new motor has rod knock...

[brian97cobra]

well boys i think im going to throw in the towel for a while. my turbo cobra was at the dyno today. but before we were done we ran into some small issues. we got most of those corrected. but then we back car off dyno to go on a test drive and now the damn thing is knocking.

this is a BRAND NEW big bore boss block stroker..

im highly pissed and upset. i came here to vent

 

[Ironhand]

Who built the motor?

Are you sure it's rod knock?

 

[brian97cobra]

well the noise gets faster with engine rpm

its coming from the bottom end when i lay under the vehicle

it just started when we took it off the dyno. so perhaps there is little to no damage. im hoping that i can just take the pan off and install new bearings.

motor has about 2 miles on it (all dyno miles)


tim matherly of MV performance built the motor. he is a good guy, im going to call him tomorrow and see just how good he is.

 

[brian97cobra]

car made 715 rwhp 673 rwtq on 93 octane and 16 psi street tune and with c16 and 23 psi we made 847 rwhp and 795 rwtq.


he said the power seemed down for what the car had done to it

 

[Ironhand]

I wonder which pistons he used and what the Piston to bore clearance is. I also wonder if he used offset wrist pins or not.

I only say that because excessive piston slap can be quite loud.

 

[racebronco2]

well the noise gets faster with engine rpm

its coming from the bottom end when i lay under the vehicle

it just started when we took it off the dyno. so perhaps there is little to no damage. im hoping that i can just take the pan off and install new bearings.

motor has about 2 miles on it (all dyno miles)

tim matherly of MV performance built the motor. he is a good guy, im going to call him tomorrow and see just how good he is.

If it's a rod knock it's usually because of low oil pressure. I would check the drivers side head. If it is a rod knock it is usually heard when revving the engine. If you disconnect the fuel injector then the knock usually goes away. If you hear it at a steady rpm it's piston related. I am speaking from experience.

 

[DSGWhippedSnake]

Sounds like it may be a hurt piston skirt. But who the hell knows...could be anything. Only way to find out is to pull it apart. Sorry to hear, hopefully it all gets straightened out.

 

[jrd699]

Wtf...... That is about as bad as it gets... Hopefully you can get builder to "help you out" maybe he will go for labor? Worth a shot to ask... I'd be ready to kill something

 

[1Bad04Mystic]

Damn man, sorry to hear, let us know how everything turns out

 

[gabe1530]

sorry to hear. hopefully its an easy fix.

 

[SlowSVT]

That sucks! :nonono:

You essentially broke your engine in on a dyno which is a pretty brutal experience for a freshly minted engine. Never ever EVER trust a new engine! There are so many things that can go wrong and you decided to expose them by taking the engine to the extreme strapping the car down on a dyno. In that situation any problems encountered will be compounded by stressing the engine to the max which may cause further damage.

Had you broken in the engine gently would have allowed the parts to "seat" to one another and heat cycle the engine you may and I repeat "may" have avoided this. If it was improperly assembled then the manner in which it was broken-in wouldn't matter but it is always prudent to start off slow and work your way up the latter until it's confirmed that the engine is sound. I put 10 hours of ground testing on my brand new aircraft engine slowly working my way up to WOT. A friend of mine blow out an oil seal on the turbo in a Cessna 210 but managed to limp it back to the airport without seizing the engine. The FAA made him "zero" the entire engine at $40K to ensure it didn't kill him and his passengers later on.

If it is rod knock from excessive bearing clearances hopefully it didn't hammer on the rod bolts as well. Had this been discovered during an "easy" break-in then I would not be as concerned. At 715 hp at high rpm's those rod bolts were exposed to repeated shock loads I would be concerned whether they have been compromised.

Checking rod bearing clearances will be difficult by access thru the oil pan but is a good place to start. It's extremely frustrating doing all that work only to find out you have to tear it apart to fix a brand new engine. Hopefully it easily remedied and you can get back to business. Keep us posted on your findings

 

[Brutal Metal]

Matherly has been around Fords for 3 decades, he's a stand up guy and racer, he Won't just blow you off Brian.. Good Luck!

 

[TwinTurbo4vGT]

That sucks! :nonono:

You essentially broke your engine in on a dyno which is a pretty brutal experience for a freshly minted engine. Never ever EVER trust a new engine! There are so many things that can go wrong and you decided to expose them by taking the engine to the extreme strapping the car down on a dyno. In that situation any problems encountered will be compounded by stressing the engine to the max which may cause further damage.

Had you broken in the engine gently would have allowed the parts to "seat" to one another and heat cycle the engine you may and I repeat "may" have avoided this. If it was improperly assembled then the manner in which it was broken-in wouldn't matter but it is always prudent to start off slow and work your way up the latter until it's confirmed that the engine is sound. I put 10 hours of ground testing on my brand new aircraft engine slowly working my way up to WOT. A friend of mine blow out an oil seal on the turbo in a Cessna 210 but managed to limp it back to the airport without seizing the engine. The FAA made him "zero" the entire engine at $40K to ensure it didn't kill him and his passengers later on.

