[SIGPIC][/SIGPIC][FONT=Comic Sans MS]'91 Shadow convertible 2.5 auto, three core RP IC, S60/.48 stg 1, ported two-piece intake/52mm TB, Menegon +1 swirl, 88 turbo cam, Venolias, Crower rods, TU deep sump pan, ported exhaust, 3" from SV to TP, Hughes TC, Peloquin diff, DSS L5 driveshafts, Shelgame cal, Koni struts/shocks. [/FONT]
I made 290whp at 19psi with an S70 and .63 stage 1 in my old Daytona, with full boost around 2700 rpm on a ported G headed 2.2. The S70 was in a stock T2 compressor housing though, but it's still a good power making turbo.
Back to the OP- I would take that head back to the machine shop and show them what happened. They are obviously responsible. The head needs new seats and you need all new valves, see if at the very least they give you a huge discount. I'm not sure if machine shops are the same over there, but around here you have to be demanding. If you show you are timid/shy and a pushover, they can sense that easily and won't do anything to help you. They may not help anyway if they are dickheads, but it's worth a try.
I'll get the head fixed, but not here in Germany! Not again!
"Never argue with a German if you're tired...". Jefferson Airplane
[SIGPIC][/SIGPIC][FONT=Comic Sans MS]'91 Shadow convertible 2.5 auto, three core RP IC, S60/.48 stg 1, ported two-piece intake/52mm TB, Menegon +1 swirl, 88 turbo cam, Venolias, Crower rods, TU deep sump pan, ported exhaust, 3" from SV to TP, Hughes TC, Peloquin diff, DSS L5 driveshafts, Shelgame cal, Koni struts/shocks. [/FONT]
In 4th and 5th I can get full boost at 2k if I want. It goes through the revs too quick in the lower gears, by the time it hits full boost its at 3k already.
So the setup now is the S60 with .48 and an 88 turbo cam. That should spool quickly. I have .91 gears and a lower than stock stall converter. I had the thin Cometic .051", but I'm changing to the .063". At this point I'm wondering if the 52mm TB is doing me any good and maybe I should go back to the 48mm.
I was going to reuse the steel top ring from my Sealed Power set and the ITM second and oil ring, but the rings are designed differently and I don't know if they would work together properly. The ITM rings have top bevels on both compression rings, and the Sealed Power has a non-beveled ring on top and a bottom bevel second ring. So I'm using the complete ITM ring set. I bought it from Rockauto for the 2.2 Turbo because they didn't list the ITM set for a 2.5. Turbo. ?
Last edited by John B; 08-23-2014 at 03:43 PM.
[SIGPIC][/SIGPIC][FONT=Comic Sans MS]'91 Shadow convertible 2.5 auto, three core RP IC, S60/.48 stg 1, ported two-piece intake/52mm TB, Menegon +1 swirl, 88 turbo cam, Venolias, Crower rods, TU deep sump pan, ported exhaust, 3" from SV to TP, Hughes TC, Peloquin diff, DSS L5 driveshafts, Shelgame cal, Koni struts/shocks. [/FONT]
I wouldn't bother changing the TB.
Today's the day the head is going back on. I still wish I knew for sure why that valve got a hole burned through it. Could too much cam retard do that? I'm using an adjustable cam gear set at 4 degrees advance for the 88 turbo cam. If the key slot on the gear is off the timing may have been retarded. The EGTs have been higher at cruise, but I figured that was the thin head gasket (.051"). If I put a degree wheel on the cam pulley instead of the crank it'll read half of actual, right? The CL on a stock cam is 118?
BTW When I pulled the head I noticed that a stud nut had lost torque! I had other things to think about so I didn't worry about it until time to re-assemble. I found one nut with raised spots on the bottom bearing surface. It looked like a socket had been used on that side and didn't have any engagement and rounded off the corners of the nut on that side. I don't know who, when, how or why because I bought the ARP stud set new (I thought...). Anyway, I sanded the raised areas flat and all is well again.
