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Engine Specific Info and Questions => IDI Engine => Topic started by: oblique on December 27, 2022, 06:53:48 pm
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Is there any difference? I know the NA blocks did not have the oil squirters for piston cooling and the intake valves in the head *may* be different between the 2 but the cranks, rods and pistons are the same?
Found a clean NA 1.6 motor at the yard and want to know if i would be able to use it as spare (or build) on my TD.
2 pics each of 1 main journal and 1 rod journal:
(https://i.ibb.co/3kwP727/20221227-103348.jpg) (https://ibb.co/3kwP727) (https://i.ibb.co/M7MXTF9/20221227-103402.jpg) (https://ibb.co/M7MXTF9) (https://i.ibb.co/WK3dDgt/20221227-103415.jpg) (https://ibb.co/WK3dDgt) (https://i.ibb.co/PZ3Pccw/20221227-103423.jpg) (https://ibb.co/PZ3Pccw)
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The very earliest td cranks had heat-treated snouts which I believe was more for running air conditioning than any other reason. I believe they quit this practice. These crankshafts have very hard bearing journals....at least the German ones. I tended to see more wear-ridging on the Brazilian cranks and I actually threw the Braz's away.
On the 1.6 and ALH engines I have rebuilt, I always hand sand the journals down to 3,000 grit and my stuff runs like the wind. I am sure others will take a dump on this suggestion.....but, the way my stuff runs, it is hard to dispute the practice. My bearings are well-oiled.
If turbocharging the n/a blocks is a crime....then, I am a BIG sinner!
Actually, in all the years I have run 1.6 engines....I have NEVER roached a crank. Follow the intelligent coaching found in the Robert Bentley manuals and ignore the billyjoebobs out there. Always use assembly lube when putting an engine together and do NOT apply hardly any oil to the rings when you slide them down the cylinder. Place your top ring gap 180 degrees away from the exhaust valve....the 2nd ring 180 off THAT first ring and place your oil gap away from the #2 gap and NOT above the wrist pin. BE VERY fussy with assembly. It all pays off. Do not wear your ball cap tilted and rotated 45 degrees from front either.
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What about overboosting NA blocks? I have a Giles pump and it will be running 15psi for sure...would the extra cooling oil would be good for longevity?
I know VW made mark2's in Brazil
Africa and China well into the 2000's but I assumed all mark2 diesels (up to '92 produktion) came from Germany. All VINs Ive seen back that up but obviously I dont know for sure. I can check the crank itself.
As for the blocks, they all seem to get the ring wear in the bore and leave a nice lip at the top, between deck and top of piston stroke...it seems to be more pronounced on boosted motors? Anyway I assume the bores should be enlarged when starting fresh..obviously the ring end gap is slightly bigger but also the rings dont sit as deeply inside the piston grooves...i assume this is a good pathway to loose some compression/blowby.
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Do not wear your ball cap tilted and rotated 45 degrees from front either.
Awh come on dad ALL the Cool kids wear em like that.
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What about overboosting NA blocks? I have a Giles pump and it will be running 15psi for sure...would the extra cooling oil would be good for longevity?
I know VW made mark2's in Brazil
Africa and China well into the 2000's but I assumed all mark2 diesels (up to '92 produktion) came from Germany. All VINs Ive seen back that up but obviously I dont know for sure. I can check the crank itself.
As for the blocks, they all seem to get the ring wear in the bore and leave a nice lip at the top, between deck and top of piston stroke...it seems to be more pronounced on boosted motors? Anyway I assume the bores should be enlarged when starting fresh..obviously the ring end gap is slightly bigger but also the rings dont sit as deeply inside the piston grooves...i assume this is a good pathway to loose some compression/blowby.
What I did with my Vanagon was to have the pistons ceramic coated. This was recommended by a couple engine builders I spoke with. They said forget adding the squirters and just get the coating. It was fairly inexpensive also. Apparently some oems are doing this now instead of spray cooling
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Interesting. Is this really the only difference? The NA block im looking at has a large "1.6D" cast into the back...are TD blocks the same? How different are the oil passges between the two? If they are different castings, maybe the TD also could be thicker or more gusseted, etc.?
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I had a TD block crack near one of the mains.
I've never had that happen to an NA block.
I know that doesn't mean much, because of the low sample numbers.
