F@#$&^$ 5k..run Good

[Felix]

Yea I know.

 

What I was getting at is that if I can get away with running a hydraulic cam with solid lifters, is that you will be fine running a mechanical cam with hydros. It may not be ideal but it will work.

 

At the end of the day it is just a simple old K motor.

[Felix]

As for your lifters pumping up, maybe you could possibly have to much lifter preload???

[madrolla68]

As for your lifters pumping up, maybe you could possibly have to much lifter preload???

 

I think it is fine when you run solid lifters ona hydro cam cause there is no way it can pump up the lifter BUT when you run hydros ona solid what happens is the opening ramp that would normally soften the opening ie: remove the tappet clearance lash and make for a nice opening actually "TAPS" the bottom of the hydro lifter causing it to lift then drop then lift again inturn causing a tiny bit of oil to be pumped into the lifter hence "PUMPING" it up ever so slightly and after a number of these it will eventually hold the valve of its seat depending on the spring tension.

 

That my take on it.

[Felix]

Here is something to think about:

 

What happens to the base circle diameter when you regrind a cam? Ok, now think about how this would affect lifter preload in a 5k with hydraulics. Then ponder a few moments on how this is corrected if the motor has non adjustable valve gear. :dance:

 

Now lets assume your 5k had been properly set up for the old reground cam. You have now put in a cam with a (larger) standard sized base circle, do you think there will be an obvious problem somewhere?

 

I could spell it out, but I would prefer you to think about it for yourself. :P

Edited March 4, 2007 by Felix

[madrolla68]

Here is something to think about:

 

What happens to the base circle diameter when you regrind a cam? Ok, now think about how this would affect lifter preload in a 5k with hydraulics. Then ponder a few moments on how this is corrected if the motor has non adjustable valve gear. :hmm:

 

Now lets assume your 5k had been properly set up for the old reground cam. You have now put in a cam with a (larger) standard sized base circle, do you think there will be an obvious problem somewhere?

 

I could spell it out, but I would prefer you to think about it for yourself. :P

 

Felix

 

Here is something to think about.

 

As i have been an engine reconditioner for 25 years i understand lifter preload and base circle diameter very well, and i also understand the point you are making that if the replacement cam has a larger base circle than the failed "reground" cam then yes the lifter internal working area could be compromised and hold the valve open.

 

On the other hand the point i was trying to make is that history shows that hydro and solid cams do not normally have the same opening and closing ramps ,hence why they use two different cam followers. In this case it would appear that to be the case going by the information supplied to us by CAM.

 

A "normal " lifter has a working range of around .120" and whether or not the whole base circle thing was explained to CAM by whoever he got advice from regarding the changeover who knows ,it would appear that there needs to be some insight into the what exactly has been put into this engine both the failed cam and the replacement item

 

Matt

[Felix]

Matt, my post wasn't directed at you. I was trying to get Cam thinking about what could be happening.

 

The first thing I would do is strip off the rocker gear, and compare the rocker pedestal height to some others.

 

When my 5k had a hydraulic reground cam in it, it also had the base of the rocker pedestals machined to match the reduced base circle diameter to maintain lifter preload. It had the same amount trimmed off the pedestals, as the reduction in radius of the B.C.D.

 

I may not be a "professional", but I have found it always pays to check the simplest things first. Especially something he could do himself simply in 20 minutes or so.

 

As for what happened to the original cam breaking, well I would be very interested in knowing what happened there myself.

 

 

Doug

Edited March 5, 2007 by Felix

[madrolla68]

Matt, my post wasn't directed at you. I was trying to get Cam thinking about what could be happening.

 

The first thing I would do is strip off the rocker gear, and compare the rocker pedestal height to some others.

 

When my 5k had a hydraulic reground cam in it, it also had the base of the rocker pedestals machined to match the reduced base circle diameter to maintain lifter preload. It had the same amount trimmed off the pedestals, as the reduction in radius of the B.C.D.

 

I may not be a "professional", but I have found it always pays to check the simplest things first. Especially something he could do himself simply in 20 minutes or so.

 

As for what happened to the original cam breaking, well I would be very interested in knowing what happened there myself.

Doug

 

Doug,everything you said was very true,and the part about checking the basics is the FUNDAMENTAL step that most "professionals" fail to do most of the time.

 

I'm with you maybe there are lifter ,spring coilbind,rocker geometry issues that were ,are being overlooked right from the start.

 

This is very uncommon as you are aware and there is a story to be told by what has happened.

 

No offence taken whatsoever,constructive critisicm is how we evolve to be better at what we do.

 

Matt

[camerondownunder88]

Hi,

Ok just before I type my reply to the latest postings I will just post pics of my dead cam shaft (semi dead) as I can save it adn reuse it later.

 

Above is the side of cam.

 

Front of pulley, Also this pulley was custom made to suit this cam as the timing mark is a tooth forwards to the original K motor pulley and it has been machined out of solid stock and not cast like a stock unit.

 

Here is the cam notice pin missing..lol It has taken the load of the cam due to the main bolt coming lose and it took the full cam load. The chip of metal also jammed in the thrust plate so I had to replace that also as it was eaten out and in a bad way.

