VWDiesel.net The IDI, TDI, and mTDI source.
Engine Specific Info and Questions => IDI Engine => Topic started by: Possum79 on December 19, 2009, 09:09:44 pm
-
I have a pretty dumb question but I don't know the right answer. I have been in the process of taking my little 1.5 apart and just started to tear into the bottom end. I put cylinder 2 and 3 at tdc and i noticed that one cylinder is slightly lower then the other maybe by like 1/16". Is that normal? I was kinda rushed to leave and didnt really check it out. Is it just the operation of stroke its at? one on combustion one on exhaust or what ever?
-
Due to machining differences it's normal for the piston protrusion to be slightly different across all 4 cylinders.
Having said that, if one is very obviously lots lower*and* there's signs of impact (impression of valves in the top of the piston (etc) it can signify a bent rod.
I don't think I've ever seen what the maximum allowable difference is... hopefully someone wise will weigh in.
-
X2
and show us some pics that would be neat to see.
-
I've heard the pistons are a matched set in order to have the same protrusion so it could be a piston out of another engine then.
-
Ill try and get some measurements tonight along with pics. I mean I can visually see a difference and went wtf. I say 1/16" because I dont think I would notice anything smaller. This kinda sucks. I have no signs of piston contact. When I took the head apart I did find three broken lifters. When I rolled the bottom end over on my stand I saw some small chunks of metal bits fall out. Now this is really started to make me sad. :P
-
Unfortunately broken lifters are a pretty reliable sign of valve-piston contact (and the resulting bent rods in some cases) but lets see what your measurements yield. Pics of the top of the pistons would be great as well.
-
1/16th inch? there has to be something bent or squished.
-
I don't think I've ever seen what the maximum allowable difference is... hopefully someone wise will weigh in.
I can't say that I'm wise, but I've always been under the impression that the max allowed difference is the range given for choosing the HG thickness.. For example, a 3 notch HG is used for a piston protrusion of .033 - .036MM.. That seems like a rather small range, but then again it doesn't take much to make the compression uneven....
-
SON OF A B WORD! After looking harder at the bottom side with the oil pan off it does look like a bent rod to my untrained eye. Anyways as far as measurements go I had piston #3 sitting .026" above the deck. And piston #2 was well over .035" under the deck. I gave up and cried a little inside. It looks like a bent rod and I did get pics but I dont think you can really see the bend. anyways here is the small size ones and Ill link to bigger ones if you want to take a better look. Im need of some new stuff here if anyone is feeling generous! ;D
This was my problem cylinder too but I was getting coolant to flow into this and screw everything up. When I took the injectors out to compression test I had coolant fly out at me. I was gonna say no valve contact but I feel like an idiot. It probably hydrolocked on me and bent that rod. Still doesnt explain where the coolant came from.
(http://www.poscarclub.com/vw_stuff/rods/small002.jpg)
(http://www.poscarclub.com/vw_stuff/rods/small004.jpg)
(http://www.poscarclub.com/vw_stuff/rods/small006.jpg)
(http://www.poscarclub.com/vw_stuff/rods/small007.jpg)
002.jpg (http://www.poscarclub.com/vw_stuff/rods/002.jpg)
004.jpg (http://www.poscarclub.com/vw_stuff/rods/004.jpg)
006.jpg (http://www.poscarclub.com/vw_stuff/rods/006.jpg)
007.jpg (http://www.poscarclub.com/vw_stuff/rods/007.jpg)
-
It makes sense though doesn't it? I had a problem of coolant getting in the cylinder and when I tried to compression test the thing I didnt take out all of the injectors at once just one at a time. And when I got to #2 I noticed coolant spraying me in the face. Hydrolocked with the injector still in there and bent the rod. If I would have taken all the injectors out at once I think I would have been in just for a resurface of the head. I cheaped out and didnt bother the first time to get the head checked out.
~Lessons learned.
-
Correct me if I'm wrong but isn't the white blobs from coolant?
If it's for sure coolant then I'd say your hg went. :'( Possibly another rod is all you'll need.
-
at least your block is vent free.
