My brothers Rav4 had some resistance when turning the crankshaft. Does this automatically mean a bent cylinder? Could it be the timing chain? When the engine runs you an hear the timing chain hit the valve cover. Thanks
Did you remove the spark plugs prior to turning the crank by hand?
Tester
yes we took them out
How much resistance? How many ft-lbs?
Then you’re probably looking at bent valves if you can hear the timing chain rubbing when the engine runs.
Tester
I have no idea we didn’t test for that. It wasnt a constant tension. It seemed to get tighter then would loosen.
We checked the wet and dry compression. All 4 cylinders were around 185 dry and three were 195ish wet and one was around 205. The results seemed to me to be too close for a bent valve but he thinks there is one.
You don’t have a bent valve if you got 185 psi. A bent valve won’t seal and without a seal the engine won’t build compression.
You need to buy some tools. A cheap beam torque wrench will allow you to measure the torque it takes to turn it over and can be used for loads of other useful things like tightening bolts to the correct torque.
If everything is copacetic within the engine, the crankshaft should turn freely with the spark plugs removed.
Tester
I’ll check in the morning. He just moved his car back to his house now. What else could cause the tension?
4 sets of piston rings, 4 pistons, 2 cams compressing 8 sets of springs one after another, a set of chaina rubbing on the guides, 4 rod bearings, 4 wrist pins, 5 main bearings and an oil pump… all the stuff in the engine that moves when it runs. Adds up to a lot of friction and it isn’t smooth.
If you and your brother are going to flip cars, you need to do a little more studying on how they actually work.
We’re not flipping it. He bought it for himself
Ok, if you are going to work on your own cars you need to study up on how they actually work.
I know the basics. He read in the Haynes manual for his Rav4 if you feel any resistance there is a problem somewhere.
If you think you have a bent cylinder, you have not learned nearly enough yet. The cylinder is one of the big round holes in the engine block the pistons go into.
I don;t care what the Haynes manual says, there is always resistance when you turn an engine over by hand. You guys just need to get enough experience to know how much is normal.
If you can hear the timing chain hitting the cover the timing chain needs to be replaced.
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You will feel resistance in EVERY engine, see @Mustangman above. Seems like the problem here is the worn timing chain or tensioner.
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Sounds like you bought a non running rig. Maybe have a mechanic look at it and pay him to tell you what’s wrong?
Are you talking about that big round hole we did a wet and dry compression test on which was mentioned earlier in this thread? Thanks for clarifying.
The tension is not constant. It goes from being extremely easy to crank to fairly difficult which was also mentioned above.
We’re checking the timing chain tensioner before taking off the timing chain…
We both have free time before next semester starts so were learning how to work on cars. My brother bought it. He’s impulsive.
And that would be expected as you’re opening valves. The only way the crank would be uniformly easy to turn is if it’s disconnected from the cams and, to a lesser extent the pistons.
But you’re there, we’re not, we have no idea how difficult is ‘fairy difficult’. What are you using to turn the crankshaft?
The only thing the Haynes manual is good for is keeping your knee off the ground if you have to kneel.
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