I'm tracking down a small oil leak around the timing cover (LT1). About to start taking it apart and could use some help and any tips/shortcuts.

Will I have to pull the rack to remove the pulleys/balancer?

Can I change seals without removing the timing cover?

If I have to remove the timing cover, do I have to remove the oil pan?

I'm changing the opti, plug wires and water pump while I'm in there and I have all of the seals and gaskets for the timing cover.

Thanks

 

No youdo not have to pull the steering rack. The hose is curved to accomodate a hub puller.

Yes you can.

You have to drop the front of the pan at the minimum.

Most likely the oil leak is from the crank hub seal. It is quite common among the LT1/4's.

 

Thanks Chris. It's looking like you nailed it on the crank seal. Won't know for sure 'till tomorrow.

 

It is very possible that you have a seal leak but a more common problem on the LT engines is a front manifold leak. Before investing a lot of time and money on front seals, make sure it is not just the manifold. A good tip is to use brake cleaner to get the front of the engine very clean and then track down the leak. Brake cleaner is not water based and won't damage the optispark but don't drown the optispark just to make sure. :)

The top timing cover seal can be taken out pretty easily with a small screwdriver. There is a little notch to pry in to get it out. The bottom one however is extremly difficult to get even with a seal puller because of the room. Honestly, your best bet is just to pull the thing off if you are sure it is a timing cover seal. You can drop just the front of the oil pan but getting them to seal again is not very easy. How many miles are on the car.

Trevor@ Exotic Muscle

 

28,000 miles - 10,000 in the last year :D .

 

Old Fart! :bs If your old ~ then so am I.....
Hope this helps when you dig into it tomorrow! ~ Purp

LT1_LT4 Balancer/Hub Removal
Unlike its SBC predecessor, the LT1/LT4 Balancer is a two piece assembly consisting of an (inner) hub, and (outer) balancer/pulley. Removal of the assembly can be frustrating if approached in the conventional way. By following the procedures below, you can safely and quickly remove the assembly with little or no problem.
1. Drain the radiator by opening the drain valve on the lower right hand (passenger side)
2. Remove the serpentine belt
3. Remove the upper radiator hose
4. Remove the water pump. When removing the water pump, it is important to remember that the LT1/LT4 water pump is attached to the engine with 3 bolts on each side, vs. its predecessor, which only had 2 bolts on each side. The center bolt on the driver side is a challenge, but can be removed without removal of the power steering pump. When removing the water pump, take care to remove the pump drive coupler along with the pump and place it on the pump drive shaft for use when re-installing the pump.
5. Mark the coil wire and all plug wires at the OptiSpark cap for easy reference when re-installing the OptiSpark unit after balancer seal repairs have been completed.
6. NOTE: There is no need to separate the balancer pulley from the hub if you intend to pull the hub off anyway. The only time you need to separate the pulley from the hub is if you are simply changing the OptiSpark. There is a match mark that is cast into the balancer assembly that allows you to mate the two pieces together in the exact orientation that they come apart. If you intend to separate the balancer pulley from the hub, locate the marks and make note for re-assembly.
7. The balancer pulley is attached to the hub with three bolts. The bolts are 7/16” SAE standard, 14 threads per inch, ¾” length (not metric). Fully remove all three bolts, and if you intend to remove the unit as a complete assembly, jump to steps 9 thru 18. If you intend to separate the assembly, continue by rethreading one bolt by a couple of turns. It is now time to separate the pulley from the hub. Most pulleys have been found to be rusted in place and require considerable effort to separate from the hub. Spraying the inside of the pulley with penetrating oil helps. Do not strike the pulley with a hammer in your frustrated attempts to remove. The best method is to position yourself under the engine with a wooden dowel rod and one healthy hammer. Position the dowel on the inside portion of the balancer when striking it with the hammer. Do not hit on the outer diameter of the pulley as damage can and will occur.
8. After successfully separating the pulley from the hub, it is now time to unbolt and remove the OptiSpark module. As with the water pump, a coupler drives the OptiSpark module and care should be taken to remove the drive shaft and place with the OptiSpark module for use when re-installing the unit.

Notice:
Contrary to what all the books say, the OptiSpark drive coupler can/will go on in more than one position. What it SHOULD say is that there is only one position in which the OptiSpark will go on that it doesn’t require tightening down in order for it to seat tightly against the timing chain cover. There is only one keyway on the back of the OptiSpark; Just make sure that it is properly lined up with the key and you are set.

