If the engine is that tired, the rest of the truck can't be far behind.

 

Well. So throw in the towel, eh? Fixing for a friend. Actually the opinion I need is concerning the ability of an internal combustion engine, primarily the 3rz-fe, to run with low compression. Looking for someone who may have been down this road (i.e. experience) that may be able to offer some real world experience with what they may have encountered. But thank you for the insight.

Per factory service manual specs, it has spark, fuel psi and timing is correct. Just lacking correct cranking compression. Anyone had similar experience with this engine? Would like to know before I start swapping if possible.

Thank you!

 

I know others that have been down the same road years ago that end up with nothing in the end. I guess if your young, have all the parts, and labor free of cost, have at it. you'll learn a lot, but for the average person with limited resources, its not a great move on something of that age, and mileage.

 

Did you listen for where the leaking air was going (crankcase, exhaust and/or intake)? Seems possible it's going into the adjacent cylinder given the center two are low.

The FSM says STD is 178 psi or greater and Min is 127 psi (both at 250 rpm. In addition difference between cylinders should be less than 14 psi.

Have you verified you have fuel and spark?

Edit: I read more of you TW post. I admire your persistence and methodical approach. Are you a disciple of Eric, Danner and Ivan? (some of my favorite YouTube mechanics).

 

Paul, thanks for the kind words of being persistent and methodical. I appreciate that. I'm an engineer by profession, and I guess that's just a part of the usual grind I've always been accustomed to. Never give up, as there's a cause/reason behind it all. Just the way our world works if you know what I mean. Often times, I'm just not smart or savy enough to figure it out. I admire folks who are.

I did try to listen, and it seemed like most was going into the crankcase when I did the leakdown test. With the new long block sitting there, I decided to go ahead and swap it out as my friend is needing his truck, and I new the install was gonna take me a while anyway working on it in my spare time. I just preferred to get the old engine to fire before pulling.

I've not started the new motor yet. Almost there. Gotta finish PS pump, Fuel system, Radiator install, Exh, and plugging ECM stuff up. Hope it starts.

 

And yes, fuel and spark are wonderful,...lol.

 

Joe - I suspect we have a lot in common. I get weary of posts where the author has replaced a bunch of OEM parts w/ aftermarket w/o attempting to test anything first, just making the troubleshooting hole deeper. I’m in the “test, don’t guess” and use service data camp.
Good luck w/ the swap. Hope you have a warm place to work.

 

From an old text book while working on radial engines, broad brush , 5.5 to 1 of the cylinder's designated compression raito for ignition to occur, if it can't hold that then the fire goes out.

 

Update. My friend decided to have me replace the 3RZFE long block to get "compression factor" out of the way. Still would not start after that. EEK!!! Fast forward to the end, the new motor started after replacing the ignition coil. On this model, it's built into the side of distributor. My feeling is that the old motor would have started with a new coil as well. Wish it would have tested bad, and it would have saved a motor swap I'm betting. On the flip side, the old motor was tired.

Still not completely sorted out yet. Still working thru a miss under 3k rpm. Above 3k at full throttle, the miss is not as noticeable. Fuel system has been rebuilt at this point also.

 

I take it there was something wrong in how you determined 'fuel and spark are wonderful'?
Either way, good to hear you got it fixed!!