Limited disassembly of a 1980 IC 196

Depends on what grade of fuel you are willing to spring for and how manifold pressure you want. 8.3 and 8 pounds will need premium +. If it were me ( it isn't) I'd have the 10 cc piston notch enlarged to drop your cr to 8>1.
 
The question becomes one of how much can be taken out of the top of the piston. Plugging numbers into the kb calculator gets me to around 8:1 if I use the following numbers: 91 cc combustion chamber, 4.145 cylinder diameter, (here's the iffy number - gasket diameter - 4.3? I know it's not perfectly round and has deviation for the exhaust valve - what do you use?), 0.040" gasket thickness, deck of 0.003" with the key here being the relief volume. If it comes with 10 cc and is enlarged to 14 cc. My question is will the piston top handle that sort of massaging. Looking at the cross section of the existing relief, it can't go much deeper, but it could go wider/longer - could another 4cc come out of it? I don't know where the material would otherwise come from, other than envisioning flycutting the piston top portion to a circle about 3" diameter (centered to the center of the piston's diameter) which would yield a roughly d shaped relief (because of the existing d shaped relief), and about 0.120" deep.

This May just screw up what's going on during the compression event, or weaken the piston, I have no idea, other than "where do I go from here". If this is a reasonable path forward, then I'll need to get the rotating assembly balanced - again.
 
Don't worry about the compression dynamics. IH was manipulating cr.

Balance. Are your pistons hung yet? If so don't even screw with your cr. A bit of boost retard and or diligent timing control and you'll be fine. One benifit of a higher static cr is better off boost performance and faster spool up.

You're doing fine. Dont' stress over this.
 
Robert,
we're past the point of me stressing, 'cause I'm already stressed silly over "what have I done here?" :d

I considered the information posted here that involved mostly others, about quench, so when I had a 7.9 c.r. And 0.073" quench, which I guess meant no quench, plus using boost, I went for the zero-decking thing and a quench of 0.043" or thereabouts, thinking I could benefit from whatever beneficial effect that would have. (it was also posited that a lower c.r. W/o quench was more detonation prone than a higher one w/quench. No argument there). But I ended up with 8.3 c.r. And that was making decisions after the pistons were installed on the rods (how does one determine deck without pistons mounted on rods?). Your concern to not mess with them is because you can't remove them and reinstall without ruining the wrist pin fit? (I'm guessing here). If so, then 8.3 is what it is.

But maybe I'm not seeing (or what I didn't see!) is that, for argument sake (not having kb's chart in front of me) that 7:5 and 9 lbs boost gives the same pressure as say 8.3 and 5 lbs boost. So overall, if I limit my boost to say 5 (maybe 6?) then I would end up in about the same place - around 11:1 or so (per the chart) anyway, so no biggie. If that's the point, then I'll go ahead and work with it. It should be a good runner (for a 4 popper) w/o boost. Better than original, anyway.

If the thing with the wrist pins isn't the reason, if I had to spend some bucks relieving the pistons and having then reweighed and matched (I understand they don't spin the piston assy's on 4poppers), then I'd not rule out going that route.

Regarding boost. It is conceivable that this system will generate 7 lbs, maybe a tad bit more (I knew a guy with a 152t setup and he had a gauge on it - they could actually do that in good tune. And my stockish corvair setup could pull 9.2 lbs., verified via datalogging with a map sensor. Surprised hell out of me). The whole point is that I always anticipated running 91 octane, possibly mid-grade, but never considered regular. I want to waste-gate it at 7 lbs. For "insurance". I also don't want to blow any head gaskets. At least my deck and head are now truly flat.

Dialing in the timing and retard will be quite easy using the megajolt/edis system.

Any additional thoughts will be greatly appreciated.
 
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Got the felpro head gasket. It appears that that little hole is about 0.025-0.030" from the edge of the fire ring. :eek6: wow that's close, but good enough?
 
