pparaska Posted October 21, 2005 Share Posted October 21, 2005 Swapped manifolds the other day to cure an oil leak and to see if I could tune easier with a Victor Jr on the 406 instead of the Holley dual plane. I had some trouble getting the front water ports to seal on the intake/heads, so I untorqued all the intake bolts and did them front to back instead of from the center out, like the manual said. That fixed the water leak, but when I started it there was a constant backfire in the exhaust from one cylinder, until I got it revved above 2000 rpm. I had to really richen the low rpm fuel map to get it to be near 14.7:1, from where I had the map with the dual plane. I drove it a few miles to work and back (they were having their annual car show during lunch, as part of the celebration to commemorate all the dough the employees donated for the United Way campaign). Pretty cool place to work, huh!! Anyway, I checked the compression (engine was cold by the evening) and it was 180-190psi until I got to cylinder # 6, which was 120, and # 8 was 160. I hooked shop air (120psi) to the spark plug hole and brought it to TDC for #6 with both valves closed. No intake or exhaust valve leaks, but WOW there was a TON of air coming out of the valve cover hole for the oil breather!!! Even had a wistle to it! It also was lightly pressurizing the cooling system, as I could watch the water level rise in the radiator fill neck. I just pulled that head and found a crack all the way around the block's deck that is about 5/64 inch from the cylinder wall deck surface. Very weird - I've never heard of that before. I guess the agressive block decking was partly responsible. It was decked to about 8.885" deck height, from the stock 9.025". The guy was supposed to deck it to 9.000", but got a bit carried away. I still don't see how that could have caused the problem. This is a 400 2 bolt block, not sure what year. "509" high nickel casting. So who has an opinion on World versus Dart blocks? And where to get one cheapest? This is the last chapter in the 406 from hell story. The next book will be much better, I'm sure . Quote Link to comment Share on other sites More sharing options...
Heavy Z Posted October 21, 2005 Share Posted October 21, 2005 Ug, cracked block...sorry Pete. So much work went into that sucker too. My fingers are crossed for next time, good luck man. Quote Link to comment Share on other sites More sharing options...
Z-Gad Posted October 21, 2005 Share Posted October 21, 2005 Sorry to hear that Pete... Quote Link to comment Share on other sites More sharing options...
MusPuppis Posted October 21, 2005 Share Posted October 21, 2005 Dart blocks are great. I cant speak for World products as I dont have any experience with them but I have had a little with the Darts (302's) and they were superb. I honestly couldnt say where to go to get them cheapest though. Quote Link to comment Share on other sites More sharing options...
dr_hunt Posted October 22, 2005 Share Posted October 22, 2005 ppraska, I've got two dart little "M" blocks, one is a 400 with 400 mains, the other is a 350 with 350 mains. Both will bore to 4.200. When you see one, they remind you of the first time you saw a girl naked, makes you want to touch it all over. I don't know about World blocks at all, but I'm sure that they are similar. I posted a price and phone for Edwards in Alb, they have the little m for about $1800, I've seen them on EBAY for about that as well. Good luck! Quote Link to comment Share on other sites More sharing options...
DavyZ Posted October 22, 2005 Share Posted October 22, 2005 ...It also was lightly pressurizing the cooling system' date=' as I could watch the water level rise in the radiator fill neck. I just pulled that head and found a crack all the way around the block's deck that is about 5/64 inch from the cylinder wall deck surface....[/quote'] Keyrapp. Man that absolutely sucks. Pete, you're a real man being able to laugh at it (cry too?) the way you do. I think your problem(s) will be solved using a Dart block. Best of wishes. BTW, remind your wife what you want for Christmas... Davy Quote Link to comment Share on other sites More sharing options...
VRJoe Posted October 22, 2005 Share Posted October 22, 2005 Pete, I guess I could say that sucks, but I'd be stating the obvious. If I can help out, let me know. I'd offer to swing down with some 357 Mag. AP, but I used them all up before it became illegal to have 'em. And yep we did use 'em up at a junk yard shooting blocks and yes they did crack the block. We giggled like little girls. After all the effort of getting some they went and made them illegal, but that's another story. This is one of those times I miss 'em, that block sure deserves one. - Joe Quote Link to comment Share on other sites More sharing options...
Guest zfan Posted October 22, 2005 Share Posted October 22, 2005 Pete, Thats interesting as my friend just tore down his 400, 30 over 509 casting block and low and behold he cracked his block and cylinder wall. I think his was from timing, detonation issues on nitrous. Still less than 1000 miles on the new build, he was pissed. Very sorry to hear about this. Did you not just get the motor put together? The after market blocks are the way to go especially when your talking about the 400 blocks. Best of luck and yes Christmas is right around the corner!!! Hurry up Santa! Mike Quote Link to comment Share on other sites More sharing options...
qwik240z Posted October 22, 2005 Share Posted October 22, 2005 Pete, Got your phone message. Sorry about your misfortune. We can surely hook up again in the spring. If I can help in any way let me know. Quote Link to comment Share on other sites More sharing options...
