You can see 4 Pistons impressive, super clean CNC porting and finishing here.
Here is our stock block. We opted to leave it stock and overbore it by the smallest amount possible to clean it up. We have mixed feelings about sleeved block. Yes you can get thicker cylinders and you can get the sleeves to buttress into each other but by cutting out the middle of the block to install them, you are reducing the engine’s overall structural integrity and turning the block into a sleeve case. Then there is this issue of doing a bottom register sleeve on a block that was previously open deck. The aluminum block expands at 2x the rate of the iron sleeve and since an open deck engine has no deck to do a top register, the sleeve is registered at the bottom of the cylinder. When the block is heated during use, it expands more than the sleeve and tends to reduce the clamping force on the head gasket which can lead to head gasket failure from the “sunk sleeve”. Because of this, we are going to keep the block stock for now and see how this holds up.
Here Howard inspects the bores. He found that the bores were close to the stock wear limit so we decided to bore them by 0.50mm, the smallest next step. You can see here that the 4B11 has a semi closed deck with buttresses keeping the cylinders from moving around too much. Hopefully, this will allow us to get away with the stock block.
To make room for our connecting rods due to our stroker crank. Howard had to mill some clearance slots in the block to make room for the rod bolts and the shoulder of the rod. This was a fairly simple operation.
The mill was used to cut the notches and the base of the cylinders.
7 comments
interesting comment about the valve job. my experience has been the dimensions and operator are more important than the machinr.
Just some random advice: Manganese bronze needs bigger tolerances compaired to steel guides: They tend to pinch valvestems when warm. Ask me how I know….
A Newen is a CNC single point cutter that cuts in a continuous radius instead of steps. It can also be programmed to open up the seat and blend the seat into the bowls.
How did Toyota make the cylinders of the 2AR-FE’s block so damn strong and rigid? It greatly exceeds the typical limts Honda’s stock cylinders and it even goes pass this semi closed deck 4B11T.
If you are doing any kind of racing that last more than a 1/4 mile, like a 30 minute road racing session, that 4Piston cylinder head will not last long. Expect to find no more valve clearance. Their valve seat job is very poor.
They talk alot and do good marketing on social networks but when there is a real quality problem due to their work they don’t follow up and look for excuses.
We solved this issue by doing a new valve job with new seats and new valves.
This same issue happened on 4 distinct heads all from 4Piston. This same problem happened to a well known USA drag racing team…
And that is exactly what happend to us and we had to redo the valve job!
4piston👎👎