Just cranked LT1 project engine--noise?
Thread Starter
Racer
Joined: Oct 2003
Posts: 429
Likes: 0
From: Plains Ga.
Just cranked LT1 project engine--noise?
I started the engine about 5:00 PM today. I'm getting a strange 'TAPPING" noise from somewhwere in the engine.
I don't think it's a rod or piston noise. I was VERY careful when assembling this engine. I am using the LT1 composite valve covers
from the original engine. I "did not" trim the drip tabs from inside of these valve covers because there did not look like they would hit the rocker arms. I am using the Crane "Gold" 1.5 to 1 ratio roller rockers
that are self-centering. Please give any ideas you may have. I oil primed the engine on the engine stand and also put the starter on and turned the engine over several times. The oil pressure is 70 psi. I installed new knock sensors and a "LT4" knock module. I did not have any sign of tapping until I started the engine. I also installed a rebuilt
4L60E trans. at the same time. All fluids are OK.
HELP!!!
JTHVETTE
I don't think it's a rod or piston noise. I was VERY careful when assembling this engine. I am using the LT1 composite valve covers
from the original engine. I "did not" trim the drip tabs from inside of these valve covers because there did not look like they would hit the rocker arms. I am using the Crane "Gold" 1.5 to 1 ratio roller rockers
that are self-centering. Please give any ideas you may have. I oil primed the engine on the engine stand and also put the starter on and turned the engine over several times. The oil pressure is 70 psi. I installed new knock sensors and a "LT4" knock module. I did not have any sign of tapping until I started the engine. I also installed a rebuilt
4L60E trans. at the same time. All fluids are OK.
HELP!!!
JTHVETTE
Burning Brakes
Joined: Nov 2003
Posts: 935
Likes: 2
From: Beverly, NJ
Originally Posted by JTHVETTE
I started the engine about 5:00 PM today. I'm getting a strange 'TAPPING" noise from somewhwere in the engine.
I don't think it's a rod or piston noise. I was VERY careful when assembling this engine. I am using the LT1 composite valve covers
from the original engine. I "did not" trim the drip tabs from inside of these valve covers because there did not look like they would hit the rocker arms. I am using the Crane "Gold" 1.5 to 1 ratio roller rockers
that are self-centering. Please give any ideas you may have. I oil primed the engine on the engine stand and also put the starter on and turned the engine over several times. The oil pressure is 70 psi. I installed new knock sensors and a "LT4" knock module. I did not have any sign of tapping until I started the engine. I also installed a rebuilt
4L60E trans. at the same time. All fluids are OK.
HELP!!!
JTHVETTE
I don't think it's a rod or piston noise. I was VERY careful when assembling this engine. I am using the LT1 composite valve covers
from the original engine. I "did not" trim the drip tabs from inside of these valve covers because there did not look like they would hit the rocker arms. I am using the Crane "Gold" 1.5 to 1 ratio roller rockers
that are self-centering. Please give any ideas you may have. I oil primed the engine on the engine stand and also put the starter on and turned the engine over several times. The oil pressure is 70 psi. I installed new knock sensors and a "LT4" knock module. I did not have any sign of tapping until I started the engine. I also installed a rebuilt
4L60E trans. at the same time. All fluids are OK.
HELP!!!
JTHVETTE
Did you adjust the valve lash? If the rocker arms are loose at all, then it will make a tapping noise. You have to check and adjust them while engine is running to get them adjusted properly. This is my experience. I hope this helps. I am sure someone else will chime in also.
Race Director
Joined: Jan 2002
Posts: 12,263
Likes: 86
From: O'Fallon Missouri
Originally Posted by JTHVETTE
I am using the LT1 composite valve covers
from the original engine. I "did not" trim the drip tabs from inside of these valve covers because there did not look like they would hit the rocker arms. I am using the Crane "Gold" 1.5 to 1 ratio roller rockers
that are self-centering.
from the original engine. I "did not" trim the drip tabs from inside of these valve covers because there did not look like they would hit the rocker arms. I am using the Crane "Gold" 1.5 to 1 ratio roller rockers
that are self-centering.
When I ran the Crane Golds, I trimmed the drip tabs. But, maybe I didn't need to.
-Mike
Thread Starter
Racer
Joined: Oct 2003
Posts: 429
Likes: 0
From: Plains Ga.
Noise From Rebuilt Lt1?
I reset the valve settings to make sure it wasn't the valve assemblly.
It sounds as if a rod or the crankshaft is touching the edge of the block as it rotates. The rods, pistons, and crank were balanced together. I used Eagle rods and torqued them according to factory specs. The crankshaft is new. The pistons are new hyper$%^ and the rings were matched for these pistons. I have drained the oil so I can remove the oil pan tommorrow morning. What I expect to find is some part of the rotating assembly to be touching the block. I may have overlooked something during assembly. The engine cranks up and runs great. I have not let it run for any longer than 10 to 15 sec. Good oil pressure. This noise started as soon as the engine started. I don't have any reason to believe it to be a bearing problem, they usually come latter.
