34 Blast....
I can provide some helpful information as I am a Hyundai Tech and I don't mean that in an inflated, "chest out" type of way....I am also an Elantra owner....
- Hyundai built a real POS engine from 2012-2015 called the "Theta" 2.4....these engines started failing on a regular basis around 100,000 miles give or take 20,000 and depending on regular maintenance history. Hyundai extended their warranty on these engines out to 120,000 miles....
No, this has nothing to do with your Elantra but everything to do with your engine and Hyundai's desperate need to maintain its customer base. I have been replacing Hyundai engines now for a couple years and have only replaced a handful of Elantra engines and those were due to driver negligence. I'll let you in on a secret....if your engine blows it's very likely Hyundai will cover it. I do more warranty work then I do customer pay work and its frustrating because warranty work doesn't pay much.
So....some recommendations for you based on what I have seen come through my shop....
1. Because you do not know the true history behind your vehicles engine I would get a timing job done. Timing chain, tensioner and chain guide. I realize this can be expensive but it will prolong your engine life considerably.
2. Stick with OEM on everything Hyundai. Oil filter, spark plugs, coils etc.....Hyundai did all of it's engine and vehicle testing with Hyundai manufactured parts. It is my experience that Hyundai engines don't do well with aftermarket parts. In fact, I would stay away from aftermarket parts all together if you want to hit 200 G's.
3. Stick to a 3,000 miles oil change. Its difficult to tell but if your one of those people that doesn't not use the exact same type of oil every oil change....premature engine oil sludging can occur if you go to many miles between oil changes. One way you can tell this is by removing your oil cap and look at the underside of the cap....is there sludge build up on the cap? On some models using a bore scope you can look down under the valve cover and see if there is sludge build up. Don't worry though because I have replaced several engines with really bad sludge build up.....Hyundai covered it.
4. joe@drivebug has an excellent suggestion....a compression check is a great idea....5-10% variance is ok. Your compression should hover somewhere around 140-150 psi....anything less you may have piston rings that wanna crap out on you....
5. Some other off the shelf stuff you can do.....
- if you do your own oil change (especially since you don't know the vehicle history) get the car up on ramps/lift or what ever and drain the engine oil.....then take a couple quarts of the same oil your using and run that through the crankcase and let it ALL drain out the bottom. Doing this drains residual oil left from the original draining. Always replace your oil drain plug gasket and an OEM oil filter.
- Sea Foam is great stuff....running sea foam through the engine will blow most of the carbon and deposits out the exhaust....
- Regular replacement of the air filter and spark plugs is a great idea....may seem like and overkill but I change my plugs every other oil change on my 94 Nissan Sentra simply because like you I want to prolong the engine life....I'm up to 320,000 miles on the car now.
Feel free to message me if you have any other questions or need help. Good luck