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Built Motor Unknown(SOLVED - Rod Knock) Cold Start Sound (Videos Inside)
12/2023 UPDATE: it was rod knock.
Hi all, dealing with a sound at startup and until the car is fully hot, after a 20 mile cruise there is no apparent noise. Engine seems to run great, has about 350-400 miles on it. Break in was 2-3PSI pulls 2k-5k then vacuum for the first 20 miles, then normal driving for 300. Recently started adding 10psi boost and that feels great too. All oil changes have been clean. Changed after 1st start, then 20 miles, then 100 miles. Oil pressure has always been perfect. Been boosted for 60k miles and 6 years, but new to built engines and the vvt platform.
The noise is a steady ticking at idle only, seems to be from the rear/exhaust side. Praying this is something stupid like an exhaust leak or just piston slap for a built engine. Noise is more apparent behind/next to the car. VVT is not hooked up yet.
This is the 2nd built motor put in the car, the first one disintegrated a rod bearing at 100 miles, pulled out - new oil pump/cooler, new crank, 1 new rod, cleaned everything including inside VVT gear and had the machine shop inspect for reassembly. Reused the pistons - there was slight piston to head contact after the bearing went on the first assembly, but was told everything could be reused.
There was a thread last year where someone posted clips of a similar noise and their solution was a new set of pistons. I feel like if I have to pull this engine again for another rebuild the HOA is gonna fine me lol. All work is being done in my driveway.
94 chassis, 2001 block and head, Supertech 9.5:1 84mm pistons, Manley Rods, ACL Bearings, Supertech +1mm valves intake and exhaust, Supertech single springs, FM Manifold, GTX2860 .64 A/R
Anyone have any ideas on things to check without pulling it out? Heading to harbor freight for a stethoscope and will be tightening the exhaust manifold nuts tomorrow.
Last edited by kaszuba; 12-04-2023 at 03:17 PM.
Reason: issue identified, might help others
Wow, didnt think your thread title was related but maybe it is. When I disassembled the first build there was one cylinder that had scuffing/wear near the middle of the pistons stroke, it was the same cylinder with the bearing failure. Hoping to find out what your conclusion is. I'll see if I can get a camera for the cylinder walls.
I had a sound that was similar and it was the water pump pulley. The bolts were loose, re-torqued with blue loctite and has been good since. Usually piston issues change with rpm, often go away when the engine speed is increased. Unfortunately to me it sounds like a rod bearing.
Get a borescope and make darn sure you don't have little smiles next to the valve cutouts on the pistons.
Found out the hard way that when VVT is fully advanced the combination of OS valves and some pistons don't work.
Well it does work for a while till it brakes a valve.
Hi all, dealing with a sound at startup and until the car is fully hot, after a 20 mile cruise there is no apparent noise. Engine seems to run great, has about 350-400 miles on it. Break in was 2-3PSI pulls 2k-5k then vacuum for the first 20 miles, then normal driving for 300. Recently started adding 10psi boost and that feels great too. All oil changes have been clean. Changed after 1st start, then 20 miles, then 100 miles. Oil pressure has always been perfect. Been boosted for 60k miles and 6 years, but new to built engines and the vvt platform.
This is the 2nd built motor put in the car, the first one disintegrated a rod bearing at 100 miles, pulled out - new oil pump/cooler, new crank, 1 new rod, cleaned everything including inside VVT gear and had the machine shop inspect for reassembly. Reused the pistons - there was slight piston to head contact after the bearing went on the first assembly, but was told everything could be reused.
There was a thread last year where someone posted clips of a similar noise and their solution was a new set of pistons. I feel like if I have to pull this engine again for another rebuild the HOA is gonna fine me lol. All work is being done in my driveway.
94 chassis, 2001 block and head, Supertech 9.5:1 84mm pistons, Manley Rods, ACL Bearings, Supertech +1mm valves intake and exhaust, Supertech single springs, FM Manifold, GTX2860 .64 A/R
Anyone have any ideas on things to check without pulling it out? Heading to harbor freight for a stethoscope and will be tightening the exhaust manifold nuts tomorrow.
I had a similar issue/ sound. Mine was an oiler bolt that had started backing out and hitting the bottom of the piston and the crank.
I had a sound that was similar and it was the water pump pulley. The bolts were loose, re-torqued with blue loctite and has been good since. Usually piston issues change with rpm, often go away when the engine speed is increased. Unfortunately to me it sounds like a rod bearing.
LeoNA called it! It was rod knock.
Got discouraged and took a break for a few months to focus on other unrelated projects with higher success rates...
Just got around to working on it again. Pulled the engine and found trashed bearings and journals everywhere. Cams, Rods, Mains
Everything's at the machine shop getting cleaned up and cams/crank polished.
Before going for the 2nd rebuild, I saw curly talking about not re-using blocks that have disintegrated a bearing because metal bits don't always get cleaned out....shoulda listened!
Yeah! Listen to me! I think I remember seeing this thread and wanting to say “pull it”, but I try not to be too pessimistic.ill speak up quicker next time.
biggest issue is the oe oil cooler/warmer, or any other oil coolers. They CANNOT be cleaned or reused.
you can reuse blocks all day, but cleaning them requires removing more plugs than you’d think, using 10-20 more cans of brake clean than you’d think, obscene amounts of compressed air, and a very bright flash light.
I have learned through this process that the experience of others is much more valuable than learning for yourself.
On the 1st build - machine shop recommended 'open up the boundary pump and clean it - theyre known to fail' - I didnt, then it failed.
Pics attached of rod 1/2 bearing journals, these were the worst...machine shop measured and said 'no problem to polish' in a matter of 10-20 seconds...
There are a few areas that get overlooked when cleaning these engines. Most shops do not want to remove the oil restrictor to the head because they are not readily available. I always pull them and make my own replacement. The block should be hot tanked and cleaned using the standard practices. Compressed air and brake clean is a good final process. The heavy cleaning should be done with solvent/mineral spirits and brushes. The other areas that get overlooked are the crank and cylinder head. The head has plugs for oil galleys that need to be removed and cleaned. No hot tanking with caustic cleaners on aluminum parts.
The crankshaft is a whole other topic. Most will claim your crank is good and can be polished. It's the path of least resistance. Shops are overly profit driven, absolutely to a fault. The cranks have blind holes filled with bearing material and grit from polishing. Removing the pressed in plugs is a PITA and then what do they get replaced with. I have not used any cranks from engines that had failures. That is going to change since the availability is declining. I will take the next one I have and will pull the plugs and see if there is enough material around the plug area to be tapped for plugs which is common for other applications. I highly recommend having your cranks ground if you have or know of a good shop that is set up to do these.
I do not use the OE oil/coolant heat exchanger because the coolant lines are a liability. The Boundary pumps are based off of a cheap chinese sourced pumps/castings. I do not recommend using these. The best option which is a bit more costly is to buy a OE VVT pump and put the boundary gears in it. The OE has better passages for the pressure relief system.
06-03-2023 | 12:25 AM
Built Motor Unknown(SOLVED - Rod Knock) Cold Start Sound (Videos Inside)
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