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Engine Specific Info and Questions => IDI Engine => Topic started by: Gizmoman on August 04, 2012, 03:38:43 pm
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I am rebuilding my 1.9 due to what appeared to be a blown HG - never saw positive sign of that but I did have a loose pre-cup on # three and the others were a bit loose as well.
Today I got into the bottom end and pulled the pistons. All look quite good with the exception of #4.
Both the barrel and the piston are scored :'(.
The bore is stock 79.51mm and all other barrels look good (however, if there were ever hone marks, they are gone) but #4 is scored down both sides (front and back) and I doubt a hone would clean it up. The top ring on #4 piston is sorta jammed into the groove. My guess this thing just got a bit too hot? What else could have caused this?
Some of the scoring actually may be some aluminum from the piston and if I were to hone it, that would go away. In other words, possibly honing is worth a try.
If anyone knows of a good shop here in San Diego, please let me know. Also, any recommendations on high quality rings and pistons would help.
Thanks
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Maybe lack of lubrication in a previous life?
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I would say this is further evidence that it was ran really hot, high egt's. The precups don't come loose with out that heat and it looks like the piston grew too much for its bore. If it has been ran like this I would recommend the shop taking a look at it.
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Yeah, I agree, defiantly got toasty in there!
I'm wondering if a plugged oil squirter on 4 could cause this as it's only #4 - the other 3 look just dandy - I would think 2&3 would be the first to go. Any thoughts?
You'd think I would have know better turning up the fuel and boost with no IC or EGT - well, I know now :)
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It is a possibility that the oil squirter was messed up, but IIRC they usually stick open not closed. Not sure on that one.
Another idea is that #4 fuel injector could have been messed up. Bad atomization causing hot spots.
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Ok, That makes sense (you usually do ;D)
While I'm putting my list of needed parts together I am also going through the K14. In the FAQ, there's tons of great info and a lot of it is from you. In particular, I need to remove the waste gate (customized an Allen wrench already) and I have it loose.
Getting it out though seems impossible. The post in the FAQ says So following Andy2's advice, I slide hammered those heat shields out of there! Here is what it looked like when they came out... lots of carbon built up:
Does he mean he used the waste gate housing as a slide hammer? Should I heat the housing up? This thing is really stuck - looks like " the heat shield is part of the casting.
Any advice appreciated.
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I did that and used the wastegate housing as a slide hammer. For the time and hassle involved send it to those guys in Ohio that rebuild the turbo for 225.00
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Right after I asked, I went back and got after it - came right out after about six "hammers".
Defiantly couldn't have been seating too well on that bet of carbon.
I'll take your advice about sending it out. Hope they don't charge extra for getting a box-o-bits :)
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Another possibility is that the exhaust or intake valve on that cylinder leaked and let out the boost air. The resulting over-fueled situation got the piston too hot and it started to melt. That would be pretty easy to check. Tip the head on it's side with the ports up and pour/spray some solvent in there. If it leaks out on the combustion face, your valves were leaking. Any impressions on the piston tops?
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OK, I did the leak test and it appears to be bleeding a bit out around both valves. As to "impressions on the piston tops" - I did notice some fairly large chunks - yes chunks of carbon in the intake ports. Some of this stuff is quite hard and there are some tiny marks on top of the piston near the edge. It actually looks like a few bits of carbon broke loose and may have gotten in there (as if could go anywhere else :)). The piston sides look like someone tossed in a few large grains of sand. Could bits of carbon do this and why would I have carbon on the intake ports anyhoo?
I 'spoze from leaky valves?
Right now the carbon is crusty but not as hard as sand. I wonder though what i's like when it's really really hot.
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I think I found a decent local machine shop to do the block boring. They say they specialize in Diesel engines.
Before I take it in to them, what would be a decent price to expect to have them just bore all four barrels to one size over from stock.
Any advise on what I should ask about - special things to consider, etc?
I am also looking at Hans pistons. I've heard they are pretty good but that I should get rings somewhere else. Any suggestions?
