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Ultra low budget project here. I am rebuilding and then swapping an LT1 & T56 into my CMC 3rd Gen. I have never done an engine rebuild on my own but I am determined to do it at home in my shop. I am a "YouTube graduate" so I should be able to do most of it lol, oh and I've also been searching the forums for months getting ready.. But I am coming across some things along the way that I have questions about that aren't covered in most resources I have read or watched. So I decided to start a rebuild / swap thread as I go along I'll post pictures and my questions as I stumble across different challenges.
To catch you up to where I am at now here are some pics and explanations.
First Picture is the #77 on my lift at home. This is the recipient vehicle.
Dropping the engine/trans w/ kmember out the bottom of the car. Carefully pulling the engine/trans up off the kmember. Another kmember drop pic.
Block opened up. So far all rod bearings showed no signs of abnormal wear. Dirty Pistons but very little wear. Must have been rebuild at some point. Mic'd out to STD size bores and pistons. Cleaned pistons go in a bag and get coated with Corrosion X while I work on the rest.
Per NASA CMC rules I need to run the stock Cam. This engine came with a nice Comp Cams K07-465-08 cam kit over $1000 from summit, but I can't use it. So, I had some stock LT1 cams laying around the shop. Cleaned them up and inspection time. Cam #1 i found had been grinded at some point. I think its trash now, but lmk your opinions. Cam #2 had some mild to moderate corrosion but I was able to clean it off with a 3m scouring pad on the end of a die grinder. It looks ok, but not perfect. Please LMK your thoughts.
LT1 stock cam #1 someone has grinded this lobe! Now its trash.
LT1 stock cam #2 I had laying around had a fair bit of corrosion. A 3m scouring pad and an angle grinder seemed to clean it up. See next pic.
Cam #2 after clean up. Looks ok I think.
This is a close up of Cam #2 on the worst part. Not perfect, but should hold together. LMK your thoughts!
Last edited by 64GunPilot; 09-23-2022 at 04:18 PM.
Reason: spelling
So I have a rod cap that has some kind of grind on it. Maybe it spun a bearing at some point in its life? IDK. For you experienced rebuilders out there, can you weigh in and tell me what you think? Should I replace this whole rod & end cap, or is this damage acceptable? I have an Iron Headed LT1 from an Impala, will it have the same PM rods? Id have to tear it completely down to steal a rod from it, but I will if I must.
This concludes my questions for now. The cleaned up cam is ok to use after 3m scouring pad cleanup? And this Rod end cap??
Last edited by 64GunPilot; 09-29-2022 at 12:03 AM.
Be sure to measure lift and multiply by 1.5 to verify you have an F/Y body stock LT1 cam and not a car/Vortec truck cam. Your lift should be .450"-.460" for the correct cam. The wrong cam will make like 240/330 instead of the 260/310 that you need. Don't you have more than 1 motor? If so, just slap the one in as is and keep on cleaning this one up. It should make the numbers even if it's old.
Be sure to measure lift and multiply by 1.5 to verify you have an F/Y body stock LT1 cam and not a car/Vortec truck cam. Your lift should be .450"-.460" for the correct cam. The wrong cam will make like 240/330 instead of the 260/310 that you need. Don't you have more than 1 motor? If so, just slap the one in as is and keep on cleaning this one up. It should make the numbers even if it's old.
I do have two. I purchased this one which was already disassembled down to the short block. Guy said it had been “rebuild in 2018” but didn’t exactly have a solid answer why it was disassembled other than it was his first time and realized he was over his head and stopped. This is the one that had the Comp Cam kit in it.
The 2nd engine is the iron headed engine out of the green Camaro. Again, no idea how iron heads ended up in that car. VIN indicates it was originally a V8 car. Idk if the whole thing came from an Impala or if it was just the heads.
Your suggestion of swapping some fresh aluminum heads on this already running engine is exactly what I was gonna do….use the 2nd short block. But when I drained the oil bronze glitter came out of the oil pan. I need to cut open the oil filter and see it’s condition. I had already kinda Set this one aside and decided to go full steam ahead with engine #1. But I suppose it’s worth cutting open #2’s filter and having a look.
