91 4.0 rebuild

[kdooxp]

New member here looking for some advice and answers. Sorry for the long post

I have a 1991 Ranger that rattles and I’m finally going to tear it down and fix it. I plan to pull the engine out and rebuild it with a comp cams (either 410 or 422), new lifters, pushrods, rockers, etc…
My questions start there: would I be better off going 410 vs 422? I’m looking to make some power but not planning on going all out with head porting and such.
From what I’ve read I need valves (to get away from the 2 piece stockers) and springs. Does anyone have any recommendations on which valves/springs?
Im also considering getting headers, but Im not sure if any of them fit on a 4x4.
Any help and suggestions would be appreciated.

 

[SenorNoob]

What's a 2 piece valve?

 

[kdooxp]

I’ve read that on some of these older ford engines they have the valve head welded on the stem. Maybe it’s not true, but that’s not the point of the post.

 

[2011Supercab]

Any help and suggestions would be appreciated.

I'd call comp cams and ask them, it's going to depend on what you are planning to do with the truck, towing, off-roading, highway cruising.

Do you want more bottom end torque, or highway performance.

Most cam places are very helpful and want you to be happy with their products.

 

[kdooxp]

Ill do that, thanks

 

[JoshT]

I'm not sure about the whole 2 piece valve thing, bit I wouldn't focus on the valves themselves too much. Instead I'd buy new heads. Later models of 4.0L had design revisions that improved the strength of the heads, and the after market castings improved it even more. I'd just get new complete head castings that will include new valves and springs. IIRC there is an article in the tech library about component selection for rebuilding the 4.0Ls.

If you want anything noticable from the cam, you probably want the 422. At one point I rebuilt my 99 4.0L and added a cam and shorty headers. I meant to order the 422, but ended up with the 410. Couldn't really tell that I had changed anything. Granted that was in a 4x4 auto and wasn't tuned for it. Which leads to my last thing in this post...

The problem I see with your plans isn't the engine itself, it's the controls. You won't see much of any gain from adding the camshaft itself, what's going to wake it up is having the tuning adjusted to account for it. Yes, the truck will learn and adjust some, but not optimized for the cam. IIRC the 91 is still on OBD-I and EEC-IV. I'm not sure that there is still anyone out there that support running for those. IIRC Moates had the hardware for it, the quarterhorse, but they closed up shop in 22 or 23 and stopped making product before that.

 

[kdooxp]

Thanks Josh,
I am going to bring my heads to my local machine shop to have them checked and he said he sells aftermarket castings so I think the bases will be covered there.

As far as tuning goes I had looked into a few options but like you said it doesn’t seem like there’s many left. There was a post on here by Doug904 that said with a calibrated MAF sensor you can make it run pretty good…is there any truth there?

 

[rhekman]

Thanks Josh,
I am going to bring my heads to my local machine shop to have them checked and he said he sells aftermarket castings so I think the bases will be covered there.

As far as tuning goes I had looked into a few options but like you said it doesn’t seem like there’s many left. There was a post on here by Doug904 that said with a calibrated MAF sensor you can make it run pretty good…is there any truth there?

I did my 300k mile rebuild a few years ago due to a cracked head, and I threw in the Comp 410 cam while I was at it. I'm still on the stock '95 EEC-V computer, and don't have any other supporting mods besides a cat-back exhaust. I do plan on a tune or an aftermarket ECU at some point, but I haven't gotten around to it. I'm sure I'm leaving some performance on the table right now. It's maybe slightly more "luggable" or harder to stall at lower RPM, but it still totally runs out of breath above 4000 RPM. Honestly though I think it's more an issue with the utterly choked head flow - shrouded valves, big lipped valve seats, tiny ports, bad valve angles, etc.

The motor runs fine on my stock computer with the stock MAF. It appears to be very sensitive to a good IAC valve, since it's slow to return to idle with the cheapy O'Reilly's replacement IAC I have installed.

