Limited disassembly of a 1980 IC 196

Good stuff to read. Thanks. I can't see the harm in doing this but I don't need a vertical learning curve at this point. Regarding the oil/coolant heat exchanger I was using. It was certainly effective, but the real estate around the left motor mount is quite busy, and the turbo exhaust makes it more so. At a minimum, I need to remove the adapter I cast to utilize the Volvo turbo brick setup. I will use that adapter I cast earlier to run remote lines from the block. I am thinking of bending up a battery box to match the battery mounting plate footprint, and mounting a remote oil filter mount to it, i.e., perpendicular to the long side of the battery. I can add the thermostatic sandwich to it (I have both Volvo versions and can go either a traditional oil cooler or the heat exchanger style). Since my oil filter will then be pointing down, I can use one of those 2 quart filters to increase oil capacity. But all that will have to wait for now.
 
A small snafu developing due to someone at the machine shop not letting me know that a closer inspection of the block showed damage (one or more eyebrows - I think that was found after honing?) requiring a re-bore to 0.030"; after I just found a set of NOS 0.020" pistons and ordered them from a vendor IHPA recommended. Called the shop and learned the owner acquired 0.030" over pistons but I do not know what brand, so that could be problematic if not SLs or NOS since they are not de-stroked. Waiting on a call back from the owner... :mad:
 
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You had a clearance issue before, if you had them hone .01-.002 out of the bore I think you'd be at a sweet spot on clearance- ~.005
 
Robert Kenney said:
You had a clearance issue before, if you had them hone .01-.002 out of the bore I think you'd be at a sweet spot on clearance- ~.005
Click to expand...
I'll have time next week to drive to the shop and discuss this in person, better than over the phone. There were two areas in two cylinders that concerned me (#3 and 4) and I suspect that is what this is all about. I am also speaking with two individuals. I think everyone isn't always on the same page. Not knocking the shop, just need better communication.

I am confused. You said that scuffing would be on both sides if there was a clearance problem - that makes sense - and there was scuffing only on the top side, which I think is the thrust side? Just trying to understand the mechanism that detonation causes scuffing. Seems it isn't really an oiling issue, then, so much as running lean. Does the piston bang against the thrust surface as it moves down? Regardless of the size of the replacement piston, increasing the clearance from 0.0035" like now to 0.0045" would be fine otherwise? Just realizing how little I actually understand...
 
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You hadn't shown both sides of the piston or discussed the scuffing locations, my statement was relating to the clearance going to zero or worse. In that case you would expect to see some level of skirt damage on the thrust and side opposite. This is not 100% of the time but to small of a clearance will compromise lubrication. If all other variables are good like oil temp and quality of oil, thermal excess is usually the cause.
I have pistons with that here and can post a photo if you'd like.

Onset of detonation can be the cause or it can the result of excessive piston temperature.

Piston to cylinder clearance consideration is a combination of both piston and cylinder temperatures. Both are variables that can be controlled. The iron cylinder has 1/2 the rate of thermal expansion as an aluminum piston.
One extreme example is a cold engine that is started and asked to produce high levels of power prior to coming up to normal operating temperature.
This is minimum cylinder diameter and maximum piston diameter.
 
Robert Kenney said:
You hadn't shown both sides of the piston or discussed the scuffing locations, my statement was relating to the clearance going to zero or worse. In that case you would expect to see some level of skirt damage on the thrust and side opposite. This is not 100% of the time but to small of a clearance will compromise lubrication. If all other variables are good like oil temp and quality of oil, thermal excess is usually the cause.
I have pistons with that here and can post a photo if you'd like.

Onset of detonation can be the cause or it can the result of excessive piston temperature.

Piston to cylinder clearance consideration is a combination of both piston and cylinder temperatures. Both are variables that can be controlled. The iron cylinder has 1/2 the rate of thermal expansion as an aluminum piston.
One extreme example is a cold engine that is started and asked to produce high levels of power prior to coming up to normal operating temperature.
This is minimum cylinder diameter and maximum piston diameter.
Click to expand...
The scuffing was only on the top sides of all pistons, as was light scoring that matched, on the bores themselves. Bottom sides were still pristine, but there two concerning areas on the bottom (exhaust) sides of two cylinders, about one-third of the way down. I'll go with detonation due to a lean condition at one point. There is no way to know now. I had a short run with an E flow compressor and a failed bearing that stuck the wheel but didn't grenade. I know that I had an overly rich needle in the Carter at that point, and then reduced it. Vehicle was (is still) noisy and difficult to sort out anything but the loudest pinging, which I haven't heard, but doesn't mean wasn't there. My hearing isn't as keen as when I was young. LOL. Without looking at the data logs, I can't tell how lean I was until I thinned out the tip and got it to 11.4:1. But I think some level of detonation did it in. Regardless, next time this engine runs it will be stock to break in the rings, then going ahead with the turbo, but only with "fuel management" that ensures at least a sufficiently rich AFR at any condition prior to tuning. In any case, time to get this thing fixed.
 