I have beat on some NA engines though.
Even the old 1.5s, and the block and crank were not what failed.
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Wow so sustained 15psi on the NA block should be fine? 😁
These are the only numbers i could see on the crank...looks like partial part numbers? Not sure how this is read.
(https://i.ibb.co/MsFqRP9/20221231-153942.jpg) (https://ibb.co/MsFqRP9) (https://i.ibb.co/gTXxf09/20221231-153932.jpg) (https://ibb.co/gTXxf09)
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Yeah I've done that and had no problem.
Even a little more.
It's a safe maximum for a 1.6D.
EGTs are more important than boost.
Keep it under 1200F.
I've spiked over 30psi with the uncontrolled VNT,.. using head studs.
Ran it at 22psi and 1200F for a sustained time,.. before I found the VNT max efficiency is around 15psi.
Flying down the interstate it sits at about 8 or 10psi with the VNT-15.
So hard to imagine 15psi sustained without a nice hill.
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Interesting. Personally, I will not be using a VNT - it will be either a factory mk2 Garrett T3 or a K14 from an AAZ with a Giles pump built to 15psi.
I would just reeaally like to know if there are structural differences between 1.6D/TD in terms of the actual design. Oil squirters aside, does the TD block have thicker walls or more/heavier gussets or whatever else...even if NA blocks have been proven...I am curious.
So junkyard photos time...what do I look for in an NA block? Assuming the deck does not have nicks or gouges..what are some indicators? I am the one that stripped this one...everything on this motor was actually in pretty nice shape, especially given our cold, salty roads up here. I've taken most parts including the crank and rod above...the head is decent but the precups have some hairline cracks....cracks between valves are all there but have not opened up at all. The cost for this thing would be about @240CDN...say 200USD:
(https://imagizer.imageshack.com/v2/320x240q90/923/No3DuK.jpg) (https://imageshack.com/i/pnNo3DuKj)
(https://imagizer.imageshack.com/v2/320x240q90/923/6yKfBX.jpg) (https://imageshack.com/i/pn6yKfBXj)
(https://imagizer.imageshack.com/v2/320x240q90/923/2tc4Wm.jpg) (https://imageshack.com/i/pn2tc4Wmj)
(https://imagizer.imageshack.com/v2/320x240q90/924/iQBDFZ.jpg) (https://imageshack.com/i/poiQBDFZj)
(https://imagizer.imageshack.com/v2/320x240q90/924/iB5X1D.jpg) (https://imageshack.com/i/poiB5X1Dj)
(https://imagizer.imageshack.com/v2/320x240q90/924/6SJigZ.jpg) (https://imageshack.com/i/po6SJigZj)
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If you loosen the cam caps and remove the lifters you can put the cam back in place and see if it rocks/ teeter-totters.
That will tell if the head is warped and how much.
I was fortunate enough to have a bunch of prechambers from old heads I scrapped.
So I don't know where to find new ones.
Looks like a hydraulic block so check the cam for chips where the valves ride.
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In terms of the head warping...do they always dish away from the cam on the ends? Otherwise the teeter-totter method cant tell you if the head is curled upwards.
I have 2 junk heads I can pull parts from..reading about precups it seems:
1. They are supposed to protrude a few thou past the deck...i assume this is because aluminum expands more than the hardened steel they are made from and the head surface is flat at temperature?
2. They are not supposed to be a tight fit cold. A light interface is ideal, again, i assume because aluminum expands more than steel.
3. You can knock them out though the injector holes and peen the head slightly if they are too loose.
I have a couple junk heads i can pull the precups from as well.
A note on valves: where do they typically wear? I assume at the guide..what about at the seat or otherwise? Retainer? Pulled one each from a cyilnder...intake has a part number but the exhaust doesn't...I have heard this might be typical of OE?
(https://i.ibb.co/4dmKrpg/20230105-171342.jpg) (https://ibb.co/4dmKrpg)
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From my experience they are always high in the center when they warp.
So the cam teeter totters.
I think prechambers protrude because they are held in by the head gasket and this allows more force on them.
It's a pretty tight fit, You'll find that out when you try to remove one.
I put a valve adjuster shim on them and smack them good before I try to remove them.
When removing them I fill the prechamber with salt so the pressure doesn't just hit one spot.
