GreyGT-C

i just replaced the front main seal on this da***d car AGAIN. It still leaks but only after 5k rpms. If i drive the car easy... no leaks. a few hard passes and the front leaf srping is covered in oil. Having someone rev the engine with it up on the lift...i stood underneath and watched it.... i KNOW it is from the front seal area.

Anyone have any clue WTH it's keeps leaking? Pulley warped/damaged perhaps? Does anyone have a pic of what the snout of the pulley looks like? Mine has a few ridges that almost look like threads on it... but they look factory machined. Could the seal eventually wear the pulley snout like that?

Anyone have an aftermarket underdrive pully for sale???

Thanks!
Shannon

jeanlucpicard

Is your crank pulley all the way on? The seal in the front engine cover is set by the pulley shaft and it sounds like maybe your pulley has moved out a bit and when you rev it up the centrfugal force pulls oil through the seal.

Also, the pulley shaft can wear a groove where the front cover o-ring seal rides - yes, I know rubber and steel but this has happened to me before - and that can sometimes lead to a leak at high RPM's. The fix would be to replace the pulley and front o-ring seal in the engine cover.

GreyGT-C

yeah.. the pulley is all the way on... but i think that it may have a groove worn in it. I just need to see a pic of a good one and i'll know if mine is normal or not.

Thanks!

STI990

Sorry this is an old thread, anyone else have this issue? I replaced mine not to long ago and now mine is leaking again..none really at idle but lots at high rpms..I replaced the stock balancer when I did the main as well..any advice is appreciated.

Corvette_chris04

I am getting ready to replace all the seals on the front of my engine. I was told that my timing chain cover was leaking, and my water pump seal. But the bottom of my engine stays coated with oil, but doesn't drip in my garage. So i think it is only at High RPMs as well. Plus my oil PSI never goes below 60. Is that normal? Everyone tells me high oil PSI is good, but not if it is causing the seals to blow.

KoreaJon

Hi Guys,

When you replace the seal, look very closely at a few things.

First, look at the surface of the harmonic balancer where the seal rides. Any groove or imperfection in that area is a potential leak.

Second, immediately before installing the timing cover, place a small bead of non-hardening sealant ~in the CORNER~ where the timing cover / oil pan / engine block meet. This little area, if not sealed, has a big potential for leaking. Don't go crazy and smear the sealant on the gasket surfaces, though!

Third, when installing the timing cover, install all of the cover bolts, but leave them loose....until AFTER the balancer is fully installed. After the balancer is in, THEN torque down the cover bolts. This automatically aligns the front main seal to the balancer shaft.


IHTH!!

KoreaJon

dutch911

Thanks for all of the info, I have a very similar problem. My second harmonic balancer (maybe 40k miles on this one) is walking itself apart and is starting to shred the serpentine belt. Oil is covering the front half of the engine, engine bay.

It's a big job and I'd rather have a permanent solution to this harmonic balancer issue. What manufacturer of harmonic balancer would go the distance? My old 2002 Yukon with a gen-3 5.3 liter went 175,000 with no issues. The vette is street use only (sure I beat it like a pinata but no actual racing). While we're in there we'll replace everything that may be worn, what else is recommended? Recommended manufacturers?

VGLNTE1

Ati for the pulley. Slp and powerbond are half the price, and there's reason for that.

LoneStarFRC

Powerbond, ftw. AFAIK, the SLP unit is actually a Powerbond. SLP is not a manufacturer, whereas Powerbond is. Powerbond was recently bought by Dayco (the engine belt company), but still make their balancers same as always. They used to use a clear-coat finish over steel, but now they anodize or powdercoat all their premium series black.

Shop around, for the Powerbond unit, prices vary. Note: if you see "Dayco" brand name it may be them, but I haven't checked in quite awhile since the buyout. It's the "Race Performance Series" you want.

Install an ARP crank bolt, not the TTY OE bolt. If you can borrow/rent one, get a crank pin kit and pin the crank.

IF you want stock diameter (none underdrive), order:

PB1117SS

The 10% underdrive unit is:

PBU1117SS10

The 25% underdrive init is:

PBU1117SS25 (this is the one I use)

I checked and found the Dayco online catalog and it has the Powerbond series listed. Remember, their "Race Performance" series is the premium unit that most everyone around here uses, as they also make an OE replacement as well. You'll notice in the link, I preselected a "generic" 2002 C5 Corvette, but that's really irrelevant as all Corvette LS engines use the same, with only a couple exceptions. The F-body LS motors use a different part number (different belt groove arrangement).

http://www.daycoproducts.com/parts?c...scription=1137

HTH

Socko

I just bought an ati. After much consideration it is the cheapest thing that is really built to last and "top tier", and works well, from my research. At around $400 they aren't cheap, but less then some of the other good brands. Biggest issue with ati is getting the right part as they have like 40 options for ls motors.

Also just buy an arp bolt and pin kit, that way you wont have to worry about it spinning off. That's what I am doing. The balancer i ordered was number 917278. Steel hub and ac pulley. 10% underdrive.

neutron82

also make sure that the front cover is centered around the crank snout!... I made the mistake of using my balancer to center the front cover the first time around and had a leak, not a bad leak but a leak nonetheless... I had to take it back apart again and the second time around I used the cover alignment tool from saccitycorvette and that worked great

reath1

If I remember correctly the pinning jig will center the timing cover pretty well for you.

VGLNTE1

I've probably installed a front cover 40 times. Never have centered one. It's a myth. Get all the bolts in, then tighten the bottom 2 first, then the rest. Don't forget the gasket sealant in the corners. Done.

My buddy broke a timing chain due to the less than desirable power bond pulley because it was balanced like a turd. He was so happy with it, he kept all the bent valves as souvenirs.
Katech, who builds a ton of road race cars said "we will only use ati"
Get your hands on a powerbond, then a ati. You will see the difference.