Hissing whistling noise

[ReneH]

Hi again.

I have done a test drive some minutes ago...what should I say...He's on the gas like hell...I don't know if this is a correct translation...but wow...only wow...and this with a non breaked in engine.

I think it will maybe good to test a bit less initial timing...maybe 8 degrees...I have the feeling that there is maybe some small backfire on full throttle... but I'm not really sure.

So you see...it seems to be only a wrong timing...nothing complicated...I will maybe do some test at the weekend.

For now, I will do my other construction sides like the android radio and other samples things like chnging the window gaskets.

[ReneH]

BTW: The hissing is still there...it's muted but is there. I will drive some miles and check the plugs to see what's up with the mixture.

Is there any break-in procedure for the engine when mounted?

[mat in tn]

is this engine a roller camshaft engine? if it is then just drive the vehicle like a responsible adult for a while until you have had a good 500 miles or so. if it has a hydraulic camshaft with non- roller lifters then you should have followed a different break in procedure before now.

[ReneH]

Hi Mat,

It has a hydraulic camshaft. But if you ask cause of the cam break in, I have done it already.

I'm asking for an engine break in. As I have bought a refurbished engine for my CJ7, I've  got a manual for a procedure of accelerating and breaking. The engine gets relatively high load and temperature during this. Nothing dangerous, but also not  driving as usual.

Cam break-in procedure was only while the car is standing still with alternating rpm.

[mat in tn]

one thing I would suggest is changing the oil rather soon. break in always "polishes" metal to metal contacts. And when it comes to the cam it polishes the cam to the lifters. "mating" them. if done properly then the lifters will rotate during operation, and we have seen many that don't rotate well and wear into the camshaft lobes". the oil carries very fine metal particles from both the rings mating to the cylinder walls and the camshaft also. hold the oil pan in the sunlight and look closely at the "shimmer" this can tell much about the success of the break in.  and no the filter will not catch it all. very fine will go through the filter.

[ReneH]

Maybe I have found the source of the hissing noise...

As I have removed the EGR, there is still a bore that ends in cap, set outside on the plenum to prevent to get a vacuum leak...so by closing this bore like I've done, there is still a bore some inch deep...like a bottleneck...

As I've added a blind plug as threading the hole with M18x1.5. I've put the plug fully inside to prevent the creation of a bottleneck and closed all with the normal Cap. I've added joining adhesive to the plug to prevent moving by vibration...






I'm exited if this hissing is all over when re-building the engine with the new cam, I've got for free as mine new was defective..

[mat in tn]

actually, I'm not thinking that will be the cause of the hissing. the fact that you have more draw through the closed throttle blades is most likely the issue. that 347 is trying to suck them inside out. with the proper afr at idle you may have a significant amount of vacuum especially with a cam designed as a stock replacement for an efi whether 5.0/ or5.8