87 Ranger 2.9 stroker (210 ci/3.5 L)

[AllanD]

Yeah I'm pretty sure the 2.9 n 4.0 blocks are the same casting, 4.0l just has a bigger bore, I've put the two side by side, n you can't really tell the difference


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The Deckheight is taller on the 4.0 block partially to accommodate the longer stroke. but this has the effect of making the intake manifold wider.

For the effort you are engaging in wouldn't it be easier to swap in a complete 4.0 engine and get the bore with the stroke?

IF I was going to mix parts between a 2.9 and a 4.0 I'd go the other way around and use a 2.9 crank with custom flat tops to make a supercharger friendly 3.3liter V6

AD

 

[TheChimera]

Update

So, after three weeks of delays from the machine shop doing the piston fitment and balancing, my internals are back. And yes, the FRPP engine dimension spreadsheet has an incorrect deck height listed for the 4.0L block. The pistons at TDC sit .5673" ABOVE the deck. So here's where things get interesting. With the time, energy and financial expenses already involved, I have a hard time giving up on this project and am courting the idea of an R&D engine to test the durability of a variable compression engine.

Here's the concept:
1. Determine compressed gasket thickness and subtract twice that measurement from the distance the piston is above the deck.
2. Trace the head gaskets onto 5/8" medium carbon steel (cast iron and steel have a thermal expansion difference of .0000006"/*F, so over a heat range of 340* [cold start to warm], the difference is only .00017") and use the CNC mill at school to cut head spacers of the calculated thickness.
3. Sandwich the spacers between head gaskets and the hone the cylinder walls to final size with torque plates to maintain a consistent bore all the way down the cylinder.
4. Replace OEM head bolts with ARP head studs of the appropriate length to ensure adequate clamping force.
5. Replace OEM lifters with roller lifters from BBC (same lifter bore diameter), which should allow use of a more aggressive cam profile if needed, but whose main purpose is to decrease friction at the camshaft. This would compensate for .300" of the increased deck height, with the remainder taken up by lash adjusters and/or lengthened pushrods. Machine clearance in front of block for camshaft thrust needle bearing.

The reasoning for this is I have been intrigued by the idea of an engine which may have its compression ratio adjusted through the replacement of spacers of varying thicknesses (thinner for higher CR, thicker for lower CR). Further, because of the extension of the piston above the deck, engine teardown would be made less challenging as all that would be needed to remove a damaged piston/rod/ring package is removal of the head/spacer/oil pan and loosening of the rod bolts, making field repairs of the engine not only possible but perhaps possible without removing the block at all.
In the interest of addressing potential concerns, it is a widely documented technique to drill TINY gas ports into the top of a piston and thin the top ring down to decrease ring drag on anything other than the power stroke. See here:
Decreasing ring tension should allow the rings (really only the top two are exposed, the oil control rings are still below deck height) to back away from the cylinder walls to reduce the chance of abnormal wear from effectively passing through the stock head gasket.

Questions/comments are most welcome. Cheers!

 

[35Remmy]

Wow, following this thread gives me a serious inferiority complex, heheh.

I think the only thing I can add is that when choosing between ARP head bolts and studs for my 302, I was told that the difference in clamping force was so minimal (maybe just for my application???) that I should spend money elsewhere. Heads obviously easier to install with studs, and that was really it. And that was from ARP.

 

[alwaysFlOoReD]

Hmmm, are you making some adapters for the intake as well?
I'm not sure how the rings will like jumping the gap, but nothing ventured - nothing gained.
Good luck,

Richard

 

[TheChimera]

The thought process behind the head studs stems from uncertainty about whether the OEM bolts will be long enough; the bolts extend into a couple of coolant passages and, I believe, an oil gallery or two, acting as a plug.

