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Engine Specific Info and Questions => IDI Engine => Topic started by: Tmarkle on October 24, 2017, 11:33:55 pm
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Just picked up a clean Rabbit a couple weeks ago. Cosmetically it very nice, but the glow plugs are dead and it loses prime, these are minor details though as I have the parts to fix them. However being it’s an 81, it has the 11mm head bolts. I have read many terrible things about the dreaded hex head bolts, but if the car is not mixing fluids, is it worth running/tuning up? I have a 12mm hydraulic motor but it needs new pistons still (timing belt failure) so I’d like to just run the bunny for a while till I have time to rebuild the other one. I have new glow plugs, a new upgraded injection pump, and new injectors I’ll install along with a 4-2-1 exhaust manifold and a mk2 1.8 intake manifold. I have everything to run it turbocharged but I’ve been frightened by the small head bolts. Has anyone attended to put in ARP head studs 1 by 1?(https://uploads.tapatalk-cdn.com/20171025/fa86af9f292d5509e8900dc609b7e895.jpg)
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Tmarkle, Nicely picked VW there.
The 11 mm head bolts are not to be feared. Your idea of 1 by 1 stud replacement with ARP studs will work. Others have done just that and have not mentioned any problems.
I would just run it the way it is with the additions of the 4-2-1 exhaust and the 1.8 manifold. I am assuming of course that the exhaust out the end of the header is 2.25 or greater.
Being a new to you car I wouldn't push it any until I got the feel for it. You never know what the PO did to it and there is no reason to try and shake it down now. Improve it over time, but for now just mod it slowly until you learn its quirks.
Baby Blue to Boot, Needs some snowflake wheels on it.
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A LONG time ago, I had a baby blue 4-door Rabbit like that. I ended up putting 1.6 TD engine block in it from a Quantum, but without the turbo, etc. I don't remember what fuel injection pump I had on it. I know there were TONS of rabbits produced, but just on the off chance that was once mine, double-check the engine code. I see you're in Montana, which isn't that far from Utah, so it's conceivable that it could have migrated that at north. But if you were in Maine, then I wouldn't have said anything.
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Thanks ORCoaster, I’m hoping to give it a good tune up and get it going for a work car. New timing belt, new glow plugs, valve adjustment, and the new pump since this one seems to be walking the belt a bit and wearing far more on the outside. If I didn’t have the new pump already I wouldn’t probably worry about it, I’d just try to run it. Obviously, it will also get new filters and fluids. I’ll be interested to do the studs 1 by 1, in hopes of saving the block.
rabbid79, I’ll take a look at the code for you. I know many people who outsource vehicles from other states so it could have once been yours. Was yours a four or five speed? This is a four.
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if you're not having any headgasket problem i wouldn't put studs in. Just drive it like it is or mod it like it is, the problems arise when it comes time to replace the headgasket, tightening the headbolts can crack the block.
if the belt is walking away from the engine you probably just need to adjust the pump bracket to get the belt to track straight.
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I've replaced studs one at a time with no problem,.. on the VNT 15 rabbit with a 1.5.
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If I decide to toss my turbo setup on it studs will definitely be on the list, but for now she will be getting a good tune up and exhaust so I can daily drive it.
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I've replaced studs one at a time with no problem,.. on the VNT 15 rabbit with a 1.5.
Out of curiosity, was this pretty simple? Just remove one head bolt, run a stud in, and torque down, and repeat for each bolt? Since I have all the parts, once I know it’s running well I’d love to boost it for some more get up and go.
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Yep, just that easy.
I did it in the proper torque sequence,.. starting in the middle.
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Began wrenching on it tonight. Trouble I found is that I can’t find the tdc mark on the flywheel. I know that the cam was a bit off time from the crank because I had to tighten the belt the night I bought it (long story) so what’s the best way to find tdc in this case? Pull the cam and pull the injectors to relieve compression and rotate motor till I find the mark? Wire through an injector hole?
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This was a running engine YES?
pull the valve cover off and rotate the engine such that the first cylinder, the one behind the timing belt has the lobes of the two cams in an upright position. Like the wings of a butterfly. You should be able to rock the engine a bit from one side of the rotation either way from that reference point and spot something on the flywheel through the peep hole on the bellhousing. Take the large plastic cap all the way off and set it aside. Position your head and a strong light to look up towards the engine block moreso than straight down. You should see a dot or a line or some indicator across from the small triangular pointer at the top of the hole.
Let us know how it goes.
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Maybe it has a 210mm gasser flywheel upgrade.
Do you see the big square blocks?
I posted in a thread about how to find TDC using fluid and a tube here awhile back.
You can use my name in a search.
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Well... Found out something I should have checked when I bought the thing. Turns out it’s a 1.5, I was checking the engine code and it’s CK. Question is will my custom 1.6 injection pump and new injectors work, I can’t see why they wouldn’t. Are 1.5s worse than an 11mm 1.6?
