This is truly a can of worms, as far as dimensions go.

I feel like I have a good idea of what most of the Eastern US racers, and many others, run in their motors, as well as those on this site.

As much as I would like to see a 7.3-7.45" rod with piston to zero deck, there are quite a few people using the 7" rod with various pistons (including customs already designed from several manufacturers). LOTS of people are running "street-strip" cars that will likely go with a 7" rod too.

Make sure you put valve reliefs in for valves up to at least 1.76"/1.5".

I would vote for making a 7.030" rod as Doc suggests, since this will be a nice step up from the factory 225 rod and will access the largest market. If the heavies want a 7.4" rod (like me), then that might be offered at a higher price later, after the 7.030" rod/piston combo is selling.

I am in for at least one set of rods/pistons/rings at whatever rod size. Let me know when they are available - I'm fired up!

Best,

Lou

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Home of Slant6-powered fun machines since 1988

Guess I'm at the wims of puplic then. Brain did say he had a piston the would work prefect with a 7 inch rod that they make already so thats an off the shelf part. But I think he wants to do a set up with out using a 2.2 piston as a base and give us a piston just for this application. Oh well I wait and see what is going to happen with everyone else changing rod sizes from this to that, but remember Tom makes the rods and Brain does the pistons so I think Tom is the key in finding out what rod we will get.

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it's like a vw, sounds like a million miles an hour but goes really slow. (for now)

Why not just make a 7" rod to use with the off-shelf piston at a low package price ($1000), then do a 7.4" rod/piston package at $200 more for the package? Seems like that would satisfy everyone.

The racers will likely pay $200 more since $1200 is still pretty affordable.

The other question: How much mass do we save going from a 7" to 7.4" package?

Best,

Lou

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Home of Slant6-powered fun machines since 1988

Did Lou get everyone dumb founded?? Well thats what Ive been tring to explain this whole time. A 7 inch rod for the street and something longer for racing, heck if my street motor works out well I may build a race motor. Then again if it is a toad well its small block time . But at lease we now have someone willing to build us bottom end parts for street and racing applications.

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it's like a vw, sounds like a million miles an hour but goes really slow. (for now)

When you say "7 inch rod" do you mean the 7.005 center to center, that the factory made or a true 7.000?

I think we are at the point were it is simply a matter of getting a price and delivery date so people can place orders. (for whatever length they are making)
DD

Oh well, I just found a 198 here local for free. That pretty much just took care of my rod needs for a 7" rod.


Jess

Well I think that if we are indeed going with a 7 inch or a 7.005 that is maybe spiltting hairs. The way i see it if there is a piston on the shelf that will work with both sizes any way you shake it really is win win. I'll call Tom and ask if there is a major under takeing in changing what he has for the length of the rod.

At some point a greater rod angle maybe over kill for some builds, not all, but I don't belive that a longer rod made for slant wont have a market. I know this may sound bad, but I mean it in a good christian way, I want what I want but at the same time I belive everyone here can profit from my undertaking in this. I do think, that if everyone agree's on the 7.005 or 7 or what ever we will make this get along faster. The stall in this project is that everyone, to coin my fraise, wants what they want. at times I wished I'd done it first and then told everyone. Everyones input is important though because we need to find the middle ground to take care of the largest group of builders. We'll see what happens I guess.

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it's like a vw, sounds like a million miles an hour but goes really slow. (for now)

Is it too late to add a poll to this thread? I guess i'm with Lucky on this, if I could find a 198 (I haven't been looking that hard), I wouldn't need rods either. Now a new rod/piston combo that was never offered before based on modern tech... that is making the cost look real good!

My vote is for 7.4 with matching piston

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We can add a poll to this thread if the originator of the thread wants that.

Yes, that is alway the choice. Either put your proposed project out into public view and take all the comments and "cross-talk" or keep the project "under wraps" until you do all your development and work-out the "kinks", then present it to the world.

I tend to do it both ways but lean more towards the "develop on my own" side of things these days. Don't get me wrong, I do seek-out "advisors" to help check my math and thinking but I keep the "in the know" group pretty small.

As for asking for design input from the public "at large", (internet forum) you just have to expect a wide range of ideas and needs. (especially from this group)
Looking back at your original post I don't think you were after design input but somehow, that is the direction the topic went.

Anyway, my "hat's off" to anyone who trys to get aftermarket parts made for the SL6, it is never easy. Please do not take any of my comments or postings as "judging" or criticism, I am simply trying to share the knowledge I have gained from building these engines, in order to get a design that is based on as much information (facts) as possible.

Oh, I also have a correction, I double-checked the center-to-center on the factory 198 con rod, it is 7.006 and the .006 is in the direction we should be going. (longer)
DD

Thanks Doc. Well I couldnt talk to Tom today I was busy and I'm sure he was as well. in giving the spec's I worked out with Tom to Brain they have a piston that will work with a "true" 7 inch rod and with stock head and gasket would yeild a 10.25/1 compression. I thought it a bit much but as we talked I gave the valve reliefs as a way of easing the compression down to 10/1. Brain seemed to like the idea and at that point he came on to here. So like I said we'll have to wait and see. I call again tomarrow and give an up date for everyone.

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it's like a vw, sounds like a million miles an hour but goes really slow. (for now)

I like round numbers. You can always deck/mill 0.006" to get back to where you were with factory 198 rods, if using them previously. 7.000" is my vote. 10:1 with valve reliefs sounds perfect to me, and easy to adjust with milling/decking in fairly small amounts.

I assume you are using a Felpro gasket as your gasket thickness (0.032-0.035") or one of the Aussie gaskets (0.045"-0.048")?? No one will use a stock steel shim (0.020-0.022") gasket.

Personally, I would do those calculations for the FelPro gasket at 0.034", which is what most people use, or there are many gaskets with 0.040" - 0.050" spec, so could design for 0.045".

Lou

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Home of Slant6-powered fun machines since 1988

7.000" Done. Let's go.

Lou, I am running a Aussie head gasket I got one from one of our gracious slanters in OZ . But in using .039 as a ref to match for a average build. Not everyone has aussie gaskets or steel shims, so the Fel-pro gasket is the base for my compression info. I belive Brain used that # as well,the.039, when he used his wizard computer to figure it out at 10.25/1 without reliefs.

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it's like a vw, sounds like a million miles an hour but goes really slow. (for now)

Sounds perfect!

Lou

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Home of Slant6-powered fun machines since 1988