Thanks
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AS far as the machinist price, I can't help you there. Prices do vary moderately, though.
As for Hans (aka Prothe) pistons, yes you can use the pistons but don't use the rings. Too many folks have reported excessive consumption post-break in. Stop by your local NAPA and order some OS Goetze's.
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Thanks Crazyandy - much appreciated. His pistons look 1st class in the photos and with what appears to be an anti-friction coating on the skirts. I noticed on the Goetze website they make metal head gaskets as well probably spendy but a wise investment.
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Just remember that "specializing in diesel" doesn't mean they know about these engines. My last machinist did reluctanly bore to the .001" size bigger than the piston. But he didn't want to as he said most diesels were bored to around .003"...that is the wear limit of our engines. I would check out the bently and ask them many questions about what their plans are to do, if you know what is expected then you will know what you need to hear. If they argue and won't do it as the bentley says then leave and find one who will. Also have your pistons in hand when boring, I wouldn't trust a shop that didn't bore to the piston and just went with a .020" over stock as some pistons measure differently.
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Excellent advice theman53, will do.
After doing a search on Gotze rings, I found some very unhappy guys who get wide ring gaps using them - even after several attempts. One poster said he goes one size over and files them to the proper gap.
I believe you have been involved in several of these discussions as well. What is your opinion?
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Regarding the bores of each cylinder, is asking the shop to bore to match each piston and number the pistons getting a bit too silly?
As I currently still have the crank in the block (rolls over very sweet with no apparent play) and I have read where having the caps torqued while it's being bored - should I leave it in? If so, what about the oil squirters?
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I don't know of any trouble with Goetze rings. Grants maybe, but not Goetze rings. My machinist had to do more than twist my arm to not use them over the Klobenschmidt that came with my pistons. I still don't know if I made the correct choice.
Not only did I not have to file but every ring I put into the bores and measured was dead on.
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My machinist had to do more than twist my arm to not use them over the Klobenschmidt that came with my pistons. I still don't know if I made the correct choice.
Not only did I not have to file but every ring I put into the bores and measured was dead on.
That also speaks to the machining job quality as well. What are your thoughts on the crank. I've never had a block bored but as I've read the caps (I'm assuming the ones that hold the crank and bearings) need to be in the block and torqued to spec to insure the bores are dead on at final assembly.
Is this true or not? and if so, does that mean just the caps and not the crank? Sorry to ask so many questions but I really want to get this right.
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Yeah just the main caps. The crank actually rides on oil and not the bearings, so it wouldn't matter if it was in or not.
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Great - 'spoze I should machine the end of the crank then while it's out then eh?
I still have the stock one and the notorious "key" that often fails. It was tight though when I took it off but as I said - I'm looking for dependability 1st.
I also read that there are better ways to drive the alternator than the stock v-belt and heavy harmonic balancer. Any info on that?
- I know I'm just full of questions :-\
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It cost me 20.00 to machine the end of the crank for the D sproket. You may not find a machinist that cheap, but IMHO you are an idiot if you could get it done for under 100.00 and don't. Even if you are running Vbelts, the added security is worth it.
Top of the page, see the FAQ link. Look for serp setup.
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These are all great questions, as I'm going through the same issues or have done them already. YES get that crank D-cut, but supply the TDI sprocket with the crank when you take it to the machinist. That way he can get it cut exactly but still make sure the crank is properly cut before recieving it after the work is done; ask me how I know. >:(
As for the alternatives to a v-belt setup, you can use an ABF serpentine belt setup or a setup for one of the TDIs IIRC. Mine looks liek a mk3 gasser-style setip, but for a diesel, just can't rememver the engine it came off of right now. I'll get the PN and find out later.
ANd to back theman53 up, yes allways have the block machines w/ main caps torqued.
As for the Goetze ring concern, I'm afraid I'm gonna have to personally back up the end gap concern. Got a set of 4 for 0.5mm over, and the gaps measured from 0.28-0.30". Anyone using sealed power or other manufacturers could probably chime in here, but I hope I'm an extreme minority. Gonna try getting 1 ring set from someone else and see whet they read out to be.
