Not sure. I think they were originally there when the engine was built. This was a lightly used original forged steel Ford crank (at least according to the builder whom I trust).

Cranks are heavy. Your builder probably dropped it a couple of times on the driveway before he stumbled in to the garage to jam it in to the block....;)

It's and original Ford steel FE crank, it has CERTAINTY had a few connecting rod bounced off of it over its life span!
That's what FE's do.....

"It's and original Ford steel FE crank, it has CERTAINTY had a few connecting rod bounced of it over its life span!
That's what FE's do....."

It was a deliberate engineered design to sell more rods and blocks.....Ingenious!

So I have the answer to these metal bits - main bearing #5 was about ready to go. %/ Glad I pulled it. (I don't have pics, just spoke to the builder by phone as I was out of town). Some scoring on the cylinder walls, so will need a cleanup overbore.

Was thinking of going with these JE pistons to keep the overbore to a minimum. Thoughts? Other recommendations?

Also, thoughts on compression ratio for 93 octane pump gas? I have stock MR iron heads. I was at 11:1 before, but the builder doing the rebuild thinks that's a bit much.

http://www.jepistons.com/Catalogs/Au...27-428_fe.aspx

Wiseco pistons; 10.6 CR for the gas around here (aluminum heads and 93 octane); and I told you the builder dropped the crank in the driveway.:cool:

I concur with Patrick on the Wiseco pistons, they seem to be nice, although JE pistons have a good reputation as well. I also agree with him on the chance that 11:1 might be pushing it a bit with 93 octane gas. Probably want to consider 10.5:1. With the head milling I am running 12.7:1 and using 110-112 octane race fuel. 11:1 is not that far below where I am at to drop from 110-93 octane in my humble opinion.

FWIW, I'm running Ross Pistons at 10.2 CR with an alloy block and heads. But we have 91 octane gas here in CA. I wouldn't run 11:1 with iron heads, but I'm not an engine expert.

It's hard to not find a good piston these days. Wiseco is kinda "old school" and not really in the limelight anymore, but I'm sure they still make a good product. They are pioneers.

I mainly use Diamond and Racetec. I can get fully custom Racetec pistons, in any bore size (.001" increments), volume, ring pack, etc., for not much more than a regular off-the-shelf forged piston.

I see a lot of pistons still offering their slugs with 1/16, 3/16 ring pack dimensions and those are far from being "current". Most of my street pistons use a 1.5/1.5/3mm ring pack and my racier stuff uses 1/1/2mm packs.

I agree with the other guys....no reason to keep the compression up. The horsepower difference between 10:1 and 11:1 is negligible, but your pistons will thank you when you get a snoot full of bad pump gas.

If that one were mine, I'd run 9.5-10:1.

File this potentially under "old wives tales" but I was "taught" that for every compression point "lost", going down numerically, you lose about 4% of your potential gross HP.

There is an excellent piston source in Colorado called Gibtec. Gibtec makes pistons for NHRA Pro-Mod, Blown Alcohol, Prostock and T/F. They pretty much live in the NHRA pro ranks but do other pistons if you ask.

The big distinction between them and everyone else is their pistons are billet pistons. Each one is machined from an extruded bar of 2618 aluminum. The pistons are available in 0.001" increments so you don't have to go the usual 0.010", 0.020" or whatever oversize. If your block cleans up at 0.002" over they will make a piston for that size bore.

In addition to being billet they have skirt and crown coatings if you want and a variety of very nice custom touches — sort of like buying billet cranks. A complete set of pistons with tool steel pins, TotalSeal rings and your choice of spiroloc's or circlips for supercharged Modmotors, like the I typically build, comes in at $1,200!

If you ever manage to hurt a piston they can build a single replacement piston for you that will be within 1 gram of the old piston. No need to buy a whole new set and no need to get a crank rebalanced and no need to bore your block into next week because that is the next size piston available for your engine. Doesn't really need saying but they can be any compression ratio your heart desires.

If you want to investigate the company and its products the phone is (303) 243-3340 and ask for Nick. They have a facebook and website presence. Very impressive product, people and pistons.


Ed

I'd say that's probably pretty close in most examples, give or take a few percent. From what I've seen, going from around 9.5 to 10.5 is negligible. When you go from 10.5 to 12.5-13, the gain is substantial, like 40-45 hp on a 680-700 hp engine.

Ed, many companies offer billet pistons. They are getting to be pretty commonplace. When you order a custom from any piston company, you can also get them in .001" increments.

Not trying to knock Gibtec, but just saying that there are others that offer the same options.

I'm sitting here trying to figure out if having to bore the block and replace the pistons is worse than having to replace the crank and a rod. Regardless, it definitely could have been worse.

You might want to ask your builder if you should replace your oil cooler. Even though I didn't have chunks of hard metal in the oil, I went ahead and replaced mine. Let me know if you decide to replace yours and I'll dig up the part number. Also, if you don't want to spend almost three hours installing the cooler like I did, let me know and I'll walk you through that because there is a sequence to removing/installing the oil cooler.

I am in complete agreement Brent. The big difference for me was the price and willingness to make a piston that was not a current product offering. When I first began using Gibtec the price for competitive billet versions was a whisker over $300 per piston for just the piston, no rings or pins.