I am fairly certain all B-Body LT1s have a knock sensor on both sides of the block instead of just the passenger side. That should tell you if someone just swapped the heads or the whole motor. The cams are different.
I am fairly certain all B-Body LT1s have a knock sensor on both sides of the block instead of just the passenger side. That should tell you if someone just swapped the heads or the whole motor. The cams are different.
Tracking the cams and heads but didn’t know about the knock sensors. Good to know. Thx.
I found this book, may be available other places cheaper, very helpful in specific LT1 Gen 2 motor rebuild...there are some small but critical nuances to the 2nd gen LT1
I have read this article awhile back before I was interested in Gen2 LT engines. Forgot it existed. I stumbled on it again and found that the cams can be identified by the stamped numbers behind the 1st lobe.
93-94 Corvette/Camaro —> 241 stamping
94-96 B-Body Iron Headed —> 600 or 779 stamping.
95-97 Corvette/Camaro —> 242 or 705 stamping.
I can confirm the cams in the pictures above are stamped with 242 indicating factory Corvette/Camaro cam.
So I have a rod cap that has some kind of grind on it. Maybe it spun a bearing at some point in its life? IDK. For you experienced rebuilders out there, can you weigh in and tell me what you think? Should I replace this whole rod & end cap, or is this damage acceptable? I have an Iron Headed LT1 from an Impala, will it have the same PM rods? Id have to tear it completely down to steal a rod from it, but I will if I must.
This concludes my questions for now. The cleaned up cam is ok to use after 3m scouring pad cleanup? And this Rod end cap??
I found a used 1995-1997 # 2-4-6-8 LT1 piston/rod assembly on eBay for $41 shipped.
I’ll reuse the bolts and nuts as long as there is no thread damage.
Who's the seller? I did the same back in 2015 when I spun a rod bearing. Got the later pistons and rods on eBay and found a late crank locally. Had the crank polished, new standard bearings, 3 stone honed the cylinders, new moly rings, and add some send. I regret not doing the cam bearings though I was in a hurry to get it back together. It still lives today and this year took a 35mm plate to choke it down to 259/311.
Firehawkjeff was the eBay seller. He has a whole set for $200 shipped but I only need 1 so I opt for the budget route. Hope it pays off.
Sometimes trying to go cheaper bites you in the *** and you end up spending more in the end.
I’m out of town this week. As soon as I get back I’m gonna cut that other engine’s oil filter and report back here with the pics and my assessment. But I’m still gonna build this engine up regardless. So while I’m out of town, still researching and buying budget parts. Will be ready for flexball hone, cleaning and reassembly when I get home. I think I can build it up quickly as long as I don’t run into anymore problems.
Total parts ordered so far:
Rings
Cam Bearings (I’ll do the install)
Main & Rod bearings
Gasket Kit
Piston / Rod Assembly
Used harness W/ VATS EGR deleted PCM
Being cheap multiple times over has paid off in spades for me. Those odds are good enough for me to keep adding send. That said, being cheap doesn't necessarily equate to being ignorant and you're certainly not headed down that path. Good enough is good enough and all you need is 260 wheel, preferably with minimal plate. The LT1 should have ample wiggle room to afford you that. Just be sure to do a full track day before hitting the Dyno. Mine refused to break in on the Dyno. I made like 20-30 pulls and nothing, I walked with a 250/275 pull. 5 minutes on the track and all of a sudden the car was freight training. Ruh roh, back to the Dyno and it was 270/3XX. Next spring I was over again. Seems it broke in twice. Which rings did you get? The iron rings break in faster but the moly lasts longer. They also require a different grit of hone.