What weight oil were you running?
Consider bumping the oil pressure to 50 psi at rpm hot. Oil flow is your friend. The crank polish will increase bearing clearances a bit and allow more at the top end for cooling.

If I had this piston issue, I would go up on clearances to .005. Make sure they use .2 above the tip of the skirt tail as the piston diameter.

Feel free to call me. You should have my number
 
Robert Kenney said:
What weight oil were you running?
Consider bumping the oil pressure to 50 psi at rpm hot. Oil flow is your friend. The crank polish will increase bearing clearances a bit and allow more at the top end for cooling.

If I had this piston issue, I would go up on clearances to .005. Make sure they use .2 above the tip of the skirt tail as the piston diameter.

Feel free to call me. You should have my number
Click to expand...

I was running 10-30. Shimming the oil pump spring shouldn't be difficult.

I'll have them increase the clearance. I'll be giving you a call to clarify some things.

Thanks again.
 
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Robert,
I've gone silent that past week or so while searching for pistons and such, and looking at what it will take to bring this back on track. An honest assessment of abilities and the learning curve ahead (I can't see any way around EFI) to make this work is that I should quit while I'm behind. I am not going to repair this engine other than what the machine shop has already done (cleaning parts, assessing the head and crankshaft). Thank you for all your help, and I truly appreciate all the time and expertise you've shared along this journey, but I can see that others with a better skill set are needed to successfully turbocharge the 152/196. Another way of saying "leave it to the professionals". I need to a simpler path to getting my Scout on the road and addressing the body and suspension issues that really need to be my priority. I am zero for two with the two 196 "rebuilds". I have owned this thing for over 10 years and have only enjoyed a few thousand miles on it and can't keep chasing my tail. I do hope that in the future I can return with other matters. I hope that you continue with your project and know that it will succeed. I want to see pics of it running.

Regards,
Mark
 
Totally understand your decision, I'm sure it was not an easy one.
One thing on fuel management, first I don't believe fuel injection is necessary, and my comment on boost referencing the power valve or enrichment circuit is common for either draw through turbocharging or supercharging.

While my Scout turbo project is parked at the moment, I will look into adding piston oiling jets, tapping into the main supply gallery.

Either way you go, godspeed Mark
 
Robert Kenney said:
Totally understand your decision, I'm sure it was not an easy one.
One thing on fuel management, first I don't believe fuel injection is necessary, and my comment on boost referencing the power valve or enrichment circuit is common for either draw through turbocharging or supercharging.

While my Scout turbo project is parked at the moment, I will look into adding piston oiling jets, tapping into the main supply gallery.

Either way you go, godspeed Mark
Click to expand...
Yes, it was a tough call, but right for me. Regarding fuel management, carb or EFI, with boost and detonation involved, and getting that sorted is a class that doesn't grade on the curve. The pistons and bearings were the report card and I got an "F". I had detonation and didn't even know. I need plug-and-play at this point in my life! On a side note, after I disassembled the engine, I was looking at that oil jet mod where the upper main is drilled and feeds a jet to squirt at the underside of the piston. They make the jigs for the LS and others, but of course not for the SV. Even had a goofy notion to drill/tap through the side of the lower block skirt and and run the squirters near the bottom of the piston at the bottom of the stroke and point up (knew of a Corvair guy that did that for an extreme build). External side oiler, kind of. So I mused about the things that are done now for modern turbo engines to make them live long lives. I think outside the box but must bow to the fact that my mental reach exceeds my physical grasp. You can pull this off, me not so much. So I have an abiding and continuing interest in how yours works out. I'll keep watching for updates.
 
Sorry to hear this. Thanks for sharing the process. Turning a tractor engine into a race engine is not easy. I pit crewed for a SCCA GP 1965 Spitfire for a few years and we won west coast regional champ running that version of a tractor engine up to 8k rpm. I think there are more people racing Triumph than IH engine and the process is a little more known.
 
I enjoyed sharing and receiving constructive advice. Your point is exactly right. I played with my Corvair turbo Corsa because although it was primitive by today's standards, it was properly developed and relatively trouble free. I can see where IH cut corners with the 152T option and it was poorly executed, never approaching the Corvair level of dependability, although same basic parts. That's a big reason a relatively large number of turbo Corvairs are still running around and being rodded. As long as you don't keep it under heavy boost for more than 60 seconds at a time (when the alarm comes on!) it will live forever.
 
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