JTHVETTE
It sounds as if a rod or the crankshaft is touching the edge of the block as it rotates. The rods, pistons, and crank were balanced together. I used Eagle rods and torqued them according to factory specs. The crankshaft is new. The pistons are new hyper$%^ and the rings were matched for these pistons. I have drained the oil so I can remove the oil pan tommorrow morning. What I expect to find is some part of the rotating assembly to be touching the block. I may have overlooked something during assembly. The engine cranks up and runs great. I have not let it run for any longer than 10 to 15 sec. Good oil pressure. This noise started as soon as the engine started. I don't have any reason to believe it to be a bearing problem, they usually come latter.
JTHVETTE
Last edited by JTHVETTE; Jul 8, 2005 at 09:58 PM.
Large Impressive Member
Joined: Jul 2003
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From: Good health is merely the slowest possible rate at which one can die
St. Jude Donor '04-'05-'06-'07
Is this a stroker George? Give us more details re/ what's stock, what's aftermarket, new, changes made and etc. What kind of rods? Is it running smoothly other than the noise? Any chance a push rod could have gotten bent or something? Is it consistent and did it quiet down any after readjusting the valves and then get louder again? Any changes in the timing set, front cover area? BTW, I'll be out of town the next week or so but will get on the internet when able. So whenever you want to send that info re/ what we'd talked about, I'll see it at some point. Keep us posted and good luck.
Thread Starter
Racer
Joined: Oct 2003
Posts: 429
Likes: 0
From: Plains Ga.
LT1 engine noise?
Originally Posted by Corvette Kid NC
Is this a stroker George? Give us more details re/ what's stock, what's aftermarket, new, changes made and etc. What kind of rods? Is it running smoothly other than the noise? Any chance a push rod could have gotten bent or something? Is it consistent and did it quiet down any after readjusting the valves and then get louder again? Any changes in the timing set, front cover area? BTW, I'll be out of town the next week or so but will get on the internet when able. So whenever you want to send that info re/ what we'd talked about, I'll see it at some point. Keep us posted and good luck.
The engine is a 2 bolt main block that has splayed 4 bolt main installed,
align bored, and align honed. The block was bored .030" over , decked (very little), and honed with a torque plate attached to the block. The crank is stock stroke (new). The cam is a CompCam 304 (.490/.510,I think?). Everything else is basicly stock, other than the valve springs,lifters, push rods,conn. rods,LT4 stock timing set, high volume oil pump,GM windage tray. I should know something first thing in the morning (8:00am/est) after I remove the oil pan.
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Safety Car
Joined: Dec 2002
Posts: 3,655
Likes: 24
From: Charleston SC
I can't see anything hitting the block, I have a 3.75 stroke with H-beams and it didn't require to much clearancing. Mabeythe windage tray is a posibility. It is hard to say without isolating the area the sound is coming from. Also what about the flexplate? a broke flexplate sounds a whole lot like a rod knock.
Thread Starter
Racer
Joined: Oct 2003
Posts: 429
Likes: 0
From: Plains Ga.
LT1 engine noise?
Originally Posted by FD2BLK
I can't see anything hitting the block, I have a 3.75 stroke with H-beams and it didn't require to much clearancing. Mabeythe windage tray is a posibility. It is hard to say without isolating the area the sound is coming from. Also what about the flexplate? a broke flexplate sounds a whole lot like a rod knock.
I don't know. The flexplate is from the engine that was in the Vette originaly. I gave it a quick check before swapping it, but I cannot say it is good for sure. I would assume that if it were bad it would have shown up with the other engine, but then again what happens when we "ASSUME" some thing, it makes an a$$ out of me! There is a possibility that the noise could be coming from the flexplate. That was one of the first places I looked. I removed the trans. dust sheild to see
if there was any problem there. The noise appeared to be coming from the rear section of the engine. I hope that I find it asap Sat. morning and it is nothing major. We have a tendency to suspect the worst sometimes.
JTHVETTE
Le Mans Master
Joined: Jan 2003
Posts: 8,596
Likes: 19
From: Portland Oregon
If you used the stock oil pan, most of the time they require a bit of clearance work with a BFH. (BIG F******G Hammer) 
It could be the crank hitting the pan that is causing your noise.
It could be the crank hitting the pan that is causing your noise.
Le Mans Master
Joined: Jul 2000
Posts: 7,639
Likes: 326
From: Greenville SC
Originally Posted by tjwong
If you used the stock oil pan, most of the time they require a bit of clearance work with a BFH. (BIG F******G Hammer) It could be the crank hitting the pan that is causing your noise.
