UPDATE: MAY 25, 2019
I examined the DNJ failed head gasket and the new Fel Pro and Toyota OE.
Like I discovered when I did my version of examining the transmission input shaft seals, WOW… I am shocked at what is being manufactured and how I can just examine it and see why the part failed, and how it is inferior to other manufacturer’s same replacement part.
The head gasket contained in the engnbldr rebuild kit, like the rocker cover gasket kit, is probably a Chinese version of a copy… a questionable quality and design. In my opinion, the head gasket visually appears to be inferior in design to Toyota and Fel Pro. The DNJ gasket basically delaminated and allowed coolant to get into the #3 cylinder. There is a separate ring that sits on top of the slipper plate and does not seal the very edge of the cylinder fire ring. It can delaminate and allow combustion gases and coolant to leak into layers of the gasket and eventually into the combustion chamber.
On the Toyota and the Fel Pro, there is no separate ring. The metal slipper plate is sealed with a 2-cylinder metal piece the wraps completely around cylinder 1 & 2, and 3 & 4 ring edge. It cannot delaminate.
The Toyota gasket is about .052” thick. (new)
The FelPro gaskest is about .062” thick. (new)
The DNJ gasket is about. 066” thick (used)
I prefer the Toyota gasket because it is thinner and should not compress as much. I assume thicker gaskets will have some affect on compression ratio. It also has a sealer bead for the timing cover to bottom of head seal.
That is my unscientific evaluation.
My lesson learned. Admittedly too late in my life! When it comes to very important and more critical gaskets or seals (like the input shaft seal, rear crankshaft seal, head gasket, I will not compromise and buy a non-Toyota gasket or seal. For me it’s absolutely not worth saving $10 or $50, have a failure and then have to rebuild something or take the time, sweat, and money to have to do a complete R&R for a premature failure.
That’s just my opinion – it may be worthless.