The 3Y-c engine will not rev?

Hi there.

I have a 3y-c engine that originally overheated due to bad hose connections and a bad water pump. The engine was overhauled, and the cylinder head gasket changed with no warpage on the cylinder head and no warpage on the block.

Now, the valves were also renewed (only the four inlets, as the old ones were worn out) and re-ground to their respective seats and fitted accordingly.

The piston rings were badly worn, and they were changed upon the overhaul. Now, the car started for the first time and idled well with no apparent problems.

But when revved up to approximately 2,000 RPMs and beyond, the engine loses power as if it has a vacuum leak somewhere. We checked vacuum leaks, spark plugs, push rod, rocker arm and even swapped a cylinder head thinking that the old one could have cracked or something. But no, the engine does the same thing.

We fitted a new distributor, checked timing chain for wear and nothing. Tensioner is fine, no rattling. No funny engine sounds are heard, the only problem is that it won't rev up.

So, we noted though, when running the engine without the tappet cover that the oil escapes between the inlet port on the cylinder head and the rocker shaft. That doesn't look normal, does it? Anyway, oil only comes out from tappet no.7 and 8 only the rest oil does not come out of the tappet jet.

This has made us suspect a weak oil pump or worn main bearings. We will confirm on Monday what happens. The only suspects are the cylinder block and main bearings or damaged cam followers. Any suggestions?

Distributor swapped, rocker shaft swapped, cylinder head swapped, chain checked timing correct, no vacuum leaks. Cam followers and main bearings not checked but will check if oil pump swap does not help. We could have used an oil pressure gauge, but we do not have one.

Sincerely,
Sizwe