If it is rod knock from excessive bearing clearances hopefully it didn't hammer on the rod bolts as well. Had this been discovered during an "easy" break-in then I would not be as concerned. At 715 hp at high rpm's those rod bolts were exposed to repeated shock loads I would be concerned whether they have been compromised.

Checking rod bearing clearances will be difficult by access thru the oil pan but is a good place to start. It's extremely frustrating doing all that work only to find out you have to tear it apart to fix a brand new engine. Hopefully it easily remedied and you can get back to business. Keep us posted on your findings

Clearly you don't know how to break in an engine. The best possible way to break it in is to beat the ever loving shit out of it. I have broken in ALL of my engines that way including mine with over 1000hp at the wheels and they are all still healthy.

 

[timspony]

Sorry to hear....best of luck!

 

[mustangman36578]

Clearly you don't know how to break in an engine. The best possible way to break it in is to beat the ever loving shit out of it. I have broken in ALL of my engines that way including mine with over 1000hp at the wheels and they are all still healthy.

i agree. From what ive heard and been told by a few engine builders is that being too easy on it actually has a possibility of harming it because the rings might not seat properly resulting in more than desired blow by. the way I broke in my motor was let it idle for about 15 min to let everything get up to temp and make sure nothing is leaking. changed the oil then took it out on some back roads and steadily took it up through the RPM band a few times.

The break in procedure might be different for an airplane engine though since they see different types of load.

 

[TRBO VNM]

That sucks! :nonono:

You essentially broke your engine in on a dyno which is a pretty brutal experience for a freshly minted engine. Never ever EVER trust a new engine! There are so many things that can go wrong and you decided to expose them by taking the engine to the extreme strapping the car down on a dyno. In that situation any problems encountered will be compounded by stressing the engine to the max which may cause further damage.

Had you broken in the engine gently would have allowed the parts to "seat" to one another and heat cycle the engine you may and I repeat "may" have avoided this. If it was improperly assembled then the manner in which it was broken-in wouldn't matter but it is always prudent to start off slow and work your way up the latter until it's confirmed that the engine is sound. I put 10 hours of ground testing on my brand new aircraft engine slowly working my way up to WOT. A friend of mine blow out an oil seal on the turbo in a Cessna 210 but managed to limp it back to the airport without seizing the engine. The FAA made him "zero" the entire engine at $40K to ensure it didn't kill him and his passengers later on.

If it is rod knock from excessive bearing clearances hopefully it didn't hammer on the rod bolts as well. Had this been discovered during an "easy" break-in then I would not be as concerned. At 715 hp at high rpm's those rod bolts were exposed to repeated shock loads I would be concerned whether they have been compromised.

Checking rod bearing clearances will be difficult by access thru the oil pan but is a good place to start. It's extremely frustrating doing all that work only to find out you have to tear it apart to fix a brand new engine. Hopefully it easily remedied and you can get back to business. Keep us posted on your findings

I would trust the engine builder who built my engine and what they want me to do for break-in. Not how someone breaks in an airplane engine.

Some builders do want certain rpm based break-in procedures followed. Others say after you go through topping off fluids a couple of times that is enough for heat cycling and then to let it rip.

So really, the customer needs to check with their builder and do what the builder advises. You do that and they can't come back at you for improper break-in.

I can tell you, Mike and L&M basically says to start off using 5w-30 or 10w-30, whatever it takes to maintain about 30psi oil pressure at warm idle. go through a few heat cycles to make sure all fluids are topped off and everything is operating correctly, then pretty much have fun. I have heard this from at least a half dozen engine builders.

Brian, very sorry to hear man. Talk to your builder and see if he can suggest a couple of things to look over and go through some checks and balances. Hopefully you asked him about his recommended break-in and hopefully you followed it.

 

[Anabolic]

should go 2-3000 miles on new engines to "break in" normal street driving/ stay out of bost first 500 miles

 

[hotcobra03]

should go 2-3000 miles on new engines to "break in" normal street driving/ stay out of bost first 500 miles

whats different on like a new car...the last 2 cars we got came out dealer lot sideways with smoke pouring off the wheels

 

[01Jes]

Sorry to hear Brian, was following your recents threads on this build. I hope the builder can aid in this terrible situation. Keep us posted.

 

[TRBO VNM]

I would trust the engine builder who built my engine and what they want me to do for break-in.

should go 2-3000 miles on new engines to "break in" normal street driving/ stay out of bost first 500 miles

Did you build his engine? What if his builder wants it done differently?

I gotta question all the people who tell someone to break-in their engine a certain way, but yet they didn't build the motor and/or they don't do it for a living or have ever actually done it. This isn't like selecting the "best" intake, exhaust, shifter.