Gibtec was willing to not only make a piston they had not previously made but do it for essentially the same price as the forged pistons I had been buying from the usual suspects. Even more attractive (to me) was that they would work with Solidworks models of the piston and turn the design process into a genuinely collaborative effort — no one else would even consider this sort of a development process with me.

Although the billet pistons can be had from many different sources today, the Gibtec guys were the only ones who would even consider working with me several years ago. It was their collaborative business model, willingness to model the piston before making any chips, ease of communication and also a stunningly competitive price when everything else was said and done.

Almost everyone of the other providers had a chance to do business (before Gibtec) in a similar fashion and each one of them declined or put the price so high they were effectively saying we are not interested in your business.

The Gibtec experience was very different, when it did not have to be. I both appreciated and respected them for their willingness to work through a new product design with a complete stranger producing a truly custom piston design for me.

I have sent many racers their way since that original design we collaborated on and they treated everyone I steered to them with the same care and respect they provided to me. I place a high value on that sort of business behavior.

While there are multiple other billet piston providers, in the end none of them engaged the opportunity or behaved like Gibtec did, so Gibtec got my business and that of a number of others I have steered to them.


Ed

Not to toot my own horn too loud, but clear back at post #10, I was pointing that direction. Although I later waffled on that after you said it was soft like a copper RTV, if I remember this correctly.

You already got advise from more knowledgeable folks than I, but I agree with 10:1 compression or less for cast iron heads. I wouldn't go over 10.5 with aluminum heads.

Although higher compression makes more power in theory, you can get into detonation problems. Then you have to pull timing out to stop the detonation or dump more fuel - maybe both. After that you can easily loose all the theoretical power the higher compression theoretically gave you, and sometime you loose more.

My brother in law was given a 406 SBC with 12.5 compression pistons that was intended to go into a alcohol race application. He dropped an RV cam in it and put it in his 2 ton dump truck. We had to pull so much timing and run so rich to keep it out of detonation that it was a fuel guzzling powerless dog. The stock 350 had way more power.

If you do not decide to replace your oil cooler, then minimally you need to flush the oil cooler and lines with some solvent and then run some fresh oil through them to make sure that there are no metal particles still in the system. Flush until you see very little oil in the solvent and then with fresh oil and run that through until it is as clear as it was going in.

I have a question regarding compression ratio and iron heads. A couple of people have said that they would cap CR with iron heads at around 10:1 and that you can go higher with aluminum heads. I recognize that for the most part modern aluminum heads flow better than standard iron heads. However, there are iron heads that flow better than standard iron heads. Is it the potential flow or the material that contributes to this thought?

My first car was a 1974 Buick with a 340 in it that had 11.25:1 compression with iron heads. My 289 race engine has 12.7:1 compression with iron heads, in fact unless aluminum heads were used on a race car when it was raced originally, all vintage race cars must run iron heads. There are people in vintage racing running up to 14:1 CR with iron heads. Of course, we are running on higher octane gas (110-112), but fuel does not seem to be the issue.

Looking forward to some education here. Thanks.

Jim

Fuel is the issue. Today's pump gas, at 92-93 octane, auto-ignites at a much lower temperature than the high octane race gasoline. In fact if it was not for the fuel going through a phase change (liquid to a gas - latent heat of evaporation) and cooling the air charge, gasoline would auto-ignite at 10:1 compression. This is the main reason why we take the AFR from 14.7:1 down to 12.5:1 at WOT. We are using the extra fuel, that we cannot burn, to cool the air charge and prevent detonation. The un-burned fuel is also making some extra pressure, as it expands from the heat. Kinda like making steam pressure with fuel. From a detonation point of view, gasoline is a poor fuel choice, but other merits make it the top choice used.

The head material is what matters, not the flow. Aluminum conducts heat much better than cast iron (About 4 times better, if memory serves). Therefore aluminum is much less likely to have a hot spot, and it can transfer heat to the water much better, thus its surface in the combustion chamber is cooler. Additionally aluminum can be machined easier and have a smoother surface. Way less potential to have a spot hot enough to act like a glow plug, and the combustion chamber runs cooler. This make aluminum capable of running higher compression, with gasoline.

Now the flip side is that conducting heat from the combustion chamber to the water is an energy transfer, therefore less power and efficiency. A trade off that is well worth the price.

And as I recall, dcdoug has the "B" cam in his car. That cam is identical to my "K" cam, but has a tighter LSA. Whereas my 245/245 at .050" is set on a 114 LSA, his cam is on a 106 angle. My dynamic compression ratio will be a bit lower than dcdoug's because my intake valve will hang open a wee bit longer. There are various calculators out on the 'net that will help you figure out your DCR, but really you should rely on a smart engine builder who has used the components before. Internet engine building software only gets you so far....;)

Ok, that makes some sense. I was wondering what in the material would make the difference and did not think that it was relative to aluminum being stronger than cast iron. Thanks.

Builder thought this was a good idea too. Send me that part number (exactly the kind of thing I like Partskeeper for ;) ). Would love the tips on installation sequence too. I'll do it now while the engine's out.