Lose the hydro's lose some spring?

51MAN · Post by **51MAN** » Sun Sep 30, 2007 9:09 am

I was wondering.
To help negate cam wear.. lose the hydro's and reduce the spring pressure... Ceramics would have done a massive chunk of that, but not available... so Jakes tool steel lifters, suitable pushrods (Alloy or chromo?)
Not worried about 6k rpm +...

Thoughts.. is it possible? ANyone know the rates of the wbx springs? maybe I can buy a set of lower rate type 1's and see...

1303wasserbug · Post by **1303wasserbug** » Sun Sep 30, 2007 11:36 am

is there a real issue with cam wear then? stock or modified. i like my hydro's, don't have an agressive cam, standard DJ cam in a 1.9

51MAN · Post by **51MAN** » Mon Oct 01, 2007 2:09 am

I have heard of 1 or 2 that have had cam trouble, but that could easily be down to other things...

This is more concerning different cams (specifically type 1 cams) unless you get a "hydro" grind, you cant use the hydro lifters with a std type 1 style cam (well, that seems to be the jist of it)

From what I understand.. the hydros need different ramp tates and the springs are stiff to make the hydro's work, which means, if you dont have the hydro's then you dont need such stiff springs.. (for the same rpm)

ANyone know what the stock springs will go to rpm wise?

How much better does the 1.9 go with the 2.1 cam? (DJ and MV cam is the same)

1303wasserbug · Post by **1303wasserbug** » Mon Oct 01, 2007 10:35 am

sorry not sure how much difference the camshaft makes to the 1.9 as never drove it without it. also have engine fitted into a beetle. oh and have a garrett t25 blowing into it

51MAN · Post by **51MAN** » Mon Oct 01, 2007 11:09 pm

1303wasserbug wrote:sorry not sure how much difference the camshaft makes to the 1.9 as never drove it without it. also have engine fitted into a beetle. oh and have a garrett t25 blowing into it

makes a bit of a difference then

Unkl Ian · Post by **Unkl Ian** » Thu Oct 11, 2007 5:44 pm

I've never heard that hydraulic cams needed stiffer springs.

Flat tappet cam problems are more common lately,due to changes in the oil.

51MAN · Post by **51MAN** » Thu Oct 11, 2007 11:37 pm

There was a bit of a discussion on here about it.. cant find it at the mo..

The hydro cam has a sharp ramp rate as it has to take out the "slack" but then the springs need to be stiffer to compensate for the oil pressure holding them off.. I think it could be better to use less spring and no preload.. Originally preload was stated as 2 turns from just touching.. but later was reduced to 1/4 to 1/2 turn... I have used 1/4 without issues..

2 turns deffo makes potential for a poor seal on the seat..

some of the lash adjusting screws I have seen ahve taken a real pounding.. all with the 2 turns and hydro's... that surely has to be put down to stiff springs and the high ramp rates of the hydro cam..

Funny thing is.. I havent seen any cam/lifter wear on the few engines I have had apart.., but I have heard it has happened.. (could have been other reasons I suppose)

Maybe I am worrying too much about lifter/cam wear but I want to improve the engine and make it reliable..

Post by **Piledriver** » Mon Oct 22, 2007 6:24 pm

The WBX doesn't seem to have the T4s cam wear issues, the 88s ~300K mile cam had no apparent wear and still had the grinding tooling pattern on the lobes--- Could have passed for "not broken in yet" had I not known it's history.

The lifters were ~flat, but had a very nice polished surface.

Could probably go another 200K. (They may yet)

Turbo motor's likely to need far more spring.

(I ended up using the Mantons I had handy, berg retainers and cutting the spring seat .100". .485 lift int/.410 ex, but could go .500 and still be .080 from bind---1.4 Chinese rockers, modified)

tencentlife · Post by **tencentlife** » Sat Feb 16, 2008 2:04 pm

I really don't think the heavier springs are a requirement to make the hydro lifters work, Si. They are there because the hydros are so much heavier.

The hydro cam rates are, if anything, slower at first than a standard grind. There is a slow ramp-up at the heel which makes the internal ball-valve open slightly by the change in inertia. This is when oil under pressure can be admitted to the inside of the lifter, if there is room for it, before the lifter is loaded much by the valve spring counterpressure. So the slow heel ramp is the adjustment phase of the cycle. Once the lifter starts to really accelerate outward the ball-valve catches up and closes and the lifter is effectively a solid. That heel phase is why you have to run hydros on a cam that is ground for them.

It isn't possible for the oil pressure to "pump up" the lifter and cause valves to be held off their seats, the dynamics of it just don't allow that to happen. Nonetheless, that myth persists.

Also, under load, oil seeps out between the internal piston and the body thru the tight tolerance between. So oil flows thru the lifter from the pressurised case bore, in thru the ball valve, and out the tolerance. Some American manufacturers actually played with the seeping-out rate to create an early form of variable valve lift. At low speeds, oil would seep out at a certain rate and lose effective lift during a single valve cycle, being replenished during the next filling phase on the cam, while at higher speeds there was less time for oil to leave the lifter so effective valve lift was greater.

I think you could lighten the valve springs if you were using solid lifters. I also think that if you were using a relatively low-lift cam, and instead getting more lift by using higher-ratio rockers, that you could also use lighter springs for the same max rpm range, since the higher ratios increase the springs' ability to keep the lifters tracking by the increase in leverage the ratio provides. This approach also decreases the total inertial losses in the valvetrain because the heavy lifters and pushrods filled with oil have to oscillate in a shorter range for the same valve lift.