Ok,
This mod works out alright with a stock cam. Rufustheram proved that for us... Unfortunately for me I found out the hard way that any cam bigger than stock will get you 4 bent intake valves <img src="/forums/images/graemlins/scared.gif" alt="" /> <img src="/forums/images/graemlins/zombie.gif" alt="" />
My smallest cam other than stock, had .430 lift and it hit. I may have gotten away with it if i used the newer 2.6 pistons instead of the flattops. But, I'll leave that for someone else to try...

Otherwise, the rebuild came out nicely with lots of power and topend using the orignal 2.6 head. Too bad the damn thing had a crack I didn't know about <img src="/forums/images/graemlins/zombie.gif" alt="" />. Got my replacement 2.6 head on it's way. I'll update later on the results.

shoootz!

Ton

Maybe a head shim would have worked. One of my Isuzu buds put a 2.3 head on a 2.6 and used a .020" shim purchased from a local machine shop. He said it ran great.

The shim would alleviate any clearance problems (up to a point, of course, with higher-lift cams), and also compression issues with the 2.3's smaller chambers atop a 2.6.

Just a thought.........ed

It's Alive!

I decided to go with a rebuilt 2.6 head. I figured I could use the cams I have with the benefit of bigger valves and port size.
I had a slight problem during the break-in period. I actually snapped the #2 valve spring in 2 pieces. I had used a set of springs from a Toyota 22R I had lying around. I ended up changing them all back to the factory Isuzu springs last night. Hopefully they hold up without any valve float.

Houlster~ Thanks for the engine mounts! I've only got the drivers side installed for now. Outstanding craftsmanship!

Can't wait to lay down some runs... <img src="/forums/images/graemlins/cheers.gif" alt="" />

Finally got some runs in <img src="/forums/images/graemlins/smile.gif" alt="" />. I resolved the valvetrain problems... Best for the day was a [email]15.7@83mph.[/email]

Rebuilt 2.6 longblock, stock compression with all the bolt-ons from my 2.3. I'm a believer of "there's no replacement for displacement". This motor has got lots of potential. I can imagine when I get around to bumping up the compression and doing some head work.

So In theory you could put a 2.3 head on a 2.6 block, and it would run alright as long as you used the stock 2.3 cam, is that what your saying???? I'm interested in this, mialy because I'm looking to get as much power(within reason) possible out of the 2.6 swap that I'll be doing next year. I know that the 2.3 head will make the compression jump up a bit , will this have ill effects if I have it bolted to a .020 or .040 bored 2.6L block??? or would I just be better off with a 2.6 head if i'm going the bored route?

sorry for the long post, but i'm really interested in this setup <img src="/forums/images/graemlins/kewl.gif" alt="" />

Yes, you'll be ok with the bored out 2.6 block and 2.3 head. You could actually use a bigger cam with the aid of a head shim but, that'll defeat the purpose if you uping the compression to begin with.

Ok thanks for the info <img src="/forums/images/graemlins/kewl.gif" alt="" /> <img src="/forums/images/graemlins/kewl.gif" alt="" /> <img src="/forums/images/graemlins/kewl.gif" alt="" />

*update*
Sad to say I dropped #4 valve guide on 1/7/06 race day. This was the guide I replaced when the valve broke last time. I mis-shifted into second gear and it revved out past 8000rpm before it fell. Luckily the valve stayed up with out hitting the piston. The piston on the otherhand has some major battle scars from the guide exploding <img src="/forums/images/graemlins/zombie.gif" alt="" />.

Ran a 15.500 @ 84mph before it broke... <img src="/forums/images/graemlins/evil.gif" alt="" />

Anywho, back to the 2.3 head on the 2.6 block. This was the only spare I head I had so I decided to do, what not to do... I made my own valve reliefs with a die-grinder and 1-1/2 cutting wheel (sorry no pics, needed the truck done asap). Valves clear the pistons now, hope it holds up for the next race.

What I need to find out now is my compression ratio. Can someone help me out with the math?
2.3L head shaved .25 thousandths, stock 2.6L block (flattops). I'm running it with 6 degress of ignition timing (advanced) on 91 octane and 2 degrees of advance cam timing to make up for the shaved head. Runs real good, but I think I need a higher octane fuel to get the best out of it.

Wish I had taken pics of my port/polish job. Polished out the combustion chambers and smoothened out the transitions <img src="/forums/images/graemlins/kewl.gif" alt="" />.

<img src="/forums/images/graemlins/cheers.gif" alt="" />

What I need to find out now is my compression ratio.

You might find some calculators on the internet that will get you close, but...you really need to know CC's of the head, head gasket thickness, bore, stroke, CC's of the piston and/or just total CC's at TDC for the cylinder. My wild guess is it is going to be high. Maybe too high. Compression test it, while there is some relation between that and CR, (a lot depends upon timing) you will know if you are close or just way up there.

How much smaller are the combustion chambers on the 2.3? If it signifigant. I would start that puppy with the timing retarded, run some high octane gas and be careful as you tune it. Without a knock sensor, by the time you hear detonation, it will be too late.

Good Luck,
Michael

The 2.3 chamber is significantly smaller, I also noticed that the 2.6 valves are shorter about the size of the keeper recess (about 1/8th of an inch). I was going to use the 2.6 valves on the 2.3, luckily I double checked the length otherwise the springs would of binded.
I think the shorter valves on the 2.6 makes up for the deeper chamber whereas the 2.3 has a shallower chamber needing a bit longer valve. Valve angles on both heads look to be the same tho.

I did initially start the motor retarded. It ran a little sluggish at first, it's at 6 degress advance right now on 91 octane pump gas. I'll play around with the timing some more after I find some race gas.
What do you think 100 or 110 octane? I was thinking of the 110 to be more on the safe side...

I haven't done a compression check yet, last time I did one was on the 2.6 head and i had 120psi across the board. I know it's kinda low, that's due to the cam profile I have in there. I did gain another 15psi when I installed the adjustable timing sprocket to 3 degrees advanced <img src="/forums/images/graemlins/kewl.gif" alt="" />.

I'll try to get a comp test done and maybe I can get a ballpark figure based on those numbers.