4.0 Timing chain replacement

Hello tacomaworld.
I am getting ready to replace my timing chain on my 09 PreRunner with the 1GR-FE engine. I am mechanically inclined and have done many engine rebuilds before. This engine is new to me so I have a question that needs to be answered before I can start.
Do you have to pull the PAN SUB-ASSEMBLY off in order to take the timing gear case off?

 

If it was me I would pull the engine out of the truck and put it on an engine rotisserie. That's what I do when I replace the timing gain in the 3.6 piece of shit chevy engine. Way easier to work on that way.

 

I am not going to remove the engine from it's bay. Besides there is so much room in there compared to my old 1992 4Runner with the 3.0 engine. This engine is much easier to work on and tions of room.

 

why do you feel the need to replace the timing chain?

I have never heard of anyone breaking one.

 

Well that's what I would do and I would just replace every seal and gasket while I'm at it. Front main, rear main, valve covers, oil pan, idler pulleys, timing cover gasket, new coolant, oil, transmission fluid would be replaced as well. If I was gonna go through that much effort I would just build it so it would be like new again.

 

I was also curious about this.

 

Me too why change it?

 

The reason I'm changing it is because one of my camshaft timing gears sensor tab broke. Since I have to change that out and I have 225k miles on the engine, I might as well replace all the timing chain assembly while I'm in there.

 

Here is the broken piece on Bank #1

 

Are you also changing sprockets?. Chain and sprockets wear out toguether.

 

Yes I am. Already ordered the whole package.

 

i was gonna say just replace that part unless it caused damage to the chain n sprockets.... otherwise those are going to be fine.

 

Normally I would agree, but my thinking is, since I have to take the timing chain cover off just to get that DAMN! long bolt off the can, I might as well replace everything since I have access to it. Better now than redoing the whole process over again in the future. Too many fish out in the bay that need catching than repairing my truck.

 

Curious what your oil change interval is? Looks pretty nasty in there.

 

Yes it does look bad. I purchased this truck from a friend and he did the oil change the day before I bought it. I just put 3k on it and I was going to clean it at the same time I changed out the timing chain and start putting synthetic oil in it and change it every 4k.

 

According to the service manual, it looks like both the sub pan and main pan need to come OFF.

 

Damn! I read that also but I saw a lot of 4.0 Timing chain replacement pics on the web with the pan still attached and some with it removed. I was just hoping that the removal is not necessary. I hate working on the ground in my old age. Oh well, thanks for the response.

 

@Torspd probably knows the answer to this.

 

Yes I believe the pan assembly comes off and I feel like something about the heads coming off rings a bell as well.

 

If it were mine, I would go completely outside the box. If you hold the new part up there and there's room to slide it in without removing the timing cover, then all you need is clearance for the bolt. Clean and prep the area for surgery. Duct tape and plastic wrap the motor. Then use a die grinder to carve a half circle out of the cover to match one of these.

http://www.streettunedmotorsports.com/parts/b/oem_dsm_half_moon_valve_gasket_md372348.jpg

Lots of 4cyl front wheel drive cars have a half moon plug like this.

Just a thought that seems like a ton less work than ripping the motor apart. Of coarse, this is assuming you know where the broken piece is. And, not, "oh, I know where it is. It's in the pan".

I'm still curious how it broke.