[Michael Eusebi]

I was tearing done a 454 I purchased to install a new roller camshaft. Below I have pictures of the pistons I took, I do not have the heads off. The pistons are .060 over. Can anyone tell what type of pistons they are forged or cast ? Thank you.

 

[X-77 keith]

I have been wrong before, but they look cast to me.

 

[Michael Eusebi]

That was my thinking. Thank you.

 

[SY1]

Agree with Keith. Never seen a forged piston with that xxxx hatch pattern cast into the bottom side of the piston head. Have seen this on most, not all, cast pistons I've come across. Can't say 100% for sure. Could be hypers though. Appears to be a laser etched logo on skirt in 2nd pic, possibly the bottom of the Speed Pro lightning logo? The newer ones with the black coated skirts don't have the line at bottom of the logo marking, so may be older Speed Pro without the coated skirt style logo? Hard to tell.

 

[Michael Eusebi]

Thank you I am glad you caught the logo. Engine is 10 - 15 years old with 20,000 miles on it so it all make sense.

 

[BillK]

They are cast but they are the hypereutectic material which will stand up to almost anything you can throw at it Virtually every engine made in the last 30 years uses them.

 

[Michael Eusebi]

That is great news. I will not be using any power adders just a street motor so that is great.

Thank you

 

[batboy]

That cylinder block appears to be already bored out to 0.060" which is typically the max you can safely go. I've heard you can bore out the older 4 bolt main blocks a bit more (I personally don't know). Anyway, might not make too many plans or order parts like piston rings until you mic the bore.

 

[Michael Eusebi]

i measured it is 0.60. I am not ordering pistons or rings. Just need a mild street motor. It has dome pistons, 820 heads, 750 carb, comp hyd roller 224/230 510 hoping for 450 - 475 hp and it needs to last 20 years with 2 k miles a year. It has good cross hatch so I think I will be fine.

 

[frankk]

Thanks for that information Bill. Didn't know hypereutectic was considered a tough material

 

[bill3337]

Thanks for that information Bill. Didn't know hypereutectic was considered a tough material

Hypereutectic is a great improvement over standard cast, but I used Keith Black hypereutectic in my injected 5.7 litre and then ran it a couple times on the drag strip. The computer chip had too much timing, so got some detonation and broke chunks out of the top land on 4 pistons. I now only use forged pistons on performance engines.

 

[BillK]

Hypereutectic is a great improvement over standard cast, but I used Keith Black hypereutectic in my injected 5.7 litre and then ran it a couple times on the drag strip. The computer chip had too much timing, so got some detonation and broke chunks out of the top land on 4 pistons. I now only use forged pistons on performance engines.

The KB pistons are the only ones I have ever seen do that. I think it is from the top rings butting. I stay away from them. Otherwise the Hypers are ok. All of the LS and Late Hemi engines use them and guys are putting Pro Chargers on them and making tons of HP. I wouldnt use them in a completely race engine but they really are not that bad

 

[Larry Madsen]

I exclusively use KB hypereutectic pistons in the engines I have built

The computer chip had too much timing, so got some detonation and broke chunks out of the top land on 4 pistons.

My understanding is the hypereutectic pistons have the first ring closer to the top, nearer the flame-front. That top ring will experience greater thermal expansion than the top ring on most typical cast or forged pistons.

This necessitates (as the KB installation instructions indicate) a wider gap for that top ring. That wider ring gap is what keeps the ring ends from hitting and binding and in the process ripping the top of the pistons off.

IMG_4644 by Larry Madsen, on Flickr

YMMV

 

[bill3337]

I exclusively use KB hypereutectic pistons in the engines I have built



My understanding is the hypereutectic pistons have the first ring closer to the top, nearer the flame-front. That top ring will experience greater thermal expansion than the top ring on most typical cast or forged pistons.

This necessitates (as the KB installation instructions indicate) a wider gap for that top ring. That wider ring gap is what keeps the ring ends from hitting and binding and in the process ripping the top of the pistons off.

IMG_4644 by Larry Madsen, on Flickr

YMMV

Yes, everything was gapped as per their recommendattions. I was on the Salt Lake City strip at the time and had to drive back to Victoria BC and it was spitting out little chunks of piston edges every so often, but I did get home, pulled off the injection and took out the computer, and went back to forged pistons and carburetor, no problems with pistons since. 4 of the pistons had pieces missing in various spots around the top land.

 

[Hogdaddy]

If I am paying big money for build, I want forged.

 

[Michael Eusebi]

I agree last motor I built was with forged. I purchased this motor and was glad that pistons were not cast and were hyper. I will not need forged for what I am doing mild street motor.