-
Correct me if I'm wrong but isn't the white blobs from coolant?
If it's for sure coolant then I'd say your hg went. :'( Possibly another rod is all you'll need.
I have had the head off the block for a while so its possible that its from taking the head off. I noticed some scrapes on the head when I took it off so I think thats where its leaking. I replaced the gasket a few months back and the one I took off wasnt broken at all other then being old and crusty. I replaced it with a new and it ran good for 5 minutes then I heard a cough and started to smoke and run like crap. When I took the head off this time I noticed the small scrapes but the gasket looked great.
-
Hydrolocked with the injector still in there and bent the rod.
Which is why there's no valve impression marks... it all makes sense, unfortunately. :'(
-
Yeah, I was wondering the same thing.
Until they actually open they're pressing against a virtually uncompromisable mass... so I can see it happening.
I'm thinking it would be exhaust lifters that would bear the brunt?
-
That doesn't sound possible to me, the hydrolock would've happened on the compression stroke so the valves wouldn't be opening.
If it happened during the exhaust stroke the valve would be opened untill real close to tdc and unless there was a puddle of coolant just sitting on the piston when the valve closed.....but it would've had to get there during the power stroke and stay there during the exhaust stroke, I can't really see that happening...... :-\
-
But I had three broken lifters and only one from the cylinder in question. It doesn't explain the other two.
-
A 1.5 rod should be easy to find.
Lots of people parting them.
-
A 1.5 rod should be easy to find.
Lots of people parting them.
Theres a few for sale I saw in the forsale section. Im waiting for one guy to get back to me about that short block but it looks like Im going with someone else.
One more question would you guys recommend I replace all the lifters due three being broken? I was thinking that the others could now be weaker. I dont know how the others broke so im just concerned.
Also I saw a thread on what bolts to replace as one time use kind of thing but I cannot find it anymore. What bolts do I NEED to replace or recommend replacing.
-
if its a 1.5, it has no stretch bolts to my knowledge. the torque sequence for the bottom end is straight forward, no torquing till xx ft bls and then 90* blah blah blah... shouldnt need any bolts unless there are some broken.
-
Also I saw a thread on what bolts to replace as one time use kind of thing but I cannot find it anymore. What bolts do I NEED to replace or recommend replacing.
I would just go to head studs for that. I have heard the 1.5 was bad for headbolts. I think its in the FAQ, but I am sure I heard the studs are the same ones for the 1.8 8v gassers.
-
ARP:# 204-4701 <- 11mm headstuds for a 1.5 diesel. Highly recommended.
-
1.5 bolts are not nearly long enough for the clamping force needed from them. they thread in what, like a whole whopping 3/4 of an inch, if that? anyone know how long the threads are on the studs that threads into the block?
-
The head studs thread into the block a tad over an inch IIRC.. I think it was like 1 1/8"... Head bolts thread in there a shy half inch at best.. IMO head studs are required on these things.. Before going too far check you block out for cracks.. If the head has already been removed and installed using the bolts it is possible that it could already be cracked... Yes they are that bad...
Here's the FAQ on this http://www.vwdiesel.net/forum/index.php?topic=21948.0 (http://www.vwdiesel.net/forum/index.php?topic=21948.0)
If you have no luck on finding a rod I think I still have a set around.. I believe they still have decent pistons with them too...
If your block is cracked there's some nut job in the IDI section who repaired one.. Highly un-reccomended procedure.. ;D
-
Block looks fine as far as cracks haven't taken it fully Apart yet to get it checked over. I already reinstalled the head once with new bolts and didn't have issues. I want studs but don't think it will be in budget although I'm not in a huge hurry to get this back on the road.
-
It usually isn't terribly difficult to see the cracks with the naked eye.. The 4 corners head bolt holes , and on the IP side of the engine the 2nd and 3rd ones in from the flywheel are the culprits... Once in a while you do get lucky though.. I think I had 1 out of 4 11mm engines not crack.. Did you do a retorque on the head bolts?
I've also been noticing that it's usually the 1981 1.6 engines that are the worst for cracks.. But it could just be due to the number of those around versus pre 1981 1.5 engines...
