to rebuild or not

[ashes29]

i have little to no experience with any dsm cars other than helping friends perform light work on them. I have "inherited" a broken 95 eclipse gst, and am just starting to try to fix it. all the mods are listed in my profile, the previous owner messed with the SAFC and had it running at max fuel at all rpm, and it ran like crap(given) now that i have it i have properly tuned it but it has developed an intermittent knock(comes and goes regardless of rpm) that is very loud, it is blowing a lot of black smoke out the back and had severely fouled plugs(had oil on them as well). My question i guess is is where should i start in troubleshooting this? a lot of the mods were put on pretty bad so my plan so far is to strip it to stock and then redo all the bad work...any ideas?

 

[trbotaln]

I would start off by doing a compression test and leakdown test.

 

[ashes29]

both came back within 5 psi of each other and all were over 160

 

[trbotaln]

You could pull the oil pan off and check for metal shavings and check for spun bearings. But your problem sounds like it may even be the head. Are you sure that you are not getting bad lifter tick?

 

[ashes29]

yup it is not lifter tick the noises are lower than that. the thing that gets me is how it comes and goes

 

[trbotaln]

check all of your belts and pulleys and otherwise try to post a sound clip of the noise.

 

[onegee]

Check your crank pulley to make sure it isnt seperating. Going over all the mods and putting them in correctly is a good idea btw.

 

[Defiant]

I'll see your harmonic balancer suggestion, and raise you a balance shaft bearing.

 

[ashes29]

identical to the problem my buddy had with his/my now 95 talon tsi (though his engine made a different noise)its a bearing from the balance shaft that made it into cylinder 1 but luckily didn't damage anything...we have the block stripped now and should be reassembling tomorrow pending new pistons. am I correct to think forged pistons are better? this car is eventually(once it is better tuned and set up) getting a bigger turbo and I want to plan for that in the internals now. also how could I tell if the turbo it has is blown? the engine ran hot, really hot the last time it ran and there is carbon buildup everywhere from an extreme rich condition so i am paranoid something got to the turbo...i just need it to last till june( I have a friend stationed in okinawa and he is bringing me a better turbo with only 200 miles on it( too much for his car, a 95 spyder with nothing done to prep the engine for more boost

 

[JohnnyC]

I had a smiliar problem. There would be a knock at different RPM's , but it was never constant, and never happened while the turbo was compressing air. It ended up being that I spun a rod bearing, and it was rod knock, so a used engine is on the way. Machine shops quoted around $2,000 to repair the damage (crank, resurfacing,etc.). A used "JDM" engine is cheaper, though risky.