 

[JoshT]

Thanks Josh,
I am going to bring my heads to my local machine shop to have them checked and he said he sells aftermarket castings so I think the bases will be covered there.

As far as tuning goes I had looked into a few options but like you said it doesn’t seem like there’s many left. There was a post on here by Doug904 that said with a calibrated MAF sensor you can make it run pretty good…is there any truth there?

I should have also mentioned that later model heads have a different combustion chamber, but I didn;t think about it until I Was replying to a different thread. Putting them on the earlier rotating assembly will increase compression ratio. I don't know what the new CR would be, but I've read it said that you would need to use midgrade or premium gas to prevent detination. The changed camshaft would probably make that even more critical.

Should be improved aftermarket castings available with the earlier combustion chamber as well if you don't want to mess with the CR.

It's been a while since I've seen that username. If memory serves me right, he is the tuner behind Bama Chips. The guy that got it started and his tuning start was at least partially in the Ranger V6s. He put together the tunes that I had for my 99 4.0L and they worked well. In other words, he knows his stuff.

IIRC the cvalibrated MAF was used to correct for larger injectors. If you don't need or won;t be installing larger injectors, I don't think a calibrated MAF would do you much good. I also don;t know if anyone is still making and selling calibrated MAFs for that application. They weren't used near as much on the later EEC-V systems, because they were easier to tune for the change through software.

I'm going off memory there so take it for what it's worth, and verify everything.

I did my 300k mile rebuild a few years ago due to a cracked head, and I threw in the Comp 410 cam while I was at it. I'm still on the stock '95 EEC-V computer, and don't have any other supporting mods besides a cat-back exhaust. I do plan on a tune or an aftermarket ECU at some point, but I haven't gotten around to it. I'm sure I'm leaving some performance on the table right now. It's maybe slightly more "luggable" or harder to stall at lower RPM, but it still totally runs out of breath above 4000 RPM. Honestly though I think it's more an issue with the utterly choked head flow - shrouded valves, big lipped valve seats, tiny ports, bad valve angles, etc.

The motor runs fine on my stock computer with the stock MAF. It appears to be very sensitive to a good IAC valve, since it's slow to return to idle with the cheapy O'Reilly's replacement IAC I have installed.

Your truck is running EEC-V compared to OPs truck running EEC-IV. EEC-V is more capable of self learning and tuning, and can respond better to changes than the earlier systems could. Your EEC-V is also easier to tune than the earleir system when and if you do decide to have it done.

 

[rhekman]

Your truck is running EEC-V compared to OPs truck running EEC-IV. EEC-V is more capable of self learning and tuning, and can respond better to changes than the earlier systems could. Your EEC-V is also easier to tune than the earleir system when and if you do decide to have it done.

That's a good point. I'm aware of the difference, but should have pointed it out more clearly.

 

[kdooxp]

I appreciate the replies. I guess I’ll have to try find a tuner in my area that still has the software. Do either of you know if the software is still available to buy? And I can tune it myself? Besides microsquirt/megasquirt? I looked into those but I’d rather keep my factory ECM if possible. I just replaced it 6 months ago.
Any info on the JET plug in modules? I’ve read a lot of mixed reviews.

 

[JoshT]

You could look into Tweecer and what hardware it supports, see if there is any thing compatible. Even with the Moates hardware, a lot of people used tweecer for tuning. There may well be other hardware that it can use that is compatible with the older EEC-IV systems.

I know nothing about the JET modules. The module itself is just an interface device, the tuning on the device is going to determine how well it works. I don;t know if JET is supported by any tuners, or if it is solely a preloaded, canned tune thing. As much as they try to advertise as such, canned tunes are not really a one size fits all thing. They might make improvements, but every vehicles is different and they might not be optomized to your particular truck and conditions.

To get a better idea about Mega/MicroSquirt, check out Sarah-N-Tuned on YouTube. She did MS on her '94 4.0L Ranger not too long ago. You may already know about that.

