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#31
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I was thinking I'd stock really crappy ones................
kidding, duh. It's not worth my trouble to stock rings. I only offered to do it as a favor to the community. There's no reason for me to stock crappy rings. Hastings rings. With a "touch hone" (fyi that's the terminology to ask for a light hone with the intention of creating the cross hatch finish without changing the bore size) you should be ok using the standard spec rings. I've done it and the end gap was still in range. That's what you do...check the end gap of the rings to make sure it isn't too large. If you don't wait until you blow your engine the wear should mostly be confined to the rings and your cyllinders will still hone out ok for standard pistons and rings. If it doesn't you have to purchase pistons and matching rings (so there's no reason for me to stock oversized rings). Quote:
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#32
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So Bill what do you say? Can you handle flow testing a head with the new valve seat geometry around the middle of the month? It would be good info for both you and me.
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#33
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Michael, I've got to fly out to Arizona later today (Sunday). I'll know better later this week (i.e., whether I'm going to have any breathing room between now and the 20th of the month when the proposal is due at NASA HQ). -Bill
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Retired NASA Rocket Scientist Most famous NASA "Child" - OSIRIS-REx delivered samples from asteroid BENNU to Earth in Sept. 2023 Center Network Member #989 '92 Fully caged, 5 speed, waiting for its fully built EG33 '92 "Test Mule", 4:44 Auto, JDM 4:44 Rear Diff with Mech LSD, Tuned headers, Full one-off suspension '92(?) Laguna, 6 spd and other stuff (still at OT's place) My Locker |
#34
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Crankshaft
Any opinions regarding replacement of the crankshaft? I am thinking of doing it just to be safe since it has had 135,000 miles of fatigue. I was also thinking of cryo treating it since there are no forging options for our cranks.
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Chuck D. 1992 Subaru SVX LS-L - Heavily modded turbo 2002 Subaru Impreza WRX- Turboxs stg3 & Susp. Mods |
#35
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honestly unless you got a defective crankshaft I would put money on the fact that your crankshaft is a hell of alot stronger than the day it left the factory.
I'd also say its not very likely that you will have strength issues unless you run some insane HP. Subaru blocks are ultra stiff and strong in thier crankshaft support compared to what most people are used to. You also have 6cyls and 3.3L compared to the poor WRX/STi folks who have to jack up the boost, and cylinderpressures to get the same HP as you. Which is usualy hell on the bearings, yet the SVX engine has more bearings and lower stress on each. One also doubts you would be running 8K rpm like many of the 2.5L people do. Though personaly 7K would be nice. ah hell 8K sounds reall good if the heads/cams being developed will take it. |
#36
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Crankshaft
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So You think the crank is stronger now? Why is that? There is a lot less bearing stress than there is on a WRX/STi of similar HP.
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Chuck D. 1992 Subaru SVX LS-L - Heavily modded turbo 2002 Subaru Impreza WRX- Turboxs stg3 & Susp. Mods |
#37
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the heat cycles can reduce stresses from casting and it can work harden surfaces seeing stress.
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#38
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David B. SVXipedia @ SVX-IW.COM -- SVX Information Warehouse 2.0 coming...eventually! Ebony 1992 SVX LS-L 5 spd Koni/GC Stebro 187k miles RIP (Rust In Pieces) 1993 SVX 5 spd Koni/GC Stebro Polyurethane bushings still available! |
#39
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I've mentioned before that I've been hearing a lot of stories of rod bearing failures from customers. (most of my customers are not on the network, though i do refer them to the network, so I get to hear a lot of failure histories on SVX's that aren't told here) While dynoing my stock SVX with low miles absolutely pristine condition engine the engine went out. I haven't taken the short apart yet but I have stripped it to the short and it's looking like it's a rod bearing failure. I was running syntech 10w40 in that engine. This started me thinking that oil clearances might not be big enough to maintain a good oil film with 10w40. Normally the synthetic is a little thinner than conventional oil. Normally oil clearance isn't so small an engine cant take thicker oil. Anyway I decided to talk with the guys at eagle who have a huge amount of experience with rotating assemblies and rotating assemblies in engines being pushed to the limit. We went over the factory specified oil clearances and they aggree that the tight side of the range is REDICULOUSLY too tight and prone to oil film break down.
I'll revise the crank work document to give both the factory spec'd range and my recomended range. I'm also going to offer crank work from an excellent crank shop. If you get the crank work done through me it will be ground to my specified range. For the performance builds the cranks will be reballanced to match our pistons and rods for a ballanced rotating assembly. Crank service for use with stock rods and Subaru pistons: $250 Crank service for use with Eagle rods and ECUtune pistons: $400 |
#40
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Also,
I'm going to stock some race proven aluminum rod bearings instead of the tri-metal ones that are standard for this engine. There's nothing wrong with tri-metal bearings but the melting point of the friction surface on the aluminum bearing is 3 times as high as on the tri-metal. Considering the evidence so far it makes sense to switch over to aluminum bearings. |
#41
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Crank
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I'm in for crank work. Does that cost include the cost of the bearings?
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Chuck D. 1992 Subaru SVX LS-L - Heavily modded turbo 2002 Subaru Impreza WRX- Turboxs stg3 & Susp. Mods |
#42
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That does not include the bearings. Maybe I will be able to offer a head package and a short block package at some point. I don't have the time right now though.
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#43
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Bearings
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Chuck D. 1992 Subaru SVX LS-L - Heavily modded turbo 2002 Subaru Impreza WRX- Turboxs stg3 & Susp. Mods |
#44
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I prefer the tri-metal bearings on the simple basis that it is my personal opinion that they are more suited for a built motor... That and I also could not find std size alum. bearings when I ordered mine.... The hi-techs are race proven and I feel just as confident with them as any other
Tom |
#45
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Subscribing to keep up with developments.
LAN, my big end went in the last rally...started and failed very quickly. I was running Castrol GTX3 (a 15W-40 mineral oil). I haven't pulled it down yet to see whether the heads survived (gee I hope they did). What special tools are required to get the pistons out? (is that the only unusual bit with the middle piston??). Also, FWIW, we were running about 2 degrees cam retard...when I wonder if it should be up around 7 degrees? (probably the wrong thread for this). LCA's were 110 and 105. M |
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