hey I have a crazy low milage 4ac motor and I have located a mr2 4age with t/vis and want to swap the 16v head with t/vis over to the 4a c block without even removing it from my sr5 . dose this sound right to you or am I going to run in to a lot of problems ? Will there be enough clearance between the 4ac pistons and the 4ag valves ? I assume the 4ac pistons are low compression and will give me enough room or maybe a thick head gasket will do the trick ?
I am going for about 20 more hp than stock and better as a daily driver then after I get about 70,000 more miles on the engine Ill swap the lower end for a 7afe bottom end and go another 70,000 like that.
absolutely wont work at all. 4A-C is 8Valves and GE 16valves.
I would have to change the pistons to get the correct notches for the valves ( right ) the bottom end is the same from what I understand .. 4a head to 4a bottom end
Last edited by clintster77; 04-01-2008 at 03:15 PM.
Reason: add
I wouldnt do it personally, yeah the head bolts on but the bottom end is build weaker that the 4A-GE is, the only thing that is the same is the bare block itself, all the internals are built to rev alot more than the 4A-C internals were ever designed to, plus it involves the same amount of work to do that as it would to do a 4A-GE swap to begin with, that would be the best bet for you.
Although a G-head on a 4AC lower end is not the optimal setup, it will work just fine. The 4AC pistons are a lower compression piston, and you will notice a significant difference in power due to this compared to a 4AGE lower end, but they will not hit the valves in the G-head (unless you loose the timing belt at high rpms). The 4AC is not setup for an oil cooler which is OK if you don't plan to be drifting/running it at high rpms for extended periods. The oil pump timing cover is setup slightly different and will have to be cut up to fit correctly with a 4AGE cover and belt, as well as changing the timing gear on the crank. Besides that it is a direct bolt up. The performance of the lower compression pistons is a significant loss, and the motor sounds somewhat weaker than a complete 4AGE. You will also have to use the heavier 4AC flywheel due to the crank having 6 bolts and the 4AGE having 8 bolts, but the same clutch can be used.
If you have any questions feel free to contact me, i have spent much time wrenching on these things, and put together some bastardized combinations.
Last edited by AA01; 04-07-2008 at 08:32 AM.
Reason: mention flywheel
nice to hear from someone who knows what they are talking about . gives me hope that it will work .. I like my 89 celica with tvis so why not upgrade my sr5 for cheap.. thanks .
Although a G-head on a 4AC lower end is not the optimal setup, it will work just fine. The 4AC pistons are a lower compression piston, and you will notice a significant difference in power due to this compared to a 4AGE lower end, but they will not hit the valves in the G-head (unless you loose the timing belt at high rpms). The 4AC is not setup for an oil cooler which is OK if you don't plan to be drifting/running it at high rpms for extended periods. The oil pump timing cover is setup slightly different and will have to be cut up to fit correctly with a 4AGE cover and belt, as well as changing the timing gear on the crank. Besides that it is a direct bolt up. The performance of the lower compression pistons is a significant loss, and the motor sounds somewhat weaker than a complete 4AGE. You will also have to use the heavier 4AC flywheel due to the crank having 6 bolts and the 4AGE having 8 bolts, but the same clutch can be used.
If you have any questions feel free to contact me, i have spent much time wrenching on these things, and put together some bastardized combinations.
ok lets say i have a 4ac engine but i wanted to convert to a 4ag. woulndt 4ag internals (crank, conrods, pistons, crank end/main caps, crank/main bearings.) it should fit snug being basically the same block (right). what else would i need.
it would be cheaper to just swap internals and the head wouldnt than to do a complete engine, tranny, and rear end swap (right)
I really dont see the point to do such. But the block is identicle between the 4AC and 4AGE the only forseeable reason to swap would be if your 4AC had a 7RIB block and your 4age was a 3rib...but even then the differences are only seen in a serious build where block strength is criticle.
Price wise, if you are going that far just get the complete 4AGE lower end. Then you wont have to deal with bearings (unless you plan to rebuild it) The reason i say this is every toyota bearing is fit per journal on the crank and block. Each block has a number stamped on each journal, as does the crank. Using these numbers you get a specific bearing size, which you bring to toyota which will give you bearings that have a near perfect fit. Unless you seriously know what you are doing inside of a motor, i reccomend using a complete lower end and not open the headache of cracking the lower end apart.
So in conclusion i would have to agree with 4agetercel's statement. "Unless you are getting it for free or damned near it, dont bother" The time that needs to be spent to do it correctly is great. And if its done wrong, well...you just lost a lower end.
So in conclusion i would have to agree with 4agetercel's statement. "Unless you are getting it for free or damned near it, dont bother" The time that needs to be spent to do it correctly is great. And if its done wrong, well...you just lost a lower end.
yea their free because I have 2 SR5s( the block I mean )
thats why I asked the ? in the first place a mr2 head is fairly cheap at the Jyard
Last edited by clintster77; 10-13-2008 at 07:07 PM.
yeah but nowadays you can find a whole 4age pretty damn cheap without having to do all this work swaping internals and all that shmeg, plus the 4ac doesnt have the oil cooler setup unless you swap that on too so you can rev it up all you want, like i said it really isnt worth the work unless your 4age's block has scored cylinder walls and you need a bare block to swap all the parts into, which in that case your internals are probubly damaged as well and need replacing
yeah but nowadays you can find a whole 4age pretty damn cheap without having to do all this work swaping internals and all that shmeg, plus the 4ac doesnt have the oil cooler setup unless you swap that on too so you can rev it up all you want, like i said it really isnt worth the work unless your 4age's block has scored cylinder walls and you need a bare block to swap all the parts into, which in that case your internals are probubly damaged as well and need replacing
I wasnt going to swap the internals at all.( from what I understand now,is that a 4age head will fit on the 4ac short block with enough clearance for the 4 valve even though the 4ac is 2 valve , due to its lower compression .)
The reason I want to do this is that when I blow up the engine I will already have the correct wiring and such to put a complete 4ag in ..I would like to just have a good daily driver ( that has tvis and a better flow than a 2 valve ,not to mention the lower compression with the good atomization that the tvis provides will allow me to run a mid to low grade gas..)
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4ac/4age head ?
( the block I mean )
Linear Mode
