Alfa Pages

[ZeNiTh-PbArM]

Hi,

Six months ago i renewed hydraulic tappets in a friend's 33. I used a brand new camshaft and camshaft housing from Alfa but used aftermarket hydraulic tappets of the AJUSA brand (made in spain).
Today i dismantled everything to solve an annoying clicking noise problem. Gess what? The tappets are dead. The top surface of these tappets is deeply pitted and scored after only 15 000 kms of reasonable driving (my friend is not the guy to redline the engine, and the oil changes were made by me).
Definitely those tappets lack the required hardness. Oh yes and the camshaft didn't survive as well. Be sure not to install this junk in your engine.



regards,
zp

[RFlower]

Hi,

Ajusa - as supplied by Oscaro? The wear looks similar to that on my tappets, see "Camshaft Woes", July 22.
3 have worn similarly to yours, 2 are destroyed, but 3 look near perfect, with slight but even wear.
My local garagiste says he has seen similar wear on Fiat OEM tappets, puts it down to bad steel/quality control.

Does the underside of the tappets look like this one? I'm wondering if mine are OEM or replacements.



Have you checked the engine oil pressure? I am fitting an oil pressure gauge right now, at least I can eliminate one possibility.
_________________
Dick Flower, Nr. Carcassonne. '94 Trofeo 1.4 ie (F), '93 Imola 1.3/1.4 ie (now for breaking) (F), '91 1.7 ie (GB)(spare car), '86 Sprint 1.5 QV (F). '87 VW Syncro camper (F), '73 NSU Ro80 (F), '99 Fiat Seicento (F)

[ZeNiTh-PbArM]

Hi,

Those were indeed supplied by Oscaro.
I've already seen OEM lifters (look like yours) destroyed by use, but that was after 150 000 to 200 000 kms of driving with possible poor use and maintenance.
Those were replaced in a perfectly functioning engine, with perfects camshafts, just because the car had 210 000 kms on it when the heads were dropped and we wanted to do some preventive maintenance at that stage.
Oil pressure has never been an issue on this car. I'll phone Oscaro and hear what they have to say about this but i doubt they will cover the damage to the engine.

regards,
zp

[RFlower]

Hi zp,

I was thinking about this last night, and remembered some of the theory of hydrodynamic and boundary lubrication which I studied many years ago.

In fact, the tappet and follower surfaces should never come into actual contact. Most of the time there should be a dynamic oil film separating them. In extreme conditions, e.g. at the tip of the cam, there may be only a boundary film, formed by EP additives in the oil.

Although the components may be of good or slightly inferior material, that should only affect their expected life, and their performance in the most extreme conditions. If there is inadequate lubrication even the best quality parts will fail.

I was reminded of an article I posted here in January 2007, and am wondering how much EP oil additives have been reduced in Europe:
http://www.minimania.com/ArticleV.cfm?DisplayID=1922

This article mentions the same points:
http://www.vscda.org/TechInfo/Bulletin4.pdf

There is a lot on this subject on the Web. Here is an example.
http://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=1537943

I suggest we all take closer look at the oil we're using. I know I will. I'll also use plenty of molybdenum disulphide grease when I reassemble the valvegear.

Dick
_________________
Dick Flower, Nr. Carcassonne. '94 Trofeo 1.4 ie (F), '93 Imola 1.3/1.4 ie (now for breaking) (F), '91 1.7 ie (GB)(spare car), '86 Sprint 1.5 QV (F). '87 VW Syncro camper (F), '73 NSU Ro80 (F), '99 Fiat Seicento (F)

[paulhide]

Very interesting!
So does that mean that we should only use valvoline VR1 or Redline 10w40?
What about Selenia?
_________________
Owner's Club 33 Registrar. Now from P4 & S2 1.7 QV
http://www.alfa-pages.co.uk/viewtopic.php?t=5188

[RFlower]

It means we should be aware that the amount of ZDDP is being gradually reduced in ACEA specifications, which the oil manufacturers tend to follow, and choose our oil carefully.

Desirable amount of ZDDP traditionally seems to be that which gives 1800ppm (0.18%) zinc and 1300ppm (0.13%) phosphorus.

Shell Helix Super 15W-40 is ACEA rated A2/B2.

I have responses from a contact in Shell; he is unable to give exact answers, as:

"Formulation information is not something we would share and is not something that is in the public domain as it could potentially damage our intellectual property in realtion to the product"

But in relation to Helix Super, he says:

"For environmental reasons the levels of Zinc additives have reduced in all commercial engine oils over the last 20 years"

and that the levels for this oil

"would typically be somewhere in the region of 0.11% to 0.13%"

So it seems that levels for A2/B2 oils are already near or even below what is desirable for old style cam follower design.

