very a lot? If so likely bad exhaust valves.
You can get a replacement head and do the swap, but it is possible to pull the head, replace the exhaust valves, lap the seats in the head, and install all new valve stem seals, hand resurface it and than install the head in one saturday. You just need to make sure you have all the parts and tools you need before you start.
having a machine shop completely rebuild another head for you would be ideal, but not really necessary. replacing exhaust valves and seals will solve 90 percent of the problem. OTOH Used heads you should be able to get from a self service wrecking yard, or another forum member, for about $50.
You can get a replacement head and do the swap, but it is possible to pull the head, replace the exhaust valves, lap the seats in the head, and install all new valve stem seals, hand resurface it and than install the head in one saturday. You just need to make sure you have all the parts and tools you need before you start.
having a machine shop completely rebuild another head for you would be ideal, but not really necessary. replacing exhaust valves and seals will solve 90 percent of the problem. OTOH Used heads you should be able to get from a self service wrecking yard, or another forum member, for about $50.
'87 Tercel 4wd SR5 (current engine swap project)
'84 Tercel 4wd (daily driver, with on going mods)
'92 Mazda MPV 4wd (wife's daily driver)
'85 Tercel 4wd DLX auto(daughter's daily driver)
'01 Honda Civic (other daughter's daily driver)
'84 Tercel 4wd (daily driver, with on going mods)
'92 Mazda MPV 4wd (wife's daily driver)
'85 Tercel 4wd DLX auto(daughter's daily driver)
'01 Honda Civic (other daughter's daily driver)
Re: High Hydrocarbons / deq and idle issues!!
Thank you. The good news is I was able to get a head rebuilt by the machine shop. They had one at one of their suppliers. It should be ready by monday at the latest. Hopefully friday so I can do the swap this weekend. I will post pics of the install and any problems that may arise.
Edit
I was told the cam on the head I pulled from the yard was in good condition,so I am planning on reusing the cam and rockers. Does anyone have any objections to this?
Edit
I was told the cam on the head I pulled from the yard was in good condition,so I am planning on reusing the cam and rockers. Does anyone have any objections to this?
- irowiki
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Re: High Hydrocarbons / deq and idle issues!!
You should see if it is flat, and if so, just clean it with a bit of sandpaper and some something flat, like a piece of granite countertop.
Former Tercel Enthusiast (not a practical family car anymore but they still have a place in my heart)
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87 Corolla FX16, 105k
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95 Camry Wagon, 197k
05 Avalon, 199k
Site administrator, if something is broken, PM me!
87 Corolla FX16, 105k
94 Jamboree RV (Ford E-350), 90k
95 Camry Wagon, 197k
05 Avalon, 199k
- Petros
- Highest Ranking Member
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- Joined: Sun Jan 28, 2007 6:31 pm
- My tercel:: '84 Tercel4wd w/extensive mods
- Location: Arlington WA USA
Re: High Hydrocarbons / deq and idle issues!!
if they are in good condition, and wear is within acceptable limits, there is no problem using the used parts. when I was in high school auto shop is was routine to have the cams from the big American made v-8 completely worn away and you had to either regrind or replace the cam shaft as part of a normal rebuild. But on most of the import cars, particularly the Japanese ones, it is very rare to have them worn out of spec, even with lots and lots of miles on them. No problem reusing them at all. the only time I have replaced a cam in a Tercel4wd (or any other Japanese engine for that matter) was because I wanted a new profile that would increase hp.
'87 Tercel 4wd SR5 (current engine swap project)
'84 Tercel 4wd (daily driver, with on going mods)
'92 Mazda MPV 4wd (wife's daily driver)
'85 Tercel 4wd DLX auto(daughter's daily driver)
'01 Honda Civic (other daughter's daily driver)
'84 Tercel 4wd (daily driver, with on going mods)
'92 Mazda MPV 4wd (wife's daily driver)
'85 Tercel 4wd DLX auto(daughter's daily driver)
'01 Honda Civic (other daughter's daily driver)
Re: High Hydrocarbons / deq and idle issues!!
Pulled the head of and this is what it looks like. Gasket was in fine shape. What do you guys think?
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Re: High Hydrocarbons / deq and idle issues!!
Number 4 looks real bad is that color the actual piston. ? catastrophic failure is very rarely something big it's usually just a hairline crack in the gasket.
i will find a tercel in a music video
That's my new goal
That's my new goal

Re: High Hydrocarbons / deq and idle issues!!
Yes it did look a little brown. However I cleaned it up and it looks hood now
I number 4 was dead when I bought due to way over tightened valves.You do not have the required permissions to view the files attached to this post.
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Re: High Hydrocarbons / deq and idle issues!!
Oh yeah much better
i will find a tercel in a music video
That's my new goal
That's my new goal

Re: High Hydrocarbons / deq and idle issues!!
