Probe Pistons?
Thread Starter
Melting Slicks
Joined: Jun 2002
Posts: 3,060
Likes: 3
From: Dublin CA
Probe Pistons?
Anyone hear of 'Probe Pistons'? West Coast Cylinder Head Racing is rebuilding my heads, and recommended these D-shaped reverse dome as a good match for the LS1 chamber in a boost application. I was deciding on Diamond, JE or Wieseco (all about the same quality I believe) before WCCHR brought up Probe.
WCCHR is more concerned about top ring down (TRD) clearance in the flycut area these days because of increasing interest in 6.2L heads, which have bigger valves. I believe these pistons have a bigger TRD space than other off the shelf brands. Not sure though.
It also looks like these pistons require the shorter stock length rod (6.098") instead of the cheaper 350ci rod (6.125"). Too bad, I have two used sets of 6.125" (Eagle H-rods, Scat I-beams).
http://www.probeindustries.com/Pisto..._LS1.htm#RDome
WCCHR is more concerned about top ring down (TRD) clearance in the flycut area these days because of increasing interest in 6.2L heads, which have bigger valves. I believe these pistons have a bigger TRD space than other off the shelf brands. Not sure though.
It also looks like these pistons require the shorter stock length rod (6.098") instead of the cheaper 350ci rod (6.125"). Too bad, I have two used sets of 6.125" (Eagle H-rods, Scat I-beams).
http://www.probeindustries.com/Pisto..._LS1.htm#RDome
Safety Car
Joined: May 2002
Posts: 3,615
Likes: 2
From: waterloo ontario
St. Jude Donor '08
Nothing wrong with Probe-they'll make anyhting you want. There very popular in the Mustang world and take alot of punishment. Plus the price is very good too. I think a set of 347 pistons are like $420 bucks. What size bore are you looking for-I'm sure they have them in 6.125 length-I'll check my catalogue.
Thread Starter
Melting Slicks
Joined: Jun 2002
Posts: 3,060
Likes: 3
From: Dublin CA
Originally Posted by eb02z06
Nothing wrong with Probe-they'll make anyhting you want. There very popular in the Mustang world and take alot of punishment. Plus the price is very good too. I think a set of 347 pistons are like $420 bucks. What size bore are you looking for-I'm sure they have them in 6.125 length-I'll check my catalogue.
I'm looking for 3.910", one of the cylinders got ovaled just enough to make the hone skip some wall, so it'll be a minimal overbore. My older block has a cracked cylinder so I don't want to weaken the cylinders too much with overboring. Besides D-shaped bowl and a strong alloy, two other important things are top ring down and thermal coating. I don't know if all vendors have the thermal coating option, or if I have to send them somewhere else.
I hope to have the car running again by mid-December, so I'm a little worried about having to order custom parts.
Last edited by blu00rdstr; Nov 8, 2006 at 12:32 PM.
Safety Car
Joined: May 2002
Posts: 3,615
Likes: 2
From: waterloo ontario
St. Jude Donor '08
Bro-are you still blower or are you turbo now? I think if your building for the future you should go with either a iron block punched 30 over-I don't think the L92 heads will work on a 3.91 bore? If that's the bore size you need than your going to have to get a custom set-I think. Richard over at WCC should know.
Thread Starter
Melting Slicks
Joined: Jun 2002
Posts: 3,060
Likes: 3
From: Dublin CA
Hi SLED, EB,
I haven't done any upgrades over the last year, I still have a D1SC1 on the garage shelf. All I've done for a year is glance at car cover as I walk past it. I can't do turbo in California. I'm not doing L92 heads, it's just that WCCHR is seeing the demand increase for those because of the larger valves and ports, so they're seeing more piston flycutting as well.
I have two shortblocks at a local machine shop (for about two months) so we can pick which one to build. One is the 25Kmi shortblock I built, and the other is the 30mi TSP shortblock. The 25Kmi motor might have cylinder cracks or it might be scratches. The 30mi motor was checked out, and one cylinder is slightly oval from a piston which tried to compress piston land while rocking on it's pin. With machining and balancing I think I might get away with a $200 bill maybe.
The A&A LS1 stg2 heads have been at WCCHR for a month. To rework them is about $500 (they're dinged up and need a few valves), and if a set of pistons are less than $500, I may be on the road for less than $1,500.
The last two things I'll need to do is add a secondary fuel supply and send the 72lb injectors out to get cleaned up and flow matched.
I haven't done any upgrades over the last year, I still have a D1SC1 on the garage shelf. All I've done for a year is glance at car cover as I walk past it. I can't do turbo in California. I'm not doing L92 heads, it's just that WCCHR is seeing the demand increase for those because of the larger valves and ports, so they're seeing more piston flycutting as well.
I have two shortblocks at a local machine shop (for about two months) so we can pick which one to build. One is the 25Kmi shortblock I built, and the other is the 30mi TSP shortblock. The 25Kmi motor might have cylinder cracks or it might be scratches. The 30mi motor was checked out, and one cylinder is slightly oval from a piston which tried to compress piston land while rocking on it's pin. With machining and balancing I think I might get away with a $200 bill maybe.
The A&A LS1 stg2 heads have been at WCCHR for a month. To rework them is about $500 (they're dinged up and need a few valves), and if a set of pistons are less than $500, I may be on the road for less than $1,500.
The last two things I'll need to do is add a secondary fuel supply and send the 72lb injectors out to get cleaned up and flow matched.
Last edited by blu00rdstr; Nov 8, 2006 at 08:11 PM.
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Melting Slicks
Joined: Mar 2002
Posts: 2,931
Likes: 2
From: Tx
Blocks are so cheap that I would try to stick with off the shelf pistons. There has to be a cheap solid ls1 block sitting around somewhere. I think a new one goes for ~$700 (but it will require different head studs).
Burning Brakes
Joined: Aug 1999
Posts: 945
Likes: 0
From: Toronto, Canada Ontario
St. Jude Donor "08
Ive boosted 18psi on a 3.905 bore (815rwhp turbo), but never tried the 3.910 stuff. I would also just start with a new block or a good used one. Again, it depends if he wants to make 500 rwhp or 800rwhp.
Former Vendor
Joined: May 2003
Posts: 1,313
Likes: 4
From: Livermore CA
Originally Posted by QuickSilver2002
Blocks are so cheap that I would try to stick with off the shelf pistons. There has to be a cheap solid ls1 block sitting around somewhere. I think a new one goes for ~$700 (but it will require different head studs).
Thread Starter
Melting Slicks
Joined: Jun 2002
Posts: 3,060
Likes: 3
From: Dublin CA
Actually the 30mi motor is a 2nd Gen block (as I found out after it was delivered). I also found the head studs are $250 a set.
From what I understand, the '97-'98 blocks have a .005" overbore limit (just a clean-up hone), and the '99-later blocks have thicker sleeves and have a .020" overbore limit. I believe it's the same .020" for both the '99-'04 old gen and '05-later new gen.
I'm sticking with the mid 600s to the wheels since I don't want to deal with fuel adders or injection. It stops being fun at stoplights at over 550rwhp anyway.
From what I understand, the '97-'98 blocks have a .005" overbore limit (just a clean-up hone), and the '99-later blocks have thicker sleeves and have a .020" overbore limit. I believe it's the same .020" for both the '99-'04 old gen and '05-later new gen.
I'm sticking with the mid 600s to the wheels since I don't want to deal with fuel adders or injection. It stops being fun at stoplights at over 550rwhp anyway.
Last edited by blu00rdstr; Nov 11, 2006 at 04:32 PM.