I was just reading the rules for the Div ll midgets and have a question. The max displacement limit is 2.411 liters or 147.15 cubic inches and o.e.m. pistons are required. Are oversize o.e.m. pistons available for the ecotec? I bought an ecotec engine from a boneyard and took it to my local machine shop. They called and told me the cylinders are scored really bad. They said they could get oversized aftermarket pistons big enough, but not o.e.m. I hope I don't have to buy another engine just because o.e.m. pistons aren't available and aftermarket pistons aren't allowed.

as per rule: Maximum displacement for 2.4L Engines: 2.4110L Liters (147.15 CID)
Must use original manufacturers OEM pistons

Wayne, I know the rule says max displacement for 2.4 engines is 2.04110 liters (147.15 CID.) What I need to know is if oversized o.e.m. pistons are available. The guy at the machine shop said .020 or .5mm oversize pistons would be the largest oversize that would be legal, but he can't guarantee the cylinders will clean up at .020 He said a lot of cylinders don't clean up even at .030, which wouldn't be legal anyway.

Sac

Using the formula CID=Bore Diameter x Bore Diameter x .7854 x stroke x number of cylinders.

The stock bore and stroke is 88mm or 3.4645" and a stroke of 98mm or 3.8583" .020 overbore would be 88.5mm or 3.4845" that overbore would be figure out to 147.1728 cubic inches. Perhaps they did not carry their dimensions to .0001 but that is where the specs are set for this engine. The problem I see is they chose some sort of very accurate CID dimension, when a simple .5mm or .020 over bore will be allowed for wear would be simpler to understand and less open to debate.

Most stock replacement pistons OEM or re manufacture replacement ones are identical including weight and crown dimensions.

That being said I think looking for a late model low mileage motor while costing a premium would still be cheaper in the long run than a overhaul and possible overbore.

Honest Dad himself

DAD, I just used the formula and the figures you gave. I came up with 145.488 CID for the stock ecotec. I don't understand why the max displacement rule would be 147.15 if you have to run o.e.m. pistons and no oversize o.e.m. pistons available. Am I missing something?

Stock ecotec pistons are available in .5mm oversize from the dealer for around $200 to $250. My thoughts on the situation would be to bring it back to the salvage yard and get another one. The concept behind this is that the engines are cheap enough that you can start over without putting to big of dent in the wallet.From what I gather all the engines are allowed .5mm for clean up.

Sac

145.488 CID is with a stock bore 147.15 assumes an overbore of .020". Carry your decimal points out to 4 places and it should get in there where it is supposed to be. But like I said >.5mm over or .020" over would be much easier to understand for the average racer. The other thing to keep in mind that that number 147.15 CID assumes .020" overbore if you come up with .005 cylinder wear (very possible on dirt W/O chrome bores) if you bore to .020" and have .005" wear you would be considered too big and called possibly for a DQ. Fortunately Wayne's Bore scope does not possess those kind of tolerances so if he sticks it down your plug hole and it looks like a stock piston you should be OK..Mental note J&E and Wisco Pistons do not look like stock pistons on their tops. OEM pistons cast top Race Pistons Machined top.

Honest Dad himself

Here is a few pics of a Honda K24A1 with MSD ign,Engler Injection. This motor happens to be a dry sump but is available in wet sump as well.( Which is much cheaper to build) This will give viewers a look at what a Honda looks like in race form. This engine was built by Jim Stewart of Stewart Engine in Indy who has years of experience with Hondas and other 4 cylinder production engines.

Here are some pics of the Honda K24A1 wet sump engine mounted in a car with the header we designed at Schoenfeld headers to fit the midget. This has been dyno tested by Jim Stewart of Stewart Engines in Indy with the Engler injection to come up with a good combo.

A lot of guys are reading all of this tec stuff and gobbly goop about D2 Midget racing and wondering if it is right for you. Remember there are all kinds of ways to get into racing. If you want to create a small fortune racing and providing you already have a large fortune simply do a Google search and there are any number of people that can help you out and furnish you with a turn key race car and while you are at it maybe a hauler to go to the races in.

IF on the other hand you are living on a pay check and have a few other obligations that require constant attention there are other approaches. 1000cc Mini Sprints have proven to be more than adequate in the performance and competition department, you might want to consider one of them. In the Mid West Old Over the Hill Midgets are everywhere. Find a good not too bent up roller, find a good late model motor and buy the adapters to install it into a Midget chassis. While not as flashy as the cast aluminum individual injectors the throttle bodies on stock motors should provide enough power to get you started. I am sure with just a little research now and probably less research once these things get to moving you will be able to find people that can cut down the wiring harness and convert them over to Methanol. Probably with just a little knowledge of electronics and circuits the racer could do the same thing>>> the wiring schematic was available. I know we did it on Mini Sprints. Don't give up from "Sticker Price Shock" there are all kind of ways to skin that cat.

Honest Dad himself