MrWOT Posted June 17, 2006 Share Posted June 17, 2006 http://www.circletrack.com/techarticles/82438/ Interesting results, should provide significant benefits in ring life, seal and piston heat dissipation. Anyone ever run across this before? Quote Link to comment Share on other sites More sharing options...
olie05 Posted June 17, 2006 Share Posted June 17, 2006 That makes alot more sense than only using torque plates. doesn't the top of the cylinder bore see more distortion than the lower parts of the cylinder bore? They can't replicate that with hot water. Quote Link to comment Share on other sites More sharing options...
MrWOT Posted June 17, 2006 Author Share Posted June 17, 2006 The top especially sees more in a siamesed bore engine. And I think they could get pretty close to running conditions with a specialized setup like that. Can't be positive though, I've never heard of anyone doing this before. Quote Link to comment Share on other sites More sharing options...
jt1 Posted June 17, 2006 Share Posted June 17, 2006 The circle track guys have been experimenting with this for years. Some think it's worthwhile, others don't. There's no doubt the block changes dimensions as it heats up, and the hot honing believers think the HH process makes for a better bore. Nonbelievers say the block doesn't heat up uniformly, some parts of the block are hotter than others, so the HH process is of little value. Nobody has figured out how to account for how stresses incurred while the engine is running change the bores. You are basically trying to push the heads and crank away from each other, and these stresses affect the dimensions also, plus the fact is they are not constant as the crank rotates thru the firing order. Imagine each firing event applying force to the crank, the crank pushing down on the main caps, the main cap bolts pulling on the block, and the head bolts pulling the other way. The net result is a stress wave passing thru the block with several orders of harmonics, all of them changing the block dimensions, with each firing event and rotation of the crank. It's a complicated equation. John Quote Link to comment Share on other sites More sharing options...
TBK Posted June 17, 2006 Share Posted June 17, 2006 Hate to HIJACK a thread but this is along the same lines. Have a 77 280 motor that started smoking, head is fresh so beleive it is the rings, havent torn down yet. is there a measurement of sometype that I can take to see if JUST honing will be ok with rings and bearing replace or if it will need BORED. Or should I just byte it and take to a machine shop! Quote Link to comment Share on other sites More sharing options...
Cody 82 ZXT Posted June 18, 2006 Share Posted June 18, 2006 Hate to HIJACK a thread but this is along the same lines. Have a 77 280 motor that started smoking' date=' head is fresh so beleive it is the rings, havent torn down yet. is there a measurement of sometype that I can take to see if JUST honing will be ok with rings and bearing replace or if it will need BORED. Or should I just byte it and take to a machine shop![/quote'] Dude that's a major Hijack. Do a search or start a new thread. Lot's of this type of info on Hybrid Z. Quote Link to comment Share on other sites More sharing options...
katman Posted June 18, 2006 Share Posted June 18, 2006 Don Potter has been hot boring and honing Z engines for 30+ years. He also uses a torque plate that exactly mimics the distortion that a real head on a gasket causes, which isn't exactly what a constant thickness block of steel (typical torque plate) does. Of course what could ruin all that is cheap aftermarket pistons. Since pistons aren't round when they're cold, you have to trust that the piston engineers have done a good job to make them round when they're at operating temperature. Important? Tuning will kill more power than hot honing will ever make, but we did put an amazing number of races on D.L.Potter engines without any degradation in leakdowns. Quote Link to comment Share on other sites More sharing options...
Pop N Wood Posted June 19, 2006 Share Posted June 19, 2006 Just switch to an LSx series motor. They anchor the head bolts into the base of the block and not near the tops of the cylinders. I read one article that says torque plates are not needed nor even useful. Quote Link to comment Share on other sites More sharing options...
MrWOT Posted June 20, 2006 Author Share Posted June 20, 2006 Just switch to an LSx series motor. They anchor the head bolts into the base of the block and not near the tops of the cylinders. I read one article that says torque plates are not needed nor even useful. Hot honing doesn't have anything to do with distortion from the head, it has to do with the fact that the bores themselves are different dimensions when hot because the thickness of the metal is not constant. Anyway, I've emailed several people in the last few days to check on this. One in particular who works for Ford in their racing division told me hot honing is standard practice on all racing engines due to the much lower failure rate of hot honed motors! He also told me when they started going from cold honed to hot honed motors their piston failure rate dropped from about 17% to around 9% in endurance applications and all of the hot honed motors made consistantly more power then the cold honed, had less oil contamination, yada yada, etc... It really makes me wonder why this isn't a more commonly known thing? Or is it and I just missed it or all these years somehow? I posted this same article on a number of other webboards and I've gotten the same responses, a select few people, most of which are "in the know" ie the ones pushing relitively large hp per displacement, and they all seem to know about it already and tell the same story, hot honed motors are far more reliable then cold honed motors. So... anyone know a machine shop in norcal that does hot honing? Quote Link to comment Share on other sites More sharing options...
TheNeedForZ Posted June 20, 2006 Share Posted June 20, 2006 It really makes me wonder why this isn't a more commonly known thing? Or is it and I just missed it or all these years somehow? I posted this same article on a number of other webboards and I've gotten the same responses' date=' a select few people, most of which are "in the know" ie the ones pushing relitively large hp per displacement, and they all seem to know about it already and tell the same story, hot honed motors are far more reliable then cold honed motors. So... anyone know a machine shop in norcal that does hot honing? [/quote'] I have an issue of "circle track" special edition that has loads of technical articles including the one your posted. Very worth the 5$ I paid for. I think you answered your own question; Unless someone is pushing for really high hp, people don't use HH or need it. As a result, few shops are equipped to or interested in providing such service. Only the serious racer type would know, and that's who you can expect to get your answer from. Ask the very same people who had positive things to say about HH. Quote Link to comment Share on other sites More sharing options...
Pop N Wood Posted June 20, 2006 Share Posted June 20, 2006 Hot honing doesn't have anything to do with distortion from the head, it has to do with the fact that the bores themselves are different dimensions when hot because the thickness of the metal is not constant. Which is why I was talking about torque plates. Quote Link to comment Share on other sites More sharing options...
jt1 Posted June 20, 2006 Share Posted June 20, 2006 Not many people do HH because it's a huge PITA. You got to seal up the block, have a water supply to supply the water at the desired temp, deal with the water lines during the honing operation, and have a means to catch the water when the HH is done. Nobody wants to dump water all over their 75K sunnen boring machine. You've got to do it twice, once for the bore and once for the hone, and there's the question of how many people will pay for it to make it a profitable venture. I guess a HH would cost 2 or 3 times as much a standard job. jt Quote Link to comment Share on other sites More sharing options...
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