Inliners International Forums General Discussion Engines 292 piston selection

I was looking into the different piston configurations available for a 292 and had a few questions. It appears the face of the stock pistons have a 30 cc depression that covers most of the piston face and I read where it offers a compression ratio of 8:1. Then the lower pistons that have a 15cc depression that will provide a 9:1 ratio. I was thinking of going with the lower pistons but then today I found someone selling flat top pistons at .040. I was wondering if anyone was familiar with flat tops for a 292. Any idea what sort of compression it would have or if there are clearance issues? I am not looking for anything to take to the strip but would like an engine with definitely more get up and go than normal.

Thanks!

Without knowing certain variables such as which cylinder head you will be using and the actual measured chamber size, the measured deck clearance you will have and the gasket thickness you will be using, there is no way to give you an accurate answer. But flat tops in a 292 will not be pump gas friendly. Stick with the smaller dish pistons.

the l.p. pistons are 9:1 +/- so if you need pistons, those would be best for pump gas. you can zero deck the block (around 30/1000) and if you still want more, deck the head. on mine, I only took 12/1000 of the head for fear of raising it too high. it runs fine on 89 octane so will buzz a little more off eventually. https://www.summitracing.com/parts/uem-1437-040/overview/make/chevrolet

The flat tops should not be a problem if you don't have an extreme cam or have removed a bunch from the block and head surfaces. Ask the seller. When I was looking for pistons for my 153 four cylinder (2/3 of a 230) I found that as the bore is increased the replacement pistons have the compression distance lowered to maintain a stock CR. I wanted zero deck height and stock replacements were farther down the hole than originals with original bore. I settled on forged flat tops for a 250 six which with a 181 crank made them stick out .020". Then life got in the way and the whole project has bee sitting a few years.

I noticed the LP pistons listed on Summit state that they are for 292s up until 1974 and there are none listed for later model 292s. Does anyone know what the differences would be between a 1974 and 1980 that would make it so the smaller dish lp pistons cant be used?

mine is a '76 and I used the summit lp pistons. I am not aware of any differences but can not say 100% that there aren't any.

They all can use the same cam, valves, lifters, rockers, springs, heads, .........What could be different? Possibly there wasn't an LP engine after 74 or Summit has a typo in their info.

So are the Silv-O-Lite Cast Pistons 1437-040 the higher compression LP pistons?

Wouldn't the LPs be the tallest and therefore the highest compression? Well there's the dish size and depth too. The 3468H and 3468Hc are taller and I bet HC is high compression. The 3488s have a cr 2.01" & the1437 is 1.935". A .075" difference.

Integrated_J_78.had researched all the various pistons, their pin height, dish, and chamfer a while back for his 250 build. He ended up a set of stock 307 cast flat top pistons that he was going to use. He is rarely on these days tho.

250s and 292s don't use the same piston. If they'd things would be easier.

Boy, I'll say. Tom Lowe's forged 292 pistons are now over 600, LPG pistons appear to be hard to come by, leaving just the stock deep dish for reasonable $$. Not much of a choice.

I have a 292 to build for my son who wants to put it in a a 57 chevy. I was hoping to find something new in the way of better then plain old stock pistons for a reasonable cost. Does not appear that will be possible at the moment. I have a 292 that was built by Kirby a number of years ago and broke a rod. It had Ross flat tops. I have them but one of the pistons is messed up. I think I will contact Ross and see what the might want to make up one piston.

Unless there are some other alternatives for a 292 piston out there.

Check with AutoTech and talk to Randy. He's made me a good deal on custom pistons in the past and can make you EXACTLY what you want. They also are RaceTech.

Lack of good pistons for the 292 is why I had Ross make them for me. Things to keep in mind when buying pistons for a 292.
1. Stock type pistons
a. Are heavy usually over 900 grams with rings/ pin
b. Use old design rings that don't seal well and are heavy
c. Have a low compression height and will sit way down in the bore giving a very poor quench

2. LP type pistons are expensive and do not come with rings and a,b,c above apply to them.

3. 12Bolt's Ross pistons
a. Have a higher compression height to help get a easy zero deck.
b. Use modern rings that are low tension (drag) and are lighter
c. Weight loss on a set is about 3 lbs in total over stock type pistons.
d. Hitting a compression of 9+ is easy with a 18CC dish instead of 30CC.
e. Made of the best piston material, these are premium pistons.
f. Come with rings/ pins/ keepers

On the topic of Ross making a single piston. They will not do it. Just went thru that. Has to be a set.

