Craft Performance engine knock

Status
Not open for further replies.
Hey guys, I was looking for some guidance on my situation. I got an Engine from craft Performance and within 140 miles I got an engine knock. Ended up being 1 burnt up piston. I didn't install this engine keep in mind a second job did. Lance over at craft mentioned the timing needs to be 34. I took car to a 3rd shop they checked it and it was 40. Now lance at craft is blaming this for the burnt up piston. Says the timing was to high and it caused that piston to burn up. My two shops say that this shouldn't have burnt up the piston. I'm stuck not knowing who to blame. I was hoping to get some thoughts on this?
 

Neil

Supporter
You didn't say what engine this is but if it is a small-block Chevrolet (SBC), it is 6 degrees to far advanced. It isn't the their fault.
 
Sorry, engine is a 410 ci windsor. Its about 520hp on dyno. It's got forge pistons, CNC Brodix LH 17 195, Compression: 10:1
 
I DOUBT IF CRAFT WILL STAND BEHIND IT BECAUSE OF IMPROPER TIMING. IGNITION KNOCK WILL DAMAGE PISTONS.. TO WHAT EXTENT I DO NOT KNOW.. DID CRAFT GIVE YOU SPECS FOR YOUR MOTOR ? CHECK THERE FOR IGN TIMING. DID YOU GIVE THESE SPECS TO THE INSTALLER ? IF CRAFT DYNOED THE MOTOR , WHY WOULD SOMEONE CHANGE THE TIMING ?
 
I DOUBT IF CRAFT WILL STAND BEHIND IT BECAUSE OF IMPROPER TIMING. IGNITION KNOCK WILL DAMAGE PISTONS.. TO WHAT EXTENT I DO NOT KNOW.. DID CRAFT GIVE YOU SPECS FOR YOUR MOTOR ? CHECK THERE FOR IGN TIMING. DID YOU GIVE THESE SPECS TO THE INSTALLER ? IF CRAFT DYNOED THE MOTOR , WHY WOULD SOMEONE CHANGE THE TIMING ?

I asked craft if it was 34 timing when you sent it why wouldn't it still be 34. He said timing sometimes can change. Then started saying every engine installer should check timing and blaming the shop who installed the engine. Crafts only proof was he sent me dyno specs showing timing was right when on dyno. The shop that installed engine has no proof of timing and nor did I ask for it because I didn't know this was needed.


I'm stuck trying to figure out whom to blame. I have no engine knowledge especially on timing.
 

Attachments

Neil

Supporter
The data above 5400 RPM makes no sense at all. The air/fuel ratio over the whole RPM range should be close to 12.5 to 1 at full throttle and it's reading above 14 to 1. That's a pretty lean mixture. Above 5400 RPM the numbers are not believable.

The timing could have been correct when it was built but if the distributor was bumped or a crank trigger was moved the timing would have moved. An "engine installer" would simply install the engine; if it was his job to tune it, you should have put that additional task in writing. I'm afraid you are a victim of your own inexperience.
 
Lean mixture will cause engine knock. 14 AFR is only good for cruising conditions. Anything other especialy when on throttle I get scrared when I see anything above 13 AFR. On wide open throttle I like to see 12 to 12.5 AFR. Anything leaner will burn pistons.
 
The data above 5400 RPM makes no sense at all. The air/fuel ratio over the whole RPM range should be close to 12.5 to 1 at full throttle and it's reading above 14 to 1. That's a pretty lean mixture. Above 5400 RPM the numbers are not believable.

The timing could have been correct when it was built but if the distributor was bumped or a crank trigger was moved the timing would have moved. An "engine installer" would simply install the engine; if it was his job to tune it, you should have put that additional task in writing. I'm afraid you are a victim of your own inexperience.
So it was my job to make sure it was tuned properly?

Sucks because I don't know how this stuff works. I told the shop that installed the engine that I didn't have any experience with this. Make sure everything is perfect likes its your own car because I don't know what needs to be looked out for. Now I got a craft engine that needs to be rebuilt and zero warranty from him.
 
