3TC engine refresh

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mickri

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Yanked the Toyota 3TC out of the midget today and started to take it apart to see what I might need to do to it. I was surprised at how clean the inside of the engine was. I didn't find any crud anywhere. Did not find any scoring or even a ridge in the cylinders. But I did find one thing that needs replacement and a mystery that I have no explanation for. The cylinders all measured 3.368 with a stock cylinder at 3.346 to 3.348. Looks like the cylinders have been bored .020 over stock. The pistons all have .050 stamped on the top. I was expecting .050 over stock. I ran my cylinder DI around one cylinder and had a run out of .002. Checked one rod journal and it was spot on stock at 1.888. So this all looks good. Now for the not so good. The push rod for the #2 cylinder intake valve was off the rocker arm and stuck between the rocker and the support. The valve lifter end is pretty badly chewed up. I will look for a replacement.

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Now for the mystery. The #1 & #2 intake valve lifters are chewed up and they were hitting the bottom of the cylinder head. We are not talking about a small nick. There is about a 1/8" gouge out of the cylinder head. I don't know how it is possible for the lifters to hit the bottom of the cylinder head. There is approximately 3/8" clearance between the lifter at the top of its stroke and the bottom of the cylinder head. Any ideas?

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Valve float is all I got if the pushrods were still in place, and might explain the one pushrod out.
 
All of the push rods were in place except for the one and there doesn't appear to be any damage to any of the other push rods.
 
Check valve spring tension, I know pushrods can have a lot of deflection, but for the lifter to touch the head, there had to be some lofting going on. Just my opinion.
 
Was it running when you got the engine?
 
The car was running when I got the engine. I started it up. It was running rough and I turned it off. I just wanted to see if it ran knowing that I was going to take it apart and replace the bearings and anything else that I found once it was apart.

I could see the #2 lifter doing something because that push rod was off the rocker arm. But there was nothing amiss with the #1 push rod.

There is a forum devoted to these engines. I have posted my question there also.
 
Valve float or some type of valve timing problem is all I can think of
-Mark
 
Keep us posted, interesting.....
 
Spoke with Randy Davis at BRD racing this morning. They specialize in these engines. Definitely a valve float problem. Probably need to replace the cam. Asked about the pistons being stamped .050 verses my measurement of the cylinders being .020 over stock. The .050 is mm not inches and correlates to a .020" over stock cylinder. Going to take the rest of the engine apart today.
 
Too much time on the limiter :)
 
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