DrewHMS97SS

Definitely have the hub machined for the key. It shouldn't be very expensive, and will guarantee the hub can be used to determine engine position, and also removes any possibility of the hub spinning.

ridiqls

Thanks, I'll ask to see if I can get it keyed. Although I'm less concerned about a keyed hub and more about the crank timing gear key for now. I'll see what the machine shop says





Anyway,
I'm thinking a standard SBC key was installed. Something like this:



Logically I feel it makes make sense that a shop didn't know the LT1 key was supposed to be notched so they used a regular SBC key, versus installing it backwards. I would assume they would have noticed when putting on the crank sprocket if the notch was backwards. If they knew to get a notched key then they'd probably know the direction it goes. But it would be believable if they didn't know the LT1s were notched

Chimera96

Given there is the possibility the shop that built the motor used a standard SBC key....it suggests they are not versed in the changes the LT1 (gen 2) is over the previous SBC. Hopefully they removed the check ball from the oil galley before cleaning the block....and more importantly re-installed it.

What compression ratio did the shop say the motor is now??

I would quiz the shop on both points...if the answer starts with a "ah..." you have some checking to do on your end. Both would require the motor to be on a engine stand to resolve/check

If they just used a standard key for the crank sprocket no big deal if you have a keyed hub. Typically a shop charges $40 to key a hub...or you can buy one for around $40-$50. IMHO a keyed hub is ALWAYS better

ridiqls

Hmm I didn't know about the check ball. I will ask him about that.

Regarding compression ratio, I assume it's just a stock LT1 compression ratio since every part on it is stock except the forged pistons. How would you check the compression ratio? And should I have any reason to suspect it would be different from stock ratio if it was built to stock specs?


Anyway, he got back to me and the crank timing sprocket key was a full sized key, not notched. So it wasn't installed backwards. He did offer to notch the key for me if I bring it back. So that being said, I'm not too worried about the notch being installed backwards inside the timing gear.

But I will have to check clearances to see if the crank hub can be pressed all the way in due to the key sticking out horizontally. I'm going to put the crank hub back into my old engine (without timing cover) and see where it stops at on the crank snout, measure it and then see if I can do the same on the new engine crank. If there's enough clearance, I won't have to grind anything and the key sticking out past the timing gear won't be an issue.

But if it has clearance problems, I'll take my crank hub to the shop and have them cut out a keyway notch so it will slide in all the way. I just need to test and measure first.



Anything else come to mind that I should ask about regarding the engine?

I don't suppose this picture shows any insight to the oil galley check ball/plug? I just took it to check the 4bolt mains as proof for later.

Chimera96

On the left side of motor, rear main cap-forward hole is where the check ball goes. If it was not removed for block cleaning there is no way the oil galley is completely clean. It is a interference fit and you use a brass drift to knock it out and re-install it. You punch it out from top and install it from bottom. There is a ridge in the oil galley it bottoms out on. It is a interference fit

You have a GM 4 bolt main block (corvette) looks like, cool

LT1 can deal with higher compression than previous gen SBC. IIRC compression is 10:8 stock. Many performance rebuilt motors are set up to about 11:3.

Your head chamber size, head gasket thickness, how much from the block and heads were decked, pistons are all part of the equation on what your compression ratio will be. Many SBC builders just assume regular older SBC which is around 8-9 ish to 1

All this should be on the "build sheet" the shop "should have" provided

Not saying they did anything wrong but without a build sheet you will have to ask. If answers are "well we usually..." or "I've been building SBC for decades, they are all the same"..are answers you don't want to hear

ridiqls

Gotcha thanks. When I went to the shop he gave me a tour of his builds and took the time to explain everything. I asked what zero deck meant and he showed me on a performance build he was building. I remember him mentioning how zero deck is used for compression but mine wouldn't have that and gave me the stock compression ratio but I forget what he said. But I believe it was considered during the build process.

This $35 wireless snake camera (Depstech camera on amazon) saved my *** twice already. Once to find TDC while the engine was still in the car and now, to look down from the top of the oil pressure sensor hole and this is what I saw:

Oil Galley Check ball in tact. Clean otherwise



So relieved I don't have to tear this down

Chimera96

Cool, great its all good. I only raised my hand because the wrong crank sprocket key was used which implied the builder was lacking in some LT1 specifics, even between 94-95 & 96 years.

Go with a keyed hub and it won't be a problem

ridiqls

I appreciate the help, better to be safe and know this for next time then not. Thanks again

Injuneer

Marshmaro

Wow..very informative ..
with the price of rebuild I'm seeing and time . I for sure would have opted for a drop in replacement ..
By me I see low mileage lt1 engines go for 300$, Fbody lt1 too. I was looking at a built one with cam afr heads cam harmonic balancer , pistons ECT..guy was asking 900 only..lol even had the 58mm throttle body Nd nice fuel rail on it..

ridiqls

Got the intake manifold on, exhaust manifold, crank hub, spark plugs, Opti, wires, etc. I only have the accessories on the left/right side and mating up the tranny and it should be good to go under the car again. I still need to replace the heater core before I put coolant in the system as well as address the AC leak somewhere so I'm going to change the O-rings on all the AC lines.

