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Engine Specific Info and Questions => IDI Engine => Topic started by: thomcat on March 06, 2009, 07:15:52 am
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I have a hairline crack running from the edge of one of the middle headbolt holes. Its aprox 5/8 inch long. My machine shop didnt think it was critical so I had them cold weld it (drill and plug). I am planning on running head studs to help with head gasket sealing and take some stress off the block . The head gasket was sealing fine when it came off . Does anyone have other measures or suggestions to help with reliability?.
Also is this a common problem? I will be picking the block up later today so If you want I will post pictures. Oh yea The engine is a 1.6 n/a from my 82 rabbit.
Thom
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DO NOT put any boost to this block. that will be the first thing to go. and then you will have more than one crack in your block. deck cracks are bad ones. but as long as your gonna stay with a stock 52 horses.. shouldnt matter too much.
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Post a picture, that way the experts here can tell you what's what :!:
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here is a pict of the crack . I Have given up on the idea of boosting this engine after finding the crack! I just hope it proves durable in NA configuration. If so I may boost my next project in a 2 door GTI .
[/img]http://i300.photobucket.com/albums/nn14/thomcat_2008/closeupcrack.jpg(http://)
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(http://i300.photobucket.com/albums/nn14/thomcat_2008/closeupcrack.jpg)
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Did this block have 11mm headbolts?
The stock 11mm headbolts don't go deep enough into the block and put too much stress on a small area.
Haven't heard of this happening with 12mm headbolt blocks.
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yep they are 11 mm head bolts
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I would helicoil it if you are worried. This will increase the area that the threads have to bear on. Not perfect but better and not real expensive. cheers Dan
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I think I would get a set of ARP headstuds and go from there as they go in the hole a lot deeper, I'll never put one of these back together without them. These 11's crack there all the time from the bolt not being long enough. that's the big reason they went to 12m/m to begin with and they go in deeper as well but they are the stretch type bolt and have their own problems and that's where the 12 m/m ARP's come in
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THe block I'm running now has more cracks than a plumbers convention.. I used head studs and some hylomar sealant on the threads into the block.. Fingers crossed it's been holding for 50,000+ miles..
Now if there's a crack between the coolant passage and the bolt hole next to the oil passage (Front of the car second bolt in from the trans) consider it toast... The oil pressure is just too much and pushes oil in the coolant.. I've debated using a thread insert for a situation like this since the inner threads are completley closed off from the outer on those, but I'm afraid it'll require removing too much metal from the block to hold properly..
Still may give it a shot one day... I'd only be out a headgasket and the thread insert if it goes sour...
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This is just a thought but if it is a question of trying something or junking the engine I wonder how filling that coolant hole with JB weld and doing the insert trick. Do you think that one whole will make it run hotter or not if it's blocked off, just a thought and depending on what the motor actualy has to withstand.
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Hmm Now that is a thought.. Not sure what would happen having that one hole blocked.. Even if it were to be partially blocked..
The hardest part woudl be getting the hole cleaned out well enough for the jb weld to stick, short of pulling the engine and having it cooked.. If it were to come to that point I'd probably just replace the darn thing..
Back in the olden days when compression was low and there wasn;t so much stress, brass was a popular block repair.. I've seen alot of old tractors and Willys Jeeps with cracks in the deck drilled and filled with brass.. I would imagine it would have about as much of a chance of holding as JB weld wil less cleaning.... Plus it would give for expansion and contraction...
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Its settled then, I will go with the head studs and good old red loctight. Whats the part # for an ARP head stud set?
With this crack I dont want to over stress anything so what is the best head gasket to use? ( I hear some require alot more force to compress. the block might not like that)
My jetta has a fatal oil pressure problem so I have had to start using my full time 4wd truck with 32 inch tires to commute :evil: . lol good incentive to get this rabbit done!.
thanks for everyones help
Thom
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Hmm Now that is a thought.. Not sure what would happen having that one hole blocked.. Even if it were to be partially blocked..
I bet you'll warp the head. I've had 2 engines where people used too much silicon sealing up the waterpump or flanges or whatever and a nice chunk of silicon got stuck in the headgasket. Both heads were severely warped in that area.
I'd use loctite thread sealer instead of red loctite.
