DenzSS

Call Diamond Pistons--the link is on the right.

Tell them what you're doing and they'll set you up right. Eagle makes a rod for the LS1 that is in the sub-500 range that should work well.

y2khawk

iTrader: (5)

Ask for Chris

For SBC rods, just tell them what rod length you want to use.

Specify rod length, desired CR, etc and they will do the rest <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />

ws6rufus

iTrader: (6)

Thanks Alot
How do I know what length rod I need?
I plan on using the stock crank?
About how much are the pistons?

ws6rufus

iTrader: (6)

Now that I have put my deposit down on a LS1 Motorsport turbo I will need to build my 6.0L to handle the boost. Is there a "on the shelf" low compression piston for this application? If not where is the most economical place to get custom made pistons? Secondly I have read several instances of guys having pistons made to fit SBC rods. What do I have to do or specify in my order to use SBC rods?

AP-Engineering

ws6rufus - Give me a call, I can take care of you. I don't think that you will find a better price than ours and I have some LS1 stuff on the shelf. If not we can do a custom for you in less than 3 weeks right now. As for the rods, eagle does make a LS1 length connecting rod but, it is not on center like the LS1 stock rods. It is offset like the old SBC. Thunder Racing might be able to hook you up with those rods, call them and ask for Paul. If they can't get you a rod, I can get you the eagles. Just give me a call and we can dicuss this.

Thanks,
Chris Gelineau
Diamond Pistons
877-552-2112 toll free

ws6rufus

iTrader: (6)

Thanks Chris,
I will give you a call once get the 6.0L motor I bought torn apart and determine what over-size bore I need.

Ling_650vette

iTrader: (1)

What about forged 8.7:1 or 9.0:1 comp pistons w/ just the 4.00" bore? Got anything in that respect?

AP-Engineering

Those would be customs. I do not have anything on the shelf in that compression ratio. Thanks for the question.

Thanks,
Chris Gelineau
Diamond Pistons
877-552-2112 toll free

Tin Indian

Chris....

I have a friend that runs a bone stock 5.7 LS1 with a twin turbo setup.

He wants to decrease the stock 10.1 to 1 CR down to approx 8.5 to 1 in order to run more boost. (He is aware that the Turbo Buicks run 8.0 CR and upwards of 20 psi boost).

He has talked about getting 6.0L heads that have material CNCd out of the chambers and thicker head gaskets. That presents 2 problems; The CR will still be at least 9.3 to 1 and he still has to deal with the **** poor stock LS1 pistons. I think they will still fail over time if he runs even 10 psi of boost.

My question to you; Can we just get an economical set of dished forged pistons that will fit in a stock bore 5.7 LS1 and be hung on the stock rods. Basically just a replacement piston that will yield maybe 8.5 to 1 CR with stock LS1 5.7 heads?

I believe, as time goes on, many many of these folks that are running forced induction LS1s would certainly purchase these pistons as a fairly simple and safe way to run fairly high boost levels without big problems associated with weak pistons and high static CR.

Thanks,
Ron
_________________________________________

<small>[ October 18, 2002, 05:19 PM: Message edited by: Kimchee and Rice ]</small>

Ling_650vette

iTrader: (1)

Chris, how much would those 9.0:1 or 8.7:1 customs be? Not like i'll be buying anytime soon, but just want to know of a estimate $

SJH

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">I have a friend that runs a bone stock 5.7 LS1 with a twin turbo setup.

He wants to decrease the stock 10.1 to 1 CR down to approx 8.5 to 1 in order to run more boost. (He is aware that the Turbo Buicks run 8.0 CR and upwards of 20 psi boost).

He has talked about getting 6.0L heads that have material CNCd out of the chambers and thicker head gaskets. That presents 2 problems; The CR will still be at least 9.3 to 1 and he still has to deal with the **** poor stock LS1 pistons. I think they will still fail over time if he runs even 10 psi of boost</font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">8.5-1 is not needed unless your going full boogie race boost.And in that case your not going to want to press fit them on stock rods so why bother with such a piston.
The motor will be a slug without boost at 8.5-1.
This is not a weak port,small valved 6cyl engine like the old turbo buicks.
Those motors needed 20+psi to make power.
You put 20+psi in a ls1 with a little work and you should be close to 1000hp.
Your right about the stock pistons failing over time. They will. It's just a matter of time once you get that cyl pressure up a bit.
Although I ran mine for almost 3 years with 200hp+ shots of spray before I finally cracked one.

Any ls1 running a simple 9.3-9.5-1 compression well tuned with 10-12psi should be no problem and is a dead simple 600+hp motor.

