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TBI, smoke and hesitation

I forgot to mention, I have the equipment, I did the tune myself and can tweak it as needed. That parts not an issue.

I also hate the leaky valve cover gaskets which was one motivation for swapping heads. Then I would need to modify my intake for the bolt angle change unless summit makes a decent "carb" style replacement head with center bolt valve covers.

Was trying to order head gaskets, but looks like I need to measure deck height, piston volume, and all that to make sure I get the right gaskets. I guess that's gotta wait until I tear it down.
 
bp71k5 said:
unless summit makes a decent "carb" style replacement head with center bolt valve covers
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Summit doesn't actually make them, world products does. But that's what they are "carb" type intake mounting but with dual valve cover mounting for perimeter or center bolt style.
 
Head gaskets are somewhat problematic if you aren't redoing the engine, and are anal like I am.

The "cheap/common" SBC head gaskets are mostly in the .043" compressed range. That's great if your block is zero-decked. Ideal quench is considered .040", stock compression height on a 350 is .025", so you need (and GM generally used) a .015" shim gasket. My worry was trying to get a .015" gasket to seal when the head bolts may have distorted the deck.

For some reason I want to say you talked about your engine in another thread, but as you start to add up prices, and this is going to sound dumb, look at the cost of a bone-stock GM crate replacement TBI engine. You may be able to find someone who is selling direct replacement heads, and if so, cost will most likely be reasonable enough to just go that route. But once you start talking Vortec's and the like (new intakes, rockers, etc.) or aftermarkets with improper bolt patterns and/or chamber CC and flow rates, the cost and complexity starts climbing very fast. And if it's a high mileage engine anyway, the cost of a crate engine starts to become more appealing.
 
dyeager535 said:
Head gaskets are somewhat problematic if you aren't redoing the engine, and are anal like I am.

The "cheap/common" SBC head gaskets are mostly in the .043" compressed range. That's great if your block is zero-decked. Ideal quench is considered .040", stock compression height on a 350 is .025", so you need (and GM generally used) a .015" shim gasket. My worry was trying to get a .015" gasket to seal when the head bolts may have distorted the deck.

For some reason I want to say you talked about your engine in another thread, but as you start to add up prices, and this is going to sound dumb, look at the cost of a bone-stock GM crate replacement TBI engine. You may be able to find someone who is selling direct replacement heads, and if so, cost will most likely be reasonable enough to just go that route. But once you start talking Vortec's and the like (new intakes, rockers, etc.) or aftermarkets with improper bolt patterns and/or chamber CC and flow rates, the cost and complexity starts climbing very fast. And if it's a high mileage engine anyway, the cost of a crate engine starts to become more appealing.
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I had it rebuilt by Scott @4X4HIGH a number of years ago and wanna say the block was decked, heads rebuilt, etc, but one time I accidentally disabled my electric fan after towing a trailer. The water temp was ok while I was moving but once I was idling for a bit trying to back the trailer into the driveway, with no airflow across the radiator, I smelled coolant, checked the water temp and saw it was crazy high, then 2 seconds later the radiator hose blew off and left me in a cloud of steam. The engine reliability (multiple new radiators that would leak coolant) has never been the same since so I'm suspecting I damaged something. I've got about 30k miles out of it so far.

My gut tells me to pull the heads and have them checked and then decide whether to just put gaskets back in and get it going again. It's very reliable except for the cooling problems that I thought were over.

Hey Scott, any chance you remember any details that might help me pick the right gasket?
 
Small but strange update as I removed the head today, expecting (hoping) a damaged block and all kinds of other damage that would give me an excuse for a big block.

Here's a picture of the cylinder, as expected, it had water in it. I don't see any obvious damage to the block. I may have caught it just in time? I'm not sure why I have water in this cylinder.

http://s1105.photobucket.com/user/bperryrm/media/Mobile Uploads/894789E8-55FC-448A-98FB-6136E8E7F9EE_zpsaqhgbkpz.jpg.html][/URL]

Here's the gasket closeup of the side facing the cylinder. Is that small gasket erosion enough to cause a leak? Seems like the metal part that surrounds the bore is still intact, but I'm not so sure. The large hole in the gasket it's touching isn't even a water passage. The water passage is the smaller hole up towards the center of the bore.

http://s1105.photobucket.com/user/bperryrm/media/Mobile Uploads/D8662B75-BC47-4957-BB0D-C69319BE2FE6_zