[FC] Synthetic oil...serious tapping

[Dale Dewald]

Hello Ben,

It seems that you may have loosened up some old sludge and debris in the 
engine with your oil change. The base stock of the Mobil 1 is likely 
different than the non-synthetic oils that were being used in the engine in 
the past. The detergent package in the Mobil 1 may have been a bit 
different too. Some of the sludge/debris may have made it to the lifter(s) 
and lodged in a check valve, holding it open slightly so that it bleeds 
down quickly.  I do not think this is a ZDDP issue--not after only one oil 
change.

This kind of problem is the basis for the theory and practice of, after 
changing any special break-in oil, using only the same brand and type of 
oil (different weights summer/winter okay) for the life of an engine.

If you want to go synthetic, I would suggest switching to Amsoil. They seem 
to understand the market niche for older engines and offer products that 
have sufficient ZDDP. They specifically recommend the following types (the 
first three letters are product code):

AMO 10W-40 Premium Protection Motor Oil
ARO 20W-50 Premium Protection Motor Oil
HDD 5W-30 Heavy Duty Diesel Oil

The above all have sufficient (1266 ppm) ZDDP for use in flat tappet 
engines. I personally use another diesel oil:

ACD 10W-30/SAE30 Heavy Duty Diesel Oil

http://www.amsoil.com/storefront/acd.aspx

This product also has 1266 ppm ZDDP. It is rather unique in that it is 
actually a straight SAE 30 weight oil but, because the base is 100% 
synthetic, it has low temperature properties equal to a 10W conventional 
oil and meets the API specification for 10W-30 oil. The upper list of oils 
all use lighter weight base stock with viscosity index improvers to 
maintain thickness at high temperatures--a practice that is well proven and 
has been in use for 50 years. However, it is my opinion that the Corvair 
engine was designed to operate with SAE 30 oil, and type ACD fits the 
bill.  A convenience factor also exists in my case. This one product is 
also used in my dad's Kubota diesel tractor, my JD lawn tractor (water 
pumper), and several other 4-cycle air cooled engines.

Amsoil also sells an engine flush that is recommended before changing to 
synthetic.

http://www.amsoil.com/storefront/acd.aspx

I have purchased this product but have not used it yet. I will be using it 
to flush the 110 engine in a 1967 4-door with 62k miles I recently 
purchased. I will make sure to post the results of the engine flush.

Dale Dewald
Hancock, MI

Sunday I leave for a week of Boy Scout Camp with Alex; no phone, no 
internet, just time to get back to basics and enjoy the wilderness...


At 21:28 7/09/2010 -0400, Ben and Lynn Stiles wrote:
>Hello everyone-
>
>I cahnged the oil in the 'Brier to Mobil 1 synthetic (10-W-40) before
>leaving for Iowa. All went well...until the second to last day when I
>started it up and such a racket!! IT was tapping like crazy. Well, we
>had to keep moving, so we did. It got quieter as it got warmer
>throughout the day. Got home with no issues. I just started it up again,
>and it is tapping plenty, though not as badly as that second to last day
>of vacation.
>
>Should I be adding the ZDDP stuff anyway, even though I went with
>synthetic oil to avoid its use? Could I be having issues with the top
>end lifters?
>
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