Get my engine out last night, rolled it over and took the oil pan off. checked all the rods for play, and one of them has a good bit of slack in it. I haven't removed the crank yet, but whats my least costly method of rebuilding the bottom end? Will a new crankshaft and rod bearing do the trick? or am i going to need to do the main bearings also? should the rod be ok or will it be damaged as well? or can i have a shop fix the crank for less then the cost of a new one?

i guess until i figure out what to do, i'll take more apart and remove the crank.

thanks.

part numbers and where to buy them would be great. Id like to stay away from the autozone crank and bearings if i can get a brand new kit for near the same price

 

Cheeepest / best / eeeeeezyest is usually a "crank kit"; crank, main brgs, & rod brgs, all in a package.

As far as part #, that would depend to some extent on what engine you're working on.

Hard to tell about the rod. Sometimes they're fine, sometimes they're destroyed. You'll find out.

Most likely, if this went on for any length of time, there's metal shavings all in the motor; and unless you tear it COMPLETELY down and run rifle brushes through all the passages without all the plugs installed (the vat doesn't dissolve metal chips) the FIRST THING that will happen, the INSTANT You crank it up the first time, is all those shavings that are lurking in those passages, will get flushed right down into your nice new bearings, and wipe them out on the spot. IOW, the idea of replacing just the crank and bearings without further effort might seem mighty attractive right now, but carries ALOT of risk of a do-over.

 

main bearings and rod bearings are pretty cheap. if i got it open i would do the mains just because of price. i wasn't going to rebuild my bottom end because i was wanting it back together but i decided to go ahead and do it. i am glad i am. bearings are about 25 dollars a set

 

well i got most of the rod caps off, and the main caps are off. the rods seem fine, but the rod bearing wiped out the crank, the 2 half's of the bearings were on top of each other. I'm most likely going to tear it completely apart to do the head gaskets and intake gasket. and figured i'd rering the pistons too. I want to do it right, but i dont want to spend a ton rebuilding a L98.

the car is a 1991 Z28, L98 350 TPI. has at least 125k miles on it.

 

Im looking at a few parts from summit.

crankshaft: Eagle 103523480. 3.48 stroke. ( thinking this is like a replacement crank for the car)
http://www.summitracing.com/parts/ESP-103523480/

man bearings: summit brand.
http://www.summitracing.com/parts/SUM-172000/

rod bearings: summit brand.
http://www.summitracing.com/parts/SUM-171000/

I have it down to the bare block right now. the cylinders look good and smooth, im thinking just a hone to them. Theres also no noticable ridges on the walls that are bad.

Are these acceptible parts for the job? Need to pull the trigger soon, will wait for the block to be honed before i order anything though. that way i dont end up needing a bore and new pistons.

thanks

 

the rod that stacked the bearings needs to be resized or replaced, otherwise your asking for problems.

i've never used those parts, but they should be fine for your needs.
i would add a set of rod bolts to the list, but thats just me.

you did check or mark all the main caps for marks or numbers indicating where they go on the block and the rod caps for which rods they go to, right?

 

Yup, if the bearing stacked, the rod is wiped. You're pretty much out of luck on crank-kitting it.

Time for a complete tear-down and rebuild.

Might as well make it a 383 since it will cost basically the same as merely repairing what you've got now. Half-a$$ing it will only be a waste of time and money, the odds of actual long-term success (like, more than 5000 miles) with that are very slim indeed.

 

another poster saying what you don't want to hear. You need to tear it down, get the block completely cleaned and that means all new bearings. The rods will need to be checked/resized/replaced.

So, you are basically looking at a total rebuild. Of course you could always just toss some parts at it, buy a $25 cylinder hone, slap on some gaskets, re-install the engine and quickly sell the car so the next owner will be the one to rebuild it completely because it's not going to last.

 

I said above that i would most likely do a complete rebuild. I know i need a new crank, main bearings, rod bearings, cam bearings, hot tank, hone cylinders, complete gasket set top to bottom. I wasnt aware about the rod being toast too, im sure i can find a replacement rod for that one. or do i need all new rods? also new main cap bolts.

I was hoping to save money buying everything in a package, i'm somewhat new to this, so i asked for some input. I'm not the type of person to do it wrong to save a penny or two and pass it on to the next fool. I want to be proud of what i accomplished and enjoy the car for a while.

 

awesome!!!

then you already have to use a machine shop. I suggest calling around to several. Ask them for a complete price including parts. I just had mine rebuilt for $1300 plus tax and that was parts included. Other shops wanted $2k. One shop quoted me $1200 for some basic services and I would still need to buy parts and install most of them.

This guy has been in business for years and just wants to charge fair prices. If my engine wasn't a roller cam then he would have upgraded the cam for the same price. Mine is a 305 but a 350 would be the same price.