The head drains into the large cavity where the tappets are. Oil drains into the crankcase through a large hole in the rear of the block. Towards the middle/front of the block in this area there is a circular drain that is plugged with what appears to be two discs pop riveted together. Getting the crud out of there is difficult and I'm going to drill out the rivet. Is this plug even necessary?
 
The question of how to wastegate this application to keep my boost at 5 lbs.

The pics of these parts have been posted previously. Cast iron wedge, cast iron manifold, and the cast iron elbow to which the turbo is bolted. Nowhere really to mount a wastegate or tap off pressure to go to a wastegate. I am not keen on modifying these very rare parts.

Two thoughts: one is to have the cast iron elbow duplicated in steel (weld appropriate steel flanges to ends of a suitably curved section of heavy wall pipe). To this a steel wastegate flange could be welded. $$$$

other is more attractive if it will pass a sufficient volume of exhaust gas. The intake manifold has the provision for egr. I can weld a small wastegate flange to an egr block off plate (or some comparable configuration) and bleed off pressure through that passage. It's my understanding that small exhaust leaks can kill boost, so why wouldn't a controlled "leak" through a hole 1/2" in diameter work? Plenty of small wastegates out there.
 
Mark don't take this the wrong way but why are you messing with these old parts? You have spent a lot of time making sure the engine is up to snuff. Why not us a modern turbine. Another note is if you over speed the old turbo it will grenade and your engine is on the receiving end of the shrapnel. :yikes: you have no way of knowing the stresses the 196 will put on the 152 sized unit till it is to late. Stepping over dollars to save dimes.



Unbeleivable advances have been made in efficiency and size.
I have a gt2554r that is going on my bored and stroked 152. More boost earlier and with less back pressure and heat.
 
Robert,
no offense taken, and I really do appreciate your input so far. I'm actually seeing an engine coming together now. Thirty years ago I rebuilt my first 196, which worked fine for what it was, but this build is better. Certainly better parts, and certainly better "technique" due to your recommendations.

The turbo itself May be the only part to update, as I'm not inclined to fab custom plumbing of any sort to support a turbo (that's simply a project I don't want to get involved in). So if there was a suitable turbo I could hang onto the elbow, I'm open. It's a t4 flange. I also see that there are turbos with integral wastegates. So it would be a matter of seeing what would match up. Still have to limit things to 5 lbs.

Of course, then with a different turbo there's the question of the carb. One day when I'm retired and have tons of time I'd like to do efi which is unquestionably the way to go. But this is not that day.

Right now I need to get the engine together. For the initial start-up it will have to be stock - the original 1bbl and exhaust and prestolite distributor. I need to ensure it will start right up and run for 20 minutes. That's not the time to sort out the crankfire system or an untested carb. And maybe put a few miles on it to work out any bugs.

At worst, what will I have? Some assumptions here. A fresh engine with a properly done valve train (cam, valves and guides)
proper clearances.
Proper quench.
Around 8.2-8.3 c.r. (looks like true stock was really about 7.9)
an improved cam grind.
Should be a smooooth runner since it's been balanced.
The crankfire system makes for an ignition system far superior to stock for precise timing and no spark scatter. My experience is that that also smooths out an engine.
If I left off the turbo, would run well with regular? I certainly hope that's the case.
If I left off the turbo, performance much better than the day it rolled off the assembly line, and probably same or better mileage.
If all that's so, then I'll be a happy camper. :thumbsup:
 
Mark pietz said:
The turbo itself May be the only part to update, as I'm not inclined to fab custom plumbing of any sort to support a turbo (that's simply a project I don't want to get involved in). So if there was a suitable turbo I could hang onto the elbow, I'm open. It's a t4 flange. I also see that there are turbos with integral wastegates. So it would be a matter of seeing what would match up. Still have to limit things to 5 lbs.

t3/t4 turbine inlet's are common. The gt 25 I have is a t25

At worst, what will I have? Some assumptions here. A fresh engine with a properly done valve train (cam, valves and guides)
proper clearances.
Proper quench.
Around 8.2-8.3 c.r. (looks like true stock was really about 7.9)
an improved cam grind.
Should be a smooooth runner since it's been balanced.
The crankfire system makes for an ignition system far superior to stock for precise timing and no spark scatter. My experience is that that also smooths out an engine.
If I left off the turbo, would run well with regular? I certainly hope that's the case. yes it should run well on 87 pump gas. Also be a more drivable engine. Way more low/mid range torque and hp and
Click to expand...