Being cheap multiple times over has paid off in spades for me. Those odds are good enough for me to keep adding send. That said, being cheap doesn't necessarily equate to being ignorant and you're certainly not headed down that path. Good enough is good enough and all you need is 260 wheel, preferably with minimal plate. The LT1 should have ample wiggle room to afford you that. Just be sure to do a full track day before hitting the Dyno. Mine refused to break in on the Dyno. I made like 20-30 pulls and nothing, I walked with a 250/275 pull. 5 minutes on the track and all of a sudden the car was freight training. Ruh roh, back to the Dyno and it was 270/3XX. Next spring I was over again. Seems it broke in twice. Which rings did you get? The iron rings break in faster but the moly lasts longer. They also require a different grit of hone.
Honestly thats the way my 383 is breaking in too. Numerous pulls tuning on the dyno. Pulled a sustained 8% grade in overdrive a few times at 80 mph and now has even more power. Took sustained heat and cylinder pressure to finally seat the rings.
Mahle rings with top ring having plasma moly face. MAH-41616CP
I planned on taking it to a HPDE event before racing to give the whole car a real good shakedown prior to putting the car back into racing action.
So many things can go wrong after a swap and I don’t want another DNF. Broke my heart last time at Hallett. Didn’t make it 3 laps during practice and my 305 TPI bottom end lost all oil pressure.
Good thought to dyno after the shakedown. I suppose I’ll run it unrestricted for the shakedown and then figure out what restrictors I need for the dyno.
I’m gonna continue using the 3rd Gen air intake with the two square air filters. I’ll just restrict it from there with square plates above the air filters like another fellow racer does.
Anyone want to weigh in on what I should target for bearing clearances?
im thinking loose with HV pump and 20w-50 oil.
something like: Bearing Clearances
Main - 0.00233 - 0.00295
Rod - 0.00207 - 0.00260
Lmk your thoughts.
Stock clearance with a max of 40W oil. You're not turning the RPM to justify a wider clearance. RPM flexes the crank more which necessitates the wider clearance to prevent metal on metal contact and then thicker oil to fill that bigger gap. Don't overthink it.
1. The Rod End cap grind is a perfectly normal thing apparently. Received the used Piston/Rod assembly and it was exactly the same. Called the guy up and he said 75% of the LT1 rods he sells have that same grind in them and supposedly nearly all SBC 305/350 have them. Guy is an experienced F-Body scrap yard so, I'll take his word for it. I apparently wasted $41 on a used Piston/Rod for a ill-perceived deficiency which was considered normal. Oh well...
Received like this.
2. Weight n Balance: Since I have a true 95-97 LT1 Piston/Rod Assembly, I decided to weigh it and compare to my existing set. First off I noticed my pistons must be aftermarket because they dont look the same. Second, the weight difference between the two is 55 grams! Looked at the crank to see if it showed any signs of being balanced. NOPE! So, this rotating assembly must go to the machine shop for balancing IMO. Kills my whole budget thing.....and my whole plan to keep the machine shop out of the picture. Machine shop said he could get to it in 3 weeks ugh!!
My existing Piston/Rod weight. 1333 grams total.
OEM 95-97 piston/rod assembly weight: 1278 grams.
3. Over to the backup plan: Gonna use the shortblock from the Iron Headed LT1. I am not certain but I think it was originally aluminum headed and later Iron Heads were installed. Because it has 1 knock sensor, and has the F-Body water pump. Cut the filter open just to make sure it was clear of aluminum and other debris. I only found one tiny spec with a magnifying glass. Started disassembling the front accessories today.
Tomorrow heads, intake, and oil pan will come off. Pull off the timing cover, clean it up, replace all the seals, and remove and inspect the camshaft. Gotta know what cam I have in it. Hoping to see a 242 or 705 stamped on it. I'll inspect and clean up the sealing surfaces. I might not even brake the transmission off of it...we shall see.
Need to order an AC delete pulley kit. I have plenty of work to do cleaning while I wait on the AC delete kit. Thats all for now. Gonna post more tomorrow after more teardown.
Last edited by 64GunPilot; 10-04-2022 at 11:33 PM.
09-23-2022, 03:51 PM
LT1 Rebuild & Swap into 3rd Gen 
