extra ZDDP / Moly needed for these 2 engines?

[gmchevroletruck]

for the following 2 engines, do they have roller cams, or flat tappets? And in either case, would you say either would need one of the oils that has high Moly, high Phosphorous, and high Zinc?

1) 94 Throttle Body Injected 5.7 (350) - Chevrolet
2) 02 5.3 (LM7) - Chevrolet

 

[AzFireGuy79]

The 94 5.7 is a flat tappet/lifter design. The 5.3 utilizes full roller lifters. I would run something like Rotella 5w-40 syn in the 5.7 because its a great oil with ZDDP and just a good 5w30 in the 5.3 I have heard some like castrol edge. That being said I run redline which has loads of zddp in it. It cant hurt, just not sure you want to spend $9 a quart on oil. The LS-1 motors like RL 5w30 from past experience. So do the Lt-1's which have roller cams.

 

[gmchevroletruck]

I'm going to go out on a limb here and show my ignorance...lol...but, what exactly is the difference between a flat tappet design and a "full roller lifter"... I was unable to decipher it from wikipedia...If an engine has hydraulic lifters, does it mean that it is a "roller lifter" style, first of all? And secondly, what is a flat tappet exactly?

 

[AzFireGuy79]

As far as lifters in overhead valve v-8's go you have standard hydraulic and and solid/ flat and roller. If a motor is a "full roller" this speaks to not only the lifters but the rocker arms as well and in some cases the timing chain. Whether they are hydraulic or solid depends on use. Modern factory spec overhead valve engines will come with hydraulic roller lifters.

As far as me referencing "flat tappet", this is what they call flat lifters. There is no roller at the end, just a machined surface that allows the tappet to rotate in its bore. Rollers of course create less wear and more hp.

 

[gmchevroletruck]

Thank you for that info... again, exposing my ignorance I ask: Would that mean that if an engine has hydraulic lifters, that it does not have flat tappets?

 

[mechtech2]

"Modern factory spec overhead valve engines will come with hydraulic rollers."
"just a machined surface that allows the tappet to rotate in it's bore"

Well, no.

Most overhead valve engines use 'flat' tappets or buckets.
When was the last flathead motor produced for cars? Overhead valve engines are the norm. Some are overhead cam, also.

A tappet may or may not rotate in it's bore, but many flat tappets are not designed to do so. The ones that do have a convex surface that rides on the cam lobe that is angled a bit.
Old school.

If the 5.7 in question is a mild passenger car engine, the cam pressures are low, and there should be no need for special high additives oils. It is already broken in.
Will it hurt to use high additive oil? Of course not.

 

[AzFireGuy79]

Speaking on GM products,(I should have speciified although thats what he is asking about) every modern overhead valve v-8 motor they produce utilizes a "roller lifter". Not a tappet or bucket. And they are hydraulic. I have owned countless Lt-1 and LS-1 motors. Traditionally tappets do rotate in the bore. Ask an engine builder. It's a fact. Some modern designs may differ.

But thanks for the correction!

 

[SteveSRT8]

I think that the interesting part was the mention of an 'overhead valve' design. It has been a while...

And I have yet to see a flat tappet that does not rotate in its bore. Can anyone provide a reasonably current design that does not?

 

[gmchevroletruck]

when we say "modern", does that apply to the truck motors put in a 94 GMC?

 

[AzFireGuy79]

The 94 TBI motor which has flat tappets is like any other V-8 before it in that the tappets rotate in their bores. I have a 92 TBI and it looks pretty much identical to my 78 K-5 350 V-8. Not much changed in that time fram believe it or not. And like I mentioned earlier all of the later designs after the TBI motors (v-8's) were roller. Hope this helps. Personally I would run an oil with a decent amount of zddp. Thats just me.

 

[gmchevroletruck]

Originally Posted By: AzFireGuy79
The 94 TBI motor which has flat tappets is like any other V-8 before it in that the tappets rotate in their bores. I have a 92 TBI and it looks pretty much identical to my 78 K-5 350 V-8. Not much changed in that time fram believe it or not. And like I mentioned earlier all of the later designs after the TBI motors (v-8's) were roller. Hope this helps. Personally I would run an oil with a decent amount of zddp. Thats just me.


