1992 RS 305 TBI

My car been smoking a lot lately while driving. Was told the issue was due to the rings. In order to rebuild the engine I was quoted around $1400 to $1600. I don't know if I should rebuild the engine or upgrade to a 350 crate engine? Might be time to retire the old engine and get some thing new?

This car will be a daily driver so no need for a performance engine.

http://www.summitracing.com/parts/na...8758/overview/


http://goo.gl/P00iBP

I know I need to swap some items in order to make that 350 work. But other than that what are the thoughts of the engines above?

 

That cost for rebuild is minimum. Even then, there isn't really any kind of guarantee. At least with a crate engine, you get a warranty that everything has been checked and built properly. A slap together rebuild or a minimum cost rebuild may last for a while but it's never a proper way to get value for your money.

I had a new diesel dropping into my F350 a couple of years ago. Cost a little more than a junkyard pull but it came with all the upgrades and a 3 year warranty. A junkyard engine might have lasted or needed a rebuilt soon after plus all the upgrades needed to be done and the new engine was far less than rebuilding the old one. To me it was a no brainer to buy a new engine.

Depending on what you exactly want to do with it, you have a couple of different options with a crate engine.

You can get a direct replacement. Everything is bone stock and anything that could have been considered worn out such as valve springs should be new even if it's all stock.

You can buy a mild crate engine with minor upgrades to suit your performance expectations.

You can buy a short block. The rotating assembly is complete. Just add some performance heads, intake etc that you already have and maybe a cam swap and drop it in.

For a factory stock street engine to maintain a daily driver, most people don't realize how much they can save with a basic crate engine swap. It's nice to say you rebuilt your engine but there are so many little things and the weeks it takes to do it right the first time can easily exceed the cost of a crate engine. With a crate engine, you can probably do the swap within a week after purchasing the engine. Getting a rebuild, expect it to take a few months before it's finished and the car is running. Proper machine shop work takes time.

 

The shops I talked to said the turn around time will be one week. Hope they are not skipping steps or some thing.

 

mu33rto,

a good shop can have one done in about a week if all parts are given at one time, machine work on block doesn't take long a couple days, heads a not even a day installing parts a day at most, if they have more than one guy working in the shop. I would be worried if they said a couple days. 1 Week is not bad at all!

 

on a side note, if you look up scoggie dickens Chevrolet, you can buy a new engine from them for around 1800.00 then just install your intake and accessories

 

"Smoking" is almost certainly NOT the rings.

Don't worry about "rebuild"; the motor probably doesn't need it.

More likely, all it needs, is valve guide seals.

Use the "positive" type. Not the "umbrella", not "O-rings"; "positive". They're SUPER expensive, maybe even as much as $35 for a full set. But that's OK, go ahead and bite off on it anyway. Still cheeeeeeper (not by much maybe, but cheeeeeeeeeeeper nonetheless) than a "rebuild".

 

Depends where the smoke is coming from I guess. Blow by?

I'm in the exact situation you are in right now but I'm looking for a bit more performance.

 

The valve guides could be worn and that will cause smoking along with the valve seals being toast. How many miles are on this 92 rs. if it is a high mileage car, then it could be time for a rebuild.

 

Come on guys.Pick up the slack.Can't believe no one told him to leak it down to pin point the problem.

 

Leakdown won't identify the #1, 80% or higher probability, cause of the symptom at hand; valve guide seals. It could leak test PERFECT and still smoke like a freight train, or leak test like 500k miles on the same oil but not smoke a wisp. Wrong test for valve guide seals. Great test for some other complaints; but not the place to start on diagnosing smoking.

 

Hey Bud.Worn out "valve guides" as so the valves are long ago not seating will show in a leakdown test.Just doing the guides and seals and not a valve job is just asking for it............

 

Sure; if the guides are SO WORN that they aren't holding the valves concentric to the seats, then yeah, sure.

Otherwise, given that about 90% of all old SBCs on the street develop this behavior eventually even when the guides themselves are fine, I'd go with seals LONG before I'd start trying to diagnose a worn casting type of problem. Just a matter of probabilities and not doing extra work that accomplishes nothing.

Now... if he had posted about "oil blowing out the PCV" or "random weird backfire in the intake and no power" or something like that, then yeah, go STRAIGHT TO the leakdown; but for smoking, not so much. Since he's not complaining about stuff like that, only smoking, odds are, all that's wrong with his motor is, it's smoking.

Match the troubleshooting technique and recommendation to the complaint, no matter how useful some other technique might be in some other situation.

 

The car runs stronger than when I first brought it. The odometer reads around 160,000 miles but I don't trust that reading. The Transmission Speed Sensor did not work when I brought it and only replaced it about 6 months ago.

Pretty sure the valve seals are gone too as the car puffs some smoke at startup. But the mechanic told me that since the car puffs at stop lights and such it had to be some thing else. Either the valve cover oil drain is plugged or the rings are gone. I check the valve cover oil drains and they are nice and clean.

I installed an air compressor air filter on the pvc valve to capture the blow by. The first week it capture a lot of oil, after that nothing much. I was talking to another mechanic who told me I can get a new engine straight from the Chevy dealer for around $1200 and have them install it.

 

Then change em.

After that, come back and tell us about the other.

Until then, not a lot of sense in playing a bunch of "maybe it's this maybe it's that" all about the most expensive thing you can throw out there.

 

It smokes at stop lights because the intake vacuum is high, and is sucking oil past the valve seals (or what remains of them).

Replacing the valve seals is an inexpensive way to verify whether or not it's the rings.

 

Does it continuously smoke, even after warming up?

My 87 Suburban only smoked until engine warmed up; this would give the valve guide rings time for expansion with heat, and then seal. Once warm it would stop smoking.

Just another idea in support of what others have already mentioned. This would be a cheap fix if you do it yourself. Just time consuming.

 

I'm in the same position as you and here's what I'm doing

https://www.thirdgen.org/forums/tbi/...-progress.html

 

The car does not smoke when cold only when it is warm or hot. I'm going to replace valve seals and lower the idle to see if that helps.