Hydraulic Lifter Preload on a 350

[#1CutlassSupreme]

Okay, so I'm easily spooked by what I read...and I’ve read a few horror stories about hydraulic lifter cams.

I'm getting closer to turning the key for the first time since rebuild on my 72' Cutlass 350 and I want to make sure I don’t kill the beast. I took the engine out to a machine shop to have it rebuilt and had the machinist install a Crane Powermax Cam with Hydraulic flat tappet lifters. The instructions with the Cam says that it needs a pre-load between .030 - .060. BUT the break in procedure from the shop says to have 0 preload. (I'm sure he's assuming that most stock rebuilds are solid lifters.)

I noticed that stock Olds rocker arms aren’t adjustable and it looks they just tighten down straight to the head. SO…do I have anything to worry about with the lifter preload or is there a way I can make sure that I’m within spec on this? .030 - .060 doesn’t leave a lot of room for error.

I've read that I could basically ruin the cam or bend the rods if there is too much pre-load. And if there isn’t enough pre-load I wouldn’t get enough oil up to the top of the rod and have some serious problems in the valve train.

Any ideas/suggestions/tricks to make sure I'm good on my pre-load?

[Oldsmaniac]

I am not sure what the correct measured preload should be...maybe FAQ's at 442.com will say. Stock valvetrain is not adjustable....slight preload is what you want to keep valvetrain quiet. If preload is too great you can buy shims/small washers that go under rocker arm bridges at head surface. If there is no preload you can buy still (hopefully) adjustable pushrods to preload lifters. You can see what kind of preload you have when the intake manifold is off and rockers bolted down and both valves closed. Look at the lifter and the clip that holds the lifter together. With preload the disc where the pushrod rests will be pushed lower than the wire clip.

[#1CutlassSupreme]

Hey Maniac, thanks for the info on checking the lifter preload at the lifter. Luckily, I haven't installed the intake manifold or the valley pan yet so I was able to check the clearance this weekend.

What I did was bring the #1 cylinder to bdc then used a straight edge and put a mark on the rod. Then I loosened the bolt on the rocker arm and measured the distance between the tightened and loosened marks.

I was concerned that I might wipe the break-in lubricant off of the freshly installed cam, but I just followed the firing order and went through each cylinder and it looks like the cam only made one turn.

Hope this post helps others dealing with the same problem.

[The_Jeremiah]

LOL i prefer the fire it up and see what happens method. : )

[#1CutlassSupreme]

Yeah, I've had way too much experience with that method to know better. I'm about $2,500 into this engine, so it's all about taking my time this round.

I did a 75' Datsun B210 I built in highschool and did a 'fire it up'...the engine caught on fire...HAHAHA!!! Didn't catch the leak in the fuel line in time. Luckily had an extinguisher near by and salvaged it.

[Jokers69]

On mine I just bolted the rockers down as designed, and ran it for 20 mins at 2000 RPM with a big fan in front of the car. IMPORTANT, along with the break in lube you put on the cam and lifters add a bottle of break in lube to the oil. I used Shell Rotella 20-50 diesel oil.

[#1CutlassSupreme]

I heard that Diesel oil has good detergents in it for breaking in engines. I was just planning on going with the engine/cam break in lube that I got from Crane Cams. Do you think that will be sufficient Joker?

Also, should I be expecting so much heat from the car that I will need an aux fan in addition to the engine fan?

[88 coupe]

Originally Posted by #1CutlassSupreme

........ it needs a pre-load between .030 - .060 ........

.010" to .060" should work with any brand of lifter.

Originally Posted by #1CutlassSupreme

........ says to have 0 preload ........

In this case, "0" does not apply to preload, but to the "zero lash" in a running engine.

Originally Posted by #1CutlassSupreme

........ I'm sure he's assuming that most stock rebuilds are solid lifters ........

Just the opposite. With solids, a specified gap (opposite of preload) is left in the valvetrain.

Originally Posted by #1CutlassSupreme

........ And if there isn’t enough pre-load I wouldn’t get enough oil up to the top of the rod and have some serious problems in the valve train.

Lack of preload would cause the valvetrain to be noisy. Nothing more, nothing less.

Norm

[Jokers69]

The break in lube from crane is a bottle thats added to the crankcase, correct? If your going to rely just on the spooge that you put on the lobes, I wouldn't. There are other brands of break in lube, but I've used the Crane.

The diesel oils have had better anti wear (zinc or ZDDP) packages since the advent of catalytic converters and stronger pollution controls on gasoline engines. Though those days are coming to a close with diesels getting more regulated with their emmissions. I always use a 20-50 diesel oil in non rollerized engines now.

As far as the fan goes, I did mine on a hot day, it's also habit I got into with rebuilt air cooled motorcycle engines. If you haven't put it all together yet, fill the block with coolant slowly through the intake before putting the t'stat housing on, keep the radiator cap off and make sure you have the heater controls open when it starts, burp all the air out so it doesn't get air pockets in the cooling system.

[#1CutlassSupreme]

Thanks Norm for the corrections on my understanding of hydraulic lifters. I've never used them before so I want to be extra cautious of my understanding. The machine shop guy mentioned that the hydraulic lifter pumps up the oil pressure. and I took that to mean that more oil reached the top of the valve train when, in fact, it meant simply that the lifter wouldn't depress as much.

Jokers-

I have the glazing lube on the cam and I'm using the crankcase break-in oil. Looking back at the price of that stuff compared to diesel oil I realize that I could have saved a few bucks.

That makes sense to use a fan on a hot day. I used to have a sandrail with a VW engine so I know a little bit about trying to keep something air cooled.

Thanks for the advise on filling the coolant, I usually just fill the radiator, turn on the heater, and give the hose a few squeezes to get the air out, but filling the intake directly seems like a better way to go.

[Oldsguy]

Originally Posted by #1CutlassSupreme

...The machine shop guy mentioned that the hydraulic lifter pumps up the oil pressure. and I took that to mean that more oil reached the top of the valve train when, in fact, it meant simply that the lifter wouldn't depress as much.

He probably meant "hydraulic lifter pumps up with oil pressure".

[Jokers69]

Looking back at the price of that stuff compared to diesel oil I realize that I could have saved a few bucks

I'm not advocating substituting one for the other, I use both.