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For boring the block, any machinist will very likely want only the bare block, main caps and bolts. The crank should be removed. The oil jets must be. Don't torque the main caps down. The machinist will want to do that after cleaning the block. As far as them cleaning the block, they won't want a block that has grime caked on. Get most all of it off first. In my experience, they will want to do the final cleaning. Depending on what process they take on cleaning it, you should replace the galley plugs, intermediate shaft bearings, oil pump bushing and freeze plugs. If memory serves, the galley plugs are 14mm. The freeze plugs are something like 36.5mm. They are not a whole number...
As far as ring end gaps being out of spec, did you mic the bores? Any increase in bore diameter will show up multiplied by three in the end gap.
If having the crank nose machined, have it trued up first with a minimal of material removed.
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As for the Goetze ring concern, I'm afraid I'm gonna have to personally back up the end gap concern. Got a set of 4 for 0.5mm over, and the gaps measured from 0.28-0.30". Anyone using sealed power or other manufacturers could probably chime in here, but I hope I'm an extreme minority. Gonna try getting 1 ring set from someone else and see whet they read out to be.
Yeah, but your machinist also completely messed up your bores, right? I wouldn't put the blame on the Goetze rings as bad as your guy was with the block. I know and 2 others I know personally have used the Goetze rings and have had 0 issues with the specs being off and close to 0 oil consumption. I have heard many internet stories of the same.
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As for the Goetze ring concern, I'm afraid I'm gonna have to personally back up the end gap concern. Got a set of 4 for 0.5mm over, and the gaps measured from 0.28-0.30". Anyone using sealed power or other manufacturers could probably chime in here, but I hope I'm an extreme minority. Gonna try getting 1 ring set from someone else and see whet they read out to be.
Yeah, but your machinist also completely messed up your bores, right? I wouldn't put the blame on the Goetze rings as bad as your guy was with the block. I know and 2 others I know personally have used the Goetze rings and have had 0 issues with the specs being off and close to 0 oil consumption. I have heard many internet stories of the same.
Yes, but not so much as to create such large ring gap numbers. Even if the bores were spot on then the gaps would still be too big.
And on that alt bracket I mentioned, PN is 028 903 143 AB, which is a TDI alt bracket after all. just make sure that when going for this setup you get a VR6 water pump pulley and a water pump w/ a 30mm hub to match.
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This is such a great forum - thanks everyone for all the informative replies!
OK, It's clear as to what I'll be taking to the machine shop. I haven't bought the "Prothe" pistons yet as I'm still not sure if the next size will clean the scratched bore on #4. I think the next size up will, but I'm not the guy boring it. That means I will need to take it to the machinist, get his professional opinion (as to the bore required to clean up), order the pistons and then hand them to him with a page from the Bentley, and make very clear that he needs to hold the .001" spec over the piston diameter.
It cost me 20.00 to machine the end of the crank for the D sproket. You may not find a machinist that cheap, but IMHO you are an idiot if you could get it done for under 100.00 and don't. Even if you are running Vbelts, the added security is worth it.
Top of the page, see the FAQ link. Look for serp setup.
As to my crank nose (man some of those threads in the FAQ on serp belts, alternator clutch pulleys, etc. got real warm ;)).
It may sound crazy (yes, I could be an idiot) but I'm leaning to just getting a new stretch bolt and properly installing the stock set-up. Firstly, the v-belt is much more forgiving than the serp (if it's not over-tightened). Plus, the current fit of the key-way is like brand new - no wobble whatsoever.
Personally, the one-way clutch is something I will stay clear of as I have had several similar devices let me down. Generally they work well in principal but are just not robust enough for this type of application. The door isn't closed yet on this "D" sprocket as I'm a fer piece off from putting belts on, but that's where I'm standing today.
The machining of the crank is a non-issue as I have a sweet Lagun mill about ten feet from me now. Maybe I'll just do the sprocket and not all the other stuff. Theman53 - any links or some direction as to the bolt on "D" style sprocket?
Thanks again everyone.