After seeing how common this problem is and figuring that most of these cars have the original short block in them I came to the conclusion that there had to be a fundamental change to the oil system when they started building these engines.I have built gen 1 small blocks in the past and have never had a problem with lifter noise.A lot of poeple have posted some good ideas but I have ruled out about 99% of them as being the problem.I also don't have a lot of faith in all the snake oil treatments,these have there place but most of us take very good care of our cars and I think some of these do more harm then good.Anyway I'll cut to the chase.
My sources of information were the HELMS factory repair manual and HPBooks-" How to Rebuild Small-Block Chevy LT1/LT4 Engines" by Marvin Mavrigian.Both are excellant sources of information.
With the poor oil circulation I noticed to the top of the engine when I adjusted my rockers with the engine running, I knew I was losing pressure between the oil pump and lifters.Hot oil pressure on my car is 25 psi @ idle and 40 psi @ cruise/not stellar but well within factory specs.This rules out badly worn bearings, cam,rod or main- otherwise my guage reading would be a lot lower.This narrowed the search to a very small area.I was losing pressure somewhere between the front and back of the three oil galleries that feed the cam and lifters.The center one feeds the cam . The two left and right of this one feed the lifters.
So I looked in the HELMS manual and studied the oiling system for the LT1 and EUREKA!....... The factory drilled a .030 hole in each of the plugs at the end of the oil galleries thet feed the lifters.GM supposedly did this to provide air bleed-off and to provide additional oiling for the timing chain.The timing chain receives it's lubrication from the oil that is returning to the pan after going through the pushrods and rocker arms.The timing chain does not require Niagra Falls to be lubricated.
" The intent of these holes is to provide an air bleed -off path for the oil and to provide additional oil for the timing chain.However engine builders debate the necessity of these holes.Also,some aftermarket experts note concern that oil escaping these holes may potentially reduce oil to the front rocker arms."
That last statement I think covers all of us having this problem.Mine sounds like the #2 or #4 cylinder.And I think everyone else has had problems with the front cylinders also.
This entire post is my opinion but I think that this is the problem,it all makes sense.These holes were probably fine on a new engine with tight bearing clearances but as these engines wear and these clearances start to open up a little it probably put the lifters over the edge and now lack enough oil pressure to do their job. A .060 oil leak is pretty big in my book.
It's an inexpensive but labor intensive fix if all you do is plug the holes.My car is due for a timing chain,distributor cap and rotor so I need to round up some parts before I do it.
These plugs are an odd size-.566 so you might want to try and locate them before your tear into it.Whatever you do - don't drill them or you will end up with metal shavings in the oil gallery.If someone else gets to try this before I do, let us all know if this fixes the problem.
Well what do you guys think? Comments,Questions?

 

deep stuff man!

 

You kind of have the cart before the horse. You say a "fix" before it has even been tried. How about doing it and letting us know the results.

The oiling holes have certainly not been a secret. Since the LT1 has the water pump driven from the cam gear, those holes might be more important than you think. If you go to an electric water pump and double roller timing set, the need for extra oiling migh be negated. I'm a bit skeptical that closing the holes will resolve any lifter tick.

MHO

 

I would be very carefull of removing those holes. LT4 ED Timing sets have been known to self distruct taking a good protion of the motor with them. Now it could be just poor metal in the ED gear sets but a lack of oil could also be a contributing factor. If you run the stock WP and timing set you may end up with the LT1 timing set having the same problem as the LT4 ED set. I am not saying that is fact just it may be a posible resuly of remiving the holes.

 

I haven't had any lifter tick in my car at all. The aftermarket rocker arms made some noise, but that's it. I will agree that the oiling system in the LT1 seems to be a bit quirky with people complaining of (myself included) mysterious oil pressure drops at high rpm/high load, low pressure at idle and the like. However, upon tear down of my last block, the bearings, cylinder walls and other wear parts looked just fine for a 140k mile motor. I was planning on doing a high volume oil pump for this new motor, but I think it will end up being a melling standard volume replacement with a "white" spring in it. I am very curious to see how this setup works.

 

OK,possible fix. All I'm looking for is a little feedback.
Thanks for your input gentlemen.

 

I have had the tick as well since owning LT1s, When I built this motor I have now the machinist put screw in plugs inthe front withno hole in them, the tick is still there. I think it has to do with the water pump drive. The cars I see with electrical WPs and Cloyes double rollers don't make near the lifter tick I have allways had.

 

i'm rebuilding my lt1 right now and will be converting to a double roller and electrice water pump. i think i might give this a try.

most of the time though lifter tick is just caused by dirty lifters that reduce the oil flow. in a high mileage motor it's probably best to just replace them out right, but if you're on a budget soaking them in carb cleaner or another solvent cleans them very well. (just make sure you soak them in oil before reinstalling) mitsubishi engines tend to have this problem too. they fix it by drilling the oil holes in the lifters slightly larger.

 

I just put together my LT1 and it had small frost plug like caps for the oil galleys? My BBC had the small oil holes in the oil galleys but they were pipe plugs with threads on them? I need help now the engine is sitting under the car ready to go in. Are you sure all LT1's had oil galley plugs with holes in them? My machine shop did not give me back my plugs! So I have no way of knowing if my plugs had the small holes in them. None of the new plugs came with holes. I'm totaly bummed out right now!

 

That seems to be the norm. The plugs are an odd size that you might only be able to find at the dealer.

 

OK, But do I need to have the oil holes in them or will my solid plugs work?

 

The oil holes are to lube the water pump gears and the cam thrust plate. A SBC don't have a cam thrust plate or gears. The statement about air bleeds are BS 'cause not ANY SBC before the LT1 had them.
If ya have put in the right oil pump for your clearances ya will have pressure everywhere. Have not had a problem in the ones I have built. The stock pump with the 3/4" pickup IS a HV pump and that is what came in it and that is what belongs in it. If ya want to listen to most they say HV isn't needed,Wellllll.

 

When my lifters tick...i add more oil, you see that way you dont have to check it



lol j/k

 

Ahhhh hell,just add 2 qts.and a couple of cans of compression,she'll be OK.

 

I seriously did this one time when i was 15, i was driving and wondered why my engine was ticking....duh i dunno lets drive it for a week or so and then decide to check the oil. Ya i was down by 3 quarts. Oh well that was a beater car which by the way still runs, even though its wrecked.