Newb looking for a bit of info on 3A scv

[Petros]

when you have the pan off I would check the rod bearings for wear. They are cheap to replace if you have to, make sure the rod cap goes on the exact same way/same direction as it came off and you torque it properly. The mains are likely fine, I would leave them (unless you find the rod bearins totally wasted).

Also, along with the timing belt, replace the rear main seal, and front cam and crank seals, replace at least the clutch friction disk. Everything else is easy to get to when the engine is in the car.

I would keep the factory water pump since it is likely better quality than any aftermarket supplier, and it is easy to change when it is in the car anyway.

[xirdneh]

(I'm assuming these are interference motors considering a total loss of compression).

i'm pretty sure the 3ac is non-interference

[IHblarp]

(I'm assuming these are interference motors considering a total loss of compression).

i'm pretty sure the 3ac is non-interference

Interesting... After the belt broke it seemed like the starter was able to turn the engine over with very little resistance and you could not hear any compression noise, but now that you mention it that might just mean that it broke in such a position that at least one valve is open in each cylinder (i'm not sure if that ever really happens but..)

petros, what exactly should i look for on the rod bearings, I assume they're of the brass bushing variety, so should I just look for scarring and galling or is there a way to measure any slop in them to determine if they're bad? The previous owner had the trans rebuilt at some point and I assume it got a clutch at the same time but I'll definitely be checking for any excessive wear and how much life it has.

right now it appears that the exhaust is going to match up with the pipe in the car but do you guys think I should take off the intake and exhaust manifold just to make sure any rodents didn't get up in there and build a nest? I imagine that would be bad news if I tried to start it with a bunch of crap up in the exhaust manifold...

[4wdchico]

You could just make your life easier in the long run by pulling the 3a head from the old motor, getting it looked over & worked if needed and then slap it on the scv mill. You would also be able to look at the cylinder bores on the scv motor and decide if rings and a hone are in order.

[Highlander]

The 3A motor is DEFINITELY a NON-interference motor, otherwise I would have panged the valves a couple of times when I broke the timing belt (the last time in the middle of passing a van on a tow lane road uphill at 9pm going home ). It's great to have that reassurance sometimes.
"The vacuum can at the back of the head may make it difficult to put the engine it the car because there is very little room between the back of the head and the firewall." It's a little tighter than without, but it can be done- the trick is to remove the power steering pump from the engine first, because the two of them DO make it nearly impossible.

[sdoan]

The first time I did it with a JDM engine I only replaced the timing belt, clutch and some hoses. The next time (a different car) I took apart a Corolla 4A engine to re-ring and rebearing it but you should probably do what Petros suggests and simply check and replace the rod bearings if needed (much simpler).

When I did the re-ring job I also replaced the timing belt, oil pump (NAPA carried the OEM Aisin), water pump, clutch, had the cylinder head rebuilt and replaced the 2 o-rings on the tube that connects the water pump to the head. You should probably check the thermostat if you are doing the water pump and o-rings. It's also a good time to replace hoses - especially the heater hoses at the back of the head - and at least check the lower radiator hose. If you decide to do the head work, get a good quality gasket set (beware of cheap gasket sets - Felpro worked for me). And it's a great idea to replace the front and rear main seals - they should be in the gasket set.

[Petros]

The bearing backing is copper or bronze, the bearing material is a soft whitish "Babbitt" metal. Look for deep scoring or wear in the whitish metal surface. Or you can buy "Plastigauge" to test it (a green plastic thread you put in the bearing, and torque it up, and than remove it to measure how much it squashes out to determine wear-it works okay and easy to use). You should be able to tell by looking at it after you clean it off.

A few small scratches will not affect it much (I would reuse that), but severe wear or gouging it should be replaced, you should be able to tell if it is badly worn. Running with dirty oil puts scratches in it, running it dry of oil will wear it off evenly. If it is worn enough so you see any of the copper base metal, it should be replaced.

If you are not sure, post a picture of the bearing surface here and we can tell you what we think. Or just replace them if in doubt, they only cost about $25 for the set of rod bearings. OTOH I would not hesitate to reuse good bearings.

Remember to put lots of oil on the bearing surfaces before you put it back together. Use "assembly lube" if you can get it (most auto parts stores sell it).

Good luck.

[IHblarp]

You could just make your life easier in the long run by pulling the 3a head from the old motor, getting it looked over & worked if needed and then slap it on the scv mill. You would also be able to look at the cylinder bores on the scv motor and decide if rings and a hone are in order.

The more I look at the differences between these motors the more I realize that I'm probably going to have to do just that^^^^. The SCV obviously came out of a fwd car with the motor transversely mounted. There is a motor mount sticking out of the timing belt cover and the exhaust is a definite no fit. The carb itself looks to be the same unit but with much more complex emission equip. Less vaccume lines going around the carb but also more elec. equip. attached. in all I think these two motors are too different to use anything other than the SCV as a short block and reusing the head, intake/exhaust from the 3A-C.

