My car went down 1 1/2 years ago due to a blown head gasket. I am just now able to do what i have been wanting to do for quite a few years now. My heads have been to the shop for cleaning and resurfacing.

1. When they were at the shop they had to take 10 thousands off the heads to make the true again. Factory head gaskets have a thickness of .049. The replacement gaskets i will be using are .039. So with 20 thousands less, what will this change my compression to?

2. Believe it or not, small town iowa where i live the best fuel is 89 octane. The next town over has 91 or 92 but is a inconvenience. Because of the increase in compression, will i have problems due to the 89 octane?

3. If my concern with #2 is a real porblem, will taking the time to polish the head's combustion chambers to remove the casting flash be enough to fix the problem? Or what can be done?

4. My Camaro is a 96 with the stock water pump. Is the the timing chain set i should use? https://www.summitracing.com/parts/clo-c-3039

5. I am looking into using this springs with a cc503 and NSA 1.6rr.
https://www.summitracing.com/parts/lun-73925k5
will these be a good choice. I am aware that i would probably have to use +.050 locks with them to get them to the proper heigth.

thanks.

 

The Lunati springs are very good...and I use them with a Comp Cam. The CC spring spec for my cam were 918....Like several others I had one break

Lloyd Elliot is who recommended, and I purchased from, the Lunati kit.

The kit comes with 7 degree locks & retainers so if you can get the installed height with those, great. My heads already had the spring pockets machined down to accept a 1.800" installed height. Lloyd advised I set these up for 1.780" so I used shims where needed under the spring locators. Use a spring height measure tool to determine if you need different locks & retainers

 

If the picture shown in that link is an actual photo, that is the correct replacement for the 95-97 vented Opti cars. The cam sprocket has the gear teeth to drive the water pump. The hole for the Opti shaft is larger and does not have spline teeth that would be on a 93/94 unvented unit. The “Application” tab confirms it’s for a 96.

My 94 owner's manual, and the 96 manual both say that with mid-grade or regular, “your vehicle may not accelerate as well.” That's different than “avoid rapid accelerations". Why not use a stock 0.049” gasket to minimize the issue. Or, keep the 0.039” gasket, and use a real time scanner to see whether you are actually experiencing knock retard? Consider a 160° t'stat and reduced cooling fan on/off temps to minimize knock. And, what is the elevation where you live? The higher you are above sea level, the lower the octane requirement. Gas stations in high elevation locations don’t carry the high octane fuel because it’s not required.

Lunati springs are fine.

Another thing I forgot to mention. There is a “low octane fuel” flag that sets if the PCM sees extended periods of knock retard. I think this defaults to less aggressive ignition timing. And reportedly in the LT1 cars, it takes some time for the PCM to self clear that flag when there is no evidence of knock retard. Not sure what triggers the clear/reset, but the point is if you have been running 89, and the low octane flag sets, just driving over to buy some 91 may not show up as improved performance immediately.

https://www.camaroz28.com/forums/lt1...octane-399127/

 

thanks for the reply. Im not sure what the elevation is. I would need to search for it. But i like in northeast iowa. Zip code 50630.

Currently for mods i have is PS full length headers, no cats, X pipe with bullets. CPT built trans with a Yank 3200 SS stall, k&n cai, lt4 km. 160* stat. 4.10 gears. Pcmforless tune. 12.83 1/4 mile, 1.83 60 foot.

 

Your at an elevation of ~1,100-ft above sea level. Standard barometric pressure is ~97.3 kPa, compared to 101.3 at sea level. That means the air where you live is only 96.1% as dense as air at sea level. In effect, an 11.0:1 static compression ratio will behave as if the CR is only ~10.6:1.

As a result, the power the engine makes will only be ~96% of what it would make at sea level. If you put it on a dyno, they will calculate the HP based on SAE or STD corrections, which tells you what the engine would make at sea level.

An additional consideration is the size of the cam you are putting in the engine. The fuel octane requirement is determined by the dynamic compression ratio (DCR), not the static compression ratio (SCR). In simplified terms, the more valve overlap on the cam, the lower the DCR.

 

the cam i will be installing is a cc503 with 1.6rr.

Last night i removed removed the hub off the crank. I had the arrow on the hub in the 12 o'clock position. Is the arrow on the hub supose to line up with the crank sprocket timing dot?

 

assuming the hub has never been off or if it was it was put back on exactly as it came off the pointed spoke would be at 12 o'clock with engine at #6 or #1 TDC....but since it is not keyed, and has a neutral balance damper, it does not matter mechanically which orientation it is on

so if it lined up with the cam and crank sprocket dots either at 6/12 oclock or 12/12 respectively...than it was on as installed from factory

 

i have never had the hub off before. I removed the hub in the 12 o'clock position and after removing the timing chain cover i noticed the crank sprocket was in the 10/11 region.

 

As noted above, position of the hub on the crank is not critical. But to get it where it (technically) belongs, see if this helps, courtesy of Shoebox: