Used engine or new heads?

I was told it had the engine replaced. I suppose it’s possible it had the heads rebuilt and resurfaced. I talked to another mechanic who told me even non interference motors can still bend the valves if it jumps time enough, or if there’s carbon built up in the pistons.

 

I guess you'll find out when you get there but I doubt that's the case. This might be the time to hand the cash over and pay a reputable shop to at least look at it.

 

That’s definitely the first step. These were the compression numbers. You’d think it would still start up and run rough at least.

 

I used to buy many oddball 4AGEs back in the late 80's, early 90's, can't say I ever had a bad one. And before that it was 18RG with the dual 44's...good times. But the same holds true. Used JDM is a great option.

 

JDM importers have been known to roll back odometers though.

Also even if it was low mileage, how do you know the valve steam seals wouldn’t be shot and suck down oil from sitting so long?

 

This is Not the original engine from 1996?

 

No, I was told it was replaced in early 2020, but they didn’t have documentation.

 

Well damn!! Who does not have the doc for something like that?
How much did ya pay for that sweet rig

 

I just traded my 97 Land Cruiser for it, which was a solid runner but kind of rough around the edges. I really regret the trade in hindsight though.

 

No one loses the paper work from an engine replacement. This sounds like someone is trying to blow smoke up you butt. A BS story to me.

 

The guys who traded it to me said the it’s final owner wasn’t a big car person and just took it to the shop and did whatever they recommended.

 

Well definitely an issue. You wanna see at least 100 psi. Next step would be a leak down test figure out where it's going.

 

It could just need the valves adjusted. Theres a Timmy the Toolman video where he shows how they can lower compression.
https://youtu.be/MOlmjtlO7TI?si=BamIr1Lp3zUhvdRo

 

Yeah, I miss those days where 4ag’s and sr20’s were plentiful. Now they’ve pretty much ran out of supply. Even JDM 5vz’s were only about 900 bucks.

 

I doubt they wouldn’t suddenly gone out of adjustment though, unless maybe that can happen with a misfire when it jumps timing?

 

I'd check to make sure it was timed right on the new belt. Did it overheat when the bearing went out? Was it running well beforehand? Stuff happens but these engines usually take a licking as long as repaired correctly.

 

It ran ok before, but started misfiring badly after the fan bracket was fixed. It could’ve gotten hot when the bracket bearing failed, but I wasn’t paying attention to temps at the time since I was rushing to an interview. The power steering and alternator light came on though, and I lost power steering. However, I looked at the temps while limping it to the mechanic, and it stayed cool. If it overheated originally and warped/cracked the heads, wouldn’t it overheat if I tried to drive it again? The bottom line is I took a running (albeit barely running) truck to the mechanic, and now it won’t even start.

 

That would certainly be my first assumption.
edit: I see a test now. hmmm. i also agree this should run with those numbers.

 

Agree. There's cosmetic head machining and then there's quality head machining.

Cosmetic head machining will remove enough metal so that the surface looks brand new, with no evidence of any pitting. Those heads look utterly pristine. They are also horrible. They can turn a noninterference engine into an interference engine as @tacoman2001$ said. But they can also raise compression way too high, even without interference.

Professional head machining removes just enough metal to make the head flat again, and to allow the head gasket to seal where it needs to. There will still be evidence of pitting where cooling passages in the block terminate against the head. When I get a machined head back, that's what I look for. Well, that is also what I specify before I hand it over.

All else being regular, with no cracks, a reman head with new valves, guides and seats and professional machining will be good.

 

This is the latest from the new mechanic I have the truck at. I’m trying to decide if I should have him look with a bore scope and do a wet compression test etc., or just say go ahead and fix the crank gear. I’d hate to put the $900 he quoted into it and still not have it run right. He did say the compression would probably come back after it starts getting gas, but it’s hard to know for sure.