Yes, I plan to make spacers for the intake manifold as well. Whether or not they are integral to the head spacers I have not decided yet; I was considering making them a separate part which could also act as a valley pan, possibly with concentric lifter bores to better support the roller lifters. The rings jumping the gap has me a little curious as well, but somebody's got to tie the key to the kite. ;-)

Also, instead of dinking around trying to find a workable stock ECU to control everything, I grabbed a DIYAutotune MS3X v3.57 standalone ECU, giving ignition control to a Crane HI6S CDI ignition box. The base tune has already been written and burned. Can we say fully sequential injection? Twin 02 sensors, twin MAP (engine and external baro), bank-to-bank knock control, EGR and flex fuel compatible. At idle the 42lb/hr injectors are only running 3.7% duty cycle, 81% at max load @ redline. Heck, the ECU can on-board datalog, PWM boost control, control two stages of nitrous (I'm not that crazy) and even has launch control. More powerful than a MoTeC M880 at half the price.

 

[Terry]

I think you are going to have troubles with your head spacers. I think the only way they will work is if you bore a step in the top of the bore in the block. Then you machine your spacers for the heads so the fit in the bores in the block and hone them together.

 

[TheChimera]

Terry, I was likewise concerned with the sealing of the primary gasket. To ensure I'm understanding you correctly, do you mean something similar to a cylinder sleeve extension on the bottom of the spacer? The main concern I have with extending the spacer into the block is the X factor of the deck thickness. I don't own or have access to a sonic tester, so boring material out of the top (actually top 1/3 of the stroke) may weaken the cylinder wall and or deck too much. Further, doing so would require removal of the fire control ring on the head gasket. My inclination was to cut a .020 deep ring slightly outside the cylinder bore and lay a hardened metal ring in the trench to give the head gasket something to bite. Likely leave a ridge of similar dimension on the bottom of the spacer as well. I've read about these features on endurance engines, which must survive more extreme loads than I hope to be putting on my engine (too frequently ;-) ) Mainly I just don't have a whole lot of material available to cut into.

 

[Terry]

You could get an iron pipe nipple that you could cut to size. The expansion of the material will be close enough to the block material so heat will not effect the spacer. The "sleeve" needs to be located so it stays static to the block and honed with them together. Thinking outside of the box, it would be really cool if you could get some junk heads and make the spacers out of them.

 

[TheChimera]

Terry, while it would be an interesting work around, after consulting my trusty 29th edition Machine Tool Handbook, I am really uncomfortable with the amount of metal left after the proposed machining operation. Here's why:

3 1/2" NPT fittings have a minimum major diameter (OD) of 3.953". The thread itself has a maximum height of .1000". This means the root of the thread would be a minimum of 3.753". The maximum would be more like 3.7675". My pistons are 3.665/3.688 in diameter (the oval shape allows for thermal expansion). This would only leave at best .0795, or .03975 per wall on the fitting. Further, this is assuming a rubbing fit, as in no clearance. After measuring my cylinder wall thickness (with a dial caliper, but did not do the math on the curvature missing from the jaws; IIRC it's an addition of .0028" giving a final dimension of 0.2078"), the 4.000" nominal OD would take up all but .0836 of the existing cylinder wall.

While the theory is sound, for this application I just feel it would require weakening the block to an excessive amount where I need stability the most, namely the sealing and clamping plane of the deck.

 

[Terry]

I will reread this when I get home. I will look at your numbers. You have a newer book than me. I have a 2nd addition.

 

[TheChimera]

Run the numbers if that is what you what. I will not destroy my only engine block, six months of work and over a year of research to test your hunch. If you are certain that your idea will work, I look forward to reading your write up on the build.

 

[Terry]

Terry, while it would be an interesting work around, after consulting my trusty 29th edition Machine Tool Handbook, I am really uncomfortable with the amount of metal left after the proposed machining operation. Here's why:

3 1/2" NPT fittings have a minimum major diameter (OD) of 3.953". The thread itself has a maximum height of .1000". This means the root of the thread would be a minimum of 3.753". The maximum would be more like 3.7675". My pistons are 3.665/3.688 in diameter (the oval shape allows for thermal expansion). This would only leave at best .0795, or .03975 per wall on the fitting. Further, this is assuming a rubbing fit, as in no clearance. After measuring my cylinder wall thickness (with a dial caliper, but did not do the math on the curvature missing from the jaws; IIRC it's an addition of .0028" giving a final dimension of 0.2078"), the 4.000" nominal OD would take up all but .0836 of the existing cylinder wall.

