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Old 10-11-2011, 07:22 PM   #76
Mark Pietz
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Default Re: Limited disassembly of a 1980 IC 196

Hole in deck with felt marker showing gasket contour. Since finer measurement indicates around 0.025-0.030" to fire ring, I think I'll plug the hole with jb weld. Sole purpose is to seal coolant from fibrous portion of gasket.

Been looking hard at the turbo sizing calculations. Here are some conclusions: I have the trw/rajay b, e, and f flow maps. The original 152t "b" flow was adequately sized for that engine. Mapping the 196 flow (5 lbs boost) to the b flow map shows it would probably run great but no margin for much more boost than that as it runs close to the surge line. I have an f flow. The f flow is a great match up to 5 lbs, then efficiency drops off the map (below 60%) at 1.5 pressure ratio (7 lbs.). If I wastegated it as I should, that would work. As far as "old" turbos go, the real great match is the e flow. I can have my f flow compressor machined for an e flow wheel (I know a guy who does this). Why would I do this? Because my carb options are frankly limited to a side draft using current exhaust manifolding, and my yh will bolt to it. I can live with that. 4-5 lbs. Will give me all I really want. I am not racing, just bumping up power for hills, etc. Another option that maps great just like the e flow is a garrett t04b s-3. But mounting a sidedraft to it would be a puzzle. I was pleased to see that for all the longhand calcs I did using macginnis' formulas and tables, the computer programs brought me in to essentially the same pressure ratios and flows. But programs are quicker.

While a short term goal would be would be to go with a f or e flow (those won't blow up) for now, I can see how to weld up a short vertical flange to mount on my manifold's upturned outlet, that could have a take-off for a wastegate, and use a t04b and go blow-through. But then what down-draft carb to use. A little digging and I found a carb appropriate rising rate regulator online today (reference boost + 5 lbs), so that stuff's out there.
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Old 10-18-2011, 09:02 AM   #77
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Default Re: Limited disassembly of a 1980 IC 196

Because some have exhorted me to deepen my understanding of engine theory - and I'm willing to learn - I've been doing some research regarding compression ratios, both static and dynamic, and I'm beginning to understand the relationship of valve timing to "real" compression. Here's what I've calculated, although I need a little guidance here. Hopefully some of these numbers will be useful for others. There are a couple of calculators out there (one on the kb piston site, another from wallace, and yet another by a guy called pat kelley), and they seem to be in agreement. Here are the basics:

I have a calculated static c.r. Of 8.3:1. Using a rod length of 7.35" for a 196/392 (I don't have a proper micrometer for this and it is my best close measurement at this time), and my isky grind IH 256h, intake close at 64 degrees abdc, I get a dynamic c.r. Of 6.62 (kb). Wallace is 6.33 (close enough agreement?). I don't have kelley's calc at hand, but iirc, it was also in this ballpark. 5 lbs. Boost gives a dynamic c.r. Of 8.48; 7 lbs. Is 9.34. Not surprisingly, the stock IH grind of closing at 58 degrees raises this latter value to 9.76. The light is dawning on me why this cam grind will be better. these calculator sites also stress the value of quench working along with this. I think I've got that base covered.

Assuming this is all so, I "think" I will be ok for the 5 lbs. W/91 octane. Some of what's out there says stay below 8.25 dynamic c.r. For pump gas. Question is if my setup does get up to 7 lbs. (definitely don't want more than this), can this be dealt with by running 91 octane (of course) and simply retarding the timing and running a bit Rich to prevent detonation? Would there be excessive heating doing this?
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Old 10-18-2011, 07:38 PM   #78
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Default Re: Limited disassembly of a 1980 IC 196

Remember that in the peak torque rpm range the cam is not going to effect effective cr and thus cylinder pressure. You will be straight up with no deration of compression. Also large rod ratios are more prone to detonate due to low off tdc piston velocities. I think you should be ok. Retard in real time.
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Old 10-19-2011, 12:07 PM   #79
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Default Re: Limited disassembly of a 1980 IC 196

This has been a real education. The effects of changing one variable and its effects on the others. How close was my 7.35" c to c on that rod?

Just got off the phone with arp. Time to get some measurements off the block and head and shoot them an order. He stated 110 ft/lbs on the bolts. I think you recommended closer to 105.

Gettin' closer.