Perfect. That clears it up...I also had to tear down the motor on my wife's Caravan this weekend (snapped timing belt), and with the valve cover off, saw the roller rockers in action with a friend turning the motor over by hand - I now know exactly what they look like, and yes, it's nothing like my 94 TBI motor lol...can totally see which is which now. Thanks for the info also, guys.

I agree...I think I'll try to find an oil with higher zddp for the TBI motor, to deal with the load pressure on the valve lifters there. I think with a stock motor and stock valve springs, the motor only has like 85 pounds of pressure on the lifter, but...still. Couldn't hurt.

Thanks for the advice.

 

[gmchevroletruck]

Correction to my above post, before someone else has to do it, lol: 85 pounds of SPRING pressure...not pressure on the lifter from the (pushrods?). OOPS...not applicable

 

[mechtech2]

Some of you don't seem to know the difference between overhead valve and overhead cam.
They are not interchangeable terms.

50 year old V8s are overhead valve engines.
So are modern overhead cam 4 valve per cylinder engines.

Flat tappets/buckets are very common in OHC engines They don't rotate. And OHC engines are not exactly rare, now.

 

[BuickGN]

While they're all OHV engines, the term is usually used to designate a pushrod engine while OHC is, well, obvious.

Also, to the OP, don't confuse the roller rockers to roller lifters.

 

[AzFireGuy79]

Mechtech- Hey if you are going to call me out then come to me thank you very much. I have been building V-8 muscle cars for quite a while. OHV has been used or pushrod for years. Its like calling a engine a motor. Is it proper, no, but we who know still use it.

Post your proof that all these flat tappets dont rotate. In the engines we were discussing here this thread, ZERO have flat tappets.

And further, I have built a few B18C5 motors and worked on several honda and toyota engines in my day so I know what a overhead cam motor is thank you very much. You know what they say about assuming things!

But thanks again for your correction and "expert knowledge" on the subject. Excuse me while I go work on my OHV, oh excuse me my pushrod motor in the garage!

 

[AzFireGuy79]

OH, and one more thing from Wikipedia-

An overhead valve (OHV) engine, also informally called pushrod engine or I-head engine, is a type of piston engine that places the camshaft within the cylinder block (usually beside and slightly above the crankshaft in a straight engine or directly above the crankshaft in the V of a V engine), and uses pushrods or rods to actuate rocker arms above the cylinder head to actuate the valves. Lifters or tappets are located in the engine block between the camshaft and pushrods. The later overhead camshaft (OHC) design avoids the use of pushrods by putting the camshaft in the cylinder head.

 

[440Magnum]

Originally Posted By: AzFireGuy79
OHV has been used or pushrod for years. Its like calling a engine a motor. Is it proper, no, but we who know still use it.


The way I read it, he was saying the same thing you are. Unless I missed something, but I've read his post and yours twice and they pretty much say the same thing.

Actually I'd take your claim even further. Calling a pushrod engine "OHV" is completely proper and correct. OHV, as you obviously know, means the valves are in the head, not in the block like a flathead (or "side-valve" or "L-head") engine. They can be actuated either by pushrods or by overhead cams, but they're still overhead valves either way.

Originally Posted By: AzFireGuy79
Post your proof that all these flat tappets dont rotate. In the engines we were discussing here this thread, ZERO have flat tappets.


I'm pretty sure a 94 Chevy 350 has flat (meaning non-roller) tappets. Why Chevy stuck with sliders so long after Ford and Mopar went roller is a mystery to me, but they did. Of course you're right- V8 flat tappets spin because the cam lobe is slightly curved across its width to make the contact point off-center of the lifter.. The only "flat tappets" I know of that don't rotate (or at least rotate much more slowly) are the shim-adjusted "bucket" style that go under rocker-less OHC engines like older water-cooled VWs. I don't know if they aren't designed to rotate, or just don't rotate well in practice.

 

[[RT] ProjUltraZ]

depends which, the 93-97 LT1 350 had rollers (f-body and vette)
maybe their trucks and vans had flats?

 

[endeavor to persevere]

GM went to rollers in the mid to late 80s in cars. I believe trucks did not go to roller lifters till 1996.