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The 1.5 is the first of a long line of diesels made for these cars. It had the 11 mm headbolts. Your 1.6 pump and injectors will work in it just fine. You can turbo the 1.5 if you want to get some additional HP out of it. I think it had less than 50 and that was pretty weak when it came to hauling the capacity of the car.
How did you miss it being a 1.5? Misrepresented merchandise? Unknown to seller?
Did you get the TDC figured out?
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I honestly don’t think the seller knew. He said it was a 1.6 and being an 81 I didn’t think to check closely. Had it been an 80 I would have been more suspicious. He didn’t have a clue about VW diesel so he probably didn’t think anything of it. Oh well, no big deal I guess. Haven’t figured out tdc yet cause I was fiddling with other things last night.
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I think they started putting the 1.6 in the 81's toward the second half of the production year. I have two 81's both built late in the year and they have 1.6's One is already oversized the other is stock.
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Got TDC figured out. Just had to rock it back and forth while watching it so I could catch it.
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So the last issue I need to sort out (for now) is one injector heat shield is stuck in the head. Any trick to getting these out when they are stuck? I was thinking maybe put a screw through the hole and crank the motor over and let the compression do the work.
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Who had this same problem just a bit ago?
It was suggested that a good stiff wire be looped in there and soak it down good with penetrating oil and pull up with sharp raps. I have a pair of needle nose pliers that I use to poke in the hole and wiggle them free. But they may not be as stuck as yours.
A screw or fine threaded bolt with one of those self tapping tips on it would allow you to pull, and rock it side to side and get it out. Just use one that is about 2 - 3 inches long so you have a good handle and leverage.
From VanBCGuy, Testing the injectors thread/
Once they're out you need to remove the heat shields. I've personally had quite good luck here and mine have always come out somewhat easily. The best tool I've used is a strong magnet - since the head is aluminum which isn't magnetic the heat shield is pretty easy to grab.
For the ones that are a bit more stuck I use an old bicycle spoke - the head of the spoke grabs the inside of the heat shield quite well. Other people have suggested using a large wood screw or cranking the motor over and having the compression blow it out. With any luck though they're not particularly stuck.
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This one is really stuck... I’ve tried using a pick with no success (except marring the heat shield) and a few raps with a punch to try to loosen it, to no avail. I’m going to try the compression trick and hopefully that does it.
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Just be sure to put the hood up and a heavy blanket over it to catch the flying piece.
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ive gotten them out with an easy-out before, it lets you grab it in the hole and also spins it to free it
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Drove a screw in the heat shield and cranked her over, it shot out like a bullet! Got the car running tonight. It is slow, but smooth under acceleration. If it sits and idles it seems to “load up” and puff a light white haze and idle ever so slightly rougher, but I think this is timing related. I thought I had it timed pretty advanced but I’ll do some fiddling. Thanks everyone for the tips and tricks. P.S. the Vince Waldon “pimp your glowplugs” is the way to go!
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My previous description of the smoke was not very accurate. It seemed like that at first but it is the fact that it’s sucking air somewhere. I did play with the timing a bit more and bled the injectors a few more times and it’s running way better but if it sits for even 30 minutes it slightly loses prime. I’m gunna go through and replace all the rubber fuel lines.
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With clear lines right?
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With clear lines right?
Yessir. I’ve got it idling nice and smooth and after running for a while it runs super smooth, and it’s surprisingly quick (for an NA) but when it is first running it wants to sputter under acceleration for the first few minutes of driving. I have the pump timed as far toward the head as it will go and the cold start out. Without the cold start out it runs like crap, warm or cold, so I’m thinking I’ll be completely resetting the timing as well.
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Yes reset the timing!!! You should not have to run with the cold start out to keep it running. And if you are at the limit towards the head do you actually know what measure of millimeters you have for timing? Or do you not have the gauge and pin setup for the back of the pump?
Do you still lose prime or did the hose swap take care of that problem?
I have a Rabbit that I have removed one of the shims on the advance piston mechanism. It is a lot quicker than the Caddy I purchased a bit back. I think I will be modifying that pump in the same way. Someone may have already snitched out one of the two shims on your pump it sounds like.
Glad the smoking has been cured.
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When I set the timing with my gauge I set it at 0.98, and it didn’t run well there at all. The farther I moved it toward the head the smoother it ran. With the cold start out it runs well after it’s warmed up. It hates to start in the cold. Barely below freezing tonight and it was a battle and a smoke show to get her running. Once it started it ran ok, hesitating just barely under acceleration as stated earlier. The pump was modified by my local shop, and they do great work. They also redid the injectors. Once it runs for a while it’s actually pretty impressive for an NA in my opinion, and a 4 speed no less. I’m not sure if it’s my timing not being right or I’m still losing prime, but I replaced all the lines with clear ones. The little injector jumpers seem to hold some air bubbles in them, maybe they are the culprit. Would a check valve on the line to the pump be beneficial? Hoping I can get this little thing going good so I can enjoy 40 mpg compared to my small block Chevy’s 9 mpg lol
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0.98 on a modified pump might still be considered retarded for your built pump. At this point I would be looking to bump the belt a tooth towards advance and then pull the pump back into a more middle position. You might be looking at running at 1.03 or someplace along that line. It should fire off better in cold weather than what it sounds like it is doing. Advance will help that, just be aware that more advance means more clatter under the hood, but it is a diesel right. That sound is OK for us to hear but others might point to your hood and tell you there is a problem with your engine. Have them stand next to a Ford or Dodge truck with a similar IP setup.
