Limited disassembly of a 1980 IC 196

Michael,
finally getting time to get into my long-term project with the 4-196. My goal was to only take the 4-banger down enought to clean it up and ensure the head and valves were in good shape, and clean out the carbon. It has either 105k or 205k, and the limited times I finally got it to run, it ran strong, idled smooth and quiet. No rumbles or knocking in the lower end - assuming that's good, but we'll see when I pull the pan.

Yanked the engine last week. Today got the head off. It's good news-bad news time, I guess. The front lower head bolt didn't come out easily, and you can see the pic that the threads were packed with dry rust. Looking inside the hole, can still see evidence of threads. No metal or stripping, but probably corroded away. Best way to proceed? I'll run a tap through it to see what I have, but then what? Helicoil? Yikes!

Number six lifter (see pic) has a circular groove that I can just pick up with a fingernail. Number five is just beginning to do same. Prognosis on cam? I'll try to get pics of the lobes.

The cylinders look great; no scoring, grooves or discoloration. Hardly any (if any) ridge. Original pistons, can see part #s on crowns. I'm guessing the lower end is good, but if I see junk in the pan when I pull it, then reassess. See pic - valve heads all have identical coloring, chambers have carbon, but not bad. Not the heavy wet stuff, fairly dry fluff stuff. Plan was to simply disassemble, tank, surface if needed, and reassemble w/new valve seals.

I can't tell if the engine has ever been opened. Head gasket is not the plain steel embossed type, but a composite of some sort. Don't know what was used on the assembly line in 1980.

Hey Mark,

hold your breath.
or I should have written don't.

I like your custom aluminum casting. Where there is a will there is a way. Keep up the good work.

Mark pietz said:

Yanked the engine last week. Today got the head off. It's good news-bad news time, I guess. The front lower head bolt didn't come out easily, and you can see the pic that the threads were packed with dry rust. Looking inside the hole, can still see evidence of threads. No metal or stripping, but probably corroded away. Best way to proceed? I'll run a tap through it to see what I have, but then what? Helicoil? Yikes!

Click to expand...

Lube up a tap and run it in by hand. You really don't need a bottoming tap. I don't expect you to need to install any thread repair items. Wash out the hole with a good blast od carb or brake cleaner and follow with compressed air while the hole is still wet.

Mark pietz said:

Number six lifter (see pic) has a circular groove that I can just pick up with a fingernail. Number five is just beginning to do same. Prognosis on cam? I'll try to get pics of the lobes.

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That odd circular pattern is fairly normal on the IH sv's. Seen it many times. I would recommend regrinding the cam and installing new lifters. Bump up the lift and some duration while you are at it. Stay below 206 intake duration @ .050. Due to the turbo application you can get away with less exhaust duration. Say 202.

Mark pietz said:

The cylinders look great; no scoring, grooves or discoloration. Hardly any (if any) ridge. Original pistons, can see part #s on crowns. I'm guessing the lower end is good, but if I see junk in the pan when I pull it, then reassess. See pic - valve heads all have identical coloring, chambers have carbon, but not bad. Not the heavy wet stuff, fairly dry fluff stuff. Plan was to simply disassemble, tank, surface if needed, and reassemble w/new valve seals.

Click to expand...

Bearings are cheap insurance while you have it appart. Roll in new rods and mains. Also gives you a chance to inspect for wear issues

Mark pietz said:

I can't tell if the engine has ever been opened. Head gasket is not the plain steel embossed type, but a composite of some sort. Don't know what was used on the assembly line in 1980.

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All ic's used a composite head gasket. The clue will be on the bearing shells. IH stampings on the back and its most likely a virgin.

I've been in the hospital the last few days.

I see nothing in these pics that tell me anything other than an old, tired engine that needs a total rebuild. No way around it, start from the block and work your way back to a runner.

No way I'd ever work on one of these motors without replacing the cam bearings as just one part of a build.

Perhaps I had been too optimistic. I'm up for a cam and lifters. Since I'll be pulling the cam, a time to check out the cam bearings (I am aware the #1 goes away - btdt). Once the cam is out, very little remains to pull the caps and check the main & rod bearings. Hate to really go further than that, but we'll see...thanks for the followup. This project May be on a slower track than I had hoped. I'll post pics & specs as they come available.