Thanks again.
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Old 10-19-2011, 02:55 PM   #80
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Default Re: Limited disassembly of a 1980 IC 196

Quite a bit really. true oem is 6.75 your rr (rod ctoc over stroke)= 1.84. For street power and torque I like 1.6. IH's are oddly large but in bus it makes sense not in a light line truck.

Use 95-105 lubed with the the arp moly bolt lube. I use 105 as a point of build torque and comp head gaskets.
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Old 10-19-2011, 04:50 PM   #81
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Default Re: Limited disassembly of a 1980 IC 196

I must have been tired last night when I was trying to measure c to c on that rod. I slipped a digit somewhere, that's why I ask to confirm. Anyway, a recheck and you are right of course. Plugging that 6.75" in, I get: 6.35 dynamic, 8.51 w/5 lbs. Boost, and 9.82 w/7 lbs. Boost. Using 64 degrees abdc. What is not clear to me in the data point they are asking, is "degrees @ 0.050" + 15 degrees". I pulled 64 degrees from my grind sheet, and assumed that was when the valve was closed, not almost closed.

so with this "better" data, still looking ok for 91 octane and pull out any unwanted boost by retarding timing?
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Old 10-19-2011, 07:44 PM   #82
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Default Re: Limited disassembly of a 1980 IC 196

You should be fine but expect to retard above 3-4 psi above ambient. Say 1.5-2 degrees/psi.
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Old 10-20-2011, 06:36 AM   #83
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Default Re: Limited disassembly of a 1980 IC 196

I'll go with that. I was looking over my megajolt datalog and timing map for when I ran my corvair a few times above 7 lbs. (once to 9.2). I usually ran 89 or 91 octane, and iirc, compression had to have been not more than 8:1 or so (it was 0.060" over but I put the thicker shims under the jugs to compensate. "rule of thumb" for that engine brought me back to about 8:1. It had the late hemi turbo chambers). I never detonated that I was aware of and the car is still out there being flogged by its current owner. At the higher "potential" manifold pressures I dialed in 16 degrees total advance (or that's what was left after retarding), but I'll have to check to see if it ever got that low. For starters, I'm going to "map" using the stock 196 curve and use 32 degrees max mechanical, and guesstimate vacuum advance under light loading using the vacuum advance range in the specs. Not hard to do. Then I superimpose retardation pretty much as you state for boost.

I know this engine isn't a 152 and its hp and torque curve will be different. In looking at the 152t hp and torque curves superimposed over the n/a curves, max hp is still around 3900 and max torque is shifted about 800 rpm up the scale (2400 rpm and 3200, respectively). The n/a 196 favors max torque at 2,000 rpm, and my uneducated guess is that the boosted max torque will be closer to 3k, but you know better based on what that cam grind will do. This engine May be a stump puller and that's pretty much what I wanted. I was also looking at the b flow boost map and how IH actually pulled off sizing it for a broad power range rather than favoring one end of the scale or the other (looking again at mcginnis' theoretical curves). I agree a more modern turbo and f.I. Is something to shoot for for future tinkering, but for now, an f flow appears to work to about 5 lb and then drops off the map below 60% @ 7 lbs, which isn't acceptable. An e wheel will flow around 70% efficiency and up the scale past 7 lbs. Nicely, and I can moderate the curve and limit boost (again, looking at mcginnis' discussion of acceleration curves) by restricting the carb side. At this time the yh May fit that bill perfectly. I have an f flow turbine, so if I'm only playing with 4k max, boost should come on a little before 3k and be done by 4k, and not exceed 7 lbs. A good place to start.

Correction: I had earlier mistated that a b flow would work on a 196. No way - no point is to the left of the 60% (choke) line. I'm also thinking that IH broadened the boost curve by choking the intake with that 1904 1-bbl, and giving it that 2 1/2" overkill exhaust system.

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Old 11-06-2011, 12:53 PM   #84
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Default Re: Limited disassembly of a 1980 IC 196

Robert,
you just never know. When calculating my compression ratio, I used some of your numbers because you had already worked some things out. Today I actually took the time to measure the boot heel in one of my four pistons. The one I just measured was 12 cc - no way it is 10 cc. So now I'm going to do the rest, but it will be likely more of the same. Quite some variability with silvolite, no? I have one of the oem pistons here and am curious to measure that heel. It looks visibly smaller than the silvolite heel. Maybe it's 10cc!