 

I just need the engine cleaned and ready for me to build it up. I'll spend $150ish at the shop on the block, the rest of the parts and labor i'll do myself. adding up some things i listed above, im right near $500 in parts and some labor. and i know im still missing some little things here and there that will prob add up too. might have to put the project on hold until i can gather some money to do everything at once.

 

When the bearing shells stack, they destroy the inner surface of the rod, which must be as precise in size and finish as the crank journal. Meaning, you need AT LEAST that one rod.

You could half-a$$ it and just change out the one; who knows, the next owner may not figure out right away that it vibrates, or that it runs funny because the cyls aren't the same because one rod is a different length from the others. Who knows.

No need for new main bolts, in any case; those basically don't go bad. TPI has protected them from any levels of stress that could cause that, and will continue to do so as long as it's on there, assuming less than about 200 HP of nitrous.

If it needs pistons, then you're already into it for about 95% of the money to make it a 383. No sense going back with a 350 crank at that point. Just buy a 383 rotating assy instead of piecing together a 350 and enjoy the extra 10% or so more power.

 

when the block is dipped, you then need new cam bearings. That is something that I pay a shop to install. Could I attempt them myself? Yes and I have but it's just so much easier and since they have the block at the shop, and the correct tools.

Next up is you'll probably need more than a hone because you had a lot of play. So a bore/hone is anywhere from $150- $200.

Now you're at a good thorough cleaning as well as bore/hone or as high as $350.

And, since it's now disassembled, you need to have the rods checked/resized/replaced. I don't know about you but I'm not the best with respect to ice and a torch and trying to press in pins into my new pistons on my resized rods.

So, why not let the shop do that?

And since your engine has unknown miles, you probably need new valve guides and a 3 angle job done so that's about $140 per head.

Another option is the Russian Roullette method and that's find one of those $500- $1,000 350's that are out there for sale and pray that you find a good one.

Reliability isn't going to be inexpensive, per se. If you allow a budget of at least $2,000 and come in under that, then you are all the better.

If you are convinced that you could do it "correctly" for $800, then yes, you could get it back up and running, but not correctly.

Money is tight for all of us. It stinks having unexpected repairs and finding that repairs are more extensive than one hoped.

 

Are these the correct main bolts i need? wasnt sure if i need large journal or small.

http://www.summitracing.com/parts/ARP-134-5001/

 

I would definitely take good advice and spend my money at the machine shop rather than waste money on expensive main cap bolts for an engine that's likely to end up with another spun bearing. We don't have a block prepped and rotating assembly balanced and clearanced because it's cool. We do it so that the motor we spent all that time and money on doesn't end up in the scrap yard before it's time. A $1,200 machine shop bill is cheap insurance.

 

good advice however it seems that the OP has chosen a different path.

And not a shot at the OP but to those that are casually following the thread, you now know how those cars that got purchased with a "fresh engine" or "rebuilt 5k miles ago" end up needing to be torn down, the crank and rods tossed out and needing a complete overhaul in order to fix that "slight knocking" sound.

Many many years ago, I tore down an old Ford 302, put in new rings, gaskets, lapped the valves and said my prayers. I didn't even bother honing it. My oil consumption went down and i got the 9 months that I needed from the car. I drove it to the boneyard enjoying the wonderful rod knock, took my $50 for the car and went home to my new car which was in the driveway.

I completely understand why some will try to just get the engine back up and running as economically as possible and squeak out some more miles. I have no issues with that unless they don't provide full disclosure when they go to sell the car.

 

Good point freind. I guess I just love my 3rd gen so much I imprint it on others.

 

I would just like to get it running and drivable so i can figure out what else the car is going to need. My plan is to pull this engine back out when i find a nice LS1 donor car. So i dont want to spend 2 grand rebuilding a stock L98 and then lose money selling it when the time comes. If i cared about making the engine last, I would go through all the steps to ensure its done right. I dont ever plan on selling the car with the current motor in it unless the buyer knows not to expect it to last or be raced and survive.

 

there's really nothing wrong with an L98. THey are fine motors for daily drivers and around town cruising. No, it isn't an LS1 nor is an LS1 an LS7. There is nothing magical about an LS1.

To find a donor LS1 would you really want to drop an unknown commodity into your vehicle? If it's cost that is the issue, rebuilding your current engine or finding a reman'd long block is going to be much more economical than looking for a replacement LS1 and getting that into the same condition as your L98 after being rebuilt correctly.

To net it out, you'll have $$ several hundreds trying to bandaid your current engine. Then you need to find another engine/computer and do all that work and you would not really know the true disposition of that LS1.

The money you spend for the bandaid would be tossed away instead of spending a wee bit more right now, doing it right and not looking back.