Off the shelf pistons and custom rods? We went through the rod thing here a few years ago and it seams like there was a Jag rod that was close.

I am not so sure that Ross is going to be the answer then. If they are unwilling to make up a single piston, with me giving them their own forging number and job number, to replace one of their own pistons that was damaged in a motor failure, I just do not see them as anyone I want to get involved with.

I heard that Ross wanted something like $1100+ to make a set of 6 pop up pistons for a 261 motor, notwithstanding that they have CNC machining info already on hand. That's a little steep.

Look, I am not saying that the best part of $700 for a set of forged flat tops is outside of reasonable, far from that. But I have a 22 year old who is just getting started in this hobby and that is a good bit of money to him. I don't want to waive the white flag and surrender just yet. There has to be some viable alternative, but maybe not.

Yes, I agree, the stock pistons are not ideal, but may end up all that is available for a low dollar build>

These are the LP pistons that sealed power apparently still makes, and summit still lists, for $250.

https://www.summitracing.com/parts/slp-980p30

I may call Venolia and see of Tom Prock (F-Troup Anglia Gasser car and top fuel car back in the day) can come up with something better. I have Venolia pistons in my 261 no issues whatsoever.

I will also contact Autotech and see what they can offer.

Did you try Egge?

Just heard back from Ross. They will not do any order for less then 4 pistons, $446 for four 292 pistons. So that's that. I have five perfectly good but totally unusable forged 292 pistons. What a bummer. No way am I dealing with a company like that. How ridiculous. Just goes to show you what they think of us little guys.

I have not tried egge but I will investigate it.

Anyone have a stock 292 piston, new or used, something cheap? I want to look at the differences between the ross pistons and the stock pistons, compression heights and ring location.

It seems like they could at least send you a forged blank so you could machine it. There are lots of small shops that could do that if they had one to work with. How badly damaged is the one you have?

Bad enough that it can’t be used. The rod broke on that cylinder and the piston got beat up. I am just so appalled. They know the blank, they know the job number so they know what machining was done. This motor was a Kirby built motor and so I know Ross has the specs and likely make these pistons up for mike Kirby on a regular enough basis. To dismiss me out of hand, with their own product, is unacceptable. I really could not believe that.

Over the years I have had a race engine or two come apart on me. Lost track one time of how many runs I had on an aluminum rod super comp Chevy motor, Too many runs on aluminum rods, and it came apart. Got Two replacement pistons from venolia no problem. All I had to do was give them the job number and they said no problem. Why this is such a problem for Ross is beyond me. And they can’t say set up time. Today’s computer controlled machines don’t require much.

I am ranting I know but that kind of customer service I can do without.

I have some cheap 292 cast pistons on my site. www.12bolt.com

Had a guy call me a few weeks ago that trashed a piston (Ross). It was a rod problem. I sent him one from a set that is kept instock. Already ordered another set of the same build # and ordered a spare to put back in the set missing a piston. Charged him a bit more than 1 piston. There is also time involved to match the weight of the new piston to my set. Try to keep my customers rolling.

You are a good man Charlie Brown. Any chance the forging for your pistons is XL387? The inscribed number on the piston I have is 69708 C. Just curious. Yes, would have been happy to pay a bit more for a single, just not in the wind with Ross.

Trying to keep my boy interested. Maybe I should rethink this and build a 250 motor.

Tom sold me four out of a set of Ross pistons for a 250 to use in my 4 cylinder. It still isn't together.

Beater,
Your going to have those pistons wore out just from dusting them!

Our engine builder says JE will reportedly custom make anything for approximately $100 a piston. This was sometime awhile back so I'm sure it's more now.