Front Cover

[TWild]

I just completed my first front cover pull down on my 87'.  I installed a new front cam bearing, cam, lifters, timing chain and gears, cracked balancer and a few other odds and ends.


One of the things I noticed was that the front cover had three threaded holes near the front edge where it contacts the oil pan (or in my case, the girdle). The seal kit I ordered was the Felpro TCS 45930 and it has a piece of cork gasket that only has two holes in it. I tossed the cork gasket and used Permatex Ultra Black Sealer in it's place. Everything went fairly well during reassembly and after a 40 minute cam break in and a 20 mile ride, I don't see any leaks. I did notice a slight clicking/ticking sound when it's running. This noise was present prior to the tear down and I had contributed it to noise from the timing chain and gears, because no tensioner was installed and the chain had a bunch of slack in it.


Because the noise was driving me crazy, I got under the car and looked and listened for the source of the noise. I noticed the slightest shinny spot on the edge of the reluctor wheel on the back of the balancer closest to the front cover. Then I noticed a slight mark on the boss in the center of the cover where it looked like it the reluctor wheel had hit it at some point in time. I contributed this to the previous builder leaving the oil slinger off, which allowed the balancer to sit a little further back.
 
Also from looking at photos, it looks like the front covers that have three threaded holes along the front protrude further to the front than the covers that on those with the two holes in the front.


Now to my questions;


1. What's the difference between a front covers that have three holes vs. two holes at the bottom front edge (Other than one hole)?


2. How much clearance is "Normal" between the reluctor wheel and the front cover? (I prob have .030 -.035 clearance).


3. Any suggestions on where clicking might be coming from is appreciated.


I did re-adjust the crank sensor and tried to move the crank forward and backward to check for end play, it seemed tight.


TW

[Scoobum]

What's the end play of the crankshaft? You can measure it with a dial indicator.

[reality]

14 bolt pan for a 4.1 or early 3.8 is 2 bolt and late 3.8 is 20 bolt pan. The front cover is different. 2 bolt vs 3 bolt front cover.

[TWild]

Thanks Guys,


I'll have to borrow a dial indicator to check the crank end play. I'll report back what I find.


I've been out of work for the last six weeks due to some surgery, so I had plenty of time to work on it. Going back to the grind tomorrow, so it will be Friday before I can check it.


Great bearing video by the way Scoobum, I can only imagine what mine look like  [size=78%] [/size]


TW

[earlbrown]

A 14 bolt cover isn't pointed and the bottom is shaped just like the piece of cork form your gasket kit. It has 2 5/16-18  holes in it.      A 20 bolt cover is pointed and has 3 1/4-20 holes in it.     What you have is a double drilled cover that can fit both.


Now you either have a later GM unit that was made right before being discountinued, or a chinese POS.  The casting doesn't exactly match the GM unit so that might be the reason you're hitting the reluctor wheel.   While you have the dial indicator, put it on the OD of the reluctor wheel too and make sure it's running true.  With the cleas spot you're seeing, It makes me think you're kissing the crank sensor.

The ticking noise might be the cam sensor shaft sliding up and down. That's pretty common.

[Steve Wood]

Be sure the balancer is torqued right as well

[TWild]

I think I have a GM front cover, because it has a GM part number cast into it. I also just shimmed the cam sensor because it had a ton of vertical play. As far as the torque on the crank bolt Mr. Steve, I tightened it to 235 lb. ft. (I think the spec was 219 but I wanted to make sure it was tight)


I'm gonna go back and check the adjustment on the crank sensor. I only set it on one blade of the reluctor and then rotated the crank and looked for contact. This time I'll check all three blades with my adjustment tool (Strip of an old ID card).


BTW Earl, I got the magnetic drain plug you sent me and I still haven't located the plug that it spit out the driver's side oil galley. 


Thanks,


TW

[TWild]

Alright,


I had a chance to check the crankshaft run out. It looks like it's supposed to be checked at the thrust bearing but since mine isn't apart, I just measured it at the face of the balancer. I ended up with .006" which as far as I can tell is within specs (.003" to .011"). I didn't measure the run out on the reluctor wheel cause it was a pain in the arse to set it up. I did go back and set the crank sensor on each of the reluctor fins and none are hitting.


Not sure why the fins on the reluctor wheel are so close to the front cover? Any body that could take a look at theirs and let me know how close yours is?


Thanks,


TW