piston options

[QWIKWE4]

There are a couple of piston options out there and I was just looking for some input on what would suit me best with my power goals.

The motor is going to be a street motor in a street car and looking for 500-550hp at the crank. I do have a budget of $2-2.5k I'm already set on a roller 210/215 cam, ARP hardware, stock rods and crank, and some head work with larger intake valves. So here are the options. Also where is the best place to buy these pistons at the best price?


Speedpro powerforged

TRW

Diamond

JE

 

[gossamer]

Speed-Pro and TRW are the same company(Federal Mogul). JE is an excellent piston, but on the pricey side for your budget. I don't have any personal experience with Diamond so I can't give an honest opinion about them. I am using the Speed-Pro L2481F in my engine and I'm very pleased with them so far. Just my $.02 As for place to buy, any vendor on this site, P.A.W. , Summit should have the JE and Speed-Pro, not sure who sells Diamond though

 

[jhanson1750]

I got the TRW's for .020 over @ summit (not a plug just a LOT less money). I found it cost effective for my build. Jon Hanson

 

[QWIKWE4]

Thanks guys I was thinking of going with the TRW/Speedpro because of the cost but I figured I would find out if people have had luck with them. I didn't want to buy them because they were cheaper and find out later that they would not support my HP goals. Thanks guys

 

[TLIMITED]

If you are going standard bore there is a set TRW L2481F on Ebay brand new for $160.00 Buy It Now!!!I just got a set last week and very happy

 

[turbofabricator]

The TRW/Speed-Pro pistons are REAL heavy. Actually the piston is pretty light, but the wrist pin is VERY heavy. They TRW pin has a .250" hole drilled through it. They use a heavy pin to match factory cast piston weight. I highly suggest you replace the heavy pin with a tool steel light weight pin. This is a decent combination of pieces. Full Throttle carries Diamond pistons, for a reasonable price. They are better than the TRW. I like the reverse dome on them, as opposed to the TRW and JE deep dish.

 

[QWIKWE4]

Would it be a good idea to raise the compression ratio? Is there a big difference to go from 8:1 to say 8.5:1 and how would this be accomplished? Different head gasket thickness?

 

[novaderrik]

if someone would make an affordable forged reverse dome (not dished) 9:1 piston for the 3.8 Buick, they would really be onto something.

 

[hemi8]

You can figure out what piston you need AFTER the block has been bored and decked and the heads are finished and ready to go. The machine shop should hold off on the final hone till the pistons show up. Also, you will need to decide up front what headgaskets you will use and find out what the compressed thickness that gasket has. If for example your pistons are right on the edge with .090 piston to valve clearance and your engine builder set things up for a .060 compressed head gasket (felpro) and then you decide you want to run a .030 steel shim head gasket, well, you won't have an engine very long. Take a look at the Ross piston website and you will see a form that needs to filled out for them to sell you a piston. These are all important measurements to make and must be made to Know the compression of your engine, otherwise you are just guessing. If you don't have the tools any competent machine shop can do the measurements. There is waay more to choosing a piston than picking a part#.
Mike
86 GN

 

[SHADOWII]

The standard...

Would it be a good idea to raise the compression ratio? Is there a big difference to go from 8:1 to say 8.5:1 and how would this be accomplished? Different head gasket thickness?

compression is 9:1 for the 3.8 and 8:1 for the 4.1 production blocks. As a side note, there was a discussion a couple of years ago, on the best pistons. I don't remember the engine builder who stated this, but he said out of all the brands, diamond was the most consistant dimensionally. He spoke of wiesco, JE, TRW and diamond. Possibly some one saved the thread on their favorites.

 

[Nick Micale]

compression is 9:1 for the 3.8 and 8:1 for the 4.1 production blocks. ............

After rebuilding a few hundred turbo Buick 3.8 engines, we have never seen a 9.1 compression on a production build?

The factory lists 8.1, and as with most GM engines this is the max, generally, most are .1-.3 under rated compression.

 

[Big Turbo Scott]

After rebuilding a few hundred turbo Buick 3.8 engines, we have never seen a 9.1 compression on a production build?

The factory lists 8.1, and as with most GM engines this is the max, generally, most are .1-.3 under rated compression.

+1 to Nick Micale. No production turbo 231 came with 9.1.

 

[SHADOWII]

Sorry ...

for the mis-information and thanks for the correction. nothing worse than starting someone out on a false notion.:redface: for the record, out of 5 engines, 3 are almost 8:1's and 2 are almost 9:1's (the latter two not stock of course. )

 

[turbofabricator]

if someone would make an affordable forged reverse dome (not dished) 9:1 piston for the 3.8 Buick, they would really be onto something.

Check with Full Throttle. They carry Diamond pistons and they ARE reverse dome. Reasonable pricing, too.