I know this has been discussed before, but anyone know a good source to buy wiescos for a 308??
Paul, try their site: http://www.wiseco.com/ I have been happy with their 2 and 4 valve models. Good quality, Venolia makes a good 2 valve one for your 308 too, as well as others. HTH The Phone # is: 440-951-6600 Kermit The pic is of set of 83mm ones that Dale @ Venolia did for us recently This puts you right around 3.1 litre, FWIW Image Unavailable, Please Login
I just spoke with Dale @ Venolia, and he is going to FAX me some newer figures , as well as a few other options. I'll PM ya in the morning, as I don't think it would be protocol to post openly. I do recall them being cheaper than the Wiseco though. Kermit
The pic is of set of 83mm ones that Dale @ Venolia did for us recently This puts you right around 3.1 litre, FWIW[/QUOTE] Hey Kermit that's a nice looking set of pistons you got there, Looks very familiar........
Yup, Randy that is the set that you saw in my shop the other day. The weights of bare pistons are: stock 335.5 grams Venolia 319.7 grams The compression should be right close to 10.75 to 1 And no I dont have 83mm gasket in stock at the moment. I have a shot of the piston and liner that is a great illustration of the "Plateau" finish I spoke of on the Break In thread I had a hell of a time getting to this point, as the original machine shop screwed all eight liners up when they bored them. Then denied it and argued for damn near 6 months. I gotta thank Mark Huson, of Huson Automotive, who is a very well known Sprint Car builder for saving the day by working late for a few days and having a lot of talent. (I have seen them dyno 410" chev small blocks to 8200 RPM, thats with a 3.75 stroke, and the 308's are under 3"!) Image Unavailable, Please Login
Wow, I just had to finally go weight my Borgo's, and find 299.5 grams. Of course, they are smaller in diameter and shorter on compression at 9.7:1, and probably not forged. I'll call wiseco today and see what they have to say, but also curious to see Venolias price as well. Kermit, you said the shop screwed up your liners, could you elaborate? Were they able to fix them or did they destroy them?
Actually Krowbar, they repeatedly screwed them up. The first side ended up at right angle to the crank, but I think he was rushing the job, and perhaps a bit of "nose candy" to keep going. That is all I can figure. I dropped them off on May 16th, and got a call on June 27th asking if I had a "spare", as he had bored one over the size. I got a used one from Bill @ GT Car Parts. THANKS BILL! and as I looked at the first ruined one, I noticed that the lower end was a lot different in wall thickness. The problem being, it was tilted toward the clutch end! So I went to LcM, (the shop) and checked, only to find that the whole side was crooked including the one that replaced the overbored one. I ship blocks to be bored with inserts in place to protect the aluminum, and the inserts had chips from boring driven deeply into them. So deep, that the were imbedded . In checking it over, I could see that what had happened was they had not cleaned the machine between doing each of the sides, and had clamped down on chips, throwing the bores sideways in relation to the crank. They insisted it was "fine". I knew better. I politely asked them for the gauge to check it and was told "we dont have one". So I came back to my shop,and built a V Block with an arm welded to it,machined to a true 90 degree, (within a half thou, and took my lapping bar with me as a basis to check it. All I had with me were snap gauges, but they work if you are patient. The lowest differance in a 4" length was .020", and the v bock gauge coincided with the tilt shown in the liner bottom. They still would not admit their mistake. I explained to them that it would not, as if it was out .020"in 4", it would be out .005" in 1" or about the rod bearing width.So to shorten the story, I had to take it as is, and find another shop capable of fixing the one side and ordered the used liners. I went a county away to Huson's shop, as he does my cranks just beautifully,and he was good enough to pitch in and help.
I just checked. Std head gasket has 83.2mm hole, despite 81mm Bore, so I guess your 83mm Bores will be ok with a std gasket.
So what is the max bore size for stock liners without overstressing them? I had originally heard 82mm was max. And, while I definetly understand the implications and philosophy of using a torque plate on the block for boring cylinders, couldnt they just as well be mounted in a fixture and bored individually? I know on American engines, like the small block Chevy 400 that had thin cylinder walls, using boring plates was almost mandatory, or so I heard. But these 308 cylinders look awfully stout. Do they really distort that much under the clamping force of the head? I mean, even though I live in a Metro area that exceeds 3 million people, there just is no one around I trust a whole lot to keep from monkeying things up.
Paul, 83mm is the max size for the 308 motors. I dida lot of research on the matter incudeing chatting wih Darton Sleeve's Engineers. Acording to them the max is .159", and I am .009" below that. I find that they seal well and run quite strong, without any ring seal problems. I prefer to use a deck plate when boring, especially any "stud motors". as they pull from the bottom, and that can lead to a distortion of the liner walls as they are clamped down. the clamping force pulls them to a slightly square hole, and if the are bored with out a plate to simulate the forces that are exerted, they aren't round when done.If I were after higher HP than a street motor, iI would want thicker liners to handle the pressures. The 288 GTO is an excellent example of that. Altought they are not actually a 308 motor, they are very similar, and they have an 80mm bore in order to handle the boost and the resultant power level that they produce. BTW. As I call, the original 288 motor was not a 105 or 106 series, but a 268C motor originally developed for Lancia's Endurance racing. I need to correct an error in the weight of the stock unit I stated yesterday. Last night, as I was in the process of calculating the exact compression ratio, I was getting the dome and valve pocket volumes, and I noticed a part of a broken ring in the second groove. I ran it past the triple beam, and it weights 328.5 without the ring piece that I missed, Both the 81 and the 83 Venolia are within .4 cc of each other in that respct, so I also CC'd the head with gasket, so I'll crunch the formula, and give the exact compresion ratio as well as the true volume of the motor. And Phil is right on the nose with the gasket being large enough. Not a problem. I spoke with Dale Yesterday afternoon, and he was still putting together a bunch of info and he planned on Faxing it then , but it did not come thru. The modem in this CPU seems to do that once in a while, but it wont miss a "Vacation to Can Cun, or Wall Street Alert"FAX. Go figure. I should hear fromhim this AM, and l will getthe info to those who wanted it then. And hopefully the true compression numbers as well. As I use the same line infor both the internet,and FAX, I had better get offline so it can comethru. Later
Boxer, I finally have the answer to your question, and a clarification. The Compression Ratio is 10.5:1, not the "guestimate" of 10.75:1 I mentioned earlier. As you can see in the pic, that is a Real number, as opposed to my eyeball. In that liner,set at the exact depth as it would be in the motor, is the piston. The head, seen in the background, was CC'ed with gasket in place. I consider it an ideal ratio for a lot of street motors, not so high as to require fueling next to a Piper Cub, but enough to make it more effecient, and therefore more powerfull. It improves economy I have been told , but that requires a lighter foot and I haven't a clue there, LOL. Kermit Image Unavailable, Please Login
