Piston Slap: Toyota’s non-hybrid, hybrid engine

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Piston Slap Toyota Inline Engine Bay
Flickr/ars666

Al writes:

I have an early ’70s vintage Toyota 2TG engine that I made into a hybrid 3T/2TG to get it up to about a 1.8 liters. I marked the two sets of timing chains and cams when I removed the heads to make sure it would go back together as it should. No matter how I position the chains and cams, I cannot get it all to line up as it was. It seems to be out a half degree on one cam.

The Toyota service manual makes reference to special tools to align the cams and chains. These aren’t readily available. Is there a way to make sure the components won’t self destruct without the special guides? The last thing I want is this self destructing when I fire it up. I’ve spun it all manually and via the starter and everything turns; I’m just trying to avoid a latent timing issue when I tune it. Any advice on setting up the DOHC cams will be appreciated.

Sajeev answers:

I’ve been privy to hybrid motor swaps in the Datsun Z-car world, but they were all overhead cam (OHC) motors. Some T-series motors were overhead-valve designs, so are you also making that big jump from OHV to DOHC? The Australian Toymods forum has hybrid motor building information, and it sounds like you’re right about needing the 2TG engine’s upper timing guides. And they are difficult to find.

Since you turned the motor and nothing smashed together, perhaps you don’t need to check piston-to-valve clearance. But for everyone else, this is when you should do the clay putty trick, or pull a valve and get a dial caliper. Learn more on both methods here.

I bet you’ll need those special tools to get the cams phased correctly, but maybe a half degree isn’t terrible enough to adversely affect drivability via wrong fluids going past the wrong valves. Wishful thinking perhaps? Sorry I couldn’t help, but I wish you luck and hope you’ll update us on your progress.

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