I'm looking at rebuilding my TPI 305. Due to its current condition I'm gonna bore it out .040. I'm looking at SpeedPro Hyp pistons, what do you recommend for rings and bearing? I'm not building a high hp motor, just a motor for cruising. So please no, you're dumb for building a 305, just buy a 350. Everything I have is already for a 305. Thanks for your input.

 

Is that you saying .040 over or the machine shop?

I would just get a standard rebuild kit once you know all the dimensions you will need. main bearings, bore, rod bearings, etc. Sounds like all you are wanting is a basic rebuild.

If you are looking to piece things together separately, Ive used Hastings rings in the past with good results (worked for what I used them for).

 

You're dumb for building a 305, just buy a 350.

You're dumb for building a 305, just buy a 350.

I said it twice because it bears repeating. You've read it before because it's good advice. As long as you use the 'right' 350, it'll run fine with all your 305 stuff. Maybe less than optimal, but "fine".

See, here's the thing... Tank, Bore, hone, cut, grind, etc will all cost the same. Parts for the 305 will cost more. You'll be in it for the same money and effort. No one wants a 305. Deep down inside you don't want a 305.

Also, unless you have a really good machine shop, look at crate motors. You can get a fresh built name brand engine with a warranty for a typical local machine shop rebuild. Machine shops are a nightmare anymore.

Sorry, I know you dont want to hear it, but you need to hear it.

 

Just get a standard goodwrench 350 crate engine. They are less than $1500 delivered! It will make more power and torque than your 305, and will be brand new from GM. There will be a LOT less down time, etc. It just doesn't make any sense at all to rebuild a 305. You can buy (good) running ones for $100 on craigslist - hell someone might give you one for free - they have ZER0 value. And when you are don spending $3000 rebuilding it - guess what? Still worth nothing.

GD

 

From your userinfo and sig: "89 Camaro RS 305 TPI 5 Speed"

Which part isn't true, "RS", or "TPI"?

Or was TPI swapped into it?

 

If you buy a goodwrench 350 don't get one of the cheap flat tappet ones. Stay roller.

 

Was a V6 RS, bought a 305 TPI to install. I tore it down to put new gaskets in it, found vertical scratches on one cylinder.

I'm rebuilding this 305, to all the 305 haters. I asked a simple question. I'm not buying a 350. I just want a cruiser. In 3 to 5 years I'm going LS. By the time I buy new injectors, knock sensor, spark control I'll have 500 more into a 350 for 50 more horse

 

i don't think anybody is trying to hate. they're just giving true experiences. if 9 out of 10 people tell you that you have a tail,...might want to turn around and look to see if your being a jack*#%. believe me, we all go through it. i have.

$500 for an extra 50HP aint a bad deal.

but some cast rings will work fine on a stock build.

put a pencil and paper to it. numbers don't lie. only you can decide if it's really worth it.

 

No, no, no. You will have WAY more into a rebuild because of MACHINE SHOP LABOR, parts costs, and YOUR TIME. A 350 crate will drop right in and turn right on. The injectors are $160ish from Southbay (forum sponsor), and the knock sensor is like $30 if that, the ESC is $75 from rockauto. A PROM chip for a stock TPI 350.... someone around here will probably send you one for beer money. That's less than $300 in PROPER ACDelco conversion parts. There isn't even any additional labor other than the PROM chip because the engine will be out.

Not to mention all the cleaning and foolishness you will be doing to get that old engine to accept gaskets and not look like a pile of junkyard.

We aren't hating on the 305. I drive one daily. They are GREAT engines as far as engines go. Better than 99% of what's being produced these days. But that doesn't change the fact that a 350 will be cheaper. And if it isn't, the 305 will be LESS reliable and may straight blow up within very short order due to cut rate parts and shoddy machine work.

The crate 350's from GM are CHEEEEEEP. The parts to make it work are CHEEEEEP. And it's guaranteed to be right. It's also immediate and clean.

Mark my words. You will spend a LOT more rebuilding a 305 than you will buying a crate 350 and dropping it in. Guaranteed.

I do this FOR A LIVING. I own a shop and have been doing this for a long, long time. Quality machine work cost a LOT of money, takes a LOT of time, and still isn't guaranteed. The GM crate engines are basically about as bulletproof of a solution as you can get.

GD

 

Okay, that makes sense.

Had the engine been installed before you tore it down?

Visible vertical scratches aren't that uncommon, and may not be too big of a deal. Any other indications of a problem like low compression or oil use?

Again, a rebuild may not be justified. Need to have more information about the scratches you found. Most likely it'll be fine for 3-5 years.

 

Machine work is 325 for what I'm having done, piston rings and bearings are another 300. Already have gasket set. Way cheaper then a crate motor

 

What machine work are you having done that will only require rings and bearings?

If your prices are all that are required, that's about $100-$200 per year of expected use. Not too bad.

 

Sorry new pistons too. But hot tank, bore .040 and cam bearing from the machine shop

 

You really should do the main line and check the crank for straight, polish etc. Rods should be trued up, etc, etc. That's very standard procedure and probably THE most common reason for short bottom end life is neglecting these items.

