Alright, part two with the 3a/4a hybrid.
I had taken the beast down to the beach for a weekend with the untouched 4a and actually got to ride across a spit of the atlantic on a ferry.
She did amazingly well and handled all the extra weight without complaint. We even kept the subs in the back with 4 people, our bags, and a bunch of stuff we brought back with us.
Well, a few months later, a friend of mine and I tried to head back down to the beach to hang out with his dad and generally have a good time. I stopped at a bank about 50 miles from home and when I started it back up, it just, wasnt right. The temp quickly shot up so I killed the motor, pulled over, left the key switch on and unplugged the fan sensor. Fan kicked on, and we set about pulling the hood off, In the middle of Durham. When it was cool, I added some water I had brought along just in case. (weird how those things happen huh?)
We then limped the mile or so to the nearest autoparts store. By limp, I mean, floor it and go as fast as possible, then cut the motor and coast. That actually worked surprisingly well. We got there, ordered a new gasket to be ready at the store near my house and dumped a bottle of "head gasket fix" in the rad. Not the cheap stuff, the $40 a bottle stuff. I let it run a little without the cap on to check for bubbles and circulate the gunk around.
I tell you whut...that dadgone stuff WORKED!
We ran all the way home at 60mph without a single problem. Gauge stayed in the middle the whole way.
We still wanted to go to the beach so we shoved it in the garage and started pulling it apart while my aunt went to grab the head gasket.
We got us a nice flat piece of marble tile? and set to work. Block cleaned up just fine.
However, the head did not.
Yup, no idea what happened there, but that killed the ability to go to the beach in the wagon. Got stuck in a PT cruiser that actually wasnt THAT bad. It was actually quite comfortable and was REALLY roomy inside.
On the way back, I made contact with a guy who claimed to have a few heads I could have for cheap. One 4a and 2 3a heads. Or so we all thought.
The supposed 4a head was shaved 10 thousandths and was the freshest, so I decided to use that one. Here it is all prepped and ready to go on the car.
There it is. However, look at the valve cover surface. Its straight, not cuved like the 4a's. Damn. Oh well, it runs, lets time it and enjoy it, we'll grab another 4a head later. I wrongly assumed the 3as valves were smaller, the ports were smaller, and just general stupid assumptions. (I later measured between my old 3a's head and my justcastaside 4a head and the valves are the same, along with the ports.) But I felt confident in thinking that, because while it ran, It wouldnt run over 4k rpm. It would break up and cause all kinds of hell. It also did not like idling below 10* of timing, and really didnt like 10* either.
Then, I did a ton of math to find out what was up.
4a. 1587 cc
Bore 81mm
stroke 77mm
ccs per cylinder 377.19
ccs per cylinder + combustion chamber 396.78????
1508 without heads. (accounts for dished pistons)
-4.93 cc piston dish.
3a 1452 cc
bore 77.5mm
stroke 77mm
ccs per cylinder 363.23
3a head on 4a block is 10.1:1 compression.
I ran it through some calculator I found online, did even more math that I cant remember right now (the above it copied straight from my notes), and It all checked out. With the shaved 3a had, I was running 10.1:1 compression. That explained why It didnt want to idle without a ton of timing and broke up in the higher rpms!
So I ran the tank down as low as possible, filled up with mid grade and then tuned the timing by ear. to where it ran the best. However, that involved pulling the distributor out and advancing that a tooth, then retarding the distributor as far back as it would go on the slide. It ran GREAT! Power throughout the entire rev range! Pulled to 6k without a hiccup! I put my timing light on it to see where it was, and it was OFF THE SCALE. So, I have no idea what my timing is, but the motor is running GREAT, never fails to start, and has amazing power.
When I say amazing, I truly mean it. you can FEEL where the power band is. If I let the clutch out at Idle to get rolling, and then STOMP it, it just goes. No bogging, no hesitation, it GOES. When the RPMs hit 3500 the front wheels SPIN for a second.
To this date, the car is still immensely fun and quite quick. But Im constantly looking for ways to upgrade it. After the GTS axle is re-geared, and the new tires and wheels go one, Ill be looking to make something most epic happen.
Here's a picture, and the only words you need to know are "TRD JAPAN"
