New 97 Bonnie, need engine rebuilding advice?

[ttocs84]

Ok, i work at an auto shop, and im fairly familiar with these cars and the 3.8l, ive put several in customers cars when their intake leaked to much and bent rods. however i just got my hands on a 97 with a bad oil pump, engine runs great, until it warms up, loses oil pressure, and you can start to hear the main bearings. Soo, instead of replacing the motor, i Really want to rebuild it myself. ive browsed around this site for a while now, and i know im gonna put the fwi on it, however im wondering what would be my best setup for internal parts.

My intended use for this car is to be my daily driver, but im a gearhead, so i cant just leave it stock! Im planning on getting a new rotating assembly, having the block hot tanked, bored .30 over, and performance cam w/roller rockers, however not sure what ratio rockers i can fit with what performance cam, also what springs to use with said rockers.

I will have more questions, but maybe these can get this conversation going!

Thanks for any advice you may have!

[tan96ssei]

for starters the oil pumps dont tend to lead to oil pressure dropping while temps increase. usually this is a sign of worn bearings. i know this from recent experience with my 96. i replaced mains and connecting rod bearings. fore warning you this is a rather big job cause there is very little clearance to push them out... meaning a complete crank removal is needed to get the block side bearings out.

second if its a DD why would you want the performance upgrades. if you think the engine is shot then my recommendation is find a used L67 (supercharged series II) and drop that in with the mods you are describing. even stock for stock the supercharged motor pumps out 40 more horses than the naturally aspirated.

if you decide either way on motor. i know that with cam no larger than a 1.8 ratio rocker. with out cam you can push up to a 1.9 ratio. as for cams the SX1 from intense or the XP from ZZP are the most popular mild cams. both sites listed below also have harder L32 (supercharged series III) connecting rods, oversized rings and pistons both diamond coated and not coated. plus on the little i did mention that excludes the numerous gaskets the main and connecting rod bearings and other misc. parts need to finish the job.

here are the sites:
http://www.intense-racing.com
http://www.zzperformance.com

[clm2112]

If you are going to overhaul it, then substitute L67 crank/rods/balancer shaft with new pistons for the overbore. Couple of vendors out there, and here, that sell pistons for the L67. The heavier rods and corresponding balance shaft will give you a larger safety margin to work with, even if you don't plan to use forced induction or nitrous oxide on the motor.

For starters, I would select a cam first that matches what you are thinking you will be doing with the car... Daily Driver, Normally Aspirated, Play toy. Something with a little more duration over stock, but not a blower cam would be a good starting point. Decisions about valve train parts will flow from the cam used (if the lift is greater than stock.)

Last though: You are about to discover that rebuilding the 3800 is not cheap compared to other motors. It's pretty easy to exceed $1500 in parts & gaskets. But there's not much in the way of surprises inside the motor. About the only thing the machine shop might have problems with is balancing the rotating assembly just because it is a V6 with a balancer shaft. They may have to do some digging and make some phone calls to figure out how it is supposed to be balanced. (I can't answer that one, but would be happy to pass along the name of the machine shop who balanced mine.)

[dangrus4060]

I 2nd that... suspect bad bearings...the way the oil pump is designed, its almost bullet proof. I just rebuilt my motor (failed #1 rod bearing on an L67) and the new crank w/ bearings, set of L32 powdered rods, timing chain & tensioner, cam sensor and complete gasket set came to a total of $1250. I wanted to do a new cam and rockers but could not afford them. Adding belts, hoses, coolant elbows, plugs, wires, filters, fluids, S/C oil, cleaning supplies, it came to just over $1600.

[ttocs84]

Ok, well let me clarify, as i said im pulling the motor and completetely going through it anyway, new crank/bearings/rotating assembly, so the it being a big job is not a problem for me, i work at a shop were i do this all day anyways.

As far as it's being a DD, yes i know it is overkill, but i still want to look into some performance upgrades, just because, this is one of my hobbies.

I have already done some pricing, and yup, rebuilding it with all new stock components and gaskets alone will cost more than a 3.4l camaro motor i rebuild with some warm valvetrain upgrades. thats why i'm asking now what i'm in for, I want to have a fairly complete build sheet before i decide to do it, otherwise ill just stick a junkyard low milage block in there and call it sold!

Also, if i were to locate a L67 (supercharged series II), would i not also have to swap in a new computer and wiring harness from said donor vehicle? what else would have to change to accomodate this?

[1337ssei]

engine,wireing/computer altho both can be made to work with an l67 with minior mods and a tuner,also a fuel pump. That is about it I think

[94SilverSSEi]

Just a clarification He has an SE. Wouldn't he have to switch out axles, tranny, etc to make the L67 work.
If yours is NA it is way more work than it is worth to swap and L67 unless of course you have a donor car.

[ttocs84]

Well at this point i dont have a donor car, so im trying to get the most out of my NA motor without spending too much, If the money is too high, i might have to build it in stages!

BTW what are the advantages of removing, or not reinstalling the balance shaft, esspecially if im having the rotating assembly balanced without it! what else has to be considered to do this, does the motor idle rough or set any codes without it?

[tan96ssei]

Not 100% sure on this, but this motor has two knock sensors and i believe that you will experience knock retard if you remove the balance shaft. i have yet to hear anyone on this site removing it also.

[00Beast]

For a DD, you're going to want the Balance shaft. Motor will vibrate quite a bit, especially at idle, with out it.

[ttocs84]

Alright, so basically what im coming up with here, is that unless i intend to take it to the track occasionally, and have tons of money to invest, i should just do a quality rebuild and make a good DD!

[00Beast]

I'm not saying don't cam it. If you have the money, absolutely do it. But, go with a mild grind, and don't go all out and remove the balance shaft, etc. Just make it a nice, quick DD.

[ttocs84]

10-4 I appreciate the advice, i think thats what ill do!

[blazerk5drew]

Im in a similar position with my olds 88. the engine lost a bearing and now im looking to do a rebuild and enhance the motor a little. This car is my workhorse and it gets used for everything. im looking to increase power in the motor without throwing reliability out the window. Im looking at a complete rebuile with higher compression pistons, .030 bore increase, an intense sx1 cam + pcm along with LIM porting and possibly porting the exhaust manifolds. The car already has a rebuilt trans with a shift kit and a high stall converter exhaust and an intake. Also i will be replacing the converter to a more high flow model.

Does anyone out there have any similar expierence with camming an NA 3.8????

[willwren]

This topic is VERY old. Please start one of your own if you like, rather than digging an old one up that tends to confuse people.