I wish it was that simple, trust me! The very front exhaust stud was drilled and tapped with a bigger bolt, but WAY sideways, I went buy a shop and they said it can be fixed but its a no guarantee fix cause of how bad the previous person that worked on it screwed it up

 

So you will need to put a nut on that crooked stud to hammer it back straight? (without F-ing the threads) Bummer.

Course I don't know your situation. I'm a jack of all trades, "smash to fit, paint to match" . I can screw anything up. (even spelling). I've "persuaded" a "non true" stud with a hammer a few times. Don't remember regretting it.

But, only that is one thing, the bigger picture is another. I'll re-read, but what is the original problem...That matters

Yea, not there. I never regretted using the bolts I took out. Just me. "you can only stretch them two times, the third is a problem" might be true. Idk.

RRRR...So, how many miles? How many more do you want?

Just thinking what you want to put into the head might be relative to what you expect out of the rest of it. I believe mine is original and passing 270K. Not sure there though.

 

The machine shop I took the head to was A & m motor on Los gatos blvd.
I also like the guys at Winchester auto on Winchester.
Both shops are very helpful.

And also, really appreciate the input from the folks here
Cruiser, your knowledge is very helpful and your input both insightful and well grounded right on the mark, thanks!

 

Back in the '70s it made a big difference in drivability, disabling the EGR was the first thing you did. They were implemented very poorly.....but time marched on and they figured it out. Unfortunately the bad rep they generated still hangs around.
They now really only cause trouble when they're not working right- valve is sticking open, etc.

Computer-controlled motors work as a system, on the assumption that the parts are all there. For example- Your engine has a knock sensor, the EGR actually helps prevent predetonation. Removing it could cause the motor to ping, triggering the knock sensor to retard timing- you end up with worse drivability than if you'd just left it alone.


Given the large difference in price, I'd be inclined to pull a scrapyard head, check it with a straightedge, lap the valves and pocket the $300 savings. Outside the 0331 heads, the 4.0 head is pretty durable, rarely warps. Those old XJ's generally die of something else.

 

I edited out an earlier post. x2 Radi. Campbell.

 

Oh yea? Well I guess I guess will need to learn more about that! (seriously). Nitrogen Oxide aside, I would think the knock sensor would attempt to keep the timing where it belongs for whatever octane (rating), or "humidity" the system is dealing with.

Yes, the Renix ECU will retard it's advancing with a signal from the knock sensor as you correctly stated. The MAP (and temp stuff), along with the 02 will trim it up. (badly stated). Besides nitrogen oxides being formed at high combustion temps, just curious, where does the "driveability" come in? not meaning to be "argumentative" just learning.

Easily there could be something here I don't get. What is it, Titanium dioxide, (or Titinia) in the 02 sensor, does not see the nitrogen oxide, or the other way around?

Ha! Well, no worries! Just stirring things up!

 

So your saying just reuse the head bolts? I guess I'm just the ultra safe train of thought where it needs replaced, but on the other hand if you can't find them ( like me) then you are stuck using what you have! As far as the head goes I have a quote from one shop for right at 300 to do the work that needs done that's if they can fix the screwed up hole, or the rebuilt for 300, I guess it's a no brainer on that one. Yeah a scrap yard would be way cheaper but you never know if you have a valve guide off or what exactly is going On with it, so it's a catch 22 on this one! Any experience with rebuilt heads? Any companies to stay away from? Thank you

 

A used head wouldn't scare me.

4.0s are not known for valve guide wear. Lap the valves and go, as long as it's straight and not loaded with gunk.

Head bolts can be reused once BTW.

 

Penniman and Richards still around?

A&M was also one of my favorites. I have forgotten most of the names since I left SJ in 1979.

 

Well maybe I might gamble, got a day off coming up and what's better than to go tear a motor apart! Definately would be on the cheaper route, clean it, new seals, lap valves and ready to bolt up

 

I will check on Penniman to see if they are still alive and kicking. Its always good to get a recommendation on a machine shop, otherwise you are playing with much more uncertainty than a used head

We shouldn't be worried about used heads, all of us are driving cars loaded with em. And you are going to rip into them so you can check of things that are out of spec and get them fixed if necessary.

 

Without the EGR to help suppress pinging the timing might be retarded more than necessary by the knock sensor. Timing retard kills engine performance, you generally want as much advance as you can get without making it ping.

 

You can use a short piece of fuel line from the valve stem to a variable speed, reversible drill. Since you are gently pulling you might need clamps on the fuel line. Easy does it. You are just "touching it up". Slow/medium, and easy, one way then the other. Re-apply compound. Wipe it and look to see what you are doing. Anything like that compound, or carborundum from paper, make darn sure you clean it well. I've even used cheap wall mart starting fluid to give things a final "pressure wash"
Of course that would be outdoors, no sparks! I also have access to kerocene and diesel. Guess the car wash might be an option for you. You can rent a valve spring compressor. I do believe .060 is the spec for warpage, end to end. You also want to lay your straightedge crosswise and see what fit's there. I would hope .020 wouldn't fit there, but I don't know the spec.

Keep in mind you will be getting into almost everything else. How's the drivers engine mount? Freeze plugs ugly? Witch injectors did you switch to? Just rambling!

 

No it's fine ramble away! I am no stranger to tearing heads apart, mostly on Chevy 350's. the motor mounts are brand new haven't even driven on them yet, I had 703 injectors in it but didn't like the way they ran ( figured out it was something else) but needless to say I already took them out and put the stockers back in, gonna grab another set at the July tomorrow

Gonna go the carwash and oven cleaner for the cleaning, hasn't ever failed me in the past, plus with Xmas soon gotta watch the funds! Final cleaning is a non issue. Got seals, pushrods, lifters on order just gotta find a good head tomorrow!

 

Cool, sounds like you have a handle on it. Been in a few 350's myself Btw, even put one in my Jag. I even heard they were considered for aircraft due to reliability, and power to weight ratio.

Was just wondering, what is wrong with the head you have? Just manifold studs? Don't forget you can file/"adjust", the manifold for a larger stud. Yea, no fun, but you are canning your head why?

OK, I see "way sideways" on that front stud. I get that. Too bad it's not here. Seems solvable, but not with computer buttons!