All you need is a good 2618 alloy shelf piston with some nice deep valve reliefs, thicker top land, and the usual aftermarket piston machining tricks.
The wiseco .005" over 2618 LS1 piston is very nice. Perhaps Diamond has a similar offering?
I paid 457$ for mine.
Those plus a 73cc head with polished chambers and going to an even thinner headgasket(.041") to give the best possible squish(remember this a wedge engine and loves a tight quench) gives me 9.4-1 compression.
11psi is nothing for this combo.
I have yet to see even 1 degree knock retard after 50+ runs.
All dropping my compression another full point would have done was to make less power.
Stock bore size?
I also have to wonder why anybody unless they are on a very tight budget would not want to go at least .005 over? Unless they are starting with a new block.
Get a nice fresh round bore with a pro cut crosshatch for a good new ringseal.
It's only about 150$ or so.
Odds are you will need to rebalance the crank anyhow for a different piston/pin weight and most guys don't have a press to swap pistons either, so your going to have to go to an engine machine shop no matter.
Steve

Tin Indian

SJH ...

Thanks for the great info. Its folks like yourself that put the "Tech" in LS1Tech.Com

I am going to make sure my friend see's this post.

You know, it amazes me how the Turbo Buick can survive so well with 20+ boost and cast pistons. Truely amazing.

I owned a modified 89 TTA (Turbo Buick drivetrain- 11.89 @ 114 daily driver) and never had piston problems with high boost and race gas, although I did blow head gaskets until I had them "pinned" at Champion Heads. No flexing after that. Didn't seem to lift either.

Anyway, thanks for the insight...

Ron,

Brian Tooley Racing

iTrader: (13)

If anyone has interest we just finished our FI CNC chamber. It will go in any 5.3, 5.7 or LS6 head and gives 73cc chambers. I will get some pics and post sometime. Brian @ TEA

SJH

Thanks Ron.
I have great respect for the turbo buick crowd.
I learned a great deal from them. I built my 3 nozzle water/alky system from info I gathered from the Buick guys.
89 TTA, yeah I remember first time I saw one was when I got smoked at the strip many years ago by one when I first had my 5.0. Nice cars...

Here is a pic of my self ported/polished 73cc chamber 98 ls1 heads I am currently running.

<img src="http://www.tech-ls1.com/extras/chamber11.jpg" alt=" - " />
Steve

Tin Indian

Pretty.. <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />

I enjoy doing my own work too. And I am not a bad wrench! .. Thats a fact, but, I can say this; Put a die grinder in my hands, and I will ruin a perfectly good set of aluminum heads quicker than Hogans Goat! <img border="0" title="" alt="[Eek!]" src="gr_eek2.gif" />

AP-Engineering

Kimchee - I have a piston that we can make work for your buddy. It will give him 8.9:1 compression with 70cc cylinder heads. These will run $570.00 and will come with our 4130 premium pins and locks. These pistons are made out of 2618 aluminum and can take 20 psi of boost, no problem. I also agree with SJH, you should rehone the block to 3.905 bore just so you have a fresh surface to start with. I would also replace the stock rods and go with something a little better at least.

Ling_650vette - A custom set of dished small block pistons will run you $610.00 for the set and will take about three weeks to get done.

Tydriver

iTrader: (2)

If I can offer some advice, looking at the picture of that cylinder head I can say that 20 psi will probably be the limit (give or take a few PSI) for the head gasket. If you notice there are only 4 bolts around the combustion chamber. This is same as the GN's and the TTA's, they Buick 3.8Ls start to experience problems with seepage (ok they blow) after 20+psi. Sure there are peeps that have pushed farther on stockers than others and theres always that person who could push it to 35psi with 10* of knock <img border="0" title="" alt="[Eek!]" src="gr_eek2.gif" /> but realistically speaking you need to upgrade the gaskets if you really wanna push it hard. I realize that this is a little off-topic but just some thing to plan on depending on the amount of BOOST you want to run. Also, if you want to push it harder than 20psi consider having the heads O-ringed or switch to a copper headgasket (does anyone make them for LS1s?) The only reason I am "UP" on this dilemma is the fact that our engines and heads have 5 bolts around the combustion chamber and at our national even we had a dude pushing 26psi on the stocker head gaskets. With no issues, instead we blow connecting rods <img border="0" alt="[Banging Head]" title="" src="graemlins/gr_banghead.gif" /> So with that in mind, keep your Comp Ratios around 9:1 to be safe in a turbo motor running HIGH boost and you should be happy. This also adds to longevity of the engine, and fuel mileage, but then again, who cares about fuel mileage ?????

Tin Indian

TEA (Brian) .. Diamond

I will pass that info to him

Thanks,
Ron Larson (Korea)