felix2566 2 Posted March 24, 2006 A mate of mine who is a professional engine builder has been doing some work on my mi16 head, we were discussing the next modifications to the engine. he is planning on having some replicas of the pug sport hi comp pistons made, he wanted to know what kind of interest there would be if he was to have them made, they would be copied directly from some original pistons. i thought i would just post it up on here to guage the interest. he is called mark maynard and his number is 01453 *****. this is not ment as an advertisment i was just wanting to find out how many people would be interested. Share this post Link to post Share on other sites
Jonmurgie 2 Posted March 24, 2006 What would the advantage be of doing 'pug sport' replicas when there are several over designs/specs that you can get off the shelf? Share this post Link to post Share on other sites
petert 554 Posted March 24, 2006 Why not buy them from QEP? Share this post Link to post Share on other sites
felix2566 2 Posted March 24, 2006 as far as i understand, and i will have a chat with mark about that, but it is just that the shape that they give is a very good one to give one the best performance from ones engine. also many manufactuers such as JE (as far as i understand) only make them to order, were as he is planning on getting about 40 sets made to have in stock. Why not buy them from QEP? i was just talking to him, he doesnt do that much on the internet, so i have just told him to have a chat with them, LOL Share this post Link to post Share on other sites
petert 554 Posted March 24, 2006 What sort of CR are you hoping to achieve? Share this post Link to post Share on other sites
felix2566 2 Posted March 24, 2006 around about 11.5/12:1 CR Share this post Link to post Share on other sites
engine killer 5 Posted March 24, 2006 as far as i understand, and i will have a chat with mark about that, but it is just that the shape that they give is a very good one to give one the best performance from ones engine. also many manufactuers such as JE (as far as i understand) only make them to order, were as he is planning on getting about 40 sets made to have in stock. i was just talking to him, he doesnt do that much on the internet, so i have just told him to have a chat with them, LOL it is not that hard to source especially in G.B. as long as i have heard, there are plenty shops selling JE and you surely don't need to buy in bulk. here is my sample of JE, the CR that i was told is about 12:1 http://community.webshots.com/photo/540063...084130750UcBxIZ Share this post Link to post Share on other sites
petert 554 Posted March 24, 2006 You don't need much of a dome to achieve that with a 1.9L and just a flat top with a 2L, if you use a thinner head gasket. The Wiseco pistons I designed have a 2cc dome. They give 11.6:1 with a 1mm gasket. The 2L flat top piston gives 11.8:1 with a 0.7mm gasket. Matt tells me the French pistons he sells are better however. Share this post Link to post Share on other sites
Robsbc 0 1 Cars Posted March 24, 2006 (edited) The obsolete Pug Sport ones for the Mi16 were made by Omega and can be bought from Skip Brown Cars as they put in an order with Omega last year for 20 sets. Edited March 24, 2006 by Robsbc Share this post Link to post Share on other sites
felix2566 2 Posted March 24, 2006 oh thats cool (skip brown) i might get in contact with them, any one have their number, i know that they dont have a web site, i had their number a while back after about a days search Matt tells me the French pistons he sells are better however. these french ones where does one get them from and who makes them? what kind of CP do they have? Share this post Link to post Share on other sites
petert 554 Posted March 24, 2006 (edited) here is my sample of JE, the CR that i was told is about 12:1 to be honest they're a pretty crappy design. They have to have a huge dome to make up for the enormous valve pockets. I'd rather have a flat top design with a thinner head gasket and pockets cut to suit the individual application. That much lift and pocket relief on the exhaust is wasted CR. Talk to Matt at QEP for the French pistons. Edited March 24, 2006 by petert Share this post Link to post Share on other sites
Robsbc 0 1 Cars Posted March 24, 2006 oh thats cool (skip brown) i might get in contact with them, any one have their number, i know that they dont have a web site, i had their number a while back after about a days search these french ones where does one get them from and who makes them? what kind of CP do they have? 01829 720492 Share this post Link to post Share on other sites
felix2566 2 Posted March 24, 2006 thanks for all the info guys, i think QEP it is then! Share this post Link to post Share on other sites
engine killer 5 Posted March 24, 2006 to be honest they're a pretty crappy design. They have to have a huge dome to make up for the enormous valve pockets. I'd rather have a flat top design with a thinner head gasket and pockets cut to suit the individual application. That much lift and pocket relief on the exhaust is wasted CR. Talk to Matt at QEP for the French pistons. sad, can't afford another set. have to save more and wait for DB's reply. Share this post Link to post Share on other sites
petert 554 Posted March 25, 2006 (edited) sorry, I guess that reads a bit harsh (I'd had a few drinks). As a mass produced piston, designed to fit 90% of the intended applications, they're fine. They've got heaps of valve to piston clearance to cater for most cam setups, without having to worry about further machining. In a perfect world however, you'd finish cutting the pockets after a trial setup of the cams. This maximises the CR. An Mi16 doesn't need a lot of exhaust timing/lift, so you can run a cam with a relatively small lift at TDC. I'll post some pics later of some pistons I've just finished machining so you can compare the difference. I'd rather achieve the compression ratio without the dome. A thinner head gasket also gives a better squish distance and allows for more valve unshrouding. Those pistons would have approx. 4-5cc of pockets and about the same in the dome. A nett result of possibly zero. Edited March 25, 2006 by petert Share this post Link to post Share on other sites
Banjo 1 Posted March 25, 2006 Felix I use maynard too, he said he's done a few mi's recently, we should meet up. Ben Share this post Link to post Share on other sites
petert 554 Posted March 25, 2006 (edited) Here's some pics of my XU10J4. This setup gives 11.8:1 with a 0.7mm gasket. The exhaust cam has 0.105" lift @ 6 deg. BTDC and results in 0.120" of piston to valve clearance. The inlet has 0.150" @ 6 deg. ATDC and gives 0.070" of piston/valve clearance. Note the piston is sitting 0.004" above the deck, resulting in 0.024" squish distance. Edited March 25, 2006 by petert Share this post Link to post Share on other sites
engine killer 5 Posted March 25, 2006 sorry, I guess that reads a bit harsh (I'd had a few drinks). not at all. they were the easiest i could get anyway. by the way, what fuel that you are running for such high cr? will ron97 still good enough? Share this post Link to post Share on other sites
petert 554 Posted March 25, 2006 Either BP100 (aviation fuel, 118 RON) or the new Optimax 100 (100 RON). Share this post Link to post Share on other sites
B1ack_Mi16 67 Posted March 25, 2006 Here's some pics of my XU10J4. This setup gives 11.8:1 with a 0.7mm gasket. The exhaust cam has 0.105" lift @ 6 deg. BTDC and results in 0.120" of piston to valve clearance. The inlet has 0.150" @ 6 deg. ATDC and gives 0.070" of piston/valve clearance. Note the piston is sitting 0.004" above the deck, resulting in 0.024" squish distance. That's close! 0.7mm I thought about 1.0mm was the minimum "safe" distance. Is that with standard rods or uprated ones that'll stretch less? Share this post Link to post Share on other sites
petert 554 Posted March 25, 2006 That's with std. rods. An 8V I built two years ago is still going strong with 0.5mm clearance. Share this post Link to post Share on other sites
