Thanks Frank, I found a 1992 for $400.00 with 89,000 miles on it
is there anything I should do to before the swap?

No, not really - just pull your engine.... before you install the Diamante block, grind off the 2 dowel pins on the Diamante engine that interfere with the A/C bracket.

You'll also need to swap your oil pan, water pump, oil pump, oil pickup tube, alternator bracket, driver side rear cam sprocket cover, distributor, upper & lower intake, rear engine hanger, dipstick, oil filter adapter - don't remember everything.... just put the Diamante engine on a stand, keep the Montero engine close by and grab what you need as you go along.

Frank

If you were going to rebuild a diamante motor, I suppose you could always put the Montero pistons instead of the Diamante ones. I'm guessing that's what is changing the CR ratio, but it still may be an interference motor due to the change in valve timing. That's just a guess, Frank and Old Colt seem to know a lot more about the V6 though.

When I worked in the machine shop, we used a general rule of 4hp per compression point change (if nothing else was changed). That was a rough number we've seen on dyno pulls. Some gained more but most were in that 4 HP range. We had a few customers that thought raising the CR was the secret sauce no one knew about, despite us rebuilders telling them to do just some basic valve bowl blending, a good 5 angle valve job and just smoothing out any obvious casting flaws in the air path would net a larger gain (we usually saw about 15-20 HP on a standard V8 with just some very minor head and deck work to even things out - kind of like a poor mans blue print job).

Yes, but you might like the Montero cams better if you used the Montero pistons. The dynamic CR would be reduced with the dished pistons and Diamante cams..... The only way to tell would be to try it. The benefit to upper rpms and the lack of worry about fuel grade might overcome any loss of low end torque.



It would not be an interference motor with the Montero pistons and Diamante cams. Valve lift is the same for both cams and valve diameters are identical, so there would be no interference. The Diamante SOHC heads are the same as the Montero SOHC heads with the exception of the cams.

The static CR is 10:1 for the Diamante pistons with Diamante cams and 8.9:1 for the Montero pistons with the Montero cams. The dynamic CR is where it gets interesting:

Dynamic CR Choices

1) 6.99:1 = Montero pistons and Diamante cams
2) 7.39:1 = Montero pistons and Montero cams
3) 7.83:1 = Diamante pistons and Diamante cams
4) 8.28:1 = Diamante pistons and Montero cams

One thing's for certain..... the #4 choice would come off the line in a hurry..... #3 would probably win the race.



Exactly - there's not as much to gain as most folks think - primarily you get a crisper throttle, but I suppose if you're building an engine for maximum HP, the CR gain is an incremental benefit. I think the amount of gain is actually a percentage and depends on engine size.... here's a calculator that shows a 3.0L to gain 5HP (3%) from 8.9:1 to 10.0:1:

CR/HP Calculator

That does not consider the change to Diamante cams... which probably adds a few more HP, but moves the power band higher.

Frank

That's good to know. I wasn't sure if there was additional lift or not on the Diamante cams (and I was hoping you'd chime in and set me straight <img src="/forums/images/graemlins/cheers.gif" alt="" /> ) and as we've all experienced, valves don't always line up with valve notches. <img src="/forums/images/graemlins/ignore.gif" alt="" />

Wow, that is just alot of info to digest

Im installing the engine from the diamonte into the montero

Thats it (its a junkyard motor)

My Montero engine has a bad piston, burning oil from # 2 cylinder

Thats why im doing the swap
Everyone wants $800.00 up for a Montero motor(if they only knew)

lol

Yep,,,my block has those ridges <img src="/forums/images/graemlins/smile.gif" alt="" />. Shame is my H.B. destroyed the Crank Snout with only around 25K on it. <img src="/forums/images/graemlins/barf.gif" alt="" />.
I also just reralized I forgot to drill and tap holes for the oil pickup mount. <img src="/forums/images/graemlins/scared.gif" alt="" />

On MPI system and sequencial injectors:

I was under the impression that seq. inj. gave a little more performance , as in lees pollution and a little better gas economy . In 90 CA dropped the EGR . I thought this might be cause emmissions and milage are improved with this system. Maybe thats just a CA thing. Mine is from back East so its a fed. ECU. I run alittle richer , I think.

You shouldn't need to drill them.... they should already be drilled and tapped. You will want to clean the threads, though - with nothing in the holes, they tend to get carboned up a lot. It takes an 8mm x 1.25 tap.



Sequential port injection does give a little better fuel control and economy, but not much. It also requires a more complicated ECU with an injector driver for each cylinder and a camshaft position sensor. The next version of MegaSquirt reportedly will have sequential injection.

I think all of the '90 3.0L Montero models had no EGR.

Frank

There are no wholes at all. This bear rib cage could have come of anything , this is a Dinsmore unit, nuff said

Now that I'm on a rent a computer I might have time to correct my spelling... <img src="/forums/images/graemlins/lol.gif" alt="" />

More thinking on this project that's too big for me...

Using the Dia entire eletric MPI sys,you have to fiqure out if the reed switch in the Dia speedometer has the same output at the same speeds as the Montero.
And those converters that mount to the Ex manifodfs, no way too twisted up , this won't work on a CA . I guess I could go get one in Nevada if it was that important to me. Nah. But it would probably be a good idea to get out of Kalifori anyway.

How did some of you out there do the Diamante DOHC swaps. One with Fed converter setup would be easier , put still seem nar impossible. Must have the patients of "Job".