dreadnought6570

'94 with 230k 6spd making some not fun noises.
There is a rattle I can only describe as uneven coming from the bottom of the motor. By that I mean the sound doesn't loop regularly like most engin noises do....it's almost random, but continuous.

Best I can tell from searches is a spun crank bearing....but I don't know.

I'm ready to do a rebuild anyway and have been doing lots of research, but I would like any advice I can get.

This is my daily driver. I would like a little more power, but I'm not looking for a dragster. Also i have read that there are some things you can do that will increase HP but your throttle response may suffer....this I do not want!

Thanks

KyleW707

LE1 h/c package $1200

SS RRR

iTrader: (2)

You need to plan a budget. If you're looking for simple N/A power then get the block checked to see if the cylinders need to be bored. If they don't you can save yourself a huge pile of cash by just reusing the entire stock rotating assembly including pistons if everything is still in good shape. All you would need is to get the block hot tanked, new freeze plugs, bearings and rings and you have a brand new short block that will be good for whatever heads/cam you want to throw at it barring for longevity sake your shift points stay south of 6500rpm. If you want good torque and power then I'd suggest LPE heads and 211 cam along with your headers of choice depending on whether or not you still have to pass emissions. The good side is you will not loose any low end. Bad news is the cam is very mild and it will not lope. If your mpg changes it will be minimal. With a good tune you are looking at around 350rwhp with stock exhaust and maybe 370rwhp with an off-road pipe. That could be good for mid 12's emissions legal or low 12's if it isn't.
Other places to call for good heads/cam packages would be AI or GTP (Gallant Technical Performance). I only detail LPE since that is from my personal experience.
Where are you from? If you are in the NE area I have a shop I can recommend.

bufmatmuslepants

iTrader: (3)

If your tearing the shortblock apart already get the rods resized for arp bolts ($80 at my local shop) and you can spin it as high as your heart desires, under the PCM limit of 7000rpm.

96capricemgr

iTrader: (1)

You have removed the serpentine belt and run the engine? You are sure the damper is good?

Cheap rebuilds cost power a LOT of the time, stupid things like lowered compression, cheap rings pistons that weigh 20% more than stock are all COMMON mistakes.

I would strongly discourage this idea of a "preventive rebuild" that you seem to have had before the noise started at least till you diagnose the noise and can begin to form an intelligent plan.

94camaroboosted

Figure out the problem before a complete tear down. Could be an easy fix. Save you slot of time and money in the end. Other wise you could waste lot of energy to fix a working item.

Best way to increase power is a heads and cam combo with a good tune.

BOLO

iTrader: (40)

It can definitely be spun bearings and will need a tear down. I would just find a low mileage replacement block to keep cost down, then top it off with a good heads and cam for more power.

KyleW707

He said he is ready for a rebuild regardless? He asked for opinions on a simple build, and yet there is only two suggestions...

97Z28SS

iTrader: (5)

Forged pistons (SRP, Probe, Mahle) Scat ProComp 4340 forged 6"rods with 7/16 cap screws and then have your crank checked and if it's useable have it turned and polished. If the crank is toast try to find a good stocker or take the opportunity to get a 4340 forged crank and build a 383. Then get your stock heads ported (LE, AI, TEA) get a cam from whomever does your heads then get a larger capacity oilpan from Moroso or Canton along with new gaskets. Or if not check the classifieds as I've seen a few already built shortblocks for sale but it depends on your time and budget.

toomany

How old is your clutch? How does it feel? When I bought my 97 Formula the kid thought it had a main/rod knock. Pull the transmission off and the a few springs fell out of the disc. Sounded just like a rod knock. I figured while I had the motor out I'd go through it. The crank was able to be polished and stock size bearings used, had 160k on it.

96capricemgr

iTrader: (1)

Why would he want a larger capacity oilpan or the substantial risk of leaks and windage issues that come with the Canton.

A lot of folks are quick to condemn things solely based on the fact they are stock and therefore automatically bad. Modding cost a LOT more than it needs to if you are going to go that route and often it forces you to spend money where no gain is to be had so you endup spending more to go slower.

dreadnought6570

Thanks!

As to questions, I'm in Oklahoma. And emissions aren't an issue...no inspections.
Guy I bought it from had already put magniflow exhaust on and cut the cyt. only have a single O2 sensor as a result.

The clutch is in great shape. Very firm and short throw.

I will run it sans belt and see what I hear. Thanks for the idea.

Like I said, I'm not 100% what's wrong and I haven't dug into it too deep as I was waiting on tax return to get started.

As it was when I decided to stop driving her in Sep, she still had great power although somewhat less than she did a few months ago and mileage started to suffer quite a bit.

I also have the pcv disconnected. I was burning oil and pulled it to check and it stopped so I'm afraid I'm getting some blow by as well.

Anything else you can think of is awesomely appreciated. I'm a pretty good mech, but this is getting beyond what I know. I love my car and want to fully restore her and enjoy the ride for years.

Thanks