Last edited by John B; 08-30-2014 at 09:35 AM.
[SIGPIC][/SIGPIC][FONT=Comic Sans MS]'91 Shadow convertible 2.5 auto, three core RP IC, S60/.48 stg 1, ported two-piece intake/52mm TB, Menegon +1 swirl, 88 turbo cam, Venolias, Crower rods, TU deep sump pan, ported exhaust, 3" from SV to TP, Hughes TC, Peloquin diff, DSS L5 driveshafts, Shelgame cal, Koni struts/shocks. [/FONT]
OK, Got it running, everything seems to be fine at 50 miles. New rings and bearings. New head. I'm very interested to see if my #1 cylinder lean condition is still there. And, of course, see if the new type rings seat and if the oil expander ring holds up this time.
Last edited by John B; 09-01-2014 at 10:16 AM.
[SIGPIC][/SIGPIC][FONT=Comic Sans MS]'91 Shadow convertible 2.5 auto, three core RP IC, S60/.48 stg 1, ported two-piece intake/52mm TB, Menegon +1 swirl, 88 turbo cam, Venolias, Crower rods, TU deep sump pan, ported exhaust, 3" from SV to TP, Hughes TC, Peloquin diff, DSS L5 driveshafts, Shelgame cal, Koni struts/shocks. [/FONT]
All is well. Rings seem seated at 50 miles. All plugs read evenly. Hallelujah!!
[SIGPIC][/SIGPIC][FONT=Comic Sans MS]'91 Shadow convertible 2.5 auto, three core RP IC, S60/.48 stg 1, ported two-piece intake/52mm TB, Menegon +1 swirl, 88 turbo cam, Venolias, Crower rods, TU deep sump pan, ported exhaust, 3" from SV to TP, Hughes TC, Peloquin diff, DSS L5 driveshafts, Shelgame cal, Koni struts/shocks. [/FONT]
Good to hear John!
Todd
Valves absorb a ton of heat from combustion and transfer it into the head through the valve seat and valve guide. So, a bad seal with the valve seat or a valve that is being held open slightly are the usual suspects.I still wish I knew for sure why that valve got a hole burned through it.
Glad to hear you have it back together!
Dont push the red button.You hear me?
Amen. I have to ship the car this month and it has to be driven to a place for the VIN to be verified to get a Colorado license, and the US military registration is only good for 30 days. We are shipping the car and our household stuff ahead, and I will work here a bit longer (my contract is up 1 Jan ). That valve went at a very awkward time. But, if it hadn't, I wouldn't have known about the broken expansion rings, so it's worked out best in the end. Also it gave me a chance to put the S60 back on which will be better suited to the mountain touring driving we plan to do. They say you get the best views of the rock slides from a convertible or motorcycle...
Last edited by John B; 09-02-2014 at 06:28 AM.
[SIGPIC][/SIGPIC][FONT=Comic Sans MS]'91 Shadow convertible 2.5 auto, three core RP IC, S60/.48 stg 1, ported two-piece intake/52mm TB, Menegon +1 swirl, 88 turbo cam, Venolias, Crower rods, TU deep sump pan, ported exhaust, 3" from SV to TP, Hughes TC, Peloquin diff, DSS L5 driveshafts, Shelgame cal, Koni struts/shocks. [/FONT]
Having given this matter a lot of thought here is what I think happened. First the machine shop ground the valves too thin. Second, the rings in that cylinder never seated causing oil to get into the chamber which caused detonation under even low boost which finaly broke the valve.
Last edited by John B; 09-02-2014 at 06:25 AM.
[SIGPIC][/SIGPIC][FONT=Comic Sans MS]'91 Shadow convertible 2.5 auto, three core RP IC, S60/.48 stg 1, ported two-piece intake/52mm TB, Menegon +1 swirl, 88 turbo cam, Venolias, Crower rods, TU deep sump pan, ported exhaust, 3" from SV to TP, Hughes TC, Peloquin diff, DSS L5 driveshafts, Shelgame cal, Koni struts/shocks. [/FONT]