While the theory is sound, for this application I just feel it would require weakening the block to an excessive amount where I need stability the most, namely the sealing and clamping plane of the deck.

Another option although it might be costly. You could have some stroker rods made and not worry about doing anything other than you might have to trim down the piston skirts. I would think that if you did some research you might find some rods of the length you need. I build and own volkswagon's as well as my truck. I can buy stroker rods for air cooled motors. You might want to check with summit or one of those stores for what you need. Stroker rods and or pistons would be the way to go. I have been a machinist for over thirty years and I don't know if I would mess with sleeves and spacers.

 

[bobbywalter]

Wow, following this thread gives me a serious inferiority complex, heheh.

I think the only thing I can add is that when choosing between ARP head bolts and studs for my 302, I was told that the difference in clamping force was so minimal (maybe just for my application???) that I should spend money elsewhere. Heads obviously easier to install with studs, and that was really it. And that was from ARP.

i...uh.... i dont think heads are easier to install with studs. especially in a vehicle. and i dont think you have all the apples on that.

on the 302 there is not enough bolts to hold boost well, or high na power and gaskets inevitably get blowed out. its a given. studs are a bit trustier for multi use....for a normal sub 350 hp build they are not justifiable for costs...but there is more holding capacity depending on cap style.







i uh, dont get your spacer deal...


offset grind the crank a bit and get a little bit shorter rod and get on with it.

i sure feel bad you did not know the 4.0 was the 351 and the 2.8/2,9 were the 302's of the cologne v6 world.....

though i am shocked someone would buy parts without spending time measuring actual blocks before making a solid plan and sending cash out. pretty expensive lesson for you to learn that fords own data can in fact be quite full of shit.

but to take this path ....

wow. let it go man.

 

[TheChimera]

Terry: I have been a machinist for over thirty years and I don't know if I would mess with sleeves and spacers.

I am also a machinist, which is why I went to the trouble off doing this math in the first place. I can't do anything about being fed bad information, however I am not going to just walk away from this after everything already done. The idea of running custom rods and thinning the skirts had occurred to me. And it would deal with the immediate problem of the piston extension. However it is not an expense I can do right now, having already put more into this than originally anticipated/budgeted. The NPT pipe fitting is a clever idea, and having reread your post about it, it may be a step in the right direction. Are you suggesting running the fitting trough a spacer simply as a collar to support the piston, and using the spacer to set the overall deck height, or...? Any chance you would be willing to sketch out your idea in the interest of clarity?

bobbywalter: but to take this path ....

wow. let it go man.

NO! I have not gone this goddamn far to just drop it because you can't fathom why I would be so inclined. An engine is nothing more than a sophisticated air pump, as I assume we all know. As long as it can maintain adequate sealing under pressure and doesn't eat itself while spinning, which it doesn't, it will work fine. And prior to starting this whole project, I had asked people on this forum whether or not the 2.9 and 4.0 deck heights were indeed different as I don't have a 4.0 block to get dimensions from. I was told that there is no visually discernible difference between the two. Once again, bad information, but excuses are buttholes.

 

[bobbywalter]

And prior to starting this whole project, I had asked people on this forum whether or not the 2.9 and 4.0 deck heights were indeed different as I don't have a 4.0 block to get dimensions from. I was told that there is no visually discernible difference between the two. Once again, bad information, but excuses are buttholes.

naaa... i dont think so. you have two threads and 17 posts as of this post i am making. i seen no experienced confirmation at all untill allan d answered.....and answered concisely due to actual experience.