I am also going to calculate the volume of the area within the gasket by using graph paper and the "squares" method and see if I come up with your 9 cc. Wouldn't hurt to see what my gasket yields.

Now here's what I'm thinking. Assuming the 9 cc is close enough for now, and using 10 cc for the heel, and 91cc for the head, that gave me my 8.3 c.r. 8:1 was what was thought to be better. Well, 12 cc in the heel gives me 8.15 based on this rationale: calculations had determined I lacked 4 cc to bring it to 8:1, so now I appear to have an extra 2 cc, I split the difference. Also, that heel is not all that smooth and I'm thinking of cleaning it up and might pick up another 1/2 - 1 cc. Then I'd be down to about 8.1 or a tick less. I am confident in doing this as I have a very precise scale (down to the gram) and will monitor my progress so all my hung piston/rod assemblies weigh the same. Those were balanced to within 1 gram at the balancer. (wow, they weigh about 2,020 grams each!) as any slight weight change is in the heel, it won't affect running balance. And if I didn't have a graduated scale, I dawned on me that I could also estimate volume by using the specific gravity of aluminum. 1 cc water = 1 gram. Dense aluminum has a specific gravity of 2.8, so 2.8 grams aluminum = 1 cc. I'll just monitor the weight change when cleaning things up, then confirm this logic by cc'ing it afterwards.

Then I can clean up the combusion chamber and maybe gain another 1/2 cc. Maybe just cleaning things up will get me to almost 8:1.

a note: if I hadn't decked this thing, the c.r. May have been around 7.75:1

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Old 11-06-2011, 02:10 PM   #85
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Default Re: Limited disassembly of a 1980 IC 196

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Old 11-06-2011, 05:43 PM   #86
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Default Re: Limited disassembly of a 1980 IC 196

Good reason to do one's own measurements.
Error is always part of the process. Either components or method of measurement. Would you like to give us some detail on your method and instruments?

I use two methods one is as seen in the sticky where you likely got my volume(which I trust) where a graduated medical syringe is used to dispense the liquid and one using a hanging graduated cylinder (lab instrument) known as a burrette as the process is so named.
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Old 11-06-2011, 06:42 PM   #87
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Default Re: Limited disassembly of a 1980 IC 196

Robert,
I don't mind at all. If I am off, then I am off. I am not using a medical syringe (I used them when in the clinical setting in a previous life, and don't always consider them as accurate as lab equipment). My graduated cylinder is simply one from a kit from summit, so it May be "good enough".

Technique:

filled cylinder to 50 cc line (lining up meniscus), using 50/50 water/alcohol, and a drop of red dye.

Using a light smear of white grease (see picture), placed plate onto top of piston, pressed down tight and got a good seal. Carefully poured liquid into teeny hole without spilling any (I have a steady hand) and filled it and tapped it to get air bubbles to come out of hole (was able to tilt piston and it worked out better than expected). When all air was out, and filled just to the hole, the cylinder read 38 cc (again, meniscus against line like the 50 cc line for consistency). Two cc's is actually quite a bit. Only sources of error are a cylinder that's inaccurate (possible), a plate that bowed (it isn't), or possibly an uneven piston top (it's flat), or something leaked out (it didn't), or I spilled some (I didn't). Occam's razor tells me the real possibility is that for whatever reason, the heels in my pistons are actually 12 cc. So I think my results are good. please let me know what you think.

A few years ago one of my jobs was checking the calculations in shielding plans for those concrete vaults they install those 20 million volt cancer treatment machines into. Did 'em all by hand to ensure the process was correct. Amazing the mistakes you find in automated calculations. The devil is in the details, which will bite you every time.

p.s. I used engineering graph paper and measured the volume of my felpro ic196 head gasket. Comes out to a tick over 8.91 cc, so I think that's very good agreement with your 9 cc.

Post script. Back from out of town trip and holiday. Yesterday cc'd the other three pistons - each is 12 cc. Cc'd one of the oem pistons. 10 cc. As to the difference in the reliefs, which is quite noticeable, I'd venture silvolite increased the volume of the bootheel to compensate for the increase in c.r. That results from oversize pistons. Going from stock 4.125 pistons to 0.060" oversize adds another 1.4 c.I. To each cylinder. My rough calculations indicate that increasing the bootheel's volume by 2 cc drops the c.r. By about 0.15 points, basically cancelling the effect.