Here's the remanufactured head. Just putting her back together now
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- Petros
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- Posts: 11941
- Joined: Sun Jan 28, 2007 6:31 pm
- My tercel:: '84 Tercel4wd w/extensive mods
- Location: Arlington WA USA
Re: High Hydrocarbons / deq and idle issues!!
from what I can see in the picture the gasket seal looks okay. though, as stated, sometimes it is hard to tell, but if bad enough usually you can see a brake in the seal against the block. It would always occur between cyl. 1 and 2.
'87 Tercel 4wd SR5 (current engine swap project)
'84 Tercel 4wd (daily driver, with on going mods)
'92 Mazda MPV 4wd (wife's daily driver)
'85 Tercel 4wd DLX auto(daughter's daily driver)
'01 Honda Civic (other daughter's daily driver)
'84 Tercel 4wd (daily driver, with on going mods)
'92 Mazda MPV 4wd (wife's daily driver)
'85 Tercel 4wd DLX auto(daughter's daily driver)
'01 Honda Civic (other daughter's daily driver)
Re: High Hydrocarbons / deq and idle issues!!
Well I got it all back together and it seems to be running better than before. Sounds like all cylinders are htting from the exhaust. Gotta readjust thr valves again after it cools off. Taking a break for now, started this like 7 hours ago. The linkage kit is a nightmare for the weber. I snipped thr cable before I saw the great ideas of using the old linkage kit in another thread. It was a pain doing it the first time fitting the cable through the bolt hole, even worse the second time and the kotter pin brrak, so I had to improvise.
After I adjust the valves again, set the timing and tune the weber I'll take it thru emissions again. Ive been lookin into rejetting thr weber also. Already from driving it it feels like a different car already. Haven't ran a compression test, but I will.
After I adjust the valves again, set the timing and tune the weber I'll take it thru emissions again. Ive been lookin into rejetting thr weber also. Already from driving it it feels like a different car already. Haven't ran a compression test, but I will.
- Petros
- Highest Ranking Member
- Posts: 11941
- Joined: Sun Jan 28, 2007 6:31 pm
- My tercel:: '84 Tercel4wd w/extensive mods
- Location: Arlington WA USA
Re: High Hydrocarbons / deq and idle issues!!
make sure you retorque the head after a few hundred miles, just to make sure it stays good.
'87 Tercel 4wd SR5 (current engine swap project)
'84 Tercel 4wd (daily driver, with on going mods)
'92 Mazda MPV 4wd (wife's daily driver)
'85 Tercel 4wd DLX auto(daughter's daily driver)
'01 Honda Civic (other daughter's daily driver)
'84 Tercel 4wd (daily driver, with on going mods)
'92 Mazda MPV 4wd (wife's daily driver)
'85 Tercel 4wd DLX auto(daughter's daily driver)
'01 Honda Civic (other daughter's daily driver)
Re: High Hydrocarbons / deq and idle issues!!
So the compression is as follows
150 on all cylinders except number 3 which is 130, but I still have readjusted the valves yet since the initial head swap. So far much better numbers than before. My number 4 was below 100 psi before the swap
150 on all cylinders except number 3 which is 130, but I still have readjusted the valves yet since the initial head swap. So far much better numbers than before. My number 4 was below 100 psi before the swap
- Petros
- Highest Ranking Member
- Posts: 11941
- Joined: Sun Jan 28, 2007 6:31 pm
- My tercel:: '84 Tercel4wd w/extensive mods
- Location: Arlington WA USA
Re: High Hydrocarbons / deq and idle issues!!
if the valves are so far out of adjustment it does not allow some or one not to seat better fix is ASAP before you drive it. If the valve does not close all the way it has no way to cool, and it will overheat. the valves cool when it closes onto the seat through the water jacket in the head.
Do not drive it until you know the valves are not adjust too tight.
It is also possible that the new valves have not fully seated, the compression numbers may improve with more driving time, presuming they are adjusted properly.
Do not drive it until you know the valves are not adjust too tight.
It is also possible that the new valves have not fully seated, the compression numbers may improve with more driving time, presuming they are adjusted properly.
'87 Tercel 4wd SR5 (current engine swap project)
'84 Tercel 4wd (daily driver, with on going mods)
'92 Mazda MPV 4wd (wife's daily driver)
'85 Tercel 4wd DLX auto(daughter's daily driver)
'01 Honda Civic (other daughter's daily driver)
'84 Tercel 4wd (daily driver, with on going mods)
'92 Mazda MPV 4wd (wife's daily driver)
'85 Tercel 4wd DLX auto(daughter's daily driver)
'01 Honda Civic (other daughter's daily driver)
Re: High Hydrocarbons / deq and idle issues!!
I did the initial valve adjustment with the head swap. After I started it up and made sure the cooling system was operational and let it get to operating temp I adjusted the valves again and re torqued the head. Then after a tank of gas or two I will then adjust valves and re torque again. I have a variable feeler gage tool I've been using. When the engine is cool I have been using .007 for intake and .011 for exhaust following the fsm sequence for valve adjustment. They are really touchy, but I feel I did alright