 

[kdooxp]

I had not heard of tweecer, time for more research.
I was a little nervous of Jet anyway, it seems like they don’t tell you what they’re changing to “increase horsepower”.
Sometimes I forget to search YouTube. I’ll look into her channel too.

 

[gaz]

@kdooxp

Your EEC-IV, has benefits that are often overlooked while it can not be tuned it will benefit from improved timing and fuel curves from either a Jones Electronics Technology (JET) or Hypertech PCM CHiP.

The way to go is with the 98+ spec heads. The redesigned (in 95) fastburn combustion chamber will bump up the compression ratio (C/R) to 10:1 with 91-94 small dish pistons. If you desire to maintain the stock C/R, then install 95-98+ large dome pistons with them. I recommend using the 98+ heads with small dome pistons @ 10:1 but I do not know how that will work with 87/89 octane as I only use premium fuel.

I do know that 10:1 is not very aggressive and I expect that you would not have a detonation issue. If you did, you could use spark plugs 2 heat ranges down to side step it.

BUILD RECOMMENDATIONS
• have a reputable machinist perform a performance valve job...why not, it will both improve your fuel economy and crispen things up.
• consider adjustable push rods; changing all of your valve train components leaves your non adjustable valve train likely out of speck. The simplest solution is a set of adjustable push today (Smith Brothers makes them)
• Deltacam of Tacoma Washington is the only place on Earth to buy hardened OHV 4.0l rockers, he bought all of them and is happy to sell you a set.
• having your stock throttle body (T/B) bored to 64mm is money well spent. It will offer a modest 2 to 3 hp/tq throughout the usable RPM range (definitely between 1,500-3,500, where the engine should spend most of it's time).
• instead of a cookie-cutter CAM, have your heads flowed and use your machinist recommendation for a custom regrind. Oregon Cam Grinding of Vancouver Washington does great work and very reasonable; a roller cam regrind from them is currently right around $200 .
• my machinist sourced an older set of Bowtie v8 dual beehive springs that matched up great. I have the part number if you want it

HEADERS
• JBA, Borla and Edelbrock were all good systems...they have only become more pricey
• I have never seen a difference between 4 wheel drive and 2 wheel drive or manual and automatic headers. #1, the transfer case is behind the transmission and #2 the transmissions on these engines have the same general spacing.
• an economic alternative to Headers is a set of 98+ spec stock Ford exhaust manifolds. They benefit from an improved flow design and are reasonably priced new, even cheaper from the wrecking yard

VALVES
I do not know what you mean by 2 piece valves.

I have been fortunate with all my 60° v6 Ford rebuilds as the original valves were still within speck, I rescued them...however a replacement set, whether by Ford new old stock or Farrea are not very expensive and the stock size valves will support power levels approaching 300hp.

 

[kdooxp]

gaz, do you have any personal experience with JET modules? Tuning is the main concern I have right now. I’d hate to burn the new engine up with a bad tune. I was under the impression I would be able to buy an inline connector of sorts and some software and tweak the tune myself, but if that’s not true I’ll need to look into something else.

If it means getting the most bang for my buck, running premium fuel is not going to be a problem. I was considering bumping compression at the start of the process but hadn’t made up my mind yet. Once I tear the engine down it’s more than likely getting new heads and I’m waiting to order pistons to check the bores in case it needs bored out. If I can find some 98tm heads I’ll more than likely put them on.

As far as machining goes, I will have the heads (even if they’re new castings) gone through with new valve springs and retainers for the increased lift cam. From the sound of it a valve job would be a good idea. I had thought about new valves but I never thought far enough to think if the engine would need them…
I was planning on getting pushrods from smithbros once I had everything back together and was able to determine the length needed.

Do you know what’s entailed for boring the TB? I have a 66 mm in my EBay cart but haven’t ordered it yet. If I can save a few dollars I may as well.

I’m also having trouble finding headers that are a guaranteed fit. There’s a lot that advertise they fit on mustangs with the 4.0 but not the rangers.

I’m not sure I realized how many questions I would have at the start so thank you for the help