Last edited by Mark Pietz; 11-28-2011 at 08:06 AM.. Reason: updated information
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Old 01-16-2012, 02:10 PM   #88
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Default Re: Limited disassembly of a 1980 IC 196

Now that the holidays are over and I have some time to get back to the project...

The business of ending up with a higher c.r. Than desirable for one of the main objectives of rebuilding the engine (turbo), I obsessed with reducing it from 8.3:1 to 8:1 the problem was due to my inexperience and getting the horse before the cart with respect to getting those pistons mounted and not checking volumes and such first. Hopefully won't make that Mistake again!

Here's the logic behind what I've done to fix that problem. I discussed the situation with the shop that balanced the rotating assembly. They offered to remove the pistons, mill out the relief to my specifications, then reinstall the pistons. They claimed a very high success rate in doing this without ruining the wrist pin fit ("you aren't the first one to get it backwards" was what he told me), but no guarantees, of course. So when I had to make that decision, I shrank back and thought better of it. But since it was clear that removing the same amount of material from the top of each piston would not upset the balance already put into each piston/rod assembly, I figured if I could very carefully grind out the necessary material, confirmed through weight removed as opposed to volume removed, then that could be a path forward. Today I finished doing just that. Here are the specs:

1 cc water = 1 gram. Since dense aluminum has a specific gravity of 2.8, 2.8 grams = 1 cc. So I needed to remove around 5.6 grams aluminum from the top of the piston. Consulting with silvolite catalogue's cross section of the piston, it was obvious the crown was thinnest at the bottom of the bootheel. So I would polish out the bootheel and extend the "d" to roughly complete the circle. Again, the machine shop would have done just this except with using an end mill, my guess was that careful grinding would be the same thing.

I have a triple-beam scale accurate to 0.1 gram. I first weighed each complete assembly (minus rings and bearings). The four piston/rod assemblies were within 0.4 grams of each other. My goal was to maintain this spread, and possibly improve upon it.

I selected the lightest assembly (1,961.0 grams) and using wide masking tape, taped it all up to keep out the grit. I weighed that assembly (adds about 9 grams!), and then began lightly grinding away at the heel's arc with a 3/4" drum sander mounted in the drill press, then switched to a 2" rotoloc disc (180 grit, iirc). Since the top of each piston has very fine concentric lines, it was easy to follow the desired contour. What resulted was actually a very nicely polished surface, much better than what was in the heel to begin with. Of course I'd grind, weigh, grind, weigh, grind, weigh, then do another, compare, weigh, compare, etc. Until I got them all down to about the same weights (within 0.3 gram), and paying particular attention to the pairs that would go up and down together. Got those to 0.2 g or better. When I finished, I cc'd the reliefs and confirmed they were now 14cc instead of the original 12cc. I now calculate a c.r. Of about 8.03:1. Close enough, no? This was a very time consuming process and took a whole day.

Last edited by Mark Pietz; 01-16-2012 at 02:20 PM.. Reason: Pictures didn't stick. See next entry
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Old 01-16-2012, 02:14 PM   #89
Mark Pietz
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Default Re: Limited disassembly of a 1980 IC 196

Trying to add pictures again!
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File Type: jpg 196 piston relief (Small).jpg (21.6 KB, 208 views)
File Type: jpg 196 piston relief 2 (Small).jpg (30.8 KB, 218 views)
File Type: jpg Piston on scale (Small).jpg (56.6 KB, 231 views)
File Type: jpg Piston set (Small).jpg (46.1 KB, 202 views)
File Type: jpg Piston set reliefs (Small).jpg (47.3 KB, 226 views)
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Old 06-30-2012, 10:58 AM   #90
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Default Re: Limited disassembly of a 1980 IC 196

Begun reassembly today. Washed block one last time, ran brushes through galleries one last time (still looked clean), wiped down and blew off all surfaces. Ditto with crankshaft.

Wiped cylinder bores and lifter bores with 30 wt break-in oil.

Cleaned bearing shells, installed dry against webs and caps, clevite assembly lube on journals, arp thread lube on threads, torqued main caps down to 80 ft. Lbs. In three stages. Smacked ends of crank with bfh (block of wood between hammer and ends, of course), between torquings.

Crankshaft turns about as easily as it can (weighs what, 75 lbs?) with a simple twist of the hand. No binding I can tell.

bagged it all up, maybe piston/rod assemblies later this week.
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