19 replies to this topic

[Jamz14]

I guess I'll start by asking:

 

Why aren't we allowed a 2nd overbore?

[chris haldeman]

Because blocks are cheap and we hear enough bitching about the first overbore.

[Jim Drago]

I agree, absolutely not needed

If you need a block james I’ll give you one, just pay the shipping

[Jamz14]

Jim,

 

Awesome! Thanks. I need 3 99 blocks and cranks that are good for a standard or 1st over bore.

[chris haldeman]

Blocks are cheap. Good cranks that is another story$$

[Jamz14]

Ah, ok then. So, expensive cranks, no more model years or parts coming into SM, what is so hard about allowing the 2nd over bore when the formula for the overbore power increase is so well accepted by people? Just add another 15lbs right?

 

I don't think that is true myself. I don't think builders can get the same linear power increase on the 2nd overbore as they can get on the first. That is my guess.

 

But if that is true, why not allow it? Guys doing the second would be down on power and carrying additional weight.

[chris haldeman]

Cranks are available new from Mazda last I looked. All I meant was that either Jim or myself would give blocks away. The reason for that is we tear down piles of light over heats or rod knock engines ect. Blocks are not damaged anywhere near the rate that heads and cranks are. Thus we end up tripping over blocks that we don’t have heads or cranks for

[chris haldeman]

Also cranks can be turned .010,.020,.030 under to restore bearing surface

[Jamz14]

Ok. I thought the last I looked cranks were not available.

 

Still need 1 to 3, 99 blocks and cranks. Price?

[RWP80000]

Ah, ok then. So, expensive cranks, no more model years or parts coming into SM, what is so hard about allowing the 2nd over bore when the formula for the overbore power increase is so well accepted by people? Just add another 15lbs right?

 

I don't think that is true myself. I don't think builders can get the same linear power increase on the 2nd overbore as they can get on the first. That is my guess.

 

But if that is true, why not allow it? Guys doing the second would be down on power and carrying additional weight.

I disagree with your claim that you "don't think builders can get the same linear power increase on the 2nd overbore".  In reality, you actually gain a slightly larger increase in additional displacement for the additional .010 in of overbore along with a slight increase in actual compression ration (which rules still required to be met for the C.R. specification as listed in the spec line chart.  

 

The other issue I see is you start adding weight and now a VVt that is already up to 2440, at first overbore, is now up to 2455.  The weight disparity is starting to impact the cars in terms of braking ability and tire load capacity. I suggest it is better keeping the cars as close to the standard bore weight limits rather than adding an additional total of up tp 30 pounds across the spec lines.

 

My recommendation would be to change the rules to allow blocks that are worn or damaged to be sleeved back to the original bore diameter.  This would allow saving a worn block along with any in decking or other machining ( i.e. line boring) done to obtain required compression chamber volumes. The rules could require that "sleeved" blocks be limited to "only"  the original/stock bore.  This would keep cars at the lower weight classification specification.  If necessary, a worn "sleeved" block could be re-sleeved in the event of a scored cylinder or just from plain wear over time.

 

Given that there currently seems to be an abundance of "useable" block core's, it may not be necessary for any rule changes at this time but introducing the 2nd overbore does not seem like a legitimate need or in the best interest of the Class.

 

Rich Powers 

[Steve Scheifler]

You may recall that we were previously allowed sleeving, then the cheater in chief started using “special” sleeves or at least claiming to and making extra power from those. As I recall there was then a change to allow only plain iron sleeves, and later switched to overbore and no sleeves. From a build cost this is the lowest cost and will be until blocks become scarce. So as you say, for now there seems insufficient cause to make a change.

[Jamz14]

Thank you all and agree. If I can get good blocks and cranks that can handle the first overbore, then I see no need in the second.

 

Based on how I do an engine, I don't think I can legally get the same additive power increase on the second overbore that I can get on the first. What I mean by that is this:

 

Lets say on the first over bore I can get 1hp gain over the standard bore. For the second over bore I don't think I would legally be able to get 2hp.

 

I don't really want to get into why I can't. With some research it might be possible I just haven't had the need to look into it deeper as we don't allow the second over.

 

Again, thank you all for your comments.

[Jim Drago]

Ah, ok then. So, expensive cranks, no more model years or parts coming into SM, what is so hard about allowing the 2nd over bore when the formula for the overbore power increase is so well accepted by people? Just add another 15lbs right?

 

I don't think that is true myself. I don't think builders can get the same linear power increase on the 2nd overbore as they can get on the first. That is my guess.

 

But if that is true, why not allow it? Guys doing the second would be down on power and carrying additional weight.

Considering there is no "real world"  definitive linear power increase from standard to first overbore, you would be a fool to take 30 lbs for it.  