As for a check valve I wouldn't go that route. The air comes in from both sides of the pump, the inlet and outlet. So it isn't something I would recommend. Tiny bubbles in the jumper hoses between injectors is OK, that is only the extra fuel that didn't get used for power. Never really a lot there, not like it is flowing like in the return to the tank. That comes from the first stage of the IP and is cooling the IP as it does its route from inlet to outlet.
If you are still losing prime you might have copper o rings that need smoothing. Inlet and outlets have them and so does the fuel filter. Start with the IP Out bolt. Get some really fine, 400 or 600 grit sandpaper, some oil and a piece of glass. Lay the sandpaper down on the glass, put on a good coat of oil and press the o ring down with your fingertips. Push it around in a figure 8 pattern an even number of times. Then look at the flat parts and see if there are lines or it is all smooth across the face. Once you have that done you should pass a flame across the ring to anneal it. Just make a quick couple of passes with a propane torch, you don't need to melt it, just turn in blue. That might help get the fine lines of past tension out of the system. I use a 1/2 inch sized rachet and a 17 mm socket to tighten them back on.
Keep working on it. Winter is coming fast and you don't want to be stranded with a low battery and hard to start combination. You will only have one try to get it running if you do. I carry a Jump and Carry battery pack, mostly for others but there have been times I needed it too.
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I will give those things a look. Thanks for all the advice ORCoaster!
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I agree, you'll have to move the timing belt one tooth on the injection pump sprocket so you can advance the timing farther.
That's probably why it stumbles after a cold start.
Having the pump tilted farther forward also makes it easier to mess with the injectors.
Then just watch those clear lines before and during startup.
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I’ll try the timing bump. Another thing is I know the fuel in it is probably decently old, which probably doesn’t help, but it does have a new fuel filter. Every once in a while I see some tiny air bubble go out the return line, and after it sits a bubble sits at the top on the line to the pump. It has an electric fuel pump which probably helps a bit but I still think there’s an air leak somewhere for sure. The pump has all new seal so I’m almost sure that’s not what’s sucking air.
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Reset the timing tonight. I advanced it by one tooth as recommended and then started it and slightly adjusted by ear, and holy smokes does it run nice. It has great power (for an NA) and purrs nicely at idle. It is quite a bit louder with the timing more advanced, but that doesn’t really bother me. Thanks everyone for the advice!
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A bubble sitting by the filter is common.
If it was sitting at the outlet of the pump or came from the input of the pump instead of the filter then it might be a mainshaft seal.
A little dip in the line between the pump and filter will let you know where it's coming from.
Glad to hear you got it running so well.
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Just out of curiosity, is it worth it to rebuild a 1.5? This one runs pretty well as I said, but after putting some miles on it I see the head gasket is leaking some oil externally. There is not much blow by at all, so I think the cylinders are probably decent. I’m thinking with ARP headstuds it would be pretty good. Thoughts? If I do decide to rebuild it I would prefer to run with a turbo.
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I know that the issue could be fixed by a simple head gasket replacement, but I’m itching to build a motor from the ground up!
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If you build a 1.5 you'll need a turbo.
It just doesn't have enough power to handle a hill and a headwind.
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If you build a 1.5 you'll need a turbo.
It just doesn't have enough power to handle a hill and a headwind.
I have everything to turbo it so that’s not a problem. With head studs and an oil cooler would it be plenty solid? I’ll also use a 5 speed transmission rather than the 4 speed. I don’t want to rebuild a motor that’s not going to be reliable or be able to takes hills.
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"I don’t want to rebuild a motor that’s not going to be reliable....."
Well, then go out and find a 1.6 and put an end to the drama already. Yes....it really is that simple.
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In Montana it’s not as simple as just finding a 1.6.... They are difficult to find and outrageously priced when you do. This is the first 1.5 I’ve had, and I’ve never rebuilt one, so I don’t know if it’s going to be reliable if I rebuild it. Some people claim that 1.5s are piles no matter what while others say they are like 6.0 powerstrokes, with headstuds they are fine. No need to get upset, and I’m not really sure what you mean by drama, just asking questions from people who I know have more experience with these cars than I do.
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My 1.5 with VNT-15 turbo worked great and took some serious abuse.
It'll work great with a turbo,... if the headstuds install properly,.. if they don't pull the threads out,... and I've only heard of studs doing that once.