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[quote="burn_your_money]I bet you'll warp the head. [/quote]
That was sort of my guess...
x2 on the sealer.. PLain ole loctite doesn;t do such a great job at sealing..
Not to mention if you do have to pull the head on it at a later date you'll find that the head won;t come up off the studs without removing the studs, or the manifolds, and the red loctite isn;t gonna make removing the studs fun...
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If you put some Loctite in the crack a day or two prior to putting the stud in, it will harden up in the middle of the crack. Loctite makes a few different thin products that will flow into the crack easily specifically for this type of use. My Loctite catalogue is at work, so I can't give you specific product numbers. The outer or surface portion won't set up, but the Loctite in the crack will set up due to the absence of air and presence of metal. Make sure you clean out the crack as well as possible (Loctite ODC, brake clean or electrical contact cleaner) and give it time to dry, then use the thin Loctite (the thinner product will wick into the crack instead of just sitting on the surface). You don't need to worry about any of the Loctite in the bolt hole as it won't harden with air present.
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After seeing that picture, I would think twice about using that block.
Replacement blocks aren't really that expensive, or hard to find IMO.
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Hmmm I'm gonna have to go investigate the loctite web site.. That may just be an option for the bolt hole that oils...
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UnfortunatlyI already have $200 plus in machine work in that block and I am way over budget as it is. I am not really worried about the crack leaking there is nowhere for the coolant to go, and it wasnt leaking before disassembly . I am going to use the red loctite to make sure the stud has enough holding power. Ill leave this engine stock and save the turbo plan for a better candidate ( and a two door, or to put a diesel in a scirocco) diesel engines are hard to find at a fair price arround here.
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With studs and no turbo I think you'll be fine... 2 years ago people were trying to give old VW diesels away.. With price of fuel and scrap last summer they are scarce around here as well...
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UnfortunatlyI already have $200 plus in machine work in that block and I am way over budget as it is. I am not really worried about the crack leaking there is nowhere for the coolant to go, and it wasnt leaking before disassembly . I am going to use the red loctite to make sure the stud has enough holding power. Ill leave this engine stock and save the turbo plan for a better candidate ( and a two door, or to put a diesel in a scirocco) diesel engines are hard to find at a fair price arround here.
I don't think you will have a problem with the stud not holding but if it doesn't the loctiite won't help in that respect. I think the best solution so far is the ARP studs and the Loctite thread sealer and the Loctite that would wick into the crack area for a little added security. Another thing to think about if you loctite the stud in with the red type it might make tear down more difficult in the future also by the head having to be lifted over the stud maby creating a clearance problem. If anything can seal a thread The Loctite thread sealer can do it and they make specialty sealers for about anything under the sun and there is no need to substitute any of their products for another because they make the right one for each purpose in the first place. It would kind of be like putting STP in Mobile One synthetic oil trying to make it better. The studs ill go a lot deeper and not pull out and the sealer is a good idea allowing you to still remove the stud. As for the head gasket, I'd use the fiber one to allow for any little bit of warp that is probably present.
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cool thanks for the advice . I am going to go with the fiber gasket as there will be no boost aplied and both head and deck are freshly machined I will forgo the red loctite and use thread sealant . lol at that price arp studs better hold! :shock: will a fiber gsket deal well with the 3retorque 3 times routine they say arp recomends?
thanks
Thom
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I don't think it would cause any problems but I just put in ARP 12 m/m's in my Rabbit motor and ARP doesn't even call for a retorque but it sure doesn't hurt as long as you do them one at a time. My last motor was a 1.6 N/A with the head resurfaced, fiber gasket and 11 m/m bolts and it leaked water to the outside right after I started it after a careful torquing on the first start. I just retorqued and it quit and never used a drop this past 3 years. I sure hope this new one stays put, it's 12 m/m and they are the torque to yeild which I didn't want to fool with and there so many grades of them you don't know what you have and all that extra 1/4 turns and all is for the birds let alone the creaking and jerking scaring you to death thinking something is cracking which is already a situation you have with the crack but the ARP's have none of that and go in deeper and those nuts torque as smooth as can be, I would definately use them as if this engine doesn't workout you will already have the studs which would eliminate the problem in your next block from happening again as they do alot in the 11 m/m's in that area.