I've had my old '83 4wd for 11 years and it still looks and runs pretty good but has 282k miles. But I just got given (traded for a dozen bagels ) an '84 4wd with only 138k miles. A nice rod knock indicates it's about to ventilate it's crankcase so I'd like to do an easy engine swap. Is there any difference in how difficult it is to swap in a FWD or RWD 4AC? What are the differences?
I've done the 3AC to 3AC swap before so I know the basics.
Also any estimate on what $ a rust free 4wd in good condition goes for?
The RWD 4AC is easier to swap in for its distributor location. Not attacking the firewall. As far as I know. lol.
THOUGH. A head will swap from a RWD to a FWD, which is nice and such. lol.
Slightly distracted by the construction crews installing the new door and kitchen-dining-room-thingy.
The head from a 3AC should also go onto a 4AC block. Though flow is in question. I'm not sure just how different they are.
RIP 10-07- 1984 Toyota Tercel SR5 4wd Wagen 6 speed
RIP 04-05- 1986 Toyota Tercel SR5 4wd Wagen 6 speed
The difference between the 4AC and 4ALC is just the different designation based on which way they point in the engine bay. The 4ALC is the transverse mounted version.
BTW, there's absolutely no difference between them if you're doing a Tercel swap. The distributors mount in the same place, regardless. The 3AC, 4AC, and 4ALC heads are identical, except for the later versions with the "wavy" valve cover.
You're probably being offered the 3A-SCV. I've seen a couple at the junkyards, and they're the only 3A engines I've seen with the wavy head.
"And to see you're really only very small
and life flows on within you and without you." George Harrison
neonsport wrote:
You're probably being offered the 3A-SCV. I've seen a couple at the junkyards, and they're the only 3A engines I've seen with the wavy head.
Yeah, I think that must be it. Have you looked in the head of one of those? Crazy - each intake runner has an aluminum vane that sticks down into the passage upstream of the valve. All 4 vanes have a bell-crank attached and all the bell-cranks are connected by a rod that is pulled by a vacuum diaphragm on at the back of the head. It seems that the intake port is partially blocked by the angle of the vane - all determined by engine vacuum. It's super complification if you ask me! And if the vacuum diaphragm goes out what happens to the vanes - flutter in the breeze?
Thanks for the info Neonsport - it'll help with the quest.
neonsport wrote:
You're probably being offered the 3A-SCV. I've seen a couple at the junkyards, and they're the only 3A engines I've seen with the wavy head.
Yeah, I think that must be it. Have you looked in the head of one of those? Crazy - each intake runner has an aluminum vane that sticks down into the passage upstream of the valve. All 4 vanes have a bell-crank attached and all the bell-cranks are connected by a rod that is pulled by a vacuum diaphragm on at the back of the head. It seems that the intake port is partially blocked by the angle of the vane - all determined by engine vacuum. It's super complification if you ask me! And if the vacuum diaphragm goes out what happens to the vanes - flutter in the breeze?
Thanks for the info Neonsport - it'll help with the quest.
Cheers
I've never looked into one of those heads, so I didn't know what the real difference was. I'd like to run across one of the dual-carb 3As in a junkyard, though.
"And to see you're really only very small
and life flows on within you and without you." George Harrison
I got a 4alc from a chevy nova. I kept my 3a manifolds, used the 4alc carb. Somehow, I think I got the vacuum lines connected almost like they need to be. The only mod that I made to the carb iis one of the vacuum ports intereferes slightly with the air cleaner. I just bent it down slightly.
) an '84 4wd with only 138k miles. A nice rod knock indicates it's about to ventilate it's crankcase 
so I'd like to do an easy engine swap. Is there any difference in how difficult it is to swap in a FWD or RWD 4AC? What are the differences?