 

Back of the wheel. As you can see it has stretched the hole and deformed it so it is not serviceable in this spot which is a pity it was a nice cam sprocket :P

 

But I have thought drill a new pin hole 180 degrees around the wheel and on this cam shaft and it should be usable just u install differently to how it would normally be done eg timing mark at bottom not top of the wheel when installing. As the cam is still good no wear and the cam face that oil sits between on the thrust plate is still good as a straight edge adn a feeler gauge showed me so I might try this cam in my 4K yet.

 

Cheers

Cameron

[camerondownunder88]

Ok now for my input.

 

When the 5K was rebuilt the cam was reground for the lifters and a new sprocket used and the posts of the rocker gear were machined and adjusted accordingly.

 

So Doug yes I can see your problem my hydros are now under more pre load then before as they were setup to suit the reground cam.

 

After installing the 4K cam I didn't have time to reset the hydros (well never done it before so no time to research and do) So not they will be under extra load BUT now I have a bigger base circle so at least my lifter will still have pre load on it as I know if a hydro lifter gets no pre load the valve train will be noisy when the engine is running and all of the hydraulic force produced by the lifter will be exerted against the lifters retaining lock, and this could cause the lock to fail.

 

But if it is to high I know the opposite occurs and the push rod descends too far (I think more than 0.060 if I'm right?), then you have excessive lifter pre load. So hydraulic lifter can pump up whatever pre load you put into it, therefore with excessive pre load, as the engine RPM and oil pressure increases, the hydraulic mechanism will pump-up the push rod seat. This will cause the valve to be open longer and lift higher. This will decrease the cylinder pressure, lowering the performance of the engine and also cause my 5K to back fire.

 

So this is why I find after I hit high RPM my motor loses a slight bit of performance. All I believe will happen is the valve seats will then slowly burn out but how long it will take is unknown. But JDM 5K motors which mine is received stainless steel nitride valves seats unlike the shit seats KE70's got here so valve seats shouldn't be a problem for me at this stage.

 

Also 8 cams were released for the 5K motor from toyota. 6 of these cross reference to solid lifter cams in other K motors 2 don't that is a directly taken from the Toyota EPC so can't be wrong. So there is a good chance I have a good cam in car.

 

Also solid lifter cams have a silencing ramp on the back of the cam so with hydro lifters there this ramp causes the lifter to pump up and not run right so that is it.

 

But got my other spare cam shaft here out today all still good so sending it to the cam shop tomorrow to get a down low economy grind on it so it is good in traffic then ill remove it at end of the year to install the SC14. :P So this cam in the car now is an emergency cam and possible correct for it.

 

As at high revs it is hard to hear but after 5000RPM the 5K is either valve bouncing due to high peak on a solid cam or it is the lifters so either way don't rev it hard it works :hmm:

 

Cheers

Cameron

[Felix]

Hey Cameron,

 

You could consider substituting your current rocker pedestals for some you may have laying around out of a 4k. It could provide a quick easy solution to getting your engine up and running with the cam you currently have in it.

 

Put your current pedestals away until you get around to redrilling the nose of your old hydro cam.

 

 

Doug

[camerondownunder88]

Hi,

Doug I know I can use 4K gear on 5K with hdro lifters and use the adjusters in the rockets to get my preset load BUT I then need ball to cup push rods not ball to ball and 4K and 3K rods aren't the right length I'm told so it will throw the rocker ration out so you need A12 rods. But I don't have any and mates engine rebuilding shop doesnt have any so at a loss there.

 

But still wanting to hear you way as it might work or be different so open to suggestions?

 

Cheers

Cameron

[Felix]

I meant to just use the pedestals themselves, not the rockers.

 

The pedestals are interchangeable. Remove the clips on the end of your 5k rocker shaft, and disassemble your 5k rocker gear. Now substitute your old machined pedestals for some untouched ones (steel 4k are good, avoid the earlier alloy ones), then reassemble retaining the non adjustable rocker arms. :P

 

Hopefully that should fix any lifter preload issues, and get your motor up and running without having to worry about burning valves, or losing power due to the lifters pumping up.

Edited March 5, 2007 by Felix

[madrolla68]

I meant to just use the pedestals themselves, not the rockers.

 

The pedestals are interchangeable. Remove the clips on the end of your 5k rocker shaft, and disassemble your 5k rocker gear. Now substitute your old machined pedestals for some untouched ones (steel 4k are good, avoid the earlier alloy ones), then reassemble retaining the non adjustable rocker arms. :P

 

Hopefully that should fix any lifter preload issues, and get your motor up and running without having to worry about burning valves, or losing power due to the lifters pumping up.

 

This sounds like a plan to me,can you check how much preload is on the existing lifters by checking how many turns it takes to loosen the rocker gear,this will tell you how much preload you have .

 

Normally on a UNC threaded bolt it is from 1/2 turn to a 1 1/2 turns that is the limit of the lifter internal travel and 1/2 makes sure it is running in the normal lifter range to avoid tappet noise.

 

So if you back of the rocker gear until the pushrods are just contacting the rocker and then tighten it down again on say no1 cylinder with no4 rocking you will see how many turns it is until the pedestal contacts the head.