When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Well it was bound to happen at some point....Motor has just under 100k and has been well maintained over the years, but couldn't take my spirited street driving anymore
Couple weeks back went WOT 1-4 and noticed an audible knock above 2500rpm after. Still had strong oil pressure and was not down on power so I thought a rocker came loose or a valve spring broke. Finally got it up on the lift today, pulled the pan and found LOTS of metal. There was even metal between the oil filter adapter housing and block. Pics below are from inside the pan.
Haven't had a chance to pull plugs and spin the motor to inspect each bearing, but pretty sure one or more of them spun.
So what to do next is the question? I'm know everyone will say build a 383/396 but not sure if that's how I want to go with this car mostly from a financial perspective. I've been looking for a new fun car that the kiddo can ride in (Chevy SS sedan, Gen5 Camaro ZL1) so i'd like to keep the rebuild cost down. Assuming a new crank needs to be purchased anyway how much more would a 383 build run? Curious to see what others have done in this position.
Last edited by 9T3VETTE; Sep 16, 2019 at 01:03 PM.
If your crank isn't damaged beyond repair, you may be able to get it turned. get the right bearing size and not really rebuild the entire motor. You will have to crack it open to see. Not that I fully support this, but it is the cheapest option.
From: Las Vegas - Just stop perpetuating myths please.
Options are nearly unlimited. To throw a few out there from cheapest to most expensive: pick your own part salvage yard, regular salvage yard, Craigslist part outs, buy an entire LT1 car just for the motor (possible you swap your aluminum heads onto a low mileage iron head motor - swapping cam also), auto parts store remanufactured like ATK, custom performance crate engines by ATK or Golen and others. Or heck I'm sure Motor City has plenty of engine shops that will rebuild yours - remove and replace it to. Local Chevy dealer service can send you in the right direction for a reputable shop.
After digging deeper this weekend I found the #8 rod bearing to be toasted.
As mentioned the bearing could probably be replaced in vehicle, but I only see this as a band-aid fix. Since it's not a DD and just a weekend car i'll take my time to repair it correctly. Two ways I leaning right now with a slim margin of victory going to option 2.
1) 383 build - rotating assembly, machine work, good set of heads (probably AFR's), neutral balance flywheel, new clutch, injectors, yada, yada. It would be BA but i'm EASILY looking at 5k+ for something like this.
2) 350 - new crank (possibly new rod on #8?) and a nice ported head/cam package from AI or EP. Cost would be much less, probably half. The other option here is to do a 355 to clean up cylinders and go with an entire new rotating assembly.
Not in a rush so i've got some time to think it out, but open to any experiences other forum members have had.
Do the band aid to make the car driveable and then pick up another LT1 to take your time and build the engine you want.
Both of your options include better heads. That is a good move for making more power. I am not sure if EP heads you mentioned are from Lloyd Elliot (Elliot port works) but their heads are less expensive and have good reports on making power too.
From: Las Vegas - Just stop perpetuating myths please.
I've been shopping for pistons for my LT1 build but the tight chamber LT1 heads require a big dish pistn volume - even more so if I deck the block for good quench.
I recommend choosing your head/chamber volume first before deciding on pistons for your stroke.
I had a 350 in my 1968 C3 Corvette for a period and I lost compression in #6 cylinder. I was building my 427 for the C3 but was months away.
That is why I did the famous "One-Piston" replacement, it received fresh rod bearings on that 1 cylinder.
On your car, I would do whatever to flush the metal out and cover it up while you replace the rod bearing in that engine. If you can do it yourself you will save a lot of money. Then build an engine that can make the power you "want" for auto crossing. I took many months but saved a bunch while building the engine I dreamed of. It also lets you appreciate how beautiful those Engines are set up and ready for action. They had mine on display at a Christmas party to advertise the builders skills.
I removed the oil pan, Harmonic balancer, Intake, Timing cover, cylinder head and simply replaced 1 piston with new rings. I took a couple hours to hone the cylinder with a 1/2" drill. It made a difference in the surface of the upper rings. I got everything back together and the engine ran fine.
Turned out that my #6 piston broke between the Compression ring and the upper oil control ring that is why I lost compression, but catching it quickly saved my cylinder. It was running 11-1 compression which may have played a part in the piston failure. The block was a 1970 LT1 anyway so it was running the higher compression. It has a set of the old famous "Double Hump" or whatever you choose to call them with hardened seats installed in it. It is a strong combination and with it I broke 20 mpg on my C3, it was 23-24 mpg on the highway with a Quadrajet.
It was a fairly straightforward job and I did it by myself in our driveway over two days. I could have rushed but getting a exact match piston to replace mine was a finding the right machine shop. I bought all good quality gaskets but the real PIA was the oil pan gasket while on your back.
