VG30E rocker arm preload?

[sewebster]

I'm in the re-assembly phase of my engine rebuild on my '91 now... I put back together one of the heads today. When I got to bolting down the rocker shafts I noticed that before I tightened the bolts the shafts weren't all the way "down" and resting on the lifter guide plate. When I torqued them just a bit (< 5 ft-lbs) then it was nice and snug. But wouldn't this be slightly opening the valves? The valves should all be shut at the camshaft at 0 degrees... unless there is some tweaked timing from the ideal 4-stroke 6 cylinder order. (edit: this is the left head, so at cyl 1 TDC they should all be shut I think).

 

Anyway, does anyone know what I'm talking about and whether it is normal? I can think of some ideas of why this could happen, but I'm just hoping all my lifters aren't seized or something. Thanks for any tips. Hopefully sometime soon I'll be able to start answering more questions than I ask!

Edited September 26, 2010 by sewebster

[MY1PATH]

Did you change your lifters? You should have if your doing a rebuild. and make sure you follow a high rpm break in process using lots of zddp for at least 20 min.

 

That being said, when there is no oil preassure it is not uncommon for a lifter to collapse a little when you tighten down the rocker shaft. When this happens the lifter takes the slack instead of opening the valve. Just make sure your rockers are nice and centered when tightneing the shaft(evently) and that one end is resting on a lifter and the other end is resting on the valve. If either end is floating more than .006" than you may have found a problem.

 

 

[sewebster]

Did you change your lifters? You should have if your doing a rebuild. and make sure you follow a high rpm break in process using lots of zddp for at least 20 min.

 

That being said, when there is no oil preassure it is not uncommon for a lifter to collapse a little when you tighten down the rocker shaft. When this happens the lifter takes the slack instead of opening the valve. Just make sure your rockers are nice and centered when tightneing the shaft(evently) and that one end is resting on a lifter and the other end is resting on the valve. If either end is floating more than .006" than you may have found a problem.

 

I replaced two of the lifters that looked like the tops might be a little worn. I didn't realize replacing them all was a standard thing to do... but the reason I didn't was the cost. They are like $30 each or something... not sure how terrible an idea this is...

 

When you say floating, you mean if the rocker can rock back and forth right now? Definitely not. It was snug when I started tightening and more snug now So adding zddp is a usual break in procedure? Where do you get this stuff. I didn't notice it in the parts stores. Maybe it is illegal in Canada or something Thanks for the help.

[Indigent]

There is a procedure for tightening those down. The final torque should be 13-16 ft lbs.

You put #1 cylinder at TDC then tighten the bolts in a gradual pattern on the 2-4-6 side. Next you put #4 cylinder at TDC and tighten the bolts in a gradual pattern on the 1-3-5 side.

[MY1PATH]

I replaced two of the lifters that looked like the tops might be a little worn. I didn't realize replacing them all was a standard thing to do... but the reason I didn't was the cost. They are like $30 each or something... not sure how terrible an idea this is...

 

When you say floating, you mean if the rocker can rock back and forth right now? Definitely not. It was snug when I started tightening and more snug now So adding zddp is a usual break in procedure? Where do you get this stuff. I didn't notice it in the parts stores. Maybe it is illegal in Canada or something Thanks for the help.

 

thats exactly it, they don't always open valves when cold and no oil preassure running. Its a good idea to change all the lifters @ ~250k miles or sooner if a rebuild is involved. Check out northern auto parts, or abc nissan. I got mine from northern, they were clevite brand and it totaled about ~130 for all 12. royal purple and brad penn racing oil contain zddp its a good idea to have at least 2 qts of a zddp containing oil in every oil change because most oil mfgrs do not put it in their oil anymore. Its a wear reducing agent, check out http://schneidercams.com/engineadditives.aspx. use the cam lube on all the shiny surfaces of your lifters and rocker pads during assembly and formula 2 for your break in (lots of zddp) DO NOT USE FORMULA 3 untill your rings have seated.

[sewebster]

There is a procedure for tightening those down. The final torque should be 13-16 ft lbs.

