3-AC hop-up or motor swap

[new2yotas]

This is kinda right up my alley, I do machining as a hobby/use to be beer $ but now its coffee..i have welded a few holes and re-drilled..ive got a good old southbend lathe and a Bridgeport clone milling machine..also have all the valve resurfacing stuff..been a hunter/gatherer for 30+ years when it comes to tooling..when I was a kid we use to put webers on everything from Datsun 510's to VW bugs...has anybody ran dual S U carbs on these yet? ..should be a fun build no matter what and I hope to be picking all of your brains so I don't find out the hard way about stuff I should avoid doing..

[Petros]

You can do it all yourself than, that will save you a lot of money and hassels. If you get the 4age with the stock flywheel, you might consider cutting it down to fit the 3ac ring gear. (there are some excellent youtube videos on how to remove/replace a ring gear). You will get a larger clutch in it.

If you are up to making your own intake manifold, a duel side draft car set up would be very hot. start searching ebay.

the imported engines, when they were available, often came with the Japanese duel SU carbs, you might find some on craig's list or ebay somewhere. That is the way they came in japan, with duel SU carbs.

I have seen lots of old Datsun 510s with webers (I have owned a few 510's my self), but not real impressed with the webers I have driven in a Tercel4wd. I think the stock carb performs better in extreme cold or hot conditions.

[new2yotas]

Yeah I like this carb most of the time..lol it sure is tempermental.. it cold starts perfect, but gives me a slow warm up even in 60 degree weather.it doesn't start very well after it warms up. I rebuilt it a while ago and have messed with the 3 adjustments according to the manual and it still has warm start issues..i might need to drill out the plug that covers the air screw , or re-jet it..its a California car and im at 4500 ft..it smells a little fat even when the choke is open..but I hear what your saying about drivability, it is smooth all the way through the power band when its right..this motor im getting is from a friend of my son who I forgot about being into mr2's..he has 4 of them and this motor supposedly will bolt in and run, he said it smoked at start-up..probably valve stem seals, but I like to start fresh when im doing stuff like this, so ill tear it all the way down and see how it mics up..being a 1985 mr2, mabe I will get lucky and it will have the early crankshaft

[new2yotas]

just a follow up with you guys, i got my motor and it has 8 hole flywheel, so i thought i would buy a new ring gear for 3ac since im still driving the yota while i rebuild the engine..any body know where to get one, and a good rebuild kit for the 4age motor> i found a couple of rebuild kits on ebay, not sure about the quality though..

[lannvouivre]

just a follow up with you guys, i got my motor and it has 8 hole flywheel, so i thought i would buy a new ring gear for 3ac since im still driving the yota while i rebuild the engine..any body know where to get one, and a good rebuild kit for the 4age motor> i found a couple of rebuild kits on ebay, not sure about the quality though..

You may be able to look at the rebuild kits to figure out what you need, then hop on rockauto and piece a kit together. I really wish I had done that on the Vibe's 1ZZ, would have saved like $100. I am currently overhauling the 3A-C engine off our white Tercel.

Here's what I'm doing:
Ordered all the gaskets I'd need. That's the head gasket, valve cover, intake and exhaust manifold gasket, valve stem seals, oil pump gasket, water pump seal and gasket, thermostat gasket, heater bypass gasket, front and rear main seals, cam seal. The 4AGE may have an oil pickup tube gasket, which you would need if that's the case. I'm going to make a silicone gasket for the oil pan because Toyota does that and it seems super-effective. I also replaced the dipstick tube and distributor o-rings.

Will have to check valves to see if I want to replace them. I will probably lap new seats for them and swap the whole head from the red Tercel to this one, and send the cam from the red one for a regrind because that one's shredded. The head on the white Tercel is going on the red one.

When it is taken apart, I'll measure the pistons and get a shop to measure and check the cylinder bore, then hone them.
If the pistons are stock size and the cylinders need no overboring, I'll use the stock pistons and order stock-size piston rings from MAHLE.
If the engine has been rebuilt before and I need to oversize the pistons and bore, I will get them bored and get oversized pistons and rings.
If the crank looks good and clean, I will check clearances. If they are good and are the stock sized ones, I will get stock size bearings.
If the bearings have the wrong clearance, I will have to measure them and calculate which oversize bearings I'll need. Hopefully they aren't super chewed-up. If they're chewed-up, I'll need to measure the crank journals to see if they have been machined before. If the crank needs machining, I'll have to figure out whether I need to just order one pair of standard bearings and use it to check and calculate what sizes I need.
These should be the only parts you need to measure before ordering.

[Petros]

I assembly my own rebuild kit, usually saves a lot money, and you do not get parts you do not need.