I am sorry that happened to your Engine. I wish you the very best in making up your mind at this point. You have nice options out here on the Corvette Forum!
You can buy a Good Quality aftermarket Forged Rotating Assembly (Crank / Rods / Piston Kit) for somewhere in the $1,700 range. Then figure another $1,500 min for a decent set of aluminum heads. Then at least another few hundred in incidentals (gasket set, good head bolts/studs,etc.) Then you need to add in the costs to machine the block - boring / honing, etc. So - you're in at around $4K in parts at that point.
IF you choose to go with a 383 Rotating Assembly, the costs are about the same, the Rotating Assembly kit will probably be a touch more expensive, and you'll need the machine shop to clearance the block for the rods. So - if you're thinking about a build with better than OE Quality rotating components - there is very little reason not to go with the 383.
One comment about a single piston replacement. I helped a friend do that on a Gen 1 SBC that was used extensively on the track (valve spring failures will do that). We weighed the piston he got against one of the OEM pistons, and the one he got was a LOT heavier. He had to remove something like 12 grams of weight to get the replacement piston to weigh the same as the others. Just something to keep in mind...
Since the motor will be pulled out out to recondition the crank/address #8 rod i'll likely go ahead and address everything (i.e rotating assembly). Just as purple mentioned i've noticed in my research over the weeks 383 rotating assemblies run about the same as a standard 350. It just seems silly to pull the engine and not go for a 383 build as i'm going to keep her for the long haul. However, there are extras with the 383 build that need to be considered like heads and a clutch setup. In the end it will run more for sure but I'm thinking 6k could cover the entire build. The other question at this point is finding a local machine shop that I can trust.
As it stands right now the wife gave me a green light for one car adventure lol - build the C4 or new car purchase (i.e family race car). So i've got some reflecting to do!
BTW, how would the ZF and rear end handle the extra power. Already the car has a 4.10 rear.
Since the motor will be pulled out out to recondition the crank/address #8 rod i'll likely go ahead and address everything (i.e rotating assembly). Just as purple mentioned i've noticed in my research over the weeks 383 rotating assemblies run about the same as a standard 350. It just seems silly to pull the engine and not go for a 383 build as i'm going to keep her for the long haul. However, there are extras with the 383 build that need to be considered like heads and a clutch setup. In the end it will run more for sure but I'm thinking 6k could cover the entire build. The other question at this point is finding a local machine shop that I can trust.
As it stands right now the wife gave me a green light for one car adventure lol - build the C4 or new car purchase (i.e family race car). So i've got some reflecting to do!
BTW, how would the ZF and rear end handle the extra power. Already the car has a 4.10 rear.
If you are goign 383 and Heads, you will also need to get a tune.
Do the band aid to make the car driveable and then pick up another LT1 to take your time and build the engine you want.
Both of your options include better heads. That is a good move for making more power. I am not sure if EP heads you mentioned are from Lloyd Elliot (Elliot port works) but their heads are less expensive and have good reports on making power too.
Good luck with your choice.
QCVette,
I might have something to help you make a decision. I pulled a 95 LT1 out of my previous C4, due to a spun rod bearing (#5). I replaced the engine with a donor from a 94 Camaro, then sold the car. I still have the engine I removed, along with a nice used stock crank I bought with the notion of doing a rebuild. I doubt that I'm going to end up rebuilding it, since my current 95 is running great (knock on wood). So, if you want to pursue Option 3, or some other iteration, let me know and maybe we can make a deal. I see you're in the Motor City, and I'm in Jackson, so I'm sort of local... Whatever you decide to do, good luck!
QCVette,
I might have something to help you make a decision. I pulled a 95 LT1 out of my previous C4, due to a spun rod bearing (#5). I replaced the engine with a donor from a 94 Camaro, then sold the car. I still have the engine I removed, along with a nice used stock crank I bought with the notion of doing a rebuild. I doubt that I'm going to end up rebuilding it, since my current 95 is running great (knock on wood). So, if you want to pursue Option 3, or some other iteration, let me know and maybe we can make a deal. I see you're in the Motor City, and I'm in Jackson, so I'm sort of local... Whatever you decide to do, good luck!
This stinks . I always thought the 93’s were bulletproof
The more I thougth about it, I think there are other issues going on. Based on the oil condtion (which was replaced earlier this year) you can see it looks a bit funky. Thinking a bit of coolant was getting in the oil and diluting it's lubrication. Oil had a faint gas smell too so a leaky injector could have contributed as well. Conbine that with high reving and we may have a cause.
Originally Posted by KyleF
If you are goign 383 and Heads, you will also need to get a tune.
