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Engine Specific Info and Questions => IDI Engine => Topic started by: NWVintage on February 28, 2013, 09:21:34 am
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Hey everyone-
So, I just finished a major overhaul on my '81 1.6d N/A. Rod bearings, piston rings, cylinder ridges/hone, head deep clean, valve lap, stem seals (guides were in excellent shape), all new gaskets from the head gasket up, timing belt/tensioner.
At the end, I reset the timing and I'm wondering what people think about different advance settings. For the early 1.6's (through '81) Bentley says .88 +/- .05. Later - IIRC - are .95 +/- .05. I went with .93, being that it's within both ranges. I haven't actually driven in yet but warmed it up to operating temp twice yesterday with some revs, followed by an oil/filter change to get any crap out of there before I start driving. Seems to run great but its a little diesel-smokey (white/blue, smells like diesel only). With the advance pulled, the smoke is barely there but with the advance in, it's fairly visible. I am using a different cam and didn't have new shims, so I didn't even measure the lifter clearance. They sound like one or two might have a little too much gap but nothing terrible.
Would improper lifter clearance cause significant smoke or should I advance the timing a bit? I am planning for a valve job in the next month or two but I honestly can't afford a shim kit at the moment.
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Drive it first. I've had that smoke on fresh motors just sitting, even warmed till when the fans cycle, and it went away after a real drive.
Pump timing varies, it's partly preference for clatter, partly what the motor will start well at, etc, etc. Lot of variables unless everything is textbook new.
And even then, fuel isn't what it was. I'd set it to .90 or thereabouts and adjust it around after the motor is broken in and settled.
My 2C
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you must drive first to seat/break-in rings. before you do this the first thing is to break in cam, at FIRST start up after a new cam/lifters, rev up to about 2000rpm for 20 min of hot run time to break in cam, you also NEED new lifter shims w/a new or another cam as old shims will transfer wear old pattern to new/another cam.
after re-ringing, it takes 500-1000 miles to break in new rings(alone).bearings take about as long too.
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If it were a brand new cam then I would agree. Follow the cam MFG recomendation. If not I would start the engine, check for leaks, then get it driving to seat the rings. They need load.
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NWV... So it runs? Great but you need to figure out the valve clearance thing. You don't need to buy a whole kit. You know, or can measure the distance between cam and shim right? And you can figure out the thickness of the shim by either removing the cam again, or getting the special pliers and tool to press the lifters down. I have them and they save taking all the caps off and timing belt crap you would have to go through.
So once you know the shim and the clearance then simple math can give you the proper shim thickness that you need and you can just buy those from a parts place or a repair shop. My local guy sells them for like 2.50 each. and he had quite the selection.
Once you get the valve clearances well in hand I expect that the smoke will be less just from that. But break in is needed as well.
by the way the money for the cam was reinvested to another here for a cruise control.
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Thanks for the info guys!
Yes ORCoaster, it runs! Thanks again for the cam!
My initial warmups were with the idle screw turned up (after I started it) to hold it around 2k rpm. The only reason I did it twice is that I wanted to get the oil changed before I started driving and I didn't have time to change it right after the initial warmup.
I got out for a couple good drives yesterday with an 8 hour cool down between. It seems better all around after. The valves sound much better and the smoke situation is also much better. Maybe both were due to a little low compression resultant of the as-yet-unseated piston rings?
How important is it actually to replace all of the lifter shims as it pertains to cam wear? I don't have extensive engine rebuild experience, but I've done a couple prior to this and I have never heard that before - of course I've never replaced the cam before either... I visually inspected each of the shims and they were in very good shape. I realize that I need to get them to the right thicknesses but is it really necessary to replace them all? I suppose its cheap insurance, though...
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People been using second hand shims on cam setups like that forever, they are not a VW specific thing. Never seen or heard of wear because of it.
The book might say use new shims, never even seen that though myself.
If they were one piece hyd lifters I'd say replace them, they are usually half crapped out anyway.
A lifter is supposed to stay with the cam lobe it started life with, by the book.
In my experience if there is no observable wear on the cam or lifter face, it'll be fine.
I'd only do that with something fairly cheap and/or easy to replace a cam in though, for the record. :)
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I gotta go with Wolf. Use what you have if they are the proper thickness for job. I have swapped shims all over the cam and not had a problem. Number side down is my only rule. As long as there is no wear on it I think it will do fine.
Now that you are an expert on rebuilding how about doing the rings in mine? I can't seem to break free from the job long enough to get time for myself these days.
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like wolf said, a lifter goes with a cam lobe, but old shims with new lifters doesnt sound critical, but its not expensive, it has new lifters, a different cam; just seems smarter to measure valve clearance and use new shims, the cams wearing surface is riding on this surface, like he said insurance.
the trick to adjusting mechanical valves (lifters) is the intakes can be closer to min clearance, but not right up on it. the exhaust can be a bigger clearance. works really good for air cooled valves. i havent had a mechanical head in a lot of years, but in an air cooled you notice just a little jump in power from doing this (as intake is a tad tighter and you can get more air in; just a little) and you cool the exhaust more (by it being closed a tad longer). much less critical in a water cooled, but as long as the intake and exaust measurements are reasonable it cannt hurt anything and your exhaust can cool a little longer (per cycle). exhaust measurement like the half way point in the book. (?.001-.002??looser than half way)
measure off the old shims and you should be able to find a parts dealer and get the exact size you measure. using one of those lifter compression tools makes it easy, while using tool make sure you have clearance at the pistons, your pushing the valves open some; dont have a piston in the way.
the measurement trick would work better with new valves/springs/etc.; though.
keeping an eye on the valve measurement will give you an idea if a valve has had it, if the gap keeps tightening up the valve stem or the lock on the stem is stretching and you may want to take care of that at that point.
