SuperSporttruck

iTrader: (2)

Hi,

I just got a couple pics back of my heads after coming back from the coaters. The problem is that the heads needed to be opened up to get the desired compression ratio, but instead of removing material form the chamber itself, they killed the qunech area. I need some advice on if this is going to run like **** or if will be acceptable. I will have to say noway pretty soon before the motor goes together any further.

SuperSporttruck

iTrader: (2)

the space is .060 deep and the quench is suppose to be .035. compression is suppose to be 11.27 to 1 on 91 octane

gollum

iTrader: (1)

Who did this work and what was their reason behind it?

SuperSporttruck

iTrader: (2)

The reason was to lower the compression, but I thought that they where going to open the area around the valves larger in order to make the combustion chamber larger, not make this little notch ???

zo6vetteman2003

iTrader: (1)

What type of heads are they? What pistons are you using in combination? This is that 408ci. I assume.

SuperSporttruck

iTrader: (2)

RHS 225 head, 408 with a flat top diamond piston with -2 valve relief

racecar

In terms of .035 quench, this is a crisis of biblical proportions. It does not look good, but heads like this have been used for years on other cars, don't kill your head guy, just tell him this is not what LS1 guys think works best. The real question is the dynamic compression ratio. If you are going to run 11.2 compression on 91 oct, what is the Dynamic compression? You need to be 8.5 or less DCR.

SuperSporttruck

iTrader: (2)

DCR is between 8.36 and 8.40, I just don't want to have any problems with detonation or running timing when it comes to tune this thing. I trying to figure out if I should say something about this, and try to get him to rectify the situation somehow, but the heads are coated already, and I didn't see the heads before the went to the coaters.

zo6vetteman2003

iTrader: (1)

I wouldn't think you will have a problem as long as you use premium fuel and pay attention to keeping the engine's cooling system running efficient under normal maintenence.

Slowhawk

iTrader: (12)

I've never seen that before on a LS1 head.Don't know if it will work or not but I wouldn't use it.

zo6vetteman2003

iTrader: (1)

I've seen the coatings but in higher compression applications. Hey sent you a PM.

SuperSporttruck

iTrader: (2)

Any engine builders have a comment on this combustion chamber ??? I talked to the guy building the motor, and He seems to think that this isn't going to be any more prone to detenation. As apposed to having left part of the quench pad there, and just removing more material around the valve in the center part of the CC.

1989GTA

Looks like they cut a groove around the edge of the "quench area". Also looks like the main portion of the quench pad is still intact. If this is true it may still work.

I have seen where people have cut grooves in the quench area to enhance combustion. The ones I have seen were straight lines radiating out from the combustion chamber. Whos knows this might work even better.

PREDATOR-Z

Funky,

I personaly don't like it. You have a dual quench area. So one is .035 and the other .095 ??
Perhaps i'm wrong, but it doesn't make sense to me. Practicaly they negated your larger quench area.

PM someone in the head business, like Tony Mamo, or Brian at TEA.

gollum

iTrader: (1)

Any good lawyers reading this post. I personally think his high dollar heads are junk now. NO QUENCH !

Brian Tooley Racing

iTrader: (13)

Many people on here have never experienced grossly wrong quench and the effects it can have on an engine. I am 42 and have been hot rodding since a kid, so I have seen some crap. My first big SBC was a 400 bored .060" over, I got it cheap, put some ported stock castings on it, intake, carb, etc. This thing would detonate like crazy with 9.5:1 compression. I then read about the quench distance being so important and about how increasing the quench above .050" could INCREASE the tendency towards detonation even though the compression would DECREASE. I knew my quench was .080" (that's right, pistons .040" in the hole with .040" gaskets) so I thought this might be the problem. So I built another 400 engine, "0" deck, smaller chamber head, .040" quench and 10.5:1 compression and it would run on 87 gas. There is a point you get to with quench where this detonation tendency starts going away again, but I think it is around .200"

Long story short, and I know I'm about to cost some poor business person some trouble, the heads are almost junk, unless you mill them till the deck is flat again and you buy pistons, which is probably what you should have done to start with.

SuperSporttruck

iTrader: (2)

Yes, one is .035 and the other is .095, I don't get it either.

redtail2426

iTrader: (10)

yeah that kinda sucks IMO

PREDATOR-Z

Yeah that is what I thought. .065 mill on those to fix is a lot (too much).
If I were you, I would get a full report by another LS1 head shop and present it to your shop for full refund.
If they do not comply, then to the courts you go.

Advice: Do not use this shop anymore after that.

racecar

They thought that they were doing the right thing by giving you more volume.
Obiviously they are not LS1 tech freaks and they do not understand the importance of a tight quench. That's a theory that has become popular in the last 5 years. Yes, your heads are screwed. If you take them to court it will be a matter of what you told them, was it in writing, open the chamber, not the quench. They are going to say that the heads are fine, and you are going to have to take the judge for a run in your car to show him that it is pinging at 8.2 DCR.