Since the motor will be pulled out out to recondition the crank/address #8 rod i'll likely go ahead and address everything (i.e rotating assembly). Just as purple mentioned i've noticed in my research over the weeks 383 rotating assemblies run about the same as a standard 350. It just seems silly to pull the engine and not go for a 383 build as i'm going to keep her for the long haul. However, there are extras with the 383 build that need to be considered like heads and a clutch setup. In the end it will run more for sure but I'm thinking 6k could cover the entire build. The other question at this point is finding a local machine shop that I can trust.
As it stands right now the wife gave me a green light for one car adventure lol - build the C4 or new car purchase (i.e family race car). So i've got some reflecting to do!
BTW, how would the ZF and rear end handle the extra power. Already the car has a 4.10 rear.
The ZF gearbox that sits behind the LT1/LT4 C4's is identiacl to the one that sat behind the LT5's C4's - those made 400 HP - so no real issues there. Basically the same for the Dana 44. The way most people hurt the Dana diffs is by bolting on slicks, and doing REAL hard launches. The ZF is normally hurt by people who drag race and subject them to power shifting... As for heads - unless you're planning to do really high RPM's - a set of good heads that will work on a 350 will be fine. THe AFR 195's are a pretty good choice, or you could check out Lloyd Eliott - he knows the LT1 heads QUITE well and does some very nice porting work.
As for a clutch set-up - these days your options are somewhat limited. How you use the car will impact your choices here. Remember - a 383 will typically make 10% or so more torque than a similar 350. BUT - again, the way you drive is the single most important thing. If you can avoid slipping the clutch when geting the car moving - the clutch can take a lot more abuse than if you are slipping it...
You're probably going to need bigger injectors, and changing the heads pretty much guarantees the need for a tune...
BTW - Speaking as someone who has pulled the engine out of more than one C4 - I'd recommend pulling the trans first, then going in with the engine hoist from the side to get the motor. The ZF gearbox is heavy - around 130 Lb, and it doesn't like to sit flat. I've had luck with pulling the two Batwing bolts and controlling the rear end with a floorjack. That allows you to get a better angle for the "C-Beam" removal and to let the shifter clear the body as the trans comes out.
The ZF gearbox that sits behind the LT1/LT4 C4's is identiacl to the one that sat behind the LT5's C4's - those made 400 HP - so no real issues there. Basically the same for the Dana 44. The way most people hurt the Dana diffs is by bolting on slicks, and doing REAL hard launches. The ZF is normally hurt by people who drag race and subject them to power shifting... As for heads - unless you're planning to do really high RPM's - a set of good heads that will work on a 350 will be fine. THe AFR 195's are a pretty good choice, or you could check out Lloyd Eliott - he knows the LT1 heads QUITE well and does some very nice porting work.
As for a clutch set-up - these days your options are somewhat limited. How you use the car will impact your choices here. Remember - a 383 will typically make 10% or so more torque than a similar 350. BUT - again, the way you drive is the single most important thing. If you can avoid slipping the clutch when geting the car moving - the clutch can take a lot more abuse than if you are slipping it...
You're probably going to need bigger injectors, and changing the heads pretty much guarantees the need for a tune...
BTW - Speaking as someone who has pulled the engine out of more than one C4 - I'd recommend pulling the trans first, then going in with the engine hoist from the side to get the motor. The ZF gearbox is heavy - around 130 Lb, and it doesn't like to sit flat. I've had luck with pulling the two Batwing bolts and controlling the rear end with a floorjack. That allows you to get a better angle for the "C-Beam" removal and to let the shifter clear the body as the trans comes out.
Thanks for the good feedback, especially on engine removal. I've been wondering about this aspect of the project.
Maybe i'm reading wrong but you recommend pulling the trans, c-beam and bathwing as on unit?
Not quite - I recommend pulling the trans first. Trans removal requires removal of the "C-Beam". So ...
I would recommend getting the car up in the air a ways -
Then removing the exhaust
Then remove the driveshaft.
Then break the "C-Beam bolts loose
Then remove the batwing bolts.
Then once the batwing is able to drop down a bit - the "C-Beam" is significantly easier to remove.
Then remove the transmission.
Then remove the bellhousing and the clutch assembly.
Then put the car back down on the ground - and get the cherry picker out to remove the engine.
And while it may seem trivial - the gearshift **** removal can be frustrating. In order to unscrew the **** - you need to remove the square pin (hiding under the gear pattern insert). That can be a real PITA. The square pin comes out by pulling it straight up. Sometimes a pair of small vice grips can get it - otherwise drill a hole in the square pin and tap it for a machine screw - screw a relatively strong screw into the threaded hole you made in the pin - and pull or pry on the screw.
Ruby's LT1 finally let go
