I have built two of these engines now one for myself and one for my son in law.
The first was all stock toyota parts(head and block not resurfaced) , but with after market pistons.
When I checked it to see if it was an interference engine ( pistons can hit valves if the timing chain breaks) it was not . I checked every cylinder on intake and exhast with the valves fully open and was able to turn the crank through TDC without contact.
The second engine ,also all stock Toyota parts( block and head not resurfaced), but with the new Toyota 8 hole pistons( old ones were 4 hole).
This engine WAS an interference engine.
Checked the same way as above and the piston would contact the valves at 30 deg BTDC on both the intake and exhast valves( the pistons still had 3/16 inch travel before TDC.
The reason I am posting this is, I told someone here that this was a noninterference engine based on my first rebuild, but clearly it depends on what parts you use, and probably what machine work was done to the engine.
Yes and no .
I have built two of these engines now one for myself and one for my son in law.
The first was all stock toyota parts(head and block not resurfaced) , but with after market pistons.
When I checked it to see if it was an interference engine ( pistons can hit valves if the timing chain breaks) it was not . I checked every cylinder on intake and exhast with the valves fully open and was able to turn the crank through TDC without contact.
The second engine ,also all stock Toyota parts( block and head not resurfaced), but with the new Toyota 8 hole pistons( old ones were 4 hole).
This engine WAS an interference engine.
Checked the same way as above and the piston would contact the valves at 30 deg BTDC on both the intake and exhast valves( the pistons still had 3/16 inch travel before TDC.
The reason I am posting this is, I told someone here that this was a noninterference engine based on my first rebuild, but clearly it depends on what parts you use, and what machine work was done to the engine.
I am considering a rebuild on mine. Do you have any thoughts on the aftermarket pistons? Size, oil holes? Let us know how they run when you get them back in the car (if not already)!
Good stuff, interesting observation on the interference with the newer OEM piston design vs aftermarket ones.
Toyota's official stance on this - the 1ZZ-FE is an interference design. I too have seen ones that definitely have interference and ones that do not - can't explain why, as the sample size I have is too small to make trends - so I always go with treating any engine as an interference design, erring on the side of caution.
Thats a heck of alot of difference in piston travel (3/16") between the two engines . With modern manufacturing , it cant be stacking. It must be a single part or two that are drasticly different( like the pistons tops) or valve lift ( different cam) . The design of the three different pistons( old 4 hole , new 8 hole and after market) looked very similar though. I am sorry that I was not able to compare the two , but by the time I hade the second engine torn down the first was put together.
Fishexpo101, were the noninterference1ZZ 's that you saw all stock?
dshadle 1 , If your cylinders are worn out of spec( I went .020 over) then you will have to go oversized, .020 is the first size up.Ask your machine shop whats available( there were quite a few different makes when I bought mine), but make sure you ask for the 8 hole pistons, because there were some 4 hole ones out there still.
If they are still in spec I would use the new toyota 8 hole pistons( toyota(AISIN) pistons dont come in larger sizes than stock , at least not that I could find.) Everything that I have seen made by AISIN has been really nice/ high quality.
My engine is in the car and running great. It feels like a brand new engine( which it is clearance wise). I did not realize how much power I had lost in 207000 miles.
As far as I know - all the engines I've played with were stock. Yes, 3/16" is unheard of with the clearances they have now. I did forget which ones were VVTi and which were not, as it was some time ago - that might have something to due with it. The VVTi one I had recently was definitely an interference one.
Great to hear everything is back together and running.
