| Author |
Message |
BretM (Bretm)
Intermediate Member
Username: Bretm
Post Number: 2015
Registered: 2-2001
| | Posted on Tuesday, March 19, 2002 - 11:59 am: | |
Nick gets a set of high comp pistons for the QV made up, they are 11:1 though so kind of high. Have to see what he says about the ins and outs of them as he's probably used them already. If not I think I would go with Weisco, they seem to be a pretty good setup, but I have heard a lot about JE too. Thanks guys for the info. Is anyone familiar with the QV liners? They are the same as any Ferrari made since the 308QV so if anyone has done any pistons on anything later than that it should be applicable. |
William Badurski (Billb)
New member
Username: Billb
Post Number: 36
Registered: 6-2001
| | Posted on Monday, March 18, 2002 - 5:12 pm: | |
I recently had a set of 12 10:1 pistons custom-made by JE Pistons. Cost was $1200 w/o rings. If you use their rings it's a few hundred bucks more. They will make any configuration you like. |
Paul Newman (Newman)
Junior Member
Username: Newman
Post Number: 104
Registered: 12-2001
| | Posted on Monday, March 18, 2002 - 3:05 pm: | |
There is no voo doo involved. Except for the funky liners the QV's have. You would have to run a hone down the liners for the ring break in but Im not sure what you can and cant do with that special coating regarding honing. Im honing mine but they are just plain steel. I thought the QV had 9.2:1 comp unlike the 8.8:1 for the 2 valve. Swapping the pistons including a hone job shouldnt take more than a couple of hours. Im dealing with Weisco. Arias is another option. There number (weisco) is 1 800 321 1364, ask for Brian, he knows Ferrari stuff, has all the engine specs to arrive at your compression request. The only hangup might be those special liners on the QV's. That could end the idea of doing pistons. Ive heard people changing them to plain steel in the past during rebuilds maybe for cost reasons, I dont know. |
BretM (Bretm)
Intermediate Member
Username: Bretm
Post Number: 2008
Registered: 2-2001
| | Posted on Monday, March 18, 2002 - 1:32 pm: | |
Things are coming along well, Nick's taking his time to do it right as I'm in no hurry with all the other work I'm doing on the car. I should have the new springs the end of this week and
then I can send them out to him.
Paul could I get the info about the piston company you're using? I'm assuming they can make all different compressions, I think 10.1 or 10.2 would be the range I would stick with (stock US is 8.6 so this would be a decent jump). Do you have to hone the cylinders for installation, I don't know how it would work with that nikasil coating?
My dad complains that I'm getting into a really big job doing this. I could understand it being a decent job, but is it some sort of automotive voo doo replacing pistons? |
Paul Newman (Newman)
Junior Member
Username: Newman
Post Number: 103
Registered: 12-2001
| | Posted on Monday, March 18, 2002 - 12:56 pm: | |
I could see rod bearings maybe needing replacing. Only if they need it. If they are shot now, you have to change them even if you dont do pistons. I would leave the crank in if all is well. I cant see any other expenses unless you opt for balancing which isnt a must do. I have spoken to other builders on this topic and provided the replacement pistons are lighter than the originals, balancing isnt needed. All the pistons should be balanced during manufacturing to equalize weights from one to the next. In my case, the old pistons are heavier with 4 rings instead of the 3 ring setup on the new ones. |
Paul Newman (Newman)
Junior Member
Username: Newman
Post Number: 102
Registered: 12-2001
| | Posted on Monday, March 18, 2002 - 12:48 pm: | |
Hows the head work coming BretM? A compression increase would go along nicely with the heads. Even if you only bump it 1 point to 10.2:1, it would be worth it and the cam change can come later when funds permit without being afraid of losing bottom end power. It will give you more options on cam selection for a great gain. |
BretM (Bretm)
Intermediate Member
Username: Bretm
Post Number: 2007
Registered: 2-2001
| | Posted on Monday, March 18, 2002 - 12:26 pm: | |
The thing that I'm afraid of is unseen costs if I was to go down this road. Things like would you replace bearings, etc? For the what Pauls saying it seems worth it price wise, but I would hate a $2500 project to turn into a $5000 project. Do you guys have any thoughts on peripherals involved in doing this? btw, thanks a lot for the info. |
arthur chambers (Art355)
Member
Username: Art355
Post Number: 303
Registered: 6-2001
| | Posted on Monday, March 18, 2002 - 11:59 am: | |
Paul:
After you assemble it, I'd take a hard run with it, and pull the plugs. If there are spots on the electrodes, you have detonation. Sometimes you can't tell if that is occurring, but the plug will always show it. If you have detonation, then back off the timing, and test it again. You will have to replace the plugs, since the others have already got the spots on the electrodes. You'll also pick up quite a bit of power once you stop the detonation. I'd check it seperately at both full throttle low and high rpm.
