[DeTomaso] How much ZDDP?

[Asa Jay Laughton]

Data?  No.
Observation, yes.

A flat tappet camshaft, regardless if the lifters are hydraulic or  
solid, relies on two pieces of metal "rubbing" against each other.   
The taper of the cam and the convex lifter promote rotation to reduce  
the amount of scuffing but it's still metal on metal contact that can  
cause wear.

Solid flat tappet lifter can usually run a bit more spring pressure  
which means the wear could be greater; more pressure at the cam to  
lifter interference.  A hydraulic might be less.

A roller lifter, either solid or hydraulic, rolls instead of scuffing.

Therefore, in -my- humble opinion, the worst case needing ZDDP is a  
solid lifter flat tappet engine.  The next case needing ZDDP is the  
hydraulic lifter flat tappet engine.  One may need it more than the  
other, but I would certainly wish to protect either one.

Asa Jay

Quoting Charles McCall <charlesmccall at gmail.com>:

> Mike Drew and I were having this identical debate off-line.
>
> I agree with Paul, and believe that any cam that has the lifters rubbing
> against the camshaft (mechanical tappet) can suffer from the lack of
> anti-scuffing additives.
>
> Mike thinks that this only applies to solid lifter camshafts.
>
> I think people are confusing solid lifter/hydraulic lifter with mechanical
> tappet/roller tappet.
>
> So right now the debate is 2-2 - Mike and Patrick think that this only
> affects solid lifter cam engines. Paul and I think that this affects
> mechanical tappet engines, both hydraulic and solid.
>
> I have solid lifters, so there's no doubt that I will look after my zddp.
> Mike has a roller lifter, so there's no doubt that he does NOT neeed to do
> so. Anyone else have any data?
>
> Charles McCall
> 1985 DeTomaso Pantera GT5-S #9375
> "Raising Pantera Awareness Across Europe"
> http://www.poca.com/index.php/gallery/?g2_itemId=2323
>
> -----Mensaje original-----
> De: detomaso-bounces at realbig.com [mailto:detomaso-bounces at realbig.com] En
> nombre de Paul - Home
> Enviado el: jueves, 24 de febrero de 2011 18:01
> Para: detomaso at realbig.com
> Asunto: Re: [DeTomaso] How much ZDDP?
>
> This is wrong.  It applies to all flat cam shafts, solid or hydraulic.
> It doesn't apply to roller cam shafts, solid or hydraulic.
>
> The ZDDP helps with the rubbing of the flat lifters against the cam
> lobe.  The roller cam shaft doesn't have the same problem because the
> rollers roll over the cam lobe.
>
> Paul
> #9270
>
> On 2/24/2011 10:52 AM, Lee, Patrick Q wrote:
>> If you have hydraulic lifters, I wouldn't sweat it, Rob.
>> The ZDDP debate only applies to solid flat tappet cam shafts.
>> There is probably no harm done by adding the ZDDP but maybe like the old
>> STP oil treatment, it does no good either. I knew guys that used to
>> swear by STP and Slick 50 etc.
>> Go figure.
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-- 
Asa Jay Laughton - sent from somewhere other than home
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