AE82 - Rebuild 16V or convert to 20V?

[TheChronic]

G'day gents,

Long time lurker, first time poster. My old AE82 Twin Cam is coming down with a case of the knocks every cold start, which has been worsening lately. I haven't pulled off the sump but it sounds suspiciously like a bottom end or main bearing is starting to let go, don't know which though. So it's starting to near that sort of time where the engine needs to be pulled and rebuilt or replaced.

I've been debating whether to go for a proper "warm" rebuild of a 16V with some 264/256 cams, better valvetrain bits and pieces and maybe some some forged pistons with slightly heightened compression, or to simply pick up a blacktop or silvertop out of an imported Japanese front cut with all the necessary bits and pieces like shifter linkages, loom, driveshafts and engine mounts. I've talked to a couple of people selling 20 valves on a regular basis and it seems like a fair few seem to get here rather sludgy and in need of attention anyway. I'd rather keep the cost of this entire thing below $2500... and considering it is a daily driver at the moment, I'll need to do all the work within a fairly quick timeline (a few weeks, maybe a month if possible). I also moved states recently, and don't have anyone that will be able to give me any help with any of the work unfortunately.

So the question is, with all the factors listed above, what's going to be easier? Either way, I'll need to get the engine out of the car which is going to be a pain in the ass with only one pair of hands. How much would I need to spend on a 16 valve to make it perform near the level of power I'd get from a blacktop? What parts of the wiring loom do I need to splice together given a 20 valve conversion route taken? What's ultimately going to take longer (assuming all the replacement bits and pieces are ordered by the time I get started)? What's going to be more cost effective and more liveable?

Lastly, I did a bit of searching for threads covering the same thing and couldn't find a heck of a lot around. Sorry if this is the sort of thing that comes up quite often.

Cheers,

-J

[oldeskewltoy]

16V 4AGE can make similar to blacktop power with a compression bump, mild to moderate cams, and a bit of careful headwork.

For evidence - http://www.toymods.org.au/forums/thr...=1#post1090620


Can you acquire a spare engine to work from? This may provide you a bit of extra time allowing you to baby the current lump, and not take it apart, but replace it once the spare has been overhauled.

Back to the thought of a swap... how electrically talented are you? Besides worrying about the possible need to rebuild a 20V, you will also need to merge the 2 wiring harnesses. Doing wiring is my downfall.... so I'd choose adding something to your 16V and keep stock management

[Ashh]

I'd go with the rebuild because:
1. You know the work you put in is actually going to solve the knock problem, and not just postpone it (though the blacktop could knock right from the get go)
2. It's more personal if you modify the engine/cooler story! (This is important to me... And is probably why none of my stuff works..)
3. Wiring is a pain and you can avoid it entirely
4. Cam-ed engines always sound better

Edit: and if you don't do any porting/polishing it shouldn't take long at all
*depends how finicky you get with main bearing clearances/ring gaps etc.

[Shakotan_Aaron]

A fresh engine will garntee years of trouble free motoring. With your budget you will get to spend more on cool bits. You could potentially be up for a week or two wait for machining depending on how busy your local machineshop is. Adding that to not knowing what size bearings etc you will need to order you maybe pushing your time frame right out to a month assuming your speedy on the tools.

Depending on how much you you can pick up a 20v for a re-ringing it wouldn't be overly expensive. Wiring really isn't as bad as people make it out to be. Its normally mostly a matter of splicing into the body loom. So wires for your ignition on, start, then dash stuff like temp, charge lights etc.

Other things you should factor in, new or have the radiator flushed, new hoses if original, new clutch while its all out.

[TheChronic]

Back again, disappeared for while there.

Leaning toward picking up a smallport 16V off Gumtree/eBay and rebuilding it while I keep the current engine running for a while. Wanted to get a 20 valve for the ITB's without needing aftermarket management, but it seems impossible to find any full package with less than 175,000km and chances are high that they're sludged anyway. So goal is now to find a 7 rib lot and start ordering some bits and pieces. Would like to keep my current gearbox as it feels pretty good for its age as well, much better than the box in my 320,000km+ Twin Cam. If I could find a decent 20 valve though... let's just say I'd love to put some little "Twin Cam 20" decals in place of the 16's on the rear doors.

Also pulled the sump off the bigport the other weekend to take a look at the bottom end. Couldn't find much of significance - the rod bearings don't have any side to side (intake to exhaust) or up and down play in them that I can feel at all, and the wristpins don't appear to have any play up and down/side to side either. One thing I did note was that the fourth cylinder had about double the end to end movement of the rest (flywheel to timing belt end), and while nothing looked properly burned, the underside of the fourth piston looked slightly darker in colour than the rest, almost more of a "red" colour in the limited light that I had. I'm pretty much stumped.