It spreads out the impact. Otherwise you can crack the prechamber right near the exit hole.
All prechambers are not created equal in size.
The prechambers from a 1.5D will fit a 1.6TD head but an NA prechamber won't.
I see most of the valve wear on the part that contacts the seats.
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Alright, in terms of the head:
1. Bentley says cam caps are not interchangeable in terms of positions...are they all different? I think folks swap camshafts all the time, no? What about the lifters? Bentley says same, don't move them around...but we do anyway?
2. Bently has nothing about cam lobe spec...just info for journal wear and shaft runout...what is a good way to tell if a cam is still good? Whats the difference between a 'just good enough' cam vs. like new?
3. How do I remove valve guides and seats from a junk head? replacements are very difficult to find, as far as I can tell.
Thanks for precup removal tips, I will try popping them out tonight.
On an unrelated note, was at a wrecker today and saw this at the vac pump..am I crazy or does that look stripped out in one direction.
(https://i.ibb.co/ZBLHMVq/20230106-152549.jpg) (https://ibb.co/ZBLHMVq) (https://i.ibb.co/Wk5CD0g/20230106-152600.jpg) (https://ibb.co/Wk5CD0g)
I was after the intermediate shaft but couldnt pull it out - it was binding even w vac pump removed - is it catching on rods or a counterweight on the crank at this position in its rotation? Head has been off for a while, bores are pretty rusty.
Also: can the intermediate shaft bearing be replaced and int. shaft ground down? I do not see the bushing as a separate part, wondering if there are aftermarket options?
Thank you for all awesome info thus far.
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Yes, cam caps are different. All different? No.
Occasionally you can find a matching cam cap from another head.
The lifter kind of wear to the bore and shouldn't be swapped to another hole.
Cam wear can usually be seen at the peak, where it has the most force against the lifter.
I think valve guides can just be hammered out. I think a shop would use a press. Hot head cold guide to put them in.
I think, from what I see in the pictures, the oil pump shaft and vacuum pump are too far gone.
Looks like they have started to "ramp" which shoves them away from each other.
I-shaft should pull right out even with the vacuum pump in place.
Turn and pull.
Don't grind the shaft down. Sometimes they need to ream the bearings after install.
I like sealed power I-shaft bearings. Others are too loose or tight.
You want it to turn a little hard by hand after new bearings and I-shaft are installed.
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Ok so camshafts themselves are the same but, the caps are matched to the head? Are they marked? If I misplace them how do I know where they go back?
Is it the same for rod and crankshaft caps?
Back to the intermediate shaft: I could not remove it even with the vac pump out. The shaft itself rotates freely but when prying thru vac pump hole it would bind..not just hit a blockage but bind on something and stick...I can only assume it must be the crankshaft if it's an interference fit in this particular position.
Valve seats: I did not see a lip for punching the seats out like you would a head race bearing on a motorcycle. I am assuming valve seats are non-reusable because they must be destroyed to remove them, correct?
https://www.youtube.com/watch?v=eZnWi6xcKqk
I did knock one of the precups out...yep, they're in there.
Valve guides are out too but I made a mess of some of them, brass is soft. I guess the head should be baked first.
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NA camshaft equals NA camshaft. I think the hydraulic cams are different.
Cam caps are marked with numbers stamped in them
Rod caps are always kept with the same rod.
Might need a slide hammer for the I-shaft. I've never heard of one not coming out.
It's not the crank interfering.
Valve seats don't usually get removed,.. they just get ground to match the valves.
I've heard putting a couple tig welds on them will cause them to shrink,.. if they do need removed.
If too much is removed the valves sit higher and on a mechanical head will mess with the clearance on the valve adjustment shims.
They only go down so thin.
That's one reason why new valves are recommended to help lower the valve.
I've heard that drilling the valve guides will make them thinner, heat them up a little and make them easier to remove.
Also makes them harder to get a grip on.
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So I am working only on hydraulic NA heads/motor. The junk head Im salvaging parts from is from a 90NA Jetta and the motor Im rebuilding is from a 91NA jetta coupe, although i may turbo it.
So are hydro NA camshafts different from Hydro turbo ones?
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I don't think they are different.
Since they have the same stroke,.. rods and crank.
Power curve would be in the same place.