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Things I can think of is possibly the LO head has a larger combustion chamber to lower the CR, but then again with the dished pistons that may not be necessary... I'm not sure since I've never worked on a quad. But otherwise Ace is right, the 086's just flow much better than the other heads for one.

Jon, you are correct. I was making educated guesses in the other post about the cams. However , and Geoff (90gtzho) will back me on this as we've spoken about this on the phone many times, I've always said while the motor has all this LO stuff on it, it always PULLED like an HO. Meaning it kicked into it's power band just under 4k RPM. LO's DO NOT do that. They have a flat steady power curve.

Now, if you read above, I've actually had a chance to physically LOOK at and MEASURE with a micrometer the cams in the car , whereas before I was making a hypothesis. They are FOR SURE HO cams. They measured out at the lift of .410 , actually a tad higher than that to be honest. I'd say they were "new" cams in the reman.

So yes, better head (much better) , new head gasket , and correct HO pieces such as the crank pulley etc. as stated above. This motor was a mix of LO and HO parts. I'm correcting that, and performance should see a SIGNIFICANT increase with the better flow and correct HO parts.

ronaconda wrote:What is the difference in the LO head and the HO head???

And you had mentioned also in the other thread that the LO pistons were dished...but with no valve reliefs. Is the only difference in the HO pistons valve reliefs???

(Not criticizing... <<< quad handicapped!!!)

Main differences? Intake and exhuast port sizes and flow. The 086 head flows a good 200% , or more, better. The 456 head is VERY restrictive.

As to the LO and HO pistons, dished LO pistons create more cylinder room , thus lowering compression. LO motors only have 9.5:1 compression whereas the flat top pistons (not quite truly "flat) seen in my engine create a 10:1 compression ratio. The valve reliefs are necessary at that point to ensure the higher lifting HO cams don't cause the valves to make contact with the motor under WOT and hard acceleration scenarios.

So, big differences between pistons are: compression, dished vs flat top, and valve reliefs.

My valves made their own reliefs when I had a stretched timing chain... LOL

3X00-Modified wrote:My valves made their own reliefs when I had a stretched timing chain... LOL

3X00-Modified wrote:My valves made their own reliefs when I had a stretched timing chain... LOL

ROFL. The pistons in my '91 Grand Am LE HO looked that when I got it. They messed up the timing and the exhaust valves tapped some light "reliefs" in the rears of the pistons, rofl.

Well, slight delay problem. The 456 valves are JUST slightly thicker in the stem than the 086 head accepts. Same diameter head and overall length on both heads, but .015 thicker in the stem. JUST enough to keep them from sliding through the valve guides in the head! I was like, you gotta be shittin' me FFS.... they sell BOTH sizes for BOTH heads.

You can buy .2745 stem thickness (which is what the 086 head requires) or .2895 which is what is in the 456 head. But both heads share the same diameter head and overall length....

The reason being , once again more proof, this is a reman motor. Valve guides were bored out and valves oversized .015 to fit.

In other words, at one time both heads had the same size valve, but the 456 head has (obviously since it's on a reman motor) been gone through and had the valves oversized....

But , a friend is sure he has what I need and will be mailing them to me. So, a few days to take care of the other odds and ends until my "new" valves get here.

Paint the blower motor cover.

Clean that nasty ass intake.

Clean that nasty ass Alternator.

Etc,etc,etc,etc....

SuzukiGhostRider wrote:

Interesting look at a quad opened up. I've never had one apart. I take it these are the lifters? Crazy stuff for 80's technology.

Sounds like it will get fixed at least. Man SGR, someone needs to teach you how to use close up/macro modes on your camera bud! lol

Yeah, the bucket lifters were ahead of their time as was the Quad itself.

I know Ace. A photographer I'm not. Even with a 10.1 MP camera I still take fuzzy pics,lol.

Ok, ladies and gents. So , today's progress left me in a VERY good mood! Yayyyy!

I took the blower cover off, and below you will see as removed (before) pic, primered, painted in black, clear coated, and two re-installed shots. Quite happy with how it came out. To the critics, I'm no Ar-Teest, but I did pretty good I think.

Also, cleaned up the intake. While it's MUCH better, I'll be doing a little more "detail cleaning" to it prior to re-installation. One before, one after pic. I should have taken a shot of how much nasty crap was in the rinse puddle as I was hosing it off. NASTY! Wonderful what a $2 can of walmart degreaser can do along with a tooth brush and some elbow grease!

Pics. Enjoy.

I was looking at the inner timing cover and I do believe I will do it tomorrow. It definitely could use new paint. Get that done and my motor put back together and I'll be one happy mother trucker!

I gotta say though, I think that painted blower motor did WONDERS for the under hood looks!

Painting the blower cover is the biggest change you can make on these cars, Granted mine wasnt bad, but I sprayed it with a textured paint and it worked out great. I used textured stuff because I did not feel like trying to get a perfect finish on it.

Obviously a bit more changed, but to not have that rusty hunk back there looks much better.

Before


After

One thing you should do there SGR, when you get it back together, hit that bay with some high pressure/steam or something. It needs a bath! lol

Looking good.

Oh, yes I agree Ace! My intention is to get the bay cleaned up before I'm all done with a good degreasing. Even with my leaks stopped up, this car leaked long enough apparently , that it was NASTY in the hidden areas. I work on cars for a living and I was still shocked at how filthy I got tearing this car down.