Any body have any experience monitoring detonation while tuning individual cylinder timing?

Which cylinders tend to detonate first in the LT1? Is this different than a sbc?

What is the timing difference between these cylinders?

Additionally, if individual timing control is not possible, what amount of power, if any, is lost just retarding the overall timing to bring the wayward cylinders back inline?

 

Good question.... I'll throw some thoughts at you later.

I would imagine that the LT1 has a bigger difference in good and bad cylinders in this reguard than a SBC, but basically the same would be good and bad.

Bret

 

Because of the intake design?

 

...probley more due to the valve spacing relative to the bore centers. It's just a specuation on my part.

 

I'll get back to this after I work out tonight hopefully....

Yeah the port layout plays into this, but more like the exhaust port layout.

Bret

 

Comon problem on SBC/LT1's is the center two exhaust ports.... They cause really hot coolant temps between them. So the exhaust valve side of the chambers in the center two cylinders is really hot, and can cause hot spots there so those holes might want less ignition lead.

I've seen some interesting coolant setups on SBC's..... (BTW Fred or Ken this would be good to merge with the reverse cooled SBC thread here)

Here is a good pictures of a reverse cooled Chevy....

http://popularhotrodding.com/enginem...r_emc_33_z.jpg

I've seen a few like that setup.

There is also another picture I have on my computer which if someone would host would be cool. It's the #2 motor in the 2004 Engine Masters that DEI helped with. Instead of plumbing coolant thru the heads they plub it into the block in between the middle two cylinder bores half way up the block. They pushed it thru there and out of the cylinder heads at the ends into a water manifold. I have to think that this gives equal cooling to the cylinders.

Only real way to tell is with thermocouples all thoughout the heads.

Actually I like the plubing to the ends of each head without a coolant crossover in there and running a small line to between the center two cylinders exhaust ports from the other side of the head. The LT1 is a little difficult because the back cylinders have to be hot as well getting warmer coolant to them. I'm still figuring out how to do that well in a LT1.

The only way you really lose power in timing is when some cylinders are hotter than others and they need less to stay out of detonation. If you can prevent that and have identical cylinders then you should be golden.

Bret

 

I appreciate the thought and infomation about the effects of coolant temperature on individual cylinder performance.

I was thinking there might be a cylinder imbalance more along the lines of uneven air flow to the cylinders creating a difference.

Additionally, combusiton chamber final configuration depending on the tolerance stack up during machining and assembly, could cause a difference.

I'd still be interested in timing differences between cylinders to accomodate any differences reguardless of cause and the potential effects on power production and detonation.

A little more of what I know, MSD appearantly makes a device that provides up to 6 degrees of individual cylinder timing control. Stock car boys appearantly file the edges of the cap to retard individual cylinders (where electronic timing control is illegal).

 

Stock car boys appearantly file the edges of the cap to retard individual cylinders (where electronic timing control is illegal).

 

I meant to say the edges of the individual cylinder terminals under the cap.

Additionally, MSD has a unit that is encased in the distributor housing for stealth type applications.

 

Bret -
If you send me the picture at; ericscher-at-mac-dot-com, I'll host it for you.


(My address is written that way to avoid e-mail harvesting robots. Just convert to the proper "@" and "." symbols.)

 

I'll e-mail that to you later tonight I don't have it at the shop

 

This ploy will do nothin' to affect or alter the timing.

 

yep they can just bend the reluctors in a regular setup.

Any real endurance Chevy making any kind of power has all the center water modifications done to get more water between those seats. You will lose the heat treat there on the heads pretty fast otherwise. There many ways do do it.

 

MSD makes a thick reluctor that allows machining it down to relocate each cylinder trigger point to be moved a few degrees either way.

 

Huh, if I’m seeing right he’s pumping the coolant in through the 4 corners of the intake and through the normal inlet on the front of the block, unless those are blocked off. Is that right? If they were blocked off it would almost make sense to just remotely mount the pump…

The only return appears to be from in between the center 2 ports which goes straight to the thermostat housing…

If you haven’t found a place yet, email it to me and I’ll put it up someplace for you.