3.4L 98mm P & C's on ebay
02-20-2004, 01:11 PM
#1
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3.4L 98mm P & C's on ebay
02-20-2004, 03:00 PM
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I bought these last year on ebay in preperation for a rebuild, they came from a wreck which was parted out. I am building for longevity and street not necessarily performance, so my machinist recommended that although the set has useful life left they would not last as long as a new set. I am rebuilding my engine myself and with the time and finances it takes don't want to do it again! These would be great for someone who tracks their car and tears down to rebuild every few years anyway.
02-21-2004, 02:26 AM
#4
D,
I dont understand really. Many of us here use 3.4 with 7.5 compression with no issues. A few of my friends track their cars regularly and hard driving over the past few yrs and use the 3.4 with 7.5 compression and no issues at all. Whats improtant is that you dont overboost, run good gas and keep your oil temps in check and your all set to go. The 3.4 piston cylinder kits are actually better than the stock 3.3's as it's fully finned, hence better cooling. This is why Alois Ruf a very reputable tuer and most of the tuners which do participate in this forum will take this approach to. Plus the slight increase in compression does improve street driving. I really dont see any set backs on going 3.4 ,7.5 compression, off course going 8:1 compression is a totally different issue again.
I dont understand really. Many of us here use 3.4 with 7.5 compression with no issues. A few of my friends track their cars regularly and hard driving over the past few yrs and use the 3.4 with 7.5 compression and no issues at all. Whats improtant is that you dont overboost, run good gas and keep your oil temps in check and your all set to go. The 3.4 piston cylinder kits are actually better than the stock 3.3's as it's fully finned, hence better cooling. This is why Alois Ruf a very reputable tuer and most of the tuners which do participate in this forum will take this approach to. Plus the slight increase in compression does improve street driving. I really dont see any set backs on going 3.4 ,7.5 compression, off course going 8:1 compression is a totally different issue again.
02-21-2004, 04:07 AM
#5
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Sameer,
Mahle now has the 3.3L with fully finned cylinders which I got with my engine rebuild last year. Since I didn't twin plug I stayed with the stock compression but also did the coatings all for under $3k new.
Mahle now has the 3.3L with fully finned cylinders which I got with my engine rebuild last year. Since I didn't twin plug I stayed with the stock compression but also did the coatings all for under $3k new.
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02-21-2004, 03:28 PM
#8
Brent,
You are still okie running at 7.5 compression which in actual fact is not really 7.5 but slightly less with single plugged. Off course twin plug would be added insurance.
You are still okie running at 7.5 compression which in actual fact is not really 7.5 but slightly less with single plugged. Off course twin plug would be added insurance.
02-22-2004, 10:29 AM
#10
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I would be very interested in these, and maybe a few questions answered here would help with a decision.
1) They look to have a Nirisit groove cut in them...I so, can that be suitably matched to the heads since another machine shop would be doing the work?
2) What is everyones experience with wear and honing these cylinders? If they are out of round, then we are really talking about going up to 100mm , is that correct?
Thanks,
Rick
'78 930
1) They look to have a Nirisit groove cut in them...I so, can that be suitably matched to the heads since another machine shop would be doing the work?
2) What is everyones experience with wear and honing these cylinders? If they are out of round, then we are really talking about going up to 100mm , is that correct?
Thanks,
Rick
'78 930
02-22-2004, 01:06 PM
#11
Brent,
Yes it will be better off course running twin plug at 1 bar but yes you can still run at 1 bar with 7.5 compression. Your totally fine as long as you dont go above 1-1.05 bar(sometimes it fluctuates a little higher with spring).
Just make sure you have good gas, additional oil cooler, fuel enrichment(added insurance) and your CO between 3 to 4%. I wouldnt take it any higher at all, it would be like dancing on very thin ice.
Yes it will be better off course running twin plug at 1 bar but yes you can still run at 1 bar with 7.5 compression. Your totally fine as long as you dont go above 1-1.05 bar(sometimes it fluctuates a little higher with spring).
Just make sure you have good gas, additional oil cooler, fuel enrichment(added insurance) and your CO between 3 to 4%. I wouldnt take it any higher at all, it would be like dancing on very thin ice.
02-22-2004, 02:18 PM
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Sameer, I assume your running 7.5 at 1bar then. How long have you been running your car like this? Yeah that's just it, I don't want to mix race gas in every tank. I would like my car to be normal where I can run pump gas on low boost like 10-12psi. Also I run 0-.5% CO since I have a different setup than most running CIS. I'm under 12:1 up top at 1bar still
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02-22-2004, 02:37 PM
#13
Nordschleife Master
I have always preferred the Mahle 3.4l pistons with the longer skirt over the Ruf ones. Not that they are bad, but they will tend to rock in the bore more than the longer skirt ones. They are lighter by a little bit though.
02-22-2004, 08:34 PM
#15
Rennlist Lifetime Member
There were a few issues with the long skirt versions for a while. This is why Ruf went with the short skirts to move more meat in between the rings. The original versions were blowing the top land off. RUF redesigned the piston and went short skirt. Lesser of the two evils for sure.