You put #1 cylinder at TDC then tighten the bolts in a gradual pattern on the 2-4-6 side. Next you put #4 cylinder at TDC and tighten the bolts in a gradual pattern on the 1-3-5 side.

 

Yeah, I have the dealer manual and followed the procedure, but since the heads are off the cylinder position is irrelevant. You just don't want the cam lobes to be pushing the lifters up when tightening.

[sewebster]

thats exactly it, they don't always open valves when cold and no oil preassure running. Its a good idea to change all the lifters @ ~250k miles or sooner if a rebuild is involved. Check out northern auto parts, or abc nissan. I got mine from northern, they were clevite brand and it totaled about ~130 for all 12. royal purple and brad penn racing oil contain zddp its a good idea to have at least 2 qts of a zddp containing oil in every oil change because most oil mfgrs do not put it in their oil anymore. Its a wear reducing agent, check out http://schneidercams.com/engineadditives.aspx. use the cam lube on all the shiny surfaces of your lifters and rocker pads during assembly and formula 2 for your break in (lots of zddp) DO NOT USE FORMULA 3 untill your rings have seated.

 

Ok, thanks for the advice. I'm not entirely sure how much all the fancy additives and stuff matter. I mean, I don't think the rest of the truck is going to last another 250k miles, even if the engine could, but who knows. The truck has 185k miles on it now.

 

I think I can easily replace the lifters just by popping the rocker covers and rockers off at any time (ie. doesn't need to delay my reassembly process) right? Presumably they come off without having to remove any other engine stuff?

 

The two I already replaced were Sealed Power brand, which I understand is supposed to be good (?) and are $22.79 each, there is also Rock Products which is $14.43 each... any idea if they are decent? Probably I should just spring for what I trust...

 

I wish I understood how the lifers work inside better to understand how they would fail. Maybe I should saw one of my old ones in half. Actually, that sounds like a good idea... hmm. Sorry for all the rambling, but this is helpful.

[Kingman]

Lol, there's a procedure for that? I set aligned everything with the new belt and tightened them all down. Haven't had any problems...

[MY1PATH]

yes you can change them at anytime but you should use zddp and a break in procedure each time you change them. These aren't BS additives I'm talking about either. They replace a compnent in oil that MFGRs nolonger use on the newer engines. ZDDP is literally (and In laymens terms)micro particles of zinc that wear down intsead of your engine internals.

Search for my cam thread, I have a video and explaination there on how lifters work and how they can be modified.

The way they usally fail is by falling out of tolerance to the point where they leak or don't hold enough oil preassure (zddp prevents this so they fail faster now than they did before 2003).

the other common thing is heat cauising brittle ness so they chip or wear at the small end.

 

you'd be surprised, if you take good care of things I bet you'll get another 200k out of engine and vehicle. I plan to have both mine for another 20 years.

[sewebster]

I placed the order for the set of lifters earlier today. Since I replaced the valve, rockers and rocker shafts, might as well do it all properly I shall look into getting some zddp around here or online.

 

Back to my original question though... if the lifters aren't "full" of oil, then you'd expect there to be more slack in the system, not less, as seems to be my experience. I was fooling around more again today though, and I think that maybe there isn't actually a time in the cycle when all the lifters are FULLY down. Probably the actual sequence is slightly tweaked from my "naive" by the textbook 4 stroke cycle. So perhaps this is why I need to apply slight force to get the rocker shafts down.

 

I'm just concerned that if my valves are actually slightly open when they should be closed that they will die because they overheat (not to mention I could lose compression) so I want to get this right. Replacing the valves again would be lame.

[wood6078]

Lucas engine break-in additive has zddp, I think. I know its high in zinc. We carry it at my store (O'Reilly's).....I'll get you a p/n for it tomorrow and make sure it has the zddp in it.

[MY1PATH]

Reccomend schneider because they void your waranty if you don't use it which means the want to sell it, or the belive in their product....

[sewebster]

Thanks guys. I found a local parts store (Lordco) has the Royal Purple line, including their break-in oil, with zddp, so I picked that up. Probably I'll keep using the regular 5W30 Royal Purple after break in (still need to figure out exactly what I want to do for break-in). Need to decide between 5W30 and 10W30 I guess, but the manual says 5W30 is preferred and it does get cold up here when I go to the mountains...

