Engine Build Progress and Questions - Page 3

longassname · #31 06-02-2007, 08:11 PM

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:

Originally Posted by SVXelerator

stock spec, but in different oversizes to account for cylinder wall wear?

moly rings?

different material for compression vs oil, or the same material for both?

Perfect Circle?

longassname · #32 06-02-2007, 08:46 PM

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.

Quote:

Originally Posted by SVXRide

Michael,
I'd love to, but I won't be able to get to anything other than NASA mission work until after the 13th of this month. I'm already working 14 hour days at work getting this mission study done, so there's not much of me left by the time I get home

-Bill

SVXRide · #33 06-02-2007, 10:42 PM

Quote:

Originally Posted by longassname

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.

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

cdigerlando · #34 06-04-2007, 12:55 PM

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.

XT6Wagon · #35 06-04-2007, 01:29 PM

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.

cdigerlando · #36 06-04-2007, 01:53 PM

Quote:

Originally Posted by XT6Wagon

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.

I probably won't be running over 6400 since I am using the level 10 automatic transmission. If the new cam profiles ECUTune has develped, develop power at higher RPMs, I might consider reprogramming the TCU to that point, but only till the HP starts falling off.

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.

XT6Wagon · #37 06-04-2007, 03:56 PM

the heat cycles can reduce stresses from casting and it can work harden surfaces seeing stress.

Earthworm · #38 06-04-2007, 07:57 PM

Quote:

Originally Posted by longassname

Do you guys want me to cary rings? If I do will anyone actually buy them? I can stock them for $150 for a set of 6.

I may also be interested in a set of stock spec rings. I have the heads off my engine (248000kms) and the cross-hatch pattern is still evident on the cylinder walls.

longassname · #39 06-05-2007, 10:08 AM

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

longassname · #40 06-05-2007, 10:11 AM

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.

cdigerlando · #41 06-05-2007, 01:09 PM

Quote:

Originally Posted by longassname

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.

Very interesting information. Now that you are doing the crank and bearings, why don't you just offer a motor rebuild package, or just short block and heads, then we can assemble them. Seems like you have hit just about everything.

I'm in for crank work. Does that cost include the cost of the bearings?

longassname · #42 06-05-2007, 01:19 PM

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.

Quote:

Originally Posted by cdigerlando

Very interesting information. Now that you are doing the crank and bearings, why don't you just offer a motor rebuild package, or just short block and heads, then we can assemble them. Seems like you have hit just about everything.

I'm in for crank work. Does that cost include the cost of the bearings?

cdigerlando · #43 06-06-2007, 08:48 AM

Quote:

Originally Posted by longassname

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.

Maybe this is a good time and place to talk about bearings. I know squat. Like you said aluminum dissipates heat much better than steel. But I wonder if steel would last longer as a wear item or if aluminum would be strong enough. I know that Tom had some pretty strong opinions regarding this issue. I'd like to hear from him on this.

TomsSVX · #44 06-06-2007, 09:02 AM

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

dynomatt · #45 06-06-2007, 06:23 PM

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