I have seen zero evidence that simply going .010 adds any power whatesoever.  

first block no charge.. each next bock $150 each plus shipping, should hone std, definitely .010

 

 

 

 

My recommendation would be to change the rules to allow blocks that are worn or damaged to be sleeved back to the original bore diameter.  This would allow saving a worn block along with any in decking or other machining ( i.e. line boring) done to obtain required compression chamber volumes. The rules could require that "sleeved" blocks be limited to "only"  the original/stock bore.  This would keep cars at the lower weight classification specification.  If necessary, a worn "sleeved" block could be re-sleeved in the event of a scored cylinder or just from plain wear over time.

 

Given that there currently seems to be an abundance of "useable" block core's, it may not be necessary for any rule changes at this time but introducing the 2nd overbore does not seem like a legitimate need or in the best interest of the Class.

 

Rich Powers 

 

We are already making/changing too many rules for little to no reason.   Sleeve? Sleeving is a permit for us to do things you don't want done.... We got rid of this for a reason. It also costs more than a replacement block. Absolutely a terrible idea. 

 

This is simple.. the rule is adequate as written.. End of story!  Once in awhile you guys need to let the dam worm float by. 

Once again we have one person asking.. One person is in no way something that needs to be addressed IMO. This is not a problem. It is one persons opinion.   

[Brandon]

We are already making/changing too many rules for little to no reason.   Sleeve? Sleeving is a permit for us to do things you don't want done.... We got rid of this for a reason. It also costs more than a replacement block. Absolutely a terrible idea. 

 

Forgive my ignorance: what can be done w/sleeving specifically that is is discouraged from an allowance perspective?

Making the block more rigid or improving the sealing surfaces or something?

[Tom Sager]

Forgive my ignorance: what can be done w/sleeving specifically that is is discouraged from an allowance perspective?

Making the block more rigid or improving the sealing surfaces or something?

I'll keep the answer to myself but I had a 1.8 built in 2010 with a sleeved block.  The rule as it was written then allowed a range of sleeve material choices and some other clever builder wiggle room.  Legal then.  I spent at least $8000 for that engine.  Worth every penny.  Ran it from about 2010 - 2013.  It was an absolute beast.  There was at least 1 other similar engine out there built by someone else and the rule got changed IIRC after there were some eyes on it. 

 

We don't want that capability and cost coming back into the class and adding to the tech burden. 

[Jim Drago]

I'll keep the answer to myself but I had a 1.8 built in 2010 with a sleeved block.  The rule as it was written then allowed a range of sleeve material choices and some other clever builder wiggle room.  Legal then.  I spent at least $8000 for that engine.  Worth every penny.  Ran it from about 2010 - 2013.  It was an absolute beast.  There was at least 1 other similar engine out there built by someone else and the rule got changed IIRC after there were some eyes on it. 

 

We don't want that capability and cost coming back into the class and adding to the tech burden. 

+1

[Jamz14]

Jim

I thought I had blocks and cranks lined up from another source, but haven't been able to secure that source.

I need a 01 crank that is STRAIGHT.

I need 2qty 99 blocks and cranks.

If there is no power increase from the overbite, why did the rules folks tack on weight? It's not the overbite itself that I think gets you the additional power. IMO it is the flexibility and room you have to dial in your specs with the overbore that gains you a power increase. If that is true, then there wouldn't be a linear increase for the second bore. If that is true, then allow the 2nd over and keep the same weight as the 1st.

[Tom Hampton]

Cranks are available new from Mazda last I looked. All I meant was that either Jim or myself would give blocks away. The reason for that is we tear down piles of light over heats or rod knock engines ect. Blocks are not damaged anywhere near the rate that heads and cranks are. Thus we end up tripping over blocks that we don’t have heads or cranks for

 

Hey....I trip over my crank all the time.  Don't you?

[Bench Racer]

Hey....I trip over my crank all the time.  Don't you?

I'd call that ^ getten back to normal.

[Jim Drago]

Jim

I thought I had blocks and cranks lined up from another source, but haven't been able to secure that source.

I need a 01 crank that is STRAIGHT.

I need 2qty 99 blocks and cranks.

If there is no power increase from the overbite, why did the rules folks tack on weight? It's not the overbite itself that I think gets you the additional power. IMO it is the flexibility and room you have to dial in your specs with the overbore that gains you a power increase. If that is true, then there wouldn't be a linear increase for the second bore. If that is true, then allow the 2nd over and keep the same weight as the 1st.

 

James

Call my cell, I can get that stuff going for you. 

 

On the additional weight.. They plugged it in a displacement calculated and theoretically it adds .5-.75 or so.  If there was no penalty.. ALL would start saying/thinking that they need to go overbore . We did not want that by any means.. We had to put some penalty otherwise all would think it was needed it.