See red text for my response.

Garrett has a huge amount of info here.
http://www.turbobygarrett.com/turbobygarrett/products/turbochargers.html
 
Reality time. I fit up that felpro pt gasket with the head dowels in place. That hole is not under the fire ring but is just about to it. Conceivably I can judiciously trim the locating dowel hole without adverse shifts to the ring rings themselves to shift it a tad more favorably.

The garrett site is great. Question, though, is aren't most (all?) new turbos lacking the compressor side seal necessary for a draw through since everything now is efi? That's simply not where I can go at this time. Of course, then you blow through a carb. I've seen how others have done that and the key part seems to be getting a rising rate regulator suitable for a carb. I know some have used the regulator from a maserati bi-turbo, surely there are other options. What "fuel management" system did you plan on for your 152?
 
It either is under the fire ring or it is not. Having more or less distance between the two does not not change things. If combustion gasses get past the ring it is over. I could only offer the possibility of peaning in some raught copper and stoning off the surface till smooth. Or fill the hole with your favorite sealant and clean the deck.

Seals are availible for all of the common turbos to work under negative pressure. Garrett can supply them that way.

Im setting mine up blow through and using dhla 40h delortos speced for the lotus esprit turbo. Seen below
 

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I'm looking at that hole and getting a sinking feeling, as it isn't really a clean hole. Looks like this was a small, corroded void uncovered when the block was surfaced. I'll fret about it tomorrow. In the meantime, I've put a "wanted" on the forum for a ic196 block as I May have to go down that road. Life's handed me worse setbacks. :rolleyes5:

edit: to try to put it to rest. My previous technique for measuring May have been defective. I now laid gasket on block with locating dowels. Used marker to blacken deck inside fire ring. Lightly scraped black w/metal edge to establish inside edge of ring. Remove gasket. Micrometer to measure gap (line of inside edge to edge of hole. 0.140"). Best measurement of width of fire ring on gasket (uncompressed - does that thing spread out once torqued down??) seems about 0.110" in that area. So it would seem 0.030" is "huge". Only concern would be edge erosion, but is that happening with the coolant holes? Probably not.

I pulled out my 1980-ish copy of mcginnis' book and worked some numbers manually, then began plugging numbers into some of the turbo calculators on the web (turbocalc is good and there's one from a site called "squirrelperformance"). Came to similar results, but a calculator is better. My overall parameters are simple. A roughly 200 c.I. Engine with a max rpm of say 4,400 (real world limit of 4k), boost starting at around 2,800 -3,000 rpm, done at 4k. One of those calculators came at it from the standpoint of "how much hp do you want?" and based on fuel burned (I used 12:1 a/f ratio, what should the bsfc be? They indicate 0.55?). If a stock 196 had a nominal rating of 110 hp and I plug in 140, then boost can come in around 5 lbs. Depending on other assumptions. I realize it is more nuanced than this, but the process is really doable. Where things get puzzling is what volumetric efficiency to assign at different rpm/boost levels. These are old 2-valve engines so I'm guessing 80%? 85% tops? Older turbo efficiencies are around 65-70%? Newer are what? And inlet temps. Plugging in those values make for big differences. Garrett's tutorials are really helpful, but it's obvious there's no substitute for experience in these things.
 
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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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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.:001_icon_idea: 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?
 
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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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.
 
Quite a bit really. :icon_rotate: 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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