2.9L w/ MegaSquirt to 4.0L w/ Ecumaster Black and a Turbo build

[konrad911]

Just thinking, maybe it's possible to change to the manual adjusted rocker arms and pushrods as in earlier 2.8L V6 engines?
I must take a look, maybe I have a set somewhere in my garage...

Anyone did it before?

 

[konrad911]

So my thoughts are - rocker arms' assembly from 2.8L almost bolts on.
The rocker arm shaft of 2.8L is about 5mm shorter and therefore the bottom two rocker arms and tower neighbouring with them are misaligned.
Should be easily solved with the towers & shaft from 4.0L (same diameter of the shaft).

The assembly is slightly higher though, so the rocker covers from 4.0L will not fit. I have the Aluminium ones from 2.8EFI that will bolt on!

Pushrods are virtually same length and by having the adjustment screw on the rocker arm...

Well I might just saved few hundred of bucks, right?

What you think???

 

[alwaysFlOoReD]

So my thoughts are - rocker arms' assembly from 2.8L almost bolts on.
The rocker arm shaft of 2.8L is about 5mm shorter and therefore the bottom two rocker arms and tower neighbouring with them are misaligned.
Should be easily solved with the towers & shaft from 4.0L (same diameter of the shaft).
View attachment 74422
The assembly is slightly higher though, so the rocker covers from 4.0L will not fit. I have the Aluminium ones from 2.8EFI that will bolt on!

View attachment 74423

Pushrods are virtually same length and by having the adjustment screw on the rocker arm...

View attachment 74424

Well I might just saved few hundred of bucks, right?

What you think???

Same ratio?

 

[konrad911]

I don’t think the ratio could be worse
I’ll compare when disassembling the assembly.

 

[konrad911]

I’m just thinking, probably will not go that way as my 2.8L assembly will work, but…

$999 and unavailable for 1:1.8 ratio kit

Tom Morana Racing Engines

However…

on eBay all shapes and colors and ratios from $129 for a set of 16 rockers, with studs. Just a mounting adapter plate needed to bolt to the head where the stock posts/towers are and then use studs to secure the rocker arms to that adapter plate.

Or I am missing something?

 

[gaz]

Konrad,
My machinist suggested that the 2.9l adjustable rockers could be adapted to the 4.0l but not for free. He likes the adjustable pushrods better. Also, if the 2.9l rocker can be adapted, cost effectively to the 4.0l, then the Improved Lift rockers that we're available back in the 1990- early 2000's would be a super great option. I have them in my 2.9l, I have been trying to dig up my old purchase info to identify the fellow that made them. If memory serves the stock 2.9l rockers are 1.46:1 and the the hi lift sets were 1.5:1. Only 0.004" but they sure work great with my cam grind!

In the 4.0l ohv, since already utilizing roller lifters, the benefit of adding a roller rocker is NEARLY 0.0% improvement. I have yet to see a roller rocker set-up work with any reliability in a 2.9 or 4.0, let alone be cost friendly. Roller rockers in the 2.9l would be a great improvement in efficiency but for the 4.0 ohv, not so much.

 

[konrad911]

Well roller lifters have this advantage, that camshaft does not wear. While roller rockers won’t wear themselves at tip touching the valve right?

so I don’t agree with your machinist

i’m thinking about them ONLY because the stock 1:1.47 ratio is barely opening the valves. Going to 1.6-1.7 would allow the engine to breath more. 1.8x? Not sure if there wouldn’t be a collision between valves and piston with 1.8x.
Wish I had them handy to try/measure.

I think I need to flip a coin - either floating rocker arms based on 2.8L manually adjusted rocker arms and push rods or roller rocker arms to achieve better ratio.

EDIT: Roller rocker arms are great for OHC / DOHC where rocker arms touch camshaft(s) directly. For OHV engines the rocker arms can be solid, as rocker arms do not touch a rotating camshaft directly right? BUT roller lifters for OHV (these are touch rotating camshaft) would be a huge upgrade for the earlier engines - if possible.