Robert/michael
this morning I had opportunity to swing by the machine shop that will be doing the work to get prices and all that, so it will be a step by step process. I last did this exact thing 30 years ago on an early 196.

I have the head apart. I have also been following the other current thread about rebuilding a v8. My needs are that my engine won't be run over 4,000 rpm. But since I have the head apart, should I go to the trouble of grinding down the smog hump in the exhaust port and do whatever limited smoothing, etc. I can do before dragging it down for a valve job?

Btw, I bought a cheap set of telescoping gauges from hf and used them with my calipers to get a quick idea of cylinder bore wear. The first three I measured this way were each (side to side) 4.125". The thrust axis (up and down) were 4.129", 4.128", and 4.129" (or close). This was with the gauge just below the ridge, at the top of the wear pattern for the top rings. Have to do the last one later and then recheck them all. Maybe justify just re-ringing?

Mark pietz said:

But since I have the head apart, should I go to the trouble of grinding down the smog hump in the exhaust port and do whatever limited smoothing, etc.

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I would remove the e-port humps. Won't help low speed performance but will improve hp.

Mark pietz said:

Btw, I bought a cheap set of telescoping gauges from hf and used them with my calipers to get a quick idea of cylinder bore wear. The first three I measured this way were each (side to side) 4.125". The thrust axis (up and down) were 4.129", 4.128", and 4.129" (or close). This was with the gauge just below the ridge, at the top of the wear pattern for the top rings. Have to do the last one later and then recheck them all. Maybe justify just re-ringing?

Click to expand...

Imho with a caliper those measurments are only a guess but then........ You need to run a real bore gauge through the bores to know set with the mic used to measure the piston intended for that particular bore . With a turbo I would add .001-.002 piston to cylinder clearance. I'd bore it but then........

The cylinders May do with a sunnen power hone to round them up. But if you don't care "lick it and stick" it back together with new iron rings. Don't go with moly or tool steel rings as they will never bed in on those oval and tapered cylindered. It is 100% your call based on what you expect to have this project yield.

Please don't take my blunt honesty on engine building as an affront to you personally. I just won't recommend anything I would not do for anyone asking me to build an engine for them. Nor will I leave any doubt as to my opinion

I do want your honest (re: blunt) opinion, that's why I asked. I don't like sunshine being blown up the skirt.

If the cylinders are that worn, then I'll likely bite it and move forward with boring, etc. Slows the project down, but I don't want regrets. I'll get the block to the shop and after he tanks it and mikes everything, then I'll know the next steps.

Thanks.

Robert or michael,

I am doing the degree-wheel thing just to see what specs it was born with. Using the positive-stop method, I've confirmed that tdc matches the pointer on the crank pulley hub. Good.

Putting a dial indicator on both intake and exhaust lifters, centerlines appear to be 109 for both (maybe within a degree of that)

here are the numbers for intake/exhaust open and close. I don't quite understand some of this yet, so please let me know how to understand these numbers.

Setting dial indicator at 0 at tdc, rotating in normal direction till indicator reads 0.050" lift, intake opens at 20 degrees btdc. Manual says 18 degrees. (is this 2 degrees advanced or retarded?)

continuing to rotate the crank, intake closes at 104 degrees (dial indicator back at 0.000).

Exhaust is confusing to me. I set the wheel back to tdc and put the dial indicator on the exhaust lifter, set to 0.000. At 0.050", I read 161 degrees, which would be 19 degrees before bottom dead center.

Continuing the rotation, exhaust closes at 42 degrees (indicator back at 0.000).

Can you walk me through making sense of these numbers as they compare to the data in the manual?

Happy to redo them if needed.

Oh, cam gear set has a 21 stamped on it.

Like a blockhead, didn't read the isky instructions closely enough. All readings now done at 0.050" lift.

Intake open at 20 degrees, closes at 160 degrees.
Exhaust opens at 160 degrees, closes at 20 degrees.

My numbers look symmetrical, which is probably good, and they seem to reproduce if I take care with rotating things around.

Now I just need to know how these numbers convert so as to compare with the manual:

intake open 18 degrees before tc, closes 58 degrees after bc
exhaust open 58 degrees before bc, closes 18 degrees after tc

it's probably real simple and I'm not just seeing it, so I'll go sit in a corner and ruminate on it all

You got the duration @ .050 correct but you denoted the intake open as btdc. It is really atdc...
Below is a link to my 4 banger cam valve timing....
Compare your data points to these..
http://www.forums.IHPartsAmerica.co...ming-set-indexing-sv-4-cyl-apps.html#post7262

The IH book valve timing is seat timing and not .050 timing while @ .050 the duration is 180* (20 - 180 + 20) the seat to seat duration in the book is 256 (18 + 180 + 58) = 256. You can measure that using datums of say .001 lifter rise. You'll find that determining seat to seat is slightly more difficult.