Looking back at your datasheet, that engine was suplied, incorrect tuned through the whole rpm range. AFR way to lean. Fuel suply incorrect.
Ill assume by seeing the datasheet its an EFI engine.
 
Lean mixture will cause engine knock. 14 AFR is only good for cruising conditions. Anything other especialy when on throttle I get scrared when I see anything above 13 AFR. On wide open throttle I like to see 12 to 12.5 AFR. Anything leaner will burn pistons.
So AFR being to much when engine builder tuned it. So did he send me an engine that was destined to burn up?
 

Neil

Supporter
This is a difficult situation that you are in. Here is what I'd recommend:

I'd approach Lance at Craft Performance with that dyno sheet in hand and ask him (not demand- things can go downhill in a hurry) why the numbers are so far off. Something was not right during that test and the engine should not have been delivered to you in that condition. Maybe if you try working with him he will see that his engine was not running properly and that he should rebuild it and show that it is functioning normally on his dyno.
 
So AFR being to much when engine builder tuned it. So did he send me an engine that was destined to burn up?
Looks like it, yes.
A volumic efficienty of more than 100% is not possible on a natural aspirated engine. You are very lucky if you reach 85% on a full race engine. Somebody filled in the wrong parameters.
With the datasheet in hands I wouldn't dare to run that engine anywhere above 4500rpm.

Again, Ill assume by the datasheet, its an Electronic Injection setup and if so, its got the wrong tune in the ECU.

If it carburretor, improper jetted, way to lean.
 
Looks like it, yes.
A volumic efficienty of more than 100% is not possible on a natural aspirated engine. You are very lucky if you reach 85% on a full race engine. Somebody filled in the wrong parameters.
With the datasheet in hands I wouldn't dare to run that engine anywhere above 4500rpm.

Again, Ill assume by the datasheet, its an Electronic Injection setup and if so, its got the wrong tune in the ECU.

If it carburretor, improper jetted, way to lean.

The way I see it I was sold a turn key ready engine. Subtract the carb I used my own holley sniper. Engine was never turn key ready because his tune was never proper from beginning. I'm out lot of money on this and craft Performance doesn't want to take any responsibility.
 

Randy V

Moderator-Admin
Staff member
Admin
Lifetime Supporter
I agree with Neil.
That engine was running so lean on the dyno, it surely had to be detonating. Much more power was to be had from that Engine had the AF ratio been Closer to 12.5:1...
There is a possibility that the engine could have been damaged during one of the dyno runs.
Yes, 40 degrees is substantially higher than I have ever seen used on a Windsor engine. Matter of fact, it’s rate to even get up to 36 total without detonation on 91 octane pump gas with CR ~10:1 and alloy heads.
That dyno sheet may well be your ticket to some form of compensation, but I would not expect a total overhaul would be covered.
 
Couple of things, at what point was your own Holley sniper fitted, was it fitted right from start at dyno session.
You state 4.030''-4.040'' pistons, which? shouldnt be both!
Is this in Cobra or GT40, was it dynoed with GT40 ( 180deg headers or dyno headers).
 
Couple of things, at what point was your own Holley sniper fitted, was it fitted right from start at dyno session.
You state 4.030''-4.040'' pistons, which? shouldnt be both!
Is this in Cobra or GT40, was it dynoed with GT40 ( 180deg headers or dyno headers).
Dyno was all with craft Performance. His carb and his shop. Engine was sent to me after dyno and equpied with my holley sniper
 
Dyno was all with craft Performance. His carb and his shop. Engine was sent to me after dyno and equipped with my holley sniper
So if engine damage is due to lean mixture, noise ( knock) should have been heard right from first start up after fitting in car.. You say it occurred after about 140 miles and on your own carb which was not on engine for dyno run. and 40deg timing was also discovered after or during that 140 miles. Im now wondering if the dyno runs at Craft were intended as power runs or simply a quick check after run in time especially with the replacement of carb for your own. If it was an effort to obtain best power readings there would/should be multiple runs & changes to Jetting & Timing.
 
Status
Not open for further replies.
Top