 

[gaz]

Yes I agree, using free floating rocker shafts in both the 2.9l and the 4.0l is a good move

Just to be clear; roller lifters or roller rockers are both great but it is using both at the same time that doesn't improve significantly more than just one.

 

[konrad911]

So I think I made up my mind. I will stick to floating rocker arms from 2.8L. That’s zero cost for me.
Later on if I decide to upgrade, this is as hard as removing rocker covers

 

[konrad911]

I moved the 2.8L rocker arms to the 4.0L shaft and posts. I did not notice that earlier, but every 2nd rocker arm is misaligned with the valve by c.a. 4mm.
I think easiest way to fix that would be to remove those 4mm from one side of the post.

 

[konrad911]

Saturday morning, what a nice time to do some milling

Started with one, just in case... 3mm of the material removed.

As it seams all fits nicely the rest followed.

Chamfered the edges and ready to install.

First head first.

The alignement of rocker arm and valve is much much better now. Even compared to the marks on the rocker arm from the stock 2.8L assembly, stock was not centric.

And here both rocker arm assemblies done.

I assembled the 2nd head rocker arm assembly just to be double sure before machining, but seems Ford was consistent. This side also needed removal of 3mm of the material from one of the side of the posts.

Ordered aluminum rod OD 28mm that I will use for turning the spacers on my lathe. I decided to go with 2017 alloy (seems slightly better than 6061), both seems to be like 2.5x more expensive than the most popular 6060 (which is very soft).

 

[konrad911]

My so called wife can be understanding sometimes

I managed to strip down the engine today.

Each cylinder has a step about 1/4" below the deck.

STD bore is (100.38mm) [3.952in]
My block which is the 1990-1994 can handle 0.060 overbore (found it somewhere in the web), with a safe 0.048 overbore (Doug Anderson) which gives 4.00 bore, which is SBC bore right?

Measured the cylinders on X / Y axis just below this step (metric) [imperial]:
1. (100.43 / 100.57) | [3.954 / 3.959]
2. (100.44 / 100.46) | [3.954 / 3.955]
3. (100.42 / 100.48) | [3.9535 / 3.956]
4. (100.44 / 100.56) | [3.954 / 3.959]
5. (100.43 / 100.54) | [3.954 / 3.958]
6. (100.43 / 100.50) | [3.954 / 3.957]

First overbore is 3.962 (0.01 + 3.952), so very close to my 4th cylinder, BUT what I see is pistons are only +0.02 / + 0.03 / +0.04.

 

[gaz]

• you can get new Mahle +0.03" on ROCKAUTO; I would buy ALL 12 if you plan to balance the bottom end.

 

[konrad911]

So I ordered some parts and waiting for them to arrive on my continent.

Ordered a tool to hone the rocker arms and towers to a proper ID, but the tool was wrong and could not handle such low ID.
Need to find a different (and affordable) tool for that purpose it seems.

I will need that to fine hone the aluminum spacers as well.

In the meantime I took a closer look at the camshaft chain toothed gear that mounts onto the crank.

These are different and not interchangeable. Seems the later engines with the 8 holes for flywheel used a wider chain.

The locking/positioning is also different. The older type gear uses a "tip"/hole while new type is woodruff key.

Unfortunately the "tip" on the older hear is too narrow and leaves about 1mm of play on the newer crank.

So the idea is to machine a woodruff key seat in the older gear and fix it the newer way.

The crankshaft nose length to the gear is same for both generations of the cranks, so the gear will be positioned in the same place.

Only difference is on gear width where it touches to the pulley/harmonic damper (?) the older gear is 7.2mm the new one in that place is 6.8mm.

But I guess 0.4mm would not be an issue for the pulley to be moved forward of the engine?

 

[konrad911]

I don't want to grumble to much, so I'll just tell I was super busy and as the parts were coming and coming and coming I did nothing to move forward.
Still lot of things on my head, but at least the parts arrived (2 months on the ship :-/).

So I have the new flywheel & clutch (257mm rather than standard 242mm) and a set of new oversized Mahle pistons (Friday I'm taking it to the machine shop for boring out the cylinders).

Photos...