tmork454

iTrader: (1)

So 2 days ago i whipped a doughnut after it rained, and as i was heading home a noise started coming from the engine. Here are some videos of the sound. Any input is appreciated.
Next the the valve cover:
https://www.youtube.com/watch?v=A-yU...ature=youtu.be
Inside the Car:

rusty vango

its best to remove the valve cover and have a look. but in listening to your videos. something is not right.

tmork454

iTrader: (1)

all the rockers seem fine i also pushed to see if the lifters were bad. Im going to do a compression check to see if its a piston ring. P.S. I have the 624 heads and no im not the idiot who put them on.

aramirez121

i know what that is its called pison slap your pistons are loose inside and are banging around inside happens from weak rings

tmork454

iTrader: (1)

A compression check would confirm that right?

aramirez121

yea you would lose compression and you can blow a hole in the block if they get stuck or bend the rods up perty bad look in you oil and see how much metal (if there is any) and you can also ge a nifty cam on a wire as i call em from home depot with a light on the end and remove your spark plugs and put it in the hole and check the walls of your cylinders to see if they are worn there will be a skipping pattern on the walls its very noticable so you'll know which piston is the one doing it

Joe Tag

iTrader: (4)

Sounds more like valve train to me. Bent push rod? Did you run it with the valve cover off and see where the noise is? Piston slap is from slop in the cylinder and wouldn't happen so suddenly. A broken skirt would and is more of a possibility.

tmork454

iTrader: (1)

Well i definitely was stupid and hadn't checked my oil and was a good 3 quarts low so i think i ruined a ring. i put new oil in today and the noise has gone down. its hard to tell if its still there.

tmork454

iTrader: (1)

so i looked closer at the engine and two of the retainers on the distributor cap were loose. could this have retarded the timing causing that rattle.

rusty vango

in a word, no. what happens when you leave the cap loose is it and the rotor button meet with catastrophic results.

tmork454

iTrader: (1)

update: i did a compression test and cylinders 1,2,3,4,6 have 120psi compression i was not able to get cylinders 5,7,8 due to the headers being in the way. Also I'm not getting spark to the plugs which is leading me to suspect something in the distributor is wrong.

rusty vango

take out the ICM and have it tested, you want to run the test 5 or 6 times in a row because they often fail when hot.and as for the compression ,that's good enough. but take the header loose so you can test the remaining cylinders. you also should test the ign coil

tmork454

iTrader: (1)

were would the icm be located on a mad street fire distributor i can't find anything on it. Also i took the cap off and there is some grayish dust in there and when i took the rotor off there was a burn mark on the bottom.

rusty vango

all I know about the MSD "streetfire" distributor is its made in CHINA!! just their way of sayin GOTCHA! IMHO the original distributor with good parts in it is WAY better ,lasts longer. grey dust/ burn marks.... bad stuff. I would just chuck it and go OEM.

tmork454

iTrader: (1)

O.K. i think my after a long review i think my distributor is the source of the problem. That problem would be pre-ignition. i found the exact description of what i was having. the website is here. "Pinging or spark knock is properly called "pre-ignition" and is often incorrectly called "valve noise" because it sounds similar to loose valves that need adjusting. The difference is that loose valves will make noise all the time, whereas pre-ignition happens on acceleration or under a load. You might hear it when going up a hill on the interstate: a rattling sound that goes away when you downshift or get off the gas."

tmork454

iTrader: (1)

So I put the new vacuum advance in and no matter were we set it it would still spark knock. Without the vacuum advance hose connected there was no noise. This makes me think that I have way to lean of a mixture. What would cause a sudden change in air fuel?