The alternative is to add octane booster, or only run it hard at high rpm, since detonation usually occurs at lower rpm, not at the top. |
Paul Newman (Newman)
Junior Member
Username: Newman
Post Number: 101
Registered: 12-2001
| | Posted on Monday, March 18, 2002 - 11:27 am: | |
When choosing your compression ratio, the fact that the engine and more importantly the heads are aluminum has a major affect on what compression ratio you can run. The 355 has 11:1 pistons (I believe) The new 575 has 11:1 also. Electronics also helps deal with the higher comp too. Cam selection is critical. Stock 308 cams with 11:1 comp may require octane boost(may). I ran a 94 Z28 with 11.5:1 comp (factory aluminum heads) with no detonation. I monitored my knock retard with a laptop and saw no pulling back of timing and no detonation registered. I also had a crane roller cam in it. My plans are to go with approx. 10.8:1, thats just how it calculated out. My pistons will arrive from weisco in ohio the first week in april. They are costing $1600 cdn including pins and rings as well as tax. The order takes 5 weeks to complete. My cams will be sent to either elgin or web cams for regrinding to compliment the compression increase and give the power Im looking for. Im not concerned about detonation. Ive been down this road before with other engines Ive built. I will be running 94 octane pump gas. The cams will cost around another $1000USD. |
Bill Sebestyen (Bill308)
Junior Member
Username: Bill308
Post Number: 122
Registered: 5-2001
| | Posted on Sunday, March 17, 2002 - 9:56 pm: | |
Bret,
Superformance lists 308 forged piston assemblies, both standard and hi-compression, for 135 BP each, including pins and rings, and new euro cams for 980 BP for a set. I'd be real hesitant in going above 10:1 CR for the reason Henry indicated. Bill |
Henry D. Chin (Hanknum)
New member
Username: Hanknum
Post Number: 6
Registered: 2-2002
| | Posted on Sunday, March 17, 2002 - 8:42 pm: | |
10.5-11? That sure seems pretty high. I'm not sure you would be able to run pump gas anymore with those CR's.
Don't know about price but I'd check with Rutlands, ID&R, Nick's, and Theiler. I'd guess a few grand at least after installation. You might want to also upgrade/modify your ignition to be able to take full advantage of the cams and pistons.
Just my $.02
Let us know what you find out. |
BretM (Bretm)
Intermediate Member
Username: Bretm
Post Number: 2003
Registered: 2-2001
| | Posted on Sunday, March 17, 2002 - 8:19 pm: | |
In my lunacy I often think to myself, if I didn't get a set of rims, or if I didn't get an exhaust, or if I sold a kidney... I could get pistons and cams instead. What are the best high comp pistons, I wouldn't want to go higher than 10.5-11? How much do they cost? Who makes them? What cams would couple well with these? How much would the cost? And, how much do you think it would all cost when all said and done?
Thanks a lot. I know some other guys are looking into these things too so it seems like a good topic to get some site info circulating on. |