New 489 Blown Head Gasket After 2 hrs run time
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New 489 Blown Head Gasket After 2 hrs run time
No compression on cyl 4 and 6, pulled head, blown head gasket, and head is etched about 1/4 in down between both cyl. My engine builder is blaming the intake not being seated properly on the heads (of course he picks the part that I installed after he rebuilt the engine) and it sucked in extra air, leaning out the mixture and causing the gasket to blow...I am not convinced, as I diligently followed the proper torque sequence. When I stopped by the shop today, the guy who built motor was not there, but his other tech was showing me marks on the intake gasket, trying to prove to me the intake was either warped or not installed right. What raised red flag was he was showing me the odd # cyl banks, whereas it was cyl 4 and 6 were the ones that got hot and blew the gasket. If it was sucking that much air to cause a bad enough lean condition to blow a gasket, wouldn't I have heard and air sucking sound/backfires/etc??? The intake was an old 454 mag sq intake, former salt water boat, so I acknowledge its not perfect, but 2 hrs of runtime (nostly idling in the slip trying to figure out what was wrong) to blow a head gasket between 4 and 6 and then etch a hole in head???
I noticed the tech was re doing the studs in the head today when reinstalling the repaired/resurfaced head...Maybe some of the studs came loose or they didn't torque the heads down right the first time??? Given the intake sat on these same heads for years with no prob before makes me suspicious. would appreciate input. This is a 489 with 188 heads, cam from Bob Madara
I noticed the tech was re doing the studs in the head today when reinstalling the repaired/resurfaced head...Maybe some of the studs came loose or they didn't torque the heads down right the first time??? Given the intake sat on these same heads for years with no prob before makes me suspicious. would appreciate input. This is a 489 with 188 heads, cam from Bob Madara
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Took the engine back to the rebuilder. He said he would take care of it. Called me to tell me I could pick it up, its running "perfect". Take the boat home, hook it up to the muffs, both batteries dead. I told him to please turn batt switch off because the fridge runs when the batt switch is on. So while charging batts, I look in the engine compartment and notice that the dist bolt washer is under the dist clamp and dist is loose as could be since the bolt is bottomed out, but can't clamp down. I also notice the clamp on the cannon harness is missing (its down in the bilge) and the TBIV module is just hanging by the harness on the bellhousing, ensuring that the first time I turn the steering wheel the PS ram would crunch it or at least disconnect the harness. So I fix that, then I try to start the boat. It starts, but the timing is 16 deg, turn it back to 10, but it barely will idle, sounds like its running on 6 cylinders again. Do a compress check...zero on 6, only 100 psi on 4, 170 on all others. Remove valve cover, exh valve on #6 is torqued down so hard, valve is hung open. Now #6 is 170 psi. Zero lash on #4 still only 100 psi, so not sure what is going on there. I watched him put the resurfaced head on with new gasket, so not sure if the one of the valves is burnt/not sealing on #4. I've missed 5 weekends in a row now, and I gave him a chance to "take care of the problem", now I'm inclined to just get in his face and get all/part of my money back and go somewhere else since each time I take it back it seems to get worse. Can I just drive it as is with one cyl a little low on comp and get through the summer and then take it somewhere else in the Fall, or could I be damaging the engine by running it this way. I'm not trying to win any races, just would like to get back on the lake and cruise around/pull kids on the tube etc. Tired of wrenching on this thing.
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Took the engine back to the rebuilder. He said he would "take care of it" and have the boat back to me so I could go to Aquapalooza July 10. Didn't happen. Called me a week later to tell me I could pick it up, its running "perfect". Take the boat home, hook it up to the muffs, both batteries dead. I told him to please turn batt switch off because the fridge runs when the batt switch is on. So while charging batts, I look in the engine compartment and notice that the dist bolt washer is under the dist clamp and dist is loose as could be since the bolt is bottomed out, but can't clamp down. I also notice the clamp on the cannon harness plug is missing (its down in the bilge) and the TBIV module is just hanging by the harness on the bellhousing, ensuring that the first time I turn the steering wheel the PS ram would crunch it or at least disconnect the harness. So I fix that, then I try to start the boat. It starts, but the timing is 16 deg, turn it back to 10, but it barely will idle, sounds like its running on 6 cylinders again. Do a compress check...zero on 6, only 100 psi on 4, 170 on all others. Remove valve cover, exh valve on #6 is torqued down so hard, valve is hung open. Now #6 is 170 psi. Zero lash on #4 still only 100 psi, so not sure what is going on there. I watched him put the resurfaced head on with new gasket, so not sure if the one of the valves is burnt/not sealing on #4. I've missed 5 weekends in a row now, and I gave him a chance to "take care of the problem", now I'm inclined to just get in his face and get all/part of my money back and go somewhere else since each time I take it back it seems to get worse. Can I just drive it as is with one cyl a little low on comp and get through the summer and then take it somewhere else in the Fall, or could I be damaging the engine by running it this way. I'm not trying to win any races, just would like to get back on the lake and cruise around/pull kids on the tube etc. Tired of wrenching on this thing.
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I hate the winter!!
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Sorry to hear of your troubles. At the point you are at, it would be difficult to say if running it would be safe. I am inclined to say I doubt it. Sounds like too many loose ends were left. Did he simply resurface that head? Or get you another head? A resurfaced head would mean the chambers on that 1 side would be a whole lot smaller than those of the other head. In order to clean up a 1/4 " deep burn ( as you said), he would have to take alot of material off the head. Taking that much off that head would raise the compression on that side by a bunch. If the head had a burn mark across it, usually the block has similiar damage, did yours? If so, he block needs to be replaced or at least have its deck flattened.
Sorry to say, but sounds like you have a recipe for disaster there.
Sorry to say, but sounds like you have a recipe for disaster there.
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he repaired head, then resurfaced it. I watched him install the repaired head, looked brand new. Don't know the compression on the other bank, but will have him check. The block was not damaged, you could barely see where it was starting to make a mark where the flame was traveling.
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The block has to be decked, also head needs to be surfaced or it will never hold. If your mechanic is not pulling the motor, he's just puttin a band aid on it. Also use Cometic gaskets.