Loud engine knock

[tjmotter]

I fixed it but anyone want to take a guess on what the problem was?

Ford 302 (0.040 over), recently rebuilt with all new parts.

Symptoms:
Loud knocking noise that starts at 3000RPM and continues at rev's above this. The noise sounded like someone hitting the side of a metal garbage can with a hammer. After warming up to 80 degrees (Celsius), the noise would be greatly reduced but you could still hear a sharp noise.

[ram_g]

Your neighbor hitting the side of your garbage can with a hammer to get you to turn that infernal beast off? :p

[tjmotter]

was that you? I heard someone else in the area was building an FFR ;)

[Gordon Levy]

What rockers and valve covers do you have?

[tjmotter]

What rockers and valve covers do you have?

Scorpion 1.6 ratio rockers
Edelbrock Elite Series Aluminum valve covers

You are on the right path with the valve train direction but there is ample clearance between the rockers and these valve covers. Turns out that one of the brand new FRP lifters was bad. My first fear after hearing of Erik's woes on the other forum was that I had spun a bearing so a couple of weeks ago I dropped the pan and checked them. No issues there so the only options left seemed to be piston slap or a bad lifter. I checked the piston and ring clearance during the build and it was right on so I didn't think that was it but the strange thing was that I didn't hear the telltale lifter clack. I had tried adjusting pre-load to see if that changed anything (1/4 turn to 1/2 turn and finally 3/4 turn) to no avail. As a last resort I pulled the intake, removed the lifters and took each of them apart. All of them looked ok but after reassembling them it became obvious that one of the lifters was a LOT softer than the others. It was almost as if there was something wrong with the bottom spring but on further investigation I found that Ford had milled the inside housing a little too big which meant that oil could escape faster than it came in. It would work ok at low revs but once I got the revs up it would quickly drain itself and cause the knocking noise. My guess is that once the engine warmed up the pieces expanded a little so that they held oil better which might explain why the noise was greatly reduced.

Regardless, a new set of lifters fixed the problem. The last thing I considered was that brand new Ford Racing Performance Product lifters could be bad.

Hope this helps someone else.

[CraigS]

I wouldn't expect that either. There are so many engine problem posts here and on two other forums, I often think to my self, why don't people just buy a crate engine from Ford? Now I know that wouldn't always bve a problem solver either. DId Ford waranty the lifter set?

[tjmotter]

CraigS,

Nope. One of the drawbacks to the build process is that it takes time. I finished my engine in 2009 (before I received my kit) but didn't get it installed into the car until early 2010. A year and a half of piddling with bodywork coupled with delays while the state of Texas worked through implementing the new SEMA process meant that any warranties had expired before the car was even on the road. The car has less than 500 miles on it and while it was started numerous times in my driveway, the problem didn't appear until I got the revs up so it wasn't easy to detect. The good news is that it was only $120 to fix but if I was going to do this again, I would have bought TrickFlow lifters instead since they allow you to purchase 1 at a time while Ford only sells them in complete sets.

As you suggest, a bad part from new stock is not something you would expect so this could just as easily happened in a crate engine as well.

At least it is fixed now and the car is running GREAT:)

Todd