As for the crank hub, my engine shop and I were emailing back and forth and he said come by with my crank and I got it keyed. Super good guy, went on no problem.


It's not ideal but I'm trying to troubleshoot the overheating issue I had before when the old engine was in the car as much as possible NOW using deductive reasoning and clues.. so that if something needs replacing I can do it before I throw the engine in the car.

Clues:
- Previous owner said car would overheat at stand still or on long drives. He bought it from the owner before him in that state and never fixed it. He drove 30 mins each way to work and managed to do it without overheating.
The stand still part tells me that there's something wrong with the cooling fans possibly.
- Car then experienced continual overheating and previous owner had a new water pump and thermostat put into the car. Did not fix it the original issue though but when I test drove it, it was a very hot day and it did not overheat during the 15 mins or so driving it.
- When I drove it home, temp was in the red during the 10 mins drive but that's because on the way home, the ****ty shop that did the water pump mickey moused the cooling hoses (earlier in the thread I posted pics) and the car lost all its coolant about 2 miles from my house. It was a hot day, around 98 degrees.
- I got home and noticed I did not hear the cooling fans despite the car having very little coolant, and temp gauge in the red. Switched around the relays and the fan relay is not the problem.
- Then the rest is in the thread here... did compression and leak down, bad engine and so I bought a new engine.

I used shbox to test the 2 temperature sensors 4th Gen LT1 F-body Tech Articles
The sensor in the water pump is showing the correct resistance. At about 60 degrees ambient temp, it shows the corresponding resistance.
The sensor that goes in the cylinder head on the driver's side that sends the temperature to the gauge cluster seems to be broken? I just checked with an ambient temp of 65 degrees, it's showing 277 ohms, which is indicating around 85 degrees. .. So it is showing 20 degrees HIGHER than what's real.

But that temperature sensor does not affect the cooling fan operations from what I understand? I mean if the sensor is showing artificially high, then it's possible that the previous owner thought the car was overheating when it wasn't because of a bad sensor that's off by 20 degrees. But I'm not sure how a car driven about 10 minutes in 98 degree weather with very little coolant could not cause the fans to kick in. The temperature gauge could have been off but I expect that in that scenario during a hot summer day, it would still cause the fans the kick in.

When I hooked up my scanner to the car, I was able to have the cooling fans come on manually in service mode or whatever. The software had a button to manually engage the cooling fans and it worked. But I wasn't able to test this with the engine running, by this time I already had the spark plugs out and stuff removed.

So I'm not sure what to think at this point.

I'm going to replace this sensor because it seems faulty anyway. Then, I guess I will have to just throw the engine in the car and start it with coolant and see what my scanner reads from the PCM. If the fans don't engage at over 220 deg F, then I will have to look further but I hope not. Because the fans are not faulty, the PCM doesn't seem faulty, fuse and relays are good, and the sensor that send the temp to the PCM (on the water pump) is good. I'm out of options so let's just hope it works.

Aside from that, the only other thing I'm trying to figure out is where all the wires on the starter goes.

Is this connection correct? (I put the ring terminal coming out of the big starter canister on the lowest stud)



Slowly but surely...

EDIT: Believe the big stud up top with the 2 nuts are for the battery terminal. The stud closest to the block is for the signal wire/purple wire. And that leaves this bottom connection with the ring terminal and 1 nut. I believe it's right but the connection is too short to tighten down. I might be missing a nut

97rebuiltZ28

You are correct, the head sensor is only connected with the gauge. It is not abnormal for the temperature gauge and the computer to show two different temperatures. Mine is about 15 degrees off. Also the LT1 engine likes to run warm. The stock fans come on low at 226 degrees and high at 235. You said it ran noce and cool when driving, the air dam under the car is the reason that they run so cool when driving at speeds.

Injuneer

Chimera96

OP

I will note, and assume you know, but the LT1 cooling system requires bleeding air out. If this is not done the car will overheat even with all fans, sensors working correctly and system full of coolant

ridiqls

Gotcha, I ordered a new temp head sensor anyway I figured mine is off by 20 degrees from the get go so it's probably faulty. I'll check the resistance on the new one today and if it's the same as the old one, then maybe it wasn't faulty and I'll just return it.

Ok awesome. I have scan9495 and a cable but I haven't had a chance to use it all that much aside from the time I hooked up it up and checked to see if I can turn the fans on manually (which I could). Also didn't see any DTC codes.

But that's a good point, I will data log once I get the engine started up so I can see what's going on and I'll post it as a CSV file. Once the engine is in the car, I'll make a new thread for the troubleshooting aspect of it. Thanks for the help.

Yep definitely will consider this. I didn't do this initially because the compression test was bad so there was no point in filling it back up with coolant. But I'm going to make sure when I put in new coolant that I bleed it properly.