TorinWalhood Posted December 31, 2013 Report Share Posted December 31, 2013 Hello all, I have encountered a very strange problem with my '69 510. Its stock L16 had a blown head gasket, So I replaced with one from Rock. I made sure to torque the headbolts to spec, and I had the head resurfaced at a machine shop. I started it for the first time today, and it ran well, but it leaked coolant from everywhere around the head; back and left and right sides. I cant explain it. Can anyone here shed some light on why? Torin Quote Link to comment
TFM1066 Posted December 31, 2013 Report Share Posted December 31, 2013 Cheap-o-gasket, No-name-Gasket, The fire rings that seal the Cylinders are way larger (thicker) the the gasket itself Quote Link to comment
datzenmike Posted December 31, 2013 Report Share Posted December 31, 2013 Even the cheapest gasket will work, just fail sooner. Obviously the intake was removed for planing... it's easy for the intake to leak from the coolant passages on the left side. Check the manifold bolts for tightness. Crack missed in head. Block damaged or not cleaned enough Foreign object caught between head and block. Were the two block alignment dowels in place? 1 Quote Link to comment
MikeRL411 Posted December 31, 2013 Report Share Posted December 31, 2013 Did you check the block for warpage? A machined head on a warped block will leak! Quote Link to comment
wayno Posted December 31, 2013 Report Share Posted December 31, 2013 What baffles me is that he says it runs good, strange. Quote Link to comment
Pacific coast Datsun Posted December 31, 2013 Report Share Posted December 31, 2013 Did you torque the head bolts in stages IE 20...40...60 & in the correct pattern ? Quote Link to comment
Draker Posted December 31, 2013 Report Share Posted December 31, 2013 Also chase all the bolt holes with a thread chaser to get them all cleaned out. Dab of oil on the head bolt thread and torque it down in stages using the correct tightening sequence!!! Once it's torqued to 60lbs.... go back once again and double check all head bolts again in the same tightening sequence. Same goes for the intake and exhaust. Quote Link to comment
datzenmike Posted December 31, 2013 Report Share Posted December 31, 2013 If you tightened the bolts full torque from the front to the back... it should at least hold water without leaking.. Quote Link to comment
zed Posted January 1, 2014 Report Share Posted January 1, 2014 Head bolts not bottomed out in the block? Quote Link to comment
Driftease Posted January 1, 2014 Report Share Posted January 1, 2014 Head bolts not bottomed out in the block? that is what i was going to say, how much was the head milled the alignment dowels will bottom out too if that is it just trim them down on a grinder but only remove the ammount milled from the head. good luck with your repair! and happy new year Quote Link to comment
izzo Posted January 1, 2014 Report Share Posted January 1, 2014 Just cake some JB weld on the head... Then use a belt sander to smooth it out once it dries. :poke: :rofl: jk dont Quote Link to comment
TorinWalhood Posted January 1, 2014 Author Report Share Posted January 1, 2014 Even the cheapest gasket will work, just fail sooner. Obviously the intake was removed for planing... it's easy for the intake to leak from the coolant passages on the left side. Check the manifold bolts for tightness. Crack missed in head. Block damaged or not cleaned enough Foreign object caught between head and block. Were the two block alignment dowels in place? There are no cracks in the head, that was checked at the shop. Also, coolant leaks out of both the left and right sides of the head, all the way along it, so it is certainly not the intake leaking, and I doubt one crack could leak this much water in so many places. All sealing surfaces were cleaned. The block was also checked for warpage, and was within tolerances. Alignment dowels were in place, and the head went down nicely. Quote Link to comment
Driftease Posted January 1, 2014 Report Share Posted January 1, 2014 if the dowels are too long you could have interference causing the head to not properly crush the steel ring and put enough pressure on the outer material this can cause leaks all the way around. Unfortunately the head will need to be removed to find what the problem actually is. Quote Link to comment
banzai510(hainz) Posted January 2, 2014 Report Share Posted January 2, 2014 I would redo it. Maybe try using a spray on Copper Kote from Parmantex but I really dont think its needed. Try a nissan gasket but I have a Felpro now and it seems to be fine on my 521. as mike said make sure the intake man is tite. Quote Link to comment
datzenmike Posted January 2, 2014 Report Share Posted January 2, 2014 if the dowels are too long you could have interference causing the head to not properly crush the steel ring and put enough pressure on the outer material this can cause leaks all the way around. Unfortunately the head will need to be removed to find what the problem actually is. . If water is coming out all sides then something is preventing the head sandwiching the gasket tightly. Could be a foreign object, even the alignment dowels or the bolts bottomed out because the head was milled or dirt and gasket material from the cleaning down in the bolt holes. Quote Link to comment
kelowg Posted January 3, 2014 Report Share Posted January 3, 2014 i dont know the details but need to measure head height, to figure how much material was removed. ratsun gurus' can chime in to guide u thru this, i hope. Quote Link to comment
datzenmike Posted January 3, 2014 Report Share Posted January 3, 2014 A mm would be a huge shave... about 0.040" maybe as much as one bolt thread. Not near enough to matter. Dirt or old removed gasket material in the bolt holes maybe. You are going to have to remove it and tell us what it was. Quote Link to comment
Driftease Posted January 3, 2014 Report Share Posted January 3, 2014 On one of my heads here that was milled 1mm, the dowel holes are 6.01mm deep and the dowels were shaved. I didnt mill the head was done in another shop 1 mm was est based off of overall height and shim thickness Quote Link to comment
Driftease Posted January 3, 2014 Report Share Posted January 3, 2014 A mm would be a huge shave... about 0.040" maybe as much as one bolt thread. Not near enough to matter. Dirt or old removed gasket material in the bolt holes maybe. You are going to have to remove it and tell us what it was. second that Quote Link to comment
datzenmike Posted January 3, 2014 Report Share Posted January 3, 2014 Actually I'm working on a 1mm shaved head AND block with a .5mm gasket. I definitely will be checking the dowels when I assemble. Quote Link to comment
Driftease Posted January 3, 2014 Report Share Posted January 3, 2014 Mitumotoyo 3 in one mic is worth its weight in gold it is perfect for measuring the depth on things like this. even a cheapo pitsburg or performance tool is good if working with non critical tolerance. http://cdn.mscdirect.com/global/images/ProductImages/0625797-23.jpg Quote Link to comment
TorinWalhood Posted January 7, 2014 Author Report Share Posted January 7, 2014 I pulled the head a second time, and put a new Felpro gasket on it. Doesn't leak a drop now. Pretty weird. I guess it must have been a defective gasket. Thanks everyone for your help. This makes one more 510 2dr back on the road. Quote Link to comment
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