A journey through the engine - Update 2

[keith]

How's the project coming along, just curious. I hope it is successful.

[Petros]

I heard from the OP this morning. he got the replacement engine in it and got it running. its starts and runs good when cold, but once it warms up it wants to die out when rpms drop below about 2500. he kept all of the external vac and fuel system that came on the new engine, but there was some slight difference so he could not connect it up the way his other engine was.

He needs to work through each system and determine that all of the vac lines are connected properly, no vac leaks, and all of the vac operated equipment is working properly. It sounds like a bad vac leak. I could also be a marginal ignition or pick-up coil that works when cold but too weak to keep it running when warm.

Any other ideas of what could cause this kind of behavior.

[dlb]

He needs to work through each system and determine that all of the vac lines are connected properly, no vac leaks, and all of the vac operated equipment is working properly. It sounds like a bad vac leak. I could also be a marginal ignition or pick-up coil that works when cold but too weak to keep it running when warm.

Any other ideas of what could cause this kind of behavior.

i have had worn out spark plug wires manifest this way. i agree that it is likely vacuum issues or a marginal electrical component.

[keith]

If he has the distributor from the old engine, he should just move it to the new one and not mess around with the one in there now. It sounds like a worn out center shaft bearing in the distributor to me.

[skyerunner]

Hey all,
It's ALIVE!!!!

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(This was just this morning after driving over the Sierra Nevada to the Owens Hot Springs )
Been working like a crazy man on this project, and it wouldn't have happened without some key advice from Petros.
So yes, the exhaust valve imbedded metal chunks all over cylinder 3.. so I figured I couldn't kill the car any worse, might as well learn how to replace an engine...

So, went down to Merced (BTW, going to picknpulls and working all day in 90-100 degree temps kindof sucks, and requires regular rehydration with Tecate Michelada's) got the engine I had already started pulling apart (I like picknpulls because I can learn how to tear apart their engines before doing mine ) The car I pulled it out of was a '85 hatchback with only 63,000 miles on it that they drove in to the junkyard with tranny issues -SCORE! So I got that one out, including the distributor, carb etc, took it home in my GF's car, and then had a hellacious time putting it back in - I had a pully system rigged off a old wood beam with my climbing rope and gear - good thing the engines on these little cars are so darn light I can lift it by myself!

Once it finally dropped into place this past weekend, it all started coming together - cleaned it out, put the head gasket on, swapped my 20k old water pump, new timing belt, left the dizzy because it looked good, and finally got it all together and running.

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Then the idle issue - I had numbered all the vacuum hoses but since it's a 4A engine from a different year they just didn't line up. So, finally I figured out that it ran great at 950rpm if I pulled the two hoses out of the little vacuum pumps on the left side just behind the overflow coolant tank... So now they're both plugged into a T junction going to the back valve. I still need to figure out what these two do and where they should be plugged in, but for now it runs pretty nice.

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Unfortunately yesterday the lock tumbler died and wouldn't let me turn the key at all, so I pulled it out - but stupidly pulled apart the switch on the back first, so now I use a leatherman to unlock the steering wheel and just hotwire the switch with the little copper plate and duct tape it in place - not elegant but functional.

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For now, I'm about to drive it to Prescott AZ, so we'll see how it goes! At least I know how to tear it apart again. Thanks for all the help!

*I'll post more photos of the destroyed cylinder, and some of the vaccuum lines soon!

[dlb]

when you say you pulled a 4a from an '85 hatchback, i'm guessing you don't mean a tercel. do you mean a corolla like this one?



i'm not sure how close you are to the pick n pull you got the engine from but perhaps the best thing to do to get the vac lines properly routed is to go back to the car you got the engine from and take a picture of the emission diagram on the underside of the hood. then you will just have to account for any different components but that should be easy. the next best thing is just to do search online for a 4a emission diagram and try to find the one that matches your car. different years and different models of cars had different carbs and emission components so that's why i think getting the diagram specific to your car is best, but the online thing would also work.

[keith]

Glad to hear it is running. The 4A and the 3A are essentially the same engine so you could swap your old intake system and distributor onto the new engine and you would not have to worry about the vacuum line differences, you just go by the chart for your car.

Of course the other alternative is the Redline Weber kit, but if you live in california, that option is off the table.

[skyerunner]

That's something I've definitely been thinking about Keith. While I live in CA, I only work here seasonally so have kept my car registered in Colorado, which I assume means I can do pretty much whatever I want I imagine there's more info on the Weber carb threads, but why/how much better is it? It seems to be running perfectly happily, but only around 25mpg highway where the old one was getting 30/32 highway even with the big roofbox on. Any ideas? I still need to set the timing correctly and a few other things, but I assume a vacuum leak/misroute could also be causing some of the lower MPG?
Best,
JB

[keith]

The big advantage to the weber is its new and its simple. However, If I were you, I would just start by taking the intake manifold and carburetor from the old engine and put it on this engine. The run all the vacuum lines just as they were before.

Check the distributor for vacuum advance and mechanical advance. Mechanical advances are prone to freezing up, especially if they sit around much. A little lube in the right place goes a long way. Vacuum advance is important too.

I did a little write up on how to get the timing right on without a timing light in this thread.

https://tercel4wd.com/forums/viewtopic.php?f=7&t=3700

I did a separate thread on this as well but can't find it right now.

[Petros]

I installed the whole emissions/carb package from my 3ac onto the new 4ac. It runs perfectly and I know the 3ac systems well. if your old system ran well it is one less thing to have to sort out. I may try and adapt the carb to my installation to see if it makes any difference in power or economy. the carb from the 4ac is same size and everything looks the same as on the one that came on the 3ac, only most of the vac tube connectors point in different directions for the transverse engine install. It may have different jetting, but the barrels are the same dia.