I'm working on getting a camera so that you guys can at least see what i'm talking about. If I had more motivation (and time) I could possibly make the SCV motor work in the terc but it would require a bunch of grafting/splicing/bastardizing that would probably result in an inferior(note: Ghetto) setup.

[4wdchico]

You could just make your life easier in the long run by pulling the 3a head from the old motor, getting it looked over & worked if needed and then slap it on the scv mill. You would also be able to look at the cylinder bores on the scv motor and decide if rings and a hone are in order.

The more I look at the differences between these motors the more I realize that I'm probably going to have to do just that^^^^. The SCV obviously came out of a fwd car with the motor transversely mounted. There is a motor mount sticking out of the timing belt cover and the exhaust is a definite no fit. The carb itself looks to be the same unit but with much more complex emission equip. Less vaccume lines going around the carb but also more elec. equip. attached. in all I think these two motors are too different to use anything other than the SCV as a short block and reusing the head, intake/exhaust from the 3A-C.

I'm working on getting a camera so that you guys can at least see what i'm talking about. If I had more motivation (and time) I could possibly make the SCV motor work in the terc but it would require a bunch of grafting/splicing/bastardizing that would probably result in an inferior(note: Ghetto) setup.

Just be sure to check the top of the pistons on the ingoing short block vs. those on the outgoing block for possible valve clearance issues via different shaped/height piston tops.

[Petros]

I would not pull the head unless there was no way to make it work in the Tercel4wd. It is extra work and cost, and your old head might have issues with the valves. The factory head gasket would be very durable and worth keeping. It is much easier to swap the intake/exhuast manifold, pan, etc.

[IHblarp]

well the motor's about ready to come out. got everything disconnected and the front cross member is removed. basically just need to unbolt the motor mounts, engine to bell housing bolts, and chase one set of wires that disappears between the tranny tunnel and trans (prob revers switch ect). My roommate is gonna bring an engine stand down from his parents house this weekend which will make swapping parts much easier.

I am definitely going to try to keep the head that's on the SCV but I'm a bit worried that it will not match the intake/exhaust manifolds from the 3A-C? We'll just have to wait and see once I get them both out and start swapping parts. It would be kinda nice to pull the head on SCV to see what kind of condition the cylinders are in but if I don't have to I most likely won't. I just want to make sure that what ever combination between the two engines that ends up going back in will be reliable and in good condition, but simplicity of the swap will also play a role.

Hope that all makes sense, its been a long day followed by some brews so....

[IHblarp]

Quick update, just got the engine pulled and mostly stripped all the parts that are going to be swapped over to the SCV. I decided it would be easier to swap the intake/carb and exhaust over rather than messing with the scv stuff so i'm basically going to end up with the same setup that came out of the car other than the fins in the head and the vac port on the rear of the head. I've taken some pics but I'm not sure of how to post them, so any help there would be appreciated.

[ARCHINSTL]

I use www.photobucket.com. It's free and easy to use, even for a 'puterphobe like moi.
After the photo is loaded to the site, you just copy the IMG line and paste it into your post and the photo magically appears!
I've never tried others, so do not know their quality, ease of use, etc.
Tom M.

[IHblarp]

ok, so i finally got some pics uploaded. for those of you that were wondering about the vac lines that actuate the SCV I will try to help as much as possible. the good news is that the vac line goes to a port in the intake manifold. the bad news is that it comes back out and goes to a t fitting which both lines have been cut. so I'm not sure where they go but i'm asssuming they went to the chassis somewhere.
first

the vac line comes out of the port and enters a steel line that runs along the intake to the front of the motor. This line also has a fitting that goes to the TSVS(i think thats what its called) on the thermostat housing.

this is the fitting the vac line goes into. this fitting is on the other motor but only has one vac line that goes directly to the tsvs.

this is the line that comes out of the fitting and has a 't' connection. From here i dont know where the lines attached. One goes back towrds the carb but is cut/disconnected and so i'm guessing it went to the chassis. (i didn't see any vac ports that were missing a line on the carb). the other heads towards the timing cover and is bunbled with a bunch of other vac lines that have all been cut.

I hope this helps, but it probably wont considering the two unknown connections

[Highlander]

Thanks for the pictures, It clears things up a bit. The fitting on the intake manifold is called a gas filter. I believe that it simply causes any gas fumes to condense and return to the intake manifold rather than getting sucked into the vacuum system. It will apply either a modified or straight manifold vacuum to the vacuum line. That leads me to believe that the SCV valve is a spring loaded return and the manifold vacuum turns the SCV at low revs (high manifold vacuum). My wife's has the vac line plugged, I'll pull try pulling vac from the fuel filter and see how it does. Hers has the standard intake manifold and exhaust for the terc on it, so they should just swap over.
After a little research (I finally got some time to do this), it seems that the swirl control valve is supposed to enlarge the intake passage at high volume demands from the engine (high rpms), if the valve is spring loaded to return on low vacuum, then the SCV is open farther in that state. The advantage is supposed to be better throttle response due to an increase in the intake velocity, which enables better cylinder filling at low RPMs.
AS I said, I'll hook up the wife's and see what we get.