What you are doing is NOT a rebuild. That's a bearing slap with a (likely uneccesary) overbore. What's wrong with the bores and pistons that are in it? Bottom end is far more important. I would ring slap it before I bearing slap it. That goes for just about any engine.

GD

 

One cylinder has deep vertical scratch in it. The motor was pulled from a running car. But yes crank will also get checked out.

 

 

Run it. Wouldn't worry about that. Think about it - ring can't catch on a vertical scratch. I've thrown rings into more engines than I can count with some measure of cylinder scuffing like that. It won't make a bit of difference - that's what? .05% of the sealing surface? Won't make any difference at all. Check for major our of round, taper, and hourglassing. If it's within say .001 - .002" or so. Run it. Won't matter. Cast iron rings and womp on it WOT from 30 to 60 mph at least 10 times. Cylinder pressure seats rings. Vary your cruising speeds for the first 50 miles. Will seal up nicely.

GD

 

Especially if you're going to be LS spendy in 3-5 years. The 305 will last that long. Use the new gaskets, seal it up and start pocketing that money.

BTW, that piston top looks awfully clean for a used, running engine.

 

If you haven't torn down the bottom end, put it back together and run it. If you've torn it down, throw it away. You'll have nearly $1,000 in reconditioning rods, new pistons, blah blah blah- For a 305.

 

I feel like some of you are giving him advice and information that is 100% false. That GM Hecho en Mexico crate engine would be lucky to make 200 HP with all the stock TPI stuff bolted to it. The 305 roller motor will be better on fuel and make just as much power. I did a very budget build on a 305 Vortec I was given for FREE a couple of years ago. Had 250K miles not it. The bores were straight and round. I ran a hone through them Changed the cam bearings. The crank was round and in spec. I polished the crank with emery cloth. I cleaned the stock pistons with an old broken ring after soaking them in a can of B12 to soften the carbon. I used standard rings and bearings throughout. I checked over the heads and decided to run them as is except for changing the valve stem seals. I had a roller lifter that had been locking up and damaged the roller cam. Not wanting to throw alot of money at a roller cam and lifters for a beater engine, I put a Lunati 268 High Efficiency flat tappet cam into it with new lifters and a new timing set. I had the correct pushrods sitting around already although they are only $4.00 ea new. I put the rehabed 305 Vortec into a 1999 Tahoe that had a 350 with a broken crank. I broke it in pedal on the floor for about 10 0-60 runs. The rings sealed right up and the engine holds 40 psi of oil pressure at 750 rpm idle. It pulls the Tahoe around very well. After about 3,000 miles I checked the compression and it was very consistent at about 180 psi in every cylinder. It does not smoke or knock. The cammed 305 actually pulls harder than a stock 350 and is better on fuel. It was only down 20 HP from the same year 350 to start with and that was with a Y-pipe and single cat vs the 350 dual cat setup. I was not even $500 into the whole build.













Finally the Tahoe it is in. Has a 3.42 gear and 4L60E that has a shift kit and stock 1,600 rpm stall converter. Pulls around the 5,000 lbs at 70 mph in OD at only 1,700 rpm. Has P305/50R20s all the way around it.

 

The latest recommendation (after updated information from the OP) is run the 305 without rebuilding it. Given the statement that an LS swap is 3-5 years down the road, doesn't make sense to spend part of the swap funds putting anything into the 305 other than putting it back together.

 

*I* would do cast iron rings (no hone), the valve stem seals, and a complete gasket set and Cloyes double roller timing set. Just to avoid oil consumption or smoking and give it best possible resale value in 3-5 years. A trouble free engine that doesn't use or leak any oil is a must IMO. Cheap insurance.

GD

 

Thanks for the reply Fast355

 

Note that his "cross hatching" is much too flat. So definitely don't follow that pic....

But seriously - you don't need to do that. Don't touch the cylinders. Just rings. That is one of the WORST ideas that people do for no good reason that they can explain because no one that does it has ever tried not doing it - if they had they wouldn't do it or recommend it.

GD

 

Actually I have skipped doing it and the engine burned a ton of oil. The walls were glazed. That was actually what was left of the GM cross hatch. Before I ever touched the crosshatch. Notice the carbon at the top of the bores was still present. So blame GM for the angle being wrong, even though that is about the same angle I have seen in numerous stock engines.

 

There's no such thing as glaze. That implies a foreign substance. Do you mean to say the walls are smooth ?

If rings didn't seat for you it's probably a result of break in procedure or using chrome faced rings. Or the bores were well outside of usable tolerances with respect to ovality, taper, hourglass, etc and should have been bored.

I re-ring hundreds of motors every year. Turbocharged applications, half of them are. I've never had one burn oil.

Honing should be done - as the last stage of a boring operation to bring about a proper plateau hone finish as recommended by the ring manufacturer - in a proper honing machine that matches spindle speed to stroke speed.

GD