You should replace the 4 exhaust valves in the 3ac rebuild, they get heat damaged over time, they are not worth the risk of reusing the old ones, they do not cost much to replace. I have seen more than a few 3ac with broken off exhaust valves embedded in the top of the piston, trashed the whole engine. My first 3ac rebuild I reused the exhaust valves and within 3 months I lost a piece of exhaust valve (fortunately it did not damage anything, it got stuck in the cat converter in the exhaust system), I had to pull the head off and replace the valve (replaced all four after that). see my head gasket replacement thread in the repair guilds section for a discussion of this issue.

Intake valves can be regound and reused, they last forever.

[new2yotas]

]Well, after removing head on my 4age ,it looks to be stock bore on the cylinders.i put an indicator on top of the block and did a quick check on con rod bearings. .002-.0025 average end play..im going to change all the bearings anyway, just curious how things were wearing at 225,000 miles. there was a very sm ridge at the top of the cyls. ill pop the pistons out tonite and hopefully all the valves.im taking some pics as I go on this , not sure if I should post any? and not quite sure how to anyway..lol

[irowiki]

There's a "post attachment" tab when you reply to a thread or post a new one.

[Petros]

on your flywheel ring gear, rather than buying a new ring gear (even if they were available), you might find a used Tercel 3a flywheel somewhere and just pop the ring gear off of it. you heat it with a torch and it slips right off, some great Youtube videos showing you how. I did it first try, it is easy.

[new2yotas]

yeah I will look for a 3 ac flywheel for the ring gear and a 4age flywheel to turn down to fit the 3ac ring gear..i didn't get the flywheel yet and probably wont..sounds like the guy I got this engine from is still looking for it and has offered to buy me one..i declined and said I would fing one. on another note, piston to cyl fit is spot on..valves/seats look good, valve guides feel great..the stem seals were shot with springs showing through 80% of the front entry way..i still cant get photos to upload..ill have one of my kids show me tomorrow..

[new2yotas]

I found this kit on ebay..any comments? its a very reasonable price, but im not familiar with this brand and they said something about not having the correct main bearings..also, I read some of your guys post about Delta Cams..anybody tried Oregon cams?..and is there a particular grind that makes more H.P. and torque..i am going to do some porting on this head..thanks in advance for all your help with my project..i read where you said to change the exhaust valves on a 3ac...are the 4age exhaust valves the same? I cleaned them up last night and did a light grind on them, actually I had to build a collet/adapter so they would fit my old Van Norman refacing machine..those stems are smaller than a briggs and Stratton..lol I guess that's what happens when you start adding valves in tight spaces..
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[Petros]

if you need all those parts it is looks like a good deal, if it includes the gaskets (which do not show in the picture). I can not tell in the listing where the parts come from, if they are US made, or made in Japan, it is a good kit. if they come from china, not likely worth it.

I only replace parts that need to be replaced, factory parts like oil pump, etc are usually durable and reliable, aftermarket parts are always a question (I have found that up to 50 percent of aftermarket parts could be junk out of the box). so it if needs a new oil pump, it would be a good buy, if your oil pump is good, you do not need a new oil pump.

[new2yotas]

I think it was japan and yes it comes with gaskets, damn near everything you could need to overhaul one of these..im hoping one of the members on here has tried this kit, but if not I will research it , read any reviews and then decide which way to go..after looking at my cams, im not so sure im going to do any regrind on them..the bottom of all the lobs are dull red which tells me, there not making contact on the followers..if my thought process is correct, they would have to grind the bottom to achieve more lift..well I got all the valves ground and lapped the intakes..i lapped 1 exhaust valve and seat and it looks like ill have to cut/grind new exhaust seats..should I change the exhaust valves? there isn't any pitting or signs of overheating..

[Petros]

the 16 valve engine is differnt, exhaust valves may be okay to reuse. I would not regrind the twin cams, the stock grind is already fairly hot for our wagon. In fact if you get adjustable cam sprockets you can "de-tune" the cams by setting one at max advance, and the other at max retard (I do not remember which is which), which has the effect of moving the torque curve down the rpm range, improving low end torque, improving fuel econmy as well. It puts peak power at about 6700 rpm instead of the 4age 7400 rpm. it would be better suited to this car, my plans for my engine swap.

[new2yotas]

I agree with you Petros, the more I look at this , the less I want to do now..at first I was planning on new cams or send them out, porting (I have to do a little)..theres always room for improvement..mill the head .030, bore the cylinders....I think I will do a light hone and get some bearings, rings, and gaskets and call it good..i am still going to build a intake manifold to run dual side drafts and now I will check out those cam gears you mentioned..should be a fun wagon..