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On a semi related note, I hate adjusting valves. They run better and the lifters don't fail, but I still dislike the damn things.
If I never have another, which I will I'm sure, it'll be too soon.
The least annoying have been old BMW with the eccentric cam, or Merc diesels if you have the skinny wrenches.
I'd still rather replace lifters every few years and give up a few ponies.
Maybe I'm getting old.
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IMO lifters are not tied to the cam lobe, they don't contact or care about the cam. They do like to stay in their native hole in the head.
I'd not drive without at least checking I had minimum clearance on all valves, it doesn't take long to burn one if it isn't closing.
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every other type of lifter (solid/mechanical, and hydro; 1 piece) are directly tied to a cam lobe as it first runs, to change up a lifter(s) that have 'run' on a cam (lobe) to another lobe will fail.
thats another reason im in favor of keeping shims on an individual lobe(also). as the shim does more than 1 thing, it determines your valve clearance (and effects valve timing just slightly; tight clearances open valves slightly longer; looser clearances valves are closed slightly longer, allowing a little more cooling); also shims ride on cam surface. partly integral to cam / lifter operation.
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If this were true, VW would specify that shims must only ever be reused on their native lifer, but they don't, because it isn't a problem.
lifter to bore wear match in the alloy head is the only reason to keep them in one spot for us.
Roller lifters which are better anyway can go on any lobe or roller cam.
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Air cooled, I do not believe what you are saying. Do you have a bentley or some manual to back it up? IIRC our manual lifters never touch the cam, the lifter has the shim and the bucket deal on top of it, then the cam IIRC. It has been 2 years since I adjusted mine and I could be off on that.
To the OP: if you don't know the values then you should before running. The way I read it before was you knew that it was in spec but at the end of spec...now I see you didn't know what values you had.
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Shims are swapped around regularly.
IIRC, the shims/lifters contact the cam lobes slightly off-center to rotate the lifter as it operates.
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Off center they are, that is how they all end up with those circles on the tops and bottoms. The be spinning man.
Not sure it you have the specs from a Bentley for the 1.6D but they are as follows:
Engine cold the intakes should be between 0.15 - 0.25 mm (.006 - .010 in)
The Exhausts should be between 0.35 -0.45 mm or (.014 - .018 in)
Engine Hot Intakes 0.20 - 0.30 mm or (.008-.012 in)
Exhausts 0.40 - 0.50 mm (.016 - .020 in)
From the timing belt to center they are EIEI Then mirror that IEIE to the trans side of the block. This is the EIEI OH! rule to remember. I have seen several sets of pistons so far that were rounded out by the valves and I think it was due to the wrong sequencing on the valve clearances. Or the wrong head gasket.
For newer valves and such I go a little to the wide side and as valves seat they come towards the middle of the range.
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They very much do wear into the bore in the head. Volvo does it. We have trouble with the lifter carrier in the M96 Porsche motors with it often. That and the lifters suck, but that's another story.
Be glad VW hyd lifters aren't a hundred bucks a pop. :) And the carrier is like six.. Each.
I've been known to use a brake cyl hone on lifter bores in redblock Volvo's to get them to spin freely through there range of motion.
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Air cooled, I do not believe what you are saying. Do you have a bentley or some manual to back it up? IIRC our manual lifters never touch the cam, the lifter has the shim and the bucket deal on top of it, then the cam IIRC.
yea, like i said i havent had a mech head engine for more than 10yrs, i dont have my bentley with me, iirc shims can be swapped. but im skeptical of that as any other lifter combo (in any other vehicle i know of; mech/hydro lifters) you cannot swap a lifter off the lobe its been running on.
lifters do rotate in bore as cam lobe is slightly on an angle and rotates lifter. if i recall its to promote a consistant, even wear pattern.
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So those massive boxes of shims they sell for like 225 bucks are just a bunch of little paperweights? Seems like the design was meant to allow swapping as wear and rebuilds occur. Thus changing the initial distance of the space between shim and cam lobe. I have not had issues moving the little slugs around. But then I do live in the PNW where they are common place.
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Air cooled, I do not believe what you are saying. Do you have a bentley or some manual to back it up? IIRC our manual lifters never touch the cam, the lifter has the shim and the bucket deal on top of it, then the cam IIRC.
yea, like i said i havent had a mech head engine for more than 10yrs, i dont have my bentley with me, iirc shims can be swapped. but im skeptical of that as any other lifter combo (in any other vehicle i know of; mech/hydro lifters) you cannot swap a lifter off the lobe its been running on.
lifters do rotate in bore as cam lobe is slightly on an angle and rotates lifter. if i recall its to promote a consistant, even wear pattern.
No, they are dead flat, offset which is why the last a long time even with crap LE oils. Even my cave man 6.2 Chevy lets you freely swap lifters around, as do all roller cams I've seen