To confuse things more, no cam grinder will give you the seat timing but a rather elusive advertised duration. In many cases they use say .006 lifter rise open and closed while others will use .004 open and .010 closed. Mainly because seat timing doesn't give a good representation of performance like .050 does. A valve only open .010 flows a minuscule amount while @ .050 things are beginning to happen..

Understanding duration/lobe center and valve timing is easier if you draw the valve events around a circle on paper placing coresponding event lines around the circle that represent the crank shaft rotation cycles. Then you can calculate the raw timing much easier that way. After a few times using a drawing you will be able to do it in your head quick as lightning.

I understand the relationships of when things should be opening and closing, it's just doing this exercise to get a baseline that I thought would be beneficial. I'm too tired tonight to think on it a whole lot more - had to fix fried wiring on my honda in the rain and a broken door latch, so my day is done. Tomorrow will be a day to start things fresh and do it all over with your data in hand. :sleepy:

after that, I need to finish the disassembly and hopefully get the block over to the machine shop this next weekend.

Still playing with this, but from a practical standpoint, I suppose I have enough to say "enough".

Carefully remeasuring I find cl to be 112 degrees for both intake and exhaust. Intake lift is 0.234", exhaust is 0.232"

values @ 0.050" are the same.
Also got values @ 0.100", but does that really help.

Things become interesting when one checks degrees at 0.001" (or tries to - big changes in degrees w/small changes in lift), and then positions vs. 0.050 or 0.100 can switch from atdc to abdc, and vice-versa. That's what I find confusing. Is it btdc or abdc, which are two ways of saying the same thing, kind of.

What I was really curious about, since it seems to be an issue, is whether this setup is advanced or retarded and if so by how much. When I rebuild all this and have a new cam, how to set that up as well.

All I will get into at this point is that a stock 152 or 196 cam is ground @ 110 lc. 256/2= 128-18=110 works for all symmetrical lobe cams.

Don't know why your event timing is discrepant either that or the cam in non stock......

Good luck with your build..

I'll play with it again tomorrow if I can, but in what I call a hell of a "duh" moment, I noticed that the summit degree wheel has two sets of numbers. Big numbers every 10 degrees and smaller ones, by tens, right under each big one. Often they match, and often not. They are different depending upon quadrant, I.e., which up or down stroke you're looking at. Big numbers for determining cl, smaller number for timing events, I guess. There are arcs denoting "bc", "atdc" and comparable notations. Sometimes not exactly clear enough for my experience level.

Now, based again on 0.050" (which I'll continue to use as a reference unless told otherwise), I see, for example, that the exhaust closes at 55 degrees. Intake still opens at 20, and closes at 20 degrees (the 20 is a smaller number under the 160). That gives you the 180 duration.

I am going to assume my tdc measurement was right, and then re-run these numbers using the smaller numbers. I think it should make more sense after that.

Thanks for your forebearance.

To determine lobe center lines, don't use the "max lift" method.

Read .100 or .200 lift locations on both sides of the lobe and divide the area between those by 2. That is a more accurate but still requires a well positioned degree wheel.

Huh. Using 0.200" lift on either side of the lobe gives me cls of 110 degrees for both I and e.

Hoohaa, good job! Nothing wrong with perfecting the method. Gad you worked it out. You will find that for lobe cl and piston indexing(tdc determination) any where you get a higher lift rate/degree of rotation the accuracy is magnitudes better.

It was hard to see on your photo but the lifter to dial indicator plunger stroke axis's should be as perfectly parallel as possible. Any angularity between their axis will give higher than actual lift values. May explain why you got high numbers for lobe lift. Iirc the oem cam had .225 lobe lift. Could be mistaken however.

The plunger on my dial indicator is fairly parallel to the direction of travel. May be off a tad, but the cosine correction would be slight. I gave up on perfection long ago.... I will double-check, but I am certain the lift numbers I reported were fairly accurate. In a few days I'll have the final numbers on everything.