Timing Chain VS. Performance Loss?

[whitey2007]

I'm working a my brother-in-law's '91 KA. I have read the other threads about the timing chain problems.. The question I have is this; Can a dieing timing chain rob some serious HP? When I test drove the car when he bought the car it had good power. At the time there was a noise coming from the valve cover. When we pulled the cover, the upper chain rider was snaped off between the two bolts. It was removed and the car fit the road.

Now the car has 4000 miles since then. The rattle/tick is REALLY loud! And the car is gutless at less than 3000 rpm. My G-tech meter reads at less that 95 HP. Can the chain cause the gutlessness?

By the way, the compesion test put the first cyclinder at 145 psi, the rest at 162 +/- 5 psi.

I have the car in my garage for repair but I need some ideas please!Thanks all!

[:: orion ::]

SHort answer: NO.

The chain (worn out or not) can't reduce performance...and I SERIOUSLY doubt the chain could slip a tooth (assuming you have at least some oil pressure).

145 compression says bad rings or ring lands to me...I think it's just a tired, beaten motor.

I'd swap in a low-mileage KA (www.car-part.com), or rebuild.

- Brian

[InsanityInc]

Yes, a worn chain or bad tensioner can reduce performance, as it will retard your cams.

But messed up cams will cause an equal compression loss, meaning you have some other problem.

[SlowBack]

I bet it's the head gasket or a warped head, but it could be any number of things really. The intake manifold temp sensor is notorious for robbing power when it goes.

[whitey2007]

What would be an easy way to check for a bent valve. I was told it was a possible problem. But, the engine still runs... so I don't think thats the answer.

[SlowBack]

Well, a bent valve would give you low compression so a compression test should give you an idea. However, a leak down test is a bit more conclusive.

[InsanityInc]

Well, a bent valve would give you low compression so a compression test should give you an idea. However, a leak down test is a bit more conclusive.

Compression tests are pretty conclusive if you know the car. If it's not burning oil, a bad compression problem isn't due to the rings, and a headgasket usually shows two adjacent cylinders with really low compression and the others with OK compression. A valve is generally a problem with a single cylinder.