Shell Helix Plus is ACEA rated A3//B4, a later spec. I don't know, but suspect it probably has lower ZDDP levels.

Oils in the US have already reached the point where old engines are being damaged, and what the US does in this area Europe will probably follow.

I intend to stick with Helix Super or similar reputable brand A2/B2 spec oil for my Imola, which has a cat. converter, and change it every 10,000km but I'm considering using ZDDPlus, maybe half a bottle per oil change, for the Sprint and my VW.

Edit: The Ro80 doesn't have valves and tappets, is happy on just about any oil!
_________________
Dick Flower, Nr. Carcassonne. '94 Trofeo 1.4 ie (F), '93 Imola 1.3/1.4 ie (now for breaking) (F), '91 1.7 ie (GB)(spare car), '86 Sprint 1.5 QV (F). '87 VW Syncro camper (F), '73 NSU Ro80 (F), '99 Fiat Seicento (F)

[Trentatre]

I don`t think it`s the oil`s fault. I ordered some lifters recently, then i read your posting. So, i hoped I woildn`t get ajusa`s too. But, unfortunately, i got.

So I sent them back and looked for another make. To make it short: They all cost at least three times as much as the ajusa ones. As my father says: If it costs nothing, it`s worth nothing.

[ZeNiTh-PbArM]

Hi,

This week i had a colleague at work check my tappets. He came up with the conclusion that original Alfa tappets have a surface hardness of 62HRC whereas the AJUSA ones were inconsistent between 54HRC and 58HRC (test performed on eight samples of each brand).
So this is clearly poor quality stuff.
Dick, your point on oil quality is interesting. However, this is the only case i've seen lifters fail for no reason at such an unusual speed. I always use 10W40 semi-synthetic oil from Total (Activa 7000) or Mobil (Super S) or Motul (4100 Power+). None of the engines i maintain (this includes a large number of vintage italian sportscars) have ever suffered damage due to insufficient lube. Are you saying we are facing a major problem with future oils? Why do modern engines with flat tappets not suffer from this matter?

regards,
zp

[RFlower]

Hi Trentatre,
In the case my tappets, which seem to be OEM, I’m pretty sure the failure was due to the oil not being changed at the correct intervals before I bought the car.
However, if the current oils, in this case Helix Super, had the EP additive level of ealier oils, then these might not have been depleted so soon, and the tappets might have survived longer.

Hi zp,
Figures I have found give a Rockwell C Hardness range of 55 to 62 as good for a tappet, 50 HRC being considered adequate in the industry and 55 HRC very good.
For comparison, axes, chisels, etc are in the range of 40 to 45 HRC.
So although the Ajusa tappets are not quite as hard as the OEM ones I don’t think that really means they are poor quality.
I also found a reference for tappets in older cars as having a hardness of 72 HRC.

I am saying we probably do face a problem with future oils, not necessarily immediately, as there is always a certain time before old stocks are used up, and camshafts and lifters in cars which have run a considerable time with fairly high levels of ZDDP will have built up a zinc/phosphate layer, which will apparently last for quite some time.

I think it is inevitable that oil specs will eventually follow the US, where flat cam wear in older cars has become a major problem, and manufacturers have changed to roller tappets for new cars. Most people buying oil believe that the latest specification must be the best, which it probably is in the case of new cars, as traditional EP additives are not friendly to (expensive) 3-way cats. So oil companies will produce to the latest spec, maybe offer some product lines for older cars.

I am not really familiar with engines more “modern” than my (1993) Imola - I’ve been retired for some years now - so don’t know if any cars in Europe have roller tappets. I do believe changes have been made to cam profiles and other factors affecting severe loading in this area, such as larger diameter tappets, wider cams, smaller, multiple valves with lighter springs, etc.


Dick




.
_________________
Dick Flower, Nr. Carcassonne. '94 Trofeo 1.4 ie (F), '93 Imola 1.3/1.4 ie (now for breaking) (F), '91 1.7 ie (GB)(spare car), '86 Sprint 1.5 QV (F). '87 VW Syncro camper (F), '73 NSU Ro80 (F), '99 Fiat Seicento (F)

[ZeNiTh-PbArM]