-
my grandpa and i have at least 7 or 8 cracked 11mm blocks, both 1.5 and 1.6.
-
my grandpa and i have at least 7 or 8 cracked 11mm blocks, both 1.5 and 1.6.
Send 'em to maxfax!!!! ;D
-
Ya know, if I knew my bubble gum job would hold for the long run I would be kicking myself for all the lesser cracked 11mm blocks I have scrapped... Of course the one that the whole corner broke off of would still be nothing more than a paper weight..
I kinda suspected that the 1.5's were equally as bad, I just don;t see as many of them around here.. 1981 must have been a good year for VW diesel sales in Central PA..
-
my grandpa and i have at least 7 or 8 cracked 11mm blocks, both 1.5 and 1.6.
Send 'em to maxfax!!!! ;D
lol, no thanks, these things need to be melted down and turned into turbo blocks. im trying to get him to stop screwing around with those old blocks and go to 12mm. he has or had a 12mm 1.6 in his truck, im pretty sure its still in there actually. but he was working on a 1.5 the other day. he brazed the corner of the block back on. (front corner, drivers side of block). brett, was your block cracked so bad that pieces were missing, or just slight cracks in the holes? either way, he thinks hes going to re use that engine cause he says it has low miles on it. but i guess we are going to see what works better, braze, or nickel rod. im thinking the nickel rod is gonna be the fix.
and wasnt 1981 the first year of the 1.6? and wasnt it the first year that they built cars in the usa? and didnt they have a plant in pa or somewhere over there?
-
THe particular block I glued together just had small cracks around the holes.. The blocks that had chunks broken loose have long gone to be melted down and made into a Prius..
Brazing was actually my first choice at repairing.. It'll actually draw into a crack like solder... However I wasn;t able to get things hot enough for it to take properly.. Or probably more to the point, I was afraid to get things that hot... Had I had the engine in pieces I may have tried it..
It wasn't uncommon back in the day to tear down an old Willy's F-Heads and see brass between the center two head bolts on the deck.. I've seen alot of other early engines that have been brazed back together as well.. Hercules ZXB and ZXA's, an old Pontiac I-6, etc.. Of course most of these engines were low RPM and low compression.. I'm sure the alloys were different too.. The alloy used on the VW engine seemed to dissapate heat much better than alot of that older stuff, I could barely get it glowing...
Rabbits & Caddys were built in an old Ford plant (I think) in New Stanton Pa from 1978 - 1984... Something to the tune of 2 million IIRC.. 1981 was the first year of the 1.6, and the only year (other than some 1982 carry overs) they had 11mm head bolts..
-
oh hell, im pretty sure my grandpa had that whole corner of the block glowing red. and im almost positive that the bore is probably out of round pretty good now. but whatever, he still doesnt believe me when i tell him his caddy will get better mileage if he times it with a gauge.
-
Gauge!??!?!? BAH! I never even layed my hands on one till 2 years ago.. About the time I started reading the gosh darned forums.. :-X Any time I have used the gauge I still end up toying with the pump till it sounds right... If I were wiser I woudl put the gauge on BEFORE I tear these things apart.. THen I'd know exactly where to set the thing back to...
I wonder how those rings would feel about a red hot block around them..... :o And, I wonder how the OP feels that we've pretty much jacked his thread.. ;D
-
I don't mind my threads being jacked. Usually leads to more questions when I read stuff. Right now Im out of questions. I should be taking the motor completely down this weekend and looking more at the block for any cracks. I need to call a guy about borrowing a trailor to tow the car to my father in laws property. He said I could store it there and work on it he didnt car. MY dad on the other hand is getting pissed its sitting in his driveway and hasnt been touched in months. hahahahaha. I really hate to ask to borrow stuff from people I dont really know that well. Also I would have to borrow my father in laws truck to pull the trailer.
-
Ultimate sad face. Car is going to pick n pull soon. I just dont have the funds to try and source the stuff needed to make this worth anything. Block is cracked.
(http://www.poscarclub.com/vw_stuff/rods/photo1.jpg)