So I have an 87 XLT 2WD that is nearing the end of its engine life as far as I can tell. Been nursing it but not sure how long after winter it has. In planning for its overhaul, I've decided to pursue a 3.5l high compression V6 OHV. Using the FRPP engine dimensions, looks like a 4.0l crank, 3.0l Vulcan con-rods and 2.8l .030 flat top pistons will net a 3.320" stroke and 3.670" bore and approximately 10.5-11:1 compression. I picked up the pistons, crank, bearings and one rod to test fit and they look like they should all work together sizewise. Need to clearance the piston skirts a bit for the crank throws, but all of the components mate nicely. Can spin the rod on the journal several times with one finger. I'll see what the block needs after the engine passes on and I yank it out.
Putting all the parts values into DynoSim engine software, with the Camcraft 252/256 cam and free-floated rocker arms, the engine should make 227 hp @5k and 300lb-ft @ 2.5k. Also should make over 200lb-ft from idle up to 5500 rpm and over 170 hp from 3000-7000.
I plan on backing this with an M5OD and BW1354/50 doubler, sent to D44/9" axles running 35/10.5/15s. Will be installing 4.0l clutch and eventually rear discs. Also 2" thick radiator and remote mounted oil filter and cooler.
So my question goes: Has anyone attempted this kind of homebrew stroker and if so, how long did it last? Also, does anyone have actual measurements on the deck height for the 2.8, 2.9 and 4.0l engines? The FRPP info says they have the same deck height, but that doesn't seem right as the 4.0l stroke is so much longer than the 2.9. Way too much to be taken care of with wrist pin height and rod length adjustments.
And before any of you say it, I WANT to stick with the 2.9. Not swapping. Be about the same price, but I won't have to monkey around with harnesses and adapters or worry about the health of the donor motor. And it'll be a true sleeper if the engine still looks like an old beat up 2.9.

1st answer......

Yeah I'm pretty sure the 2.9 n 4.0 blocks are the same casting, 4.0l just has a bigger bore, I've put the two side by side, n you can't really tell the difference


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2nd answer

No experience but I'm looking forward to seeing this

1st serious question.....and obviously not a confirmation of deck height

Stupid question but If the 2.8/9 and 4.0 blocks are the same why not use 4.0 heads??

1st guy that actually measured something a time or two.

The Deckheight is taller on the 4.0 block partially to accommodate the longer stroke. but this has the effect of making the intake manifold wider.

For the effort you are engaging in wouldn't it be easier to swap in a complete 4.0 engine and get the bore with the stroke?

IF I was going to mix parts between a 2.9 and a 4.0 I'd go the other way around and use a 2.9 crank with custom flat tops to make a supercharger friendly 3.3liter V6

AD

and made a logical suggestion.


what you propose to do is convert a 2,9 block into a 4.0 block.


YES it will eat itself in the manner i see proposed unless you keep the rings below the spacer without full sleeves. so full sleeves are needed with a spacer to sy the least.......why does a yz 250 live a much shorter life then its four stroke counter part.....and to keep it peak 20-30 hrs between re-rings.


add to that, the explorer many years outsold the competition combined....and untill the sohc 4.0 and v8 were introduced in 95-96 it only came with a 4.0.




4.0 blocks as 2.9 and 3.0's are not rare or costly....the 80 dollars it would cost to ship it is more then i would pay for one.....why you did not take the time to go to the junkyard and tear a few apart with your measuring tools and knowledge capacity....all models involved.. 2.9, 3.0, and 4.0 is beyond me with ambitions of this magnitude.

so build a bad ass 2.9 or get a 4.0 block.


or. get a real engine. these gas gobbling slobs are not worth the time it takes to rebuild.... but thats just my useless opinion. i sure as hell would not use it to invest a serious amount of money to build power to punish a d44 and 9 inch with 35 inch tires.


and wait till you find out how off the sim programs can be.

i am not trying to insult you, i am trying to keep you from beating your head against the wall and wasting your hard earned money.