Hydraulic cam followers

[jimk04]

Today I had a look at the lifters I have here out of a 99/2000 3.4.

Marked up INA 577.16. When I google the 577.9 mentioned in a previous post, I find nothing, but the 577.16 does come up.

I watched those you tube videos, very interesting to the point today I dismantled a few, and they would all seem serviceable.

One word of warning I would heed if rebuiling lifters, in one video the guy uses a magnet to keep holdof all the small parts....DONT DO THIS....the spring and ball for the check valve are SO small that if they become magnetized, I would imagine would effect their operation.

The other video, the guy says not to open up the relief valve element, but to me this step is very necessary to successfully renovate a stuck lifter, as you need to clean this out if it's gunged up with old oil.

I also purchased a BGA lifter today so I will have a good compare tomorrow against the INA.

Also got my shop to speak to Febi Bilstein about the ones they list, hoping they would be INA, but the technical line said that they had them made for themselves....?

[Jake Raby]

Now for the funny part.. When approaching INA at the International Motorsport Show a few months ago, they denied ever building this lifter, or even having a part number for it.

Be less concerned with the hydraulic properties, and more concerned with the physical properties of the lifter crown. The surface finish also matters, especially during break in/ work hardening. I have seen some of the replacement lifters that literally had a surface that was achieved with a scotchbrite wheel. Thats what you'll get when you pay for a cheap lifter, and its no way to achieve a proper roughness average.

I get calls about this all the time. The quickest way to cost yourself thousands of dollars is by trying to save a couple hundred. We call it "Stupidity tax" around here, and it gets paid a lot.

[linderpat]

Originally Posted by Jake Raby

.... The quickest way to cost yourself thousands of dollars is by trying to save a couple hundred. We call it "Stupidity tax" around here, and it gets paid a lot.

This is worthy of a signature quote. There is nothing more true. On cars as highly engineered and constructed as Porsches, I rarely consider anything other than OE Porsche parts, especially for critical areas such as drive train or suspension. Exceptions are parts developed by reputable vendors and used with good results over long periods of time, or Audi/VW parts that are often the same but labled with different part numbers. Unless a part is NLA, there are few reasons to deviate from spec. Remember, you don't have to purchase from dealers. You can get the real stuff from good vendors, like Pelican, and others at great prices (in the 928 world, we have exceptional vendors, including 928RUs, Roger Tyson, who has also supplied me with Boxster parts).

[whitecliffs]

Originally Posted by jimk04

Today I had a look at the lifters I have here out of a 99/2000 3.4.

Marked up INA 577.16. When I google the 577.9 mentioned in a previous post, I find nothing, but the 577.16 does come up.

I watched those you tube videos, very interesting to the point today I dismantled a few, and they would all seem serviceable.

One word of warning I would heed if rebuiling lifters, in one video the guy uses a magnet to keep holdof all the small parts....DONT DO THIS....the spring and ball for the check valve are SO small that if they become magnetized, I would imagine would effect their operation.

The other video, the guy says not to open up the relief valve element, but to me this step is very necessary to successfully renovate a stuck lifter, as you need to clean this out if it's gunged up with old oil.

I also purchased a BGA lifter today so I will have a good compare tomorrow against the INA.

Also got my shop to speak to Febi Bilstein about the ones they list, hoping they would be INA, but the technical line said that they had them made for themselves....?

Hi Jim, its steve from boxa aka Marseille, did the same as you over the weekend with some of the spare lifters i have after seeing that video, took a hell of a pull to get one of them apart both looked ok but wouldn't fancy reusing them after the force needed to pull them apart, i'm sticking with my old set which were running quiet before i removed them

[jimk04]

Hey Steve, yes I thought this was your thread. It has dug up some interesting info.

I would be happy to reuse them after taking them to bits, but I understand the call you make, like Jake says, costly if it all goes wrong

Must get on with my 3.4 build!

[jimk04]

tappet crown observations, no objective measurements, I wouldnt have the means, but you can SEE a slight difference.

BGA



INA (admittedly with 50k miles on) definitely 'flatter'. I dont think there is any discernable wear on here, as the mark from the valve is very central, doesnt contact wide enough to have flattened out a crown.

[Gelbster]

Tappet crown- thank you for sharing the observations.
What significance does this have for the jammed-up-in-the-bucket tappet problem?
Does the crown(offset slightly?) cause the tappet to rotate rotate ? And does a little rotation prevent jamming?
Or does jamming occur if there is almost total leak-down of oil from the tappet when the car sits for a long time ? Then when you eventually restart ,the tappet has no hydraulic 'cushion' ,so it gets hammered up into the bucket ?
All WAG but it would be good to understand this issue.

[JFP in PA]

Originally Posted by Gelbster

Tappet crown- thank you for sharing the observations.
What significance does this have for the jammed-up-in-the-bucket tappet problem?
Does the crown(offset slightly?) cause the tappet to rotate rotate ? And does a little rotation prevent jamming?
Or does jamming occur if there is almost total leak-down of oil from the tappet when the car sits for a long time ? Then when you eventually restart ,the tappet has no hydraulic 'cushion' ,so it gets hammered up into the bucket ?
All WAG but it would be good to understand this issue.

Go back and reread Jake's comments about the crown finish and hardness. If the face against the cam is not hardened, and with a crown to promote rotation, the crown will wear into a mushroom shape, making it impossible to remove, while also tearing up the cams.

Anyone that has ever wiped out a flat tappet cam will know exactly what he is referring to.

[jimk04]

I cant comment on the crown's 'job', I can only see that the BGA tappet has a more pronounced crown. It isnt offset Gelbster, just me struggling to capture the image in a phone!

The tappet would only leak down and then get hammered in if the relief valve element was gunged up. I have had these to pieces and when you put them back together they spring about all over, but you fill this tappet in these pictures up with oil by depressing the tiny ball/spring and then it allows oil in, and it becomes pretty solid....how you need it.

I assume the ball depressing happens with engine oil pressure in situ, but like I say if the tiny relief mechanism is blocked with old oil, it wont work effectively.

This is all my take on the whole thing, nothing certain here.

[Jake Raby]

Originally Posted by JFP in PA

Go back and reread Jake's comments about the crown finish and hardness. If the face against the cam is not hardened, and with a crown to promote rotation, the crown will wear into a mushroom shape, making it impossible to remove, while also tearing up the cams.

Anyone that has ever wiped out a flat tappet cam will know exactly what he is referring to.

Exactly.. I don't give a damn about the contact surface to the valve stem, as long as its the proper hardness.

The crown that follows the cam lobe is whats absolutely unforgiving and effects lifter surface speed and reset as the cam lobe wipes across it. This is a critical dimension and one thousandth of an inch may as well be a mile.

FYI- I have seen brand new lifters come with improper crown radius, and we have to check every single lifter that we install because of this. It sucks, but we save our asses every time that we do it.

Assume nothing, quantify everything.