Brad-ManQ45 Posted October 22, 2005 Share Posted October 22, 2005 Man, that doesn't, suck, it BLOWS. Sorry to hear about your misfortune. From what I've been able to gather, the WP blocks run at least $600 cheaper than the Dart. I'll be interested in hearing differences between the two... Quote Link to comment Share on other sites More sharing options...
shortbed454 Posted October 22, 2005 Share Posted October 22, 2005 sorry to here about your block. i have built two 509 block 400's and i have never had them crack one me. i hope you can get a replacement soon and get it back on the road. Quote Link to comment Share on other sites More sharing options...
pparaska Posted October 22, 2005 Author Share Posted October 22, 2005 Thanks for all the kind thoughts! But I think I sounded a false alarm! Sorry! The crack may not be a crack that shouldn't be there.... I talked to the guy that built the shortblock and he says that he can't remember if he sleeved it but what I was describing (5/64" "crack" around the cylinder) sure does sound like the thin sleeve you use to sleeve the 400 blocks. He's pretty sure what I was seeing is the sleeve moving down a bit (less than .001" from what I can tell) from the deck. He see's no way that I could get air from the pressurized cylinder test through that crack into the crankcase, like I was describing and I agree. He had me rock the # 6 piston and another one at TDC to verify that the skirt on the #6 piston hadn't collapsed or broken off. I told him about using the Cometic MLS gaskets and right away he said he suspects that my leak is from the cylinder into the lifter valley across the gasket surface. He said he's had nothing but trouble with them on the older engines, usually water leaks (sounds familiar, I've been there on this build as well!). Like grumpyvette, he's had good luck recently with NAPA copper shims, with some copper spray on them. He had me lay a straight edge across the block surface and the head surface to see what was up there - less than .001" gap - I couldn't even see light under the straight edge. I cleaned the surfaces, threads in the block and the bolts and I'm about to put a .040" thick Fel-Pro composition gasket on and do the pressure test again. He's confident that it will fix the problem. If it does, I'll put one on the other bank of the engine and put her back together. If all works out, I'll be on the road again in a few days. Quote Link to comment Share on other sites More sharing options...
Mikelly Posted October 22, 2005 Share Posted October 22, 2005 Damn man! That's a better solution than our discussion on the phone last night! Hope you're back up and running ASAP! I actually worked on mine today! Planets must have aligned or something! Mike Quote Link to comment Share on other sites More sharing options...
VRJoe Posted October 22, 2005 Share Posted October 22, 2005 Great news, hope it works. Be sure to use the right obscenities during the install just to be on the safe side. - Joe Quote Link to comment Share on other sites More sharing options...
pparaska Posted October 22, 2005 Author Share Posted October 22, 2005 Well, it was a nice try, but no luck. Both #6 and #8 are still leaking and down on compression (110 and 145 respectively). They went up to 145 and 215 psi with oil squirted in them. Glenn McCoy was over while I did this. Theories: - crack in cylinder wall between #6 and #8 near top - but I didn't see any. - two bad sets of rings or crack sets of rings in those cylinders - damaged pistons (ring lands, etc.) in those cylinders. She's broken. I'll pull the head again, and the pan and yank pistons #6 and #8 to see what's up with the cylinder dimensions (using a dial bore gage) and check the pistons and rings carefully. Quote Link to comment Share on other sites More sharing options...
Administrators BRAAP Posted October 22, 2005 Administrators Share Posted October 22, 2005 Pete, So sorry to hear about your misfortune. I hope you are able to find a financially reasonable solution soon. If there is anything I can do to help, let me know. Quote Link to comment Share on other sites More sharing options...
blueovalz Posted October 23, 2005 Share Posted October 23, 2005 Sorry to read about your Z troubles Pete. Keep us informed on how (and why) it goes. Quote Link to comment Share on other sites More sharing options...
pparaska Posted October 24, 2005 Author Share Posted October 24, 2005 Hey, it's only an engine. I have my health, and a daily driver . Pulled #6 piston - all looks very normal. Rings intact, not stuck, lands, clearances look fine. I noticed that on both the #6 and #8 cylinder wall, in the first 1 inch below the deck, in the area next to the siamesed wall between the two cylinders there is a brown area that looks like where blowby was pretty bad. Out came the dial bore gage. Here's what the bore measurements look like about 1/4" below the deck, on the leaking cylinder, #6: Look closely at how quickly and by how much the dimensions change from the 9 o'clock to 11 o'clock area. 0.0045" in about 60 degrees. That's pretty big, and no ring will seal that much variation in that short distance. I believe this is the cause for the leak. Here's a good cylinder, #2: The builder says he's done plenty of sleeves in 400 SBCs and never seen this happen. So this is some kind of a fluke I guess. Bad luck follows this car... No way I'm going to get this repaired. And since my parts are for a .030" over 400, finding another stock block that hasn't been bored from the STANDARD bore will be tough. So I'm probably going for a bottom of the line Dart Little M block. I'll be ordering this week. Quote Link to comment Share on other sites More sharing options...
jbk240z Posted October 24, 2005 Share Posted October 24, 2005 Pete, good luck on the rebuild, I'm sorry to hear about your wacked-out cylinders. Quote Link to comment Share on other sites More sharing options...
pparaska Posted October 24, 2005 Author Share Posted October 24, 2005 After talking to my machine shop and reading some of grumpyvette's and other's posts on chevytalk, I decided on the Dart Little M block over the World Motown block. I decided on the 350 Main, 9.025 deck height, 4.125 bore Sportsman block (that means only the 4 center mains are 4 bolt, and ductile instead of steel caps), PN 31151211. CNC-Motorsports.com, has it for $1806. That's almost the lowest price I could find. The reasons I went with them is the $75 to anywhere (business or residence) in the US shipping, and their good phone sales service. John was quite helpful, and reminded me I'd need rings . I got out for $1995.95 with rings and shipping. OUCH! Quote Link to comment Share on other sites More sharing options...
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