Thread: 2.0l engine rebuilt, lack of power

The only thing I can think of - my experience in a similar situation (over fifty years ago) was that I put the same nearly new plugs back in, forgetting that I had gone up a temperature grade to burn off the oil that was fouling them. Got from Sydney to Dalby before the electrodes wore to points causing preignition and loss of power at high throttle openings.

I assume you have checked there is nothing obvious such as partial blockage in the air intake, or throttle not fully opening?.

Also, is the centrifugal advance free?

Originally Posted by cjc_td5

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I was careful to set the cam timing on the cam chain sprocket during assembly. Is this a potential cause? The ignition timing is set as far advanced as I can go without it pinging.
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It certainly is a potential cause. When I got it wrong the engine started easily, idled smoothly , but had significantly less power.

However, my experience suggests that you might have more power than I had. I think my Series III would have struggled to reach 80km/h and it was only one tooth retarded.

IIRC, it wasn't just lack of top end revs; it was a lack of power right through the range.

So while it is possibly the problem, yours doesn't sound as bad as I would have expected.

Someone else might know if the amount of advance you are able to set is a clue to whether this is the answer.

Hi, I think cam timing is out or tappets are set too tight.

Paul.

Originally Posted by vnx205

It certainly is a potential cause. When I got it wrong the engine started easily, idled smoothly , but had significantly less power.

However, my experience suggests that you might have more power than I had. I think my Series III would have struggled to reach 80km/h and it was only one tooth retarded.

IIRC, it wasn't just lack of top end revs; it was a lack of power right through the range.

So while it is possibly the problem, yours doesn't sound as bad as I would have expected.

Someone else might know if the amount of advance you are able to set is a clue to whether this is the answer.

It does feel like a retardation issue, which was why I initially played with the ignition timing. It made a indefinable difference but still left it flat at the top end of the rev range.

Lower revs power is hard to gauge. It's no rocket ship but it moves off from an intersection ok, just starts running out of steam by 60-70km/h.

Would glazing of the bores cause lack of power? I had some carb & timing issues when I first put it together and it spent a bit of time idling before it got a hard run to bed in the rings. I had a bit of oil vapour venting from the crankcase which worried me at the time, but this has since reduced. Suppose a compression test today wouldn't hurt?

Comp test is a good idea, it's not unusual for blow by until rings are bedded in , hopefully you are using a diesel grade engine oil.
Did you ensure the carb jets were not blocked when you did the rebuild ?
It may be possible to get the cam timing out if the cam side was 1 tooth out it would effectively mean 1/2 tooth out on the crank.
If the compression is equally down from factory specs that would point to cam timing

Originally Posted by discorevy

Comp test is a good idea, it's not unusual for blow by until rings are bedded in , hopefully you are using a diesel grade engine oil.
Did you ensure the carb jets were not blocked when you did the rebuild ?
It may be possible to get the cam timing out if the cam side was 1 tooth out it would effectively mean 1/2 tooth out on the crank.
If the compression is equally down from factory specs that would point to cam timing

Compression test done 100-102psi dry across all cylinders. 108-110psi wet.

Mmmm, too low I think. Time to check valve timing?

I had that problem when I was a teenager and I rebuilt a Fiat engine. lots of head scratching, I even paid for a dyno test. Turned out I had installed the camshaft 1 tooth retarded. Terry