It could be the crank hitting the pan that is causing your noise.
Thread Starter
Racer
Joined: Oct 2003
Posts: 429
Likes: 0
From: Plains Ga.
LT1 engine noise?
Originally Posted by tjwong
If you used the stock oil pan, most of the time they require a bit of clearance work with a BFH. (BIG F******G Hammer) It could be the crank hitting the pan that is causing your noise.
It could be the crank hitting the pan that is causing your noise.I pulled the oil pan, windage tray and the oil pump. I have found nothing to cause a tapping noise (similar to a rod knock) nowhere in the rotating assembly. I checked for crank clearance, rod clearance, piston clearance, anything that might be touching or rubbing. I find no lost motion in the wrist pins, rod bearings, or crank bearings. I am wondering if it could be combustion knock? HELP, I'm SOL now!!!
JTHVETTE
Thread Starter
Racer
Joined: Oct 2003
Posts: 429
Likes: 0
From: Plains Ga.
LT1 engine noise?
I decided while I had the oil pan off I would remove the rod caps and inspect the rod bearings. I started with #7 & 8 cyl. and found a "little" scratching from debris. I did #6 & 5 and #4 & 3 cyls. and found about the same amount of scratching from debris. When I got to #1 & 2 cyl.
I found #1 to be like the rest, but #2 had a LOT of scratching from debris. None of the rod journals appeared to have ANY damage. I got a new set of rod bearings to install Sunday afternoon.
How much wear is needed to a rod bearing to make it "knock" when the engine is running? I'm hoping that the problem noise is the rod bearings on #2 cyl.
I also checked the crank clearance by putting blue layout fluid on the counterweights to see if any of them were rubbing the block. I didn't see any sign of contact. I then pu a light film of white lithum grease over the layout fluid to ckeck for rubbing, same results.
I will let you what happens with the new rod bearings.
JTHVETTE
I found #1 to be like the rest, but #2 had a LOT of scratching from debris. None of the rod journals appeared to have ANY damage. I got a new set of rod bearings to install Sunday afternoon.
How much wear is needed to a rod bearing to make it "knock" when the engine is running? I'm hoping that the problem noise is the rod bearings on #2 cyl.
I also checked the crank clearance by putting blue layout fluid on the counterweights to see if any of them were rubbing the block. I didn't see any sign of contact. I then pu a light film of white lithum grease over the layout fluid to ckeck for rubbing, same results.
I will let you what happens with the new rod bearings.
JTHVETTE
Burning Brakes
Joined: Nov 2004
Posts: 781
Likes: 0
Take a close look at the windage tray. It has a couple spots where it is stamped for rigidity that are in close proximity of the rod bolts on the down stroke. I recently did a stock stroke with H-beams and they hit the rear of the windage tray that bolts to the mains.
Thread Starter
Racer
Joined: Oct 2003
Posts: 429
Likes: 0
From: Plains Ga.
LT1 engine noise?
Originally Posted by 500hp
Take a close look at the windage tray. It has a couple spots where it is stamped for rigidity that are in close proximity of the rod bolts on the down stroke. I recently did a stock stroke with H-beams and they hit the rear of the windage tray that bolts to the mains.
After I change the rod bearings out, I'm going to put the oil pump and windage tray back in and check for rod and crank rubbing. I've looked at the tray and didn't see any signs of rubbing. At this point I'm hoping to find something simple that's causing my problem.
JTHVETTE
Thread Starter
Racer
Joined: Oct 2003
Posts: 429
Likes: 0
From: Plains Ga.
Restarted LT1 project engine--no noise!!!!!
Well guys it was one of two things or both. The rod and main bearings
were "Clevite 77" series "H" that were in the engine which I changed to
series "P". There was some debris in the oil also (not much). All of the bearings were scuffed . The crank journals looked good. The #2 rod bearing was worn the worst and probably was the "tapping" noise I was hearing. There is no noise as of today other than some header leaks I need to take care of. The oil pressure
was 80 psi at 2,000 rpm. Hope somebody else learns from this "Charlie Fox".
I know I did!!!!!
Thanks, JTHVETTE
were "Clevite 77" series "H" that were in the engine which I changed to
series "P". There was some debris in the oil also (not much). All of the bearings were scuffed . The crank journals looked good. The #2 rod bearing was worn the worst and probably was the "tapping" noise I was hearing. There is no noise as of today other than some header leaks I need to take care of. The oil pressure
was 80 psi at 2,000 rpm. Hope somebody else learns from this "Charlie Fox".
I know I did!!!!!
Thanks, JTHVETTE
Last edited by JTHVETTE; Jul 11, 2005 at 08:41 PM.