Hi,

i got the opportunity to get a good technical discussion with an engineer working in the technical department of a major valvetrain components manufacturer.
He said that all OEM tappets are in the range of 59-64HRC, and that hardening process/hardening depth is critical to get sufficient wear resistance. The tappets have to be of good quality steel to begin with, 100Cr6 or 16MnCr5 are suitable ; then the lifters are thermally treated, carbo-nitrided, tempered, then nitrocarburized. The company did benchmark competitors products, including competitors supplying cheaper stuff, and came up with the conclusion that most of these suffered from poor manufacturing which resulted in the following facts :
- lifters not fully compensating for lash due to inaccurate clearance in the hydraulic sleeve. Normal compression speed is around 2s/mm under 100kg force, some products leak oil to fast resulting in speeds above 0.1s/mm. As a result the lifters do not compensate properly and the cams knock against the lifters causing increased wear
- lifters not turning in their housings freely enough, resulting in increased contact pressure and wear (reason : inadequate manufacturing tolerances, and/or tappet deformation under load)
- insufficient heat treatment (critical) resulting in quick destruction of the tappet and cam

We also had a lengthy talk about lubrication, which is a complicated matter ; to make a long story short, the hydrodynamic lubrication theory applied to the cam-tappet interface shows that lubrication film thickness can be reduced to nothing under certain circumstances.
To avoid this, extreme pressure agents like ZnDTP are incorporated in oils, as well as friction modifiers like MoDTC. The latters are mandatory as they are the only ones to compensate for soot contamination occuring during oil life.
Reduced levels of chemicals in the oil, as well as infrequent oil changes, will reduce tappet life. However, wear due to these factors will occur over an extended engine operation time. What happened to me is most likely due to poor quality of the tappets (too quick to be due to other factors)

I learnt as well that aftermarket ZnDTP additives are a massive scam, as they cannot dissolve correctly in the oil. Oil manufacturers use ultrasonic mixing technology, which has to arise at an early production stage, since it would destroy multigrade oils if applied after the oil is made.

regards,
zp

[Brit01]

I'm opening up this old thread as I have recently installed INA lightweight tappets in my 8v 33. (034 109 309, F-46516.72)

100kms so far.
I had to remove them as one of the bores was too worn. I have sourced a new cam box with much better bores.

I will be re-installing it very soon with the same INA tappets. A nice circular pattern on each tappet and all smooth after break in period.
Moly paste added and a 15 minute 2500 rpm break in.

I wrote to INA today to see if they can provide me with the hardness of the tappet face.

I don't want these to fail as I have also bought new OE cams.

If anyone knows the hardness of INA tappets please let me know.
_________________
S2 33 1988 1.7 QV
Dellorto DRLA40 (32mm venturi)

[Brit01]

The INA tappets have an HRC of 56.9 (HV 660)

[Brit01]

I investigated the HRC (HV) hardness of the face of the hydraulic tappets.

The aftermarket tappets I use are INA (034 109 309, F-46516.72) . These were cross referenced and have done 100 kms so far without issues. Very lightweight which gives a good response.

The heavy original AR tappets had an Vickers Hardness Number 'HV' of around 710-790 (59 -64 Rockwell C Scale Hardness 'HRC') and I am a bit concerned about the longevity of the INA tappets due to their lower HV value. BUT the original AR tappets were much heavier so maybe needed a harder surface for that. I don't know.

Rockwell C Hardness states ranges of 55 to 62 as good for a tappet, 50 HRC being considered adequate in the industry and 55 HRC very good.

The INA tappets are 660 HV = 56.9 HRC

No quite up to the hardness of the original AR tappets BUT I've received 2 'OE' tappets and both were different in regards to weight and shape of the oil hole. So some significant inconsistency with the OE tappets so who knows there real HRC value.

I imagine INA are consistent and state:

Special characteristics:

The tappet is directly activated
Very high rigidity
Small moving mass due to the manufacturing process
High quality surfaces and heat treatment processes in cam contact in order to achieve low friction and high anti-wear protection
Highly cost-effective

----

OE Fiat TC tappets (33mm dia shim sits on bucket) 56 HRc
Fera - 58 HRc
Wurth - 61 HRc

----
Conclusion from other contacts mainly GC members:

Tappet damage is almost always due to bad lubrication, or bad quality hardening of the cam shafts on the boxer and 16V TS engines. Cheap oil, infrequent changes, bad air filters, mangled carter ventilation systems will all have their effect on lubrication.

Driving on with worn tappets will kill cams rapidly, so usually, by the time people take in their badly maintained car, cams are worn sufficiently to not be able to tell the root cause without a lot of investigation.

Don't worry too much about the hardness of the INA tappets. They are OEM on several german car engines that have a good reputation for longevity.
_________________
S2 33 1988 1.7 QV
Dellorto DRLA40 (32mm venturi)