[MY1PATH]

Break in procedure. (I'm gonna litter this site with my ZDDP and break in procedures lol)

Start engine and raise rpm to 2k rpms. If there is problem shut off and correct it. DO NOT LET THE ENGINE IDLE.

Aproximite timing at 2k rpm is ~32* but turing the dizzy by sound till it runs smoothly is acceptable for the break in process.

 

2k rpm 5 min

3k rpm 10 min

fluctuate 2~3k for 5 min

let idle double check timing and shut off.

 

at this point I reccomend changing your oil.

I also recomend you have zddp in your oil @ all times because it protects the lifters. Most oils nolonger contain this substance.

Don't rev above 4000rpm for the first 250 miles

[sewebster]

What about hard accelerations to seat the piston rings? People seem to be all about this on the internet

[MY1PATH]

What about hard accelerations to seat the piston rings? People seem to be all about this on the internet

 

 

there is as much contraversey one way as there is the other, I personally am beliver in the above but many will argue the opposite.

So if you are a beliver in the above, by all means step on the gas as hard as you like as long as you watch the RPMs...

The rpm thing and staying below 4k rpm is to facilitate proper blending of the cam and lifter surfaces without skipping or chattering beteen parts(can be very bad but usually doesn't happen) This is mostly for new cams but its good to do so on new lifters too. as the 2 surfaces find a common track in their wear pattern Higher rpms can be had without skip and chatter. Its not the end of the world if you loose track and hit 4500 rpm, your auto may like to shift there but consider being ligther on the pedal if its shifting higher than that. 250 miles is less than a weeks driving for most ppl so you should be able to get your lifter/cam break in good.

[sewebster]

there is as much contraversey one way as there is the other, I personally am beliver in the above but many will argue the opposite.

So if you are a beliver in the above, by all means step on the gas as hard as you like as long as you watch the RPMs...

The rpm thing and staying below 4k rpm is to facilitate proper blending of the cam and lifter surfaces without skipping or chattering beteen parts(can be very bad but usually doesn't happen) This is mostly for new cams but its good to do so on new lifters too. as the 2 surfaces find a common track in their wear pattern Higher rpms can be had without skip and chatter. Its not the end of the world if you loose track and hit 4500 rpm, your auto may like to shift there but consider being ligther on the pedal if its shifting higher than that. 250 miles is less than a weeks driving for most ppl so you should be able to get your lifter/cam break in good.

 

I have a manual, so should be easier to control the shifting

 

Yeah, I haven't really decided what I think yet. Oh well. I wonder if I should use this expensive Royal Purple break in oil for the first go in the garage, or if I should use conventional oil plus the zddp additive, then change after the first few minuts you described to the Royal Purple synthetic.

 

What's so bad about idling? Low oil pressure?

 

Do you think I should crank the engine around for a minute or so with the starter with the coil disconnected (or plugs out?) in order to prime the oil pump and get some oil moving?

[MY1PATH]

I have a manual, so should be easier to control the shifting

 

Yeah, I haven't really decided what I think yet. Oh well. I wonder if I should use this expensive Royal Purple break in oil for the first go in the garage, or if I should use conventional oil plus the zddp additive, then change after the first few minuts you described to the Royal Purple synthetic.

 

What's so bad about idling? Low oil pressure?

 

Do you think I should crank the engine around for a minute or so with the starter with the coil disconnected (or plugs out?) in order to prime the oil pump and get some oil moving?

Yes, Oil is only 7~10 psi at idle, for the break in the lifters need high oil preassure and proper component speeds to facilitate the proper friction levels for break in and hardning. Picture fan with the cover off truing full speed. If you poke the wind side you finger may bounce off it and you say owch but turning on low your finger would go between the blades and cut you. Thats how it works, too low a speed and they will grind eachother instead of polish eachother.

These pumps do not require priming but you will hear the lifters for the first minute or so unitll lifters themselves preasureize, this is their most crucial moment Use the break in additve for this time and again for the rest of the break in.

[wood6078]

Just b/c I said I would....even though u don't need it. :-)

 

Lucas engine break-in oil additive p/n 10063