9. Finally, it is now time to remove the hub. The center bolt that holds the hub on the crankshaft snout is 7/16” fine thread (not metric). I have found that I can generally break the center bolt loose by placing a 6 sided socket on the bolt, with a ½” breaker bar attached. By striking the breaker bar with that healthy hammer you just used in step #7, you can break the torque on the bolt.
10. Fully remove the bolt, remove the washer from the bolt, then re-install the bolt by 3 full turns.
11. Re-read step #10. If you skip this step, you are a screwed pooch.
12. The “General” was thinking when he installed the power steering rack hydraulic lines as he has installed a loop in the lines that allow the use of a balancer puller without interference of the puller jack screw. Check it out, you will be glad that he did this.
13. Use a standard balancer puller that requires the use of 3 puller bolts that fit into 3 slots on the crab portion. Make sure that you use a tip on the jack screw end that is a flat rotating plate, not a sharp point, because you will eventually place the jack screw end directly on the head of the center bolt of the hub and you don’t want to damage it.
14. Next, select three new (or used) 7/16” bolts that are of sufficient length to slip thru the puller and fully thread into the hub where you previously removed the 3 bolts in step #7. If you do not have 3 – 7/16” bolts that are the proper length, you can use bolts that are slightly smaller than the tapped holes so you can slip them completely thru the hub. Make sure that the bolts are of sufficient length so that you can insert them completely thru the puller assembly and the hub, with a flat washer on each end, and a nut on the backside.
15. Rotate the entire hub assembly until the (^) mark is at the 12:00 position before removing the hub. When re-installing the hub, make sure that you install it back in the same orientation. This is a balance mark, and although it really won’t make too much difference if you fail to do this, it is there for a purpose, so try to do the right thing here.
16. Position the puller onto the front of the hub, with the jack end of the jackscrew slid thru the power steering line loop, and attach as mentioned above.
17. You are now ready to slowly remove the hub from the crankshaft snout. As you turn the jackscrew in a clockwise rotation, the hub will slide off the crankshaft. Keep doing this until you feel the hub come loose, or until you back it out against the shoulder of the center bolt.
18. You have successfully removed the balancer hub. Now, time to R&R that front seal assembly.
PurpleC4

:seeya Purp


[Modified by PurpleC4, 7:15 PM 1/8/2002]

 

I have a '94 with 33,00 miles and am getting ready to do the same repair. I have examined the front intake and it looks ok. I believe my leak is from the distributor shaft seal. Will not know for sure until the water pump and opti are removed. The timing cover must be removed for the distributor seal. I believe the crank seal can be removed without pulling the timing cover off. I have already purchased a front end re-seal kit about $12.00. It includes the waterpump gaskets,crank main seal,distributor seal and timing cover gasket. I should get started within the next two weeks or so. I have a set of rhino stands and plan on using them. Hopefully that will get me high enough. I know that the pan must be dropped to remove the timing cover ( or as previousely stated the front lowered ). Additionally you may have to remove the cats, starter, and oil filter housing to gain access to the pan. The O2 sensors should be removed to drain the block but not necessary. Keep me informed on your progress if you get into it before I do and I will do the same.

 

Purp- Old? What? Had another Bday last week - don't know what is causing them, but I've had way too many.

Thanks for the most excellent instructions. I think we will have the entire hub assy off this AM. Need to confirm the actual location of the leak and try to fix it without taking off more stuff than we actually need to.

Steve - I'll keep you posted. The factory manual sez what you are saying about removal of the starter, etc. I was hoping it wasn't so, but from Trevor's post, it looks like it may be the way to go if the crank seal has to be replaced. I bought 2 seals, so I can try it once with the timing cover in place and then do it right if I have to.

Don't know about the Rino Ramps. Looks like it would be real hard without some more clearance - especially if you get under there and have to drop the exhaust. May just be me though - I'm not a low rider model. The Rinos are about the same height as my belly. Good luck.

 

Update. Got the hub and pully off. Could not pull them both together cuz the pulley hit on the rack before the hub cleared - no big deal.

Having trouble figuring out where the leak is coming from. The intake, timing cover and oil pan gaskets look good. The top seals in the timing cover are dry and seem perfect. The lower seal is a bit more suspicious looking, but really doesn't seem to be leaking.

One of the bolts (the lower one) that holds the opti on seems suspect. The whole area around the timing cover has a light coat of crud stuck to it, but just below this bolt it is perfectly clean. Kinda like the oil leak was washing it clean.

We are going to replace the seals (in place) and put some sealant on the opti bolts and see what happens.

Comments and suggestions welcome.

 

I feel your pain. After all that work you really want the leak to hit you right in the face so that there is no question. Looking at mine I can see the bottom plug wire that attaches to the opti wet ( passanger side ). Were any of your plug wires wet ? Did the hub pulley come off pretty easy or did you have to persuade it off from under the car ? I uderstand about being a low rider, but those days left me a long time ago, after 50 who is counting anyway. Do you have access to a lift or is the car jacked ?
I believe you said you were going to replace the opti, just out of curiosity did you take the old one apart yet ?

 

Steve - The leak was not a high volume deal. Never had any spots on the driveway. If you looked underneath there would be 2 or 3 "drops" on the crossmember and most of the center part of the crossmenber was damp with oil. Likewise, most of the area around the timing cover was kinda moist looking.

Long story on the lift. I have GMPP extended warranty - Would rather have the leak than go to dealer. Found out some really good guys that restore vettes (4 top flites this year) could do the work. They havent worked on Lt1s much so Its kinda like a fun project for them and we are all pitching in - kinda like doing it at home with a bunch of friends.

I told 'em it was missing and was probably oil in the opti so they talked the GM guy out of an opti :D . I'm waiting to finish everything before I look at the opti.

Oh yea, the pulley. We marked the pulley & hub before removing. The puller we tried to use didn't fit right, so a trip to the NAPA store for a smaller puller and all is well. Hub was not hard, but had to bump it from behind with a wood block like the guys said. Hit it in the center web, not on the outer edges.

If I had to do it at home, I would back the car on to the Rinos then jack the front as high as I could and chock it up real good. You have to be able to get to it from the top and bottom. We must have run the lift up and down about 200 times.