LT4 ED Timing Set Failure...what needs to be done??
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Joined: May 2003
Posts: 6,661
From: LA (lower Alabama)
Re: LT4 ED Timing Set Failure...what needs to be done??
Originally Posted by NOMAD
My one stock short block thats disassembled does have the .030 holes in it. My engine thats in the car also has them. The one in the car was built by a very reputable company (who shall remain nameless because they dont do work for the general public) who has done R&D development for Roush racing and Many other top racing teams in NASCAR, NHRA, etc.
I'd say it wouldn't hurt, but I'm sure it's not a necessity. That .030 is not moving much oil since it's not under pressure.
-Shannon
I'd say it wouldn't hurt, but I'm sure it's not a necessity. That .030 is not moving much oil since it's not under pressure.
-Shannon
If ya want to make the WP gear last ya better have the holes in it.
A conventional small block didn't have them for any reason. It has the same lifter oiling galleys and never had problems with air. So they didn't have holes and they didn't have a WP gear to need extra lube again no need for holes and the chain and lifters did fine.
LT1 ta da---- has a gear and has holes. Now what would ya think the holes were for? They were put there by a GM engineer that forsaw a problem with the gear in millions of cars.
Who do ya thing knows, the GM engineer that did the mod for thousands and a stock engine will run 200,000 miles or a engine builder who has built maybe hundreds of LT1's and don't care the miles it goes as they make more money if it don't go 200,000.
Some builders may honestly believe it doesn't matter.
The plugs the holes are in are under DIRECT oil pump pressure.
Last edited by 1racerdude; Dec 6, 2005 at 11:43 PM.
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Joined: Oct 2005
Posts: 414
Re: LT4 ED Timing Set Failure...what needs to be done??
First of all I know the small (aprox 30thou) holes give additional oiling to the chain & pump drive gear, and not having them could easily be the problem in many cases, but Just another thought pertaining to this issue........Iv'e also seen a few LT4 GM ED timing chain's sets flat out break, and/or have their water pump drive gears get eaten when people "or builders" don't press the new drive gear that comes with the GM LT4 timing chain kit on properly...........I can think of three cases (people I know) where metal shavings were run through the motor, by having the gear improperly spaced betwen the backside of the chain, and the retainer plate.......when pressing the new drive gear on, with the fairly tight tollerances ya have on either side of the gear, many people don't take the time nesessary to make sure they have adequate clearance on both sides.......any rubbing in this area, and it almost always ends on a bad note, and in all the cases I know of, the contact could not be heard while driving
......
......
Last edited by Joe B; Dec 7, 2005 at 03:53 AM.
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Joined: Dec 1969
Posts: 165
From: Tallahassee, FL USA
Re: LT4 ED Timing Set Failure...what needs to be done??
Originally Posted by 1racerdude
If ya want to make the WP gear last ya better have the holes in it.
A conventional small block didn't have them for any reason. It has the same lifter oiling galleys and never had problems with air. So they didn't have holes and they didn't have a WP gear to need extra lube again no need for holes and the chain and lifters did fine.
LT1 ta da---- has a gear and has holes. Now what would ya think the holes were for? They were put there by a GM engineer that forsaw a problem with the gear in millions of cars.
Who do ya thing knows, the GM engineer that did the mod for thousands and a stock engine will run 200,000 miles or a engine builder who has built maybe hundreds of LT1's and don't care the miles it goes as they make more money if it don't go 200,000.
Some builders may honestly believe it doesn't matter.
The plugs the holes are in are under DIRECT oil pump pressure.
A conventional small block didn't have them for any reason. It has the same lifter oiling galleys and never had problems with air. So they didn't have holes and they didn't have a WP gear to need extra lube again no need for holes and the chain and lifters did fine.
LT1 ta da---- has a gear and has holes. Now what would ya think the holes were for? They were put there by a GM engineer that forsaw a problem with the gear in millions of cars.
Who do ya thing knows, the GM engineer that did the mod for thousands and a stock engine will run 200,000 miles or a engine builder who has built maybe hundreds of LT1's and don't care the miles it goes as they make more money if it don't go 200,000.
Some builders may honestly believe it doesn't matter.
The plugs the holes are in are under DIRECT oil pump pressure.
Those, with lots of experience, who worked on previoius small-blocks may not know the LT1 needs extra lubrication for the water pump drive gearing that the previous engine didn't.
I would never take the chance.
My LT4 ED timing set has 35000 miles on it in my '92 Y-Body with the original engine and no problems -- so, the holes can't hurt.
Tom Piper
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Joined: Nov 2001
Posts: 646
From: West Palm Beach, FL
Re: LT4 ED Timing Set Failure...what needs to be done??
I had an LT4 ED set lose it's teeth too. I think it was caused by a new Bosch waterpump that didn't turn easily enough. I'm not sure because I installed them at the same time. But anyhow, here's a pic of the teeth all worn down.
http://z28.reanimator.org/stuff/camgear1.jpg
The small waterpump gear didn't look worn, but I replaced the whole set, and a new GM waterpump, and I haven't had any problems since.
http://z28.reanimator.org/stuff/camgear1.jpg
The small waterpump gear didn't look worn, but I replaced the whole set, and a new GM waterpump, and I haven't had any problems since.
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Joined: Mar 2001
Posts: 2,521
From: Costa Mesa, CA
Re: LT4 ED Timing Set Failure...what needs to be done??
I decided to switch to the electric waterpump and play it safe by taking the load off of that waterpump drive gear. I swore that I'd never use that electric pump again because I just don't trust it, but when it came down to possibly having a bunch of metal filings in my pan screwing up my new forged internals vs having to re-install the electric pump and do some more wiring I chose what I think to be the safer route. I guess I freed up a little more power this way too......
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Joined: May 2005
Posts: 2,161
From: Colorado
Re: LT4 ED Timing Set Failure...what needs to be done??
hey mikey~ that was the SAME exact thing that happened to me. Do you have those oil holes drilled into your plugs like previously mentioned? I am willing to be mine doesn't... :-( Guess this spring I will have to tear into the damned thing again for the 4th fricken time. This is getting really old! I wish I would have taken my motor to a reputable shop now!
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Joined: Dec 1969
Posts: 165
From: Tallahassee, FL USA
Re: LT4 ED Timing Set Failure...what needs to be done??
Since we stole your thread over on the CorvetteForum, I thought you might want to see how it is proceeding over there -- read to the end posts to see what you think on the subject:
http://forums.corvetteforum.com/show...2&page=1&pp=20
Tom Piper
http://forums.corvetteforum.com/show...2&page=1&pp=20
Tom Piper
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Joined: Nov 2001
Posts: 103
From: Sterling Heights, MI
Re: LT4 ED Timing Set Failure...what needs to be done??
Wow! this thread exploded. Anyways... I knew about the holes in the oil gallery plugs before throwing it back together but I read in the "How to Rebuild an LT1/LT4 Engine" that they weren't that crucial. I wish I would've known better before hand but I trusted that book. Another weird thing was when I pulled the timing cover off I also noticed that the small waterpump gear could be spun on the waterpump driveshaft by hand. I haven't had the chance to pull the wp driveshaft assembly off yet because I've been away at school. Anyone else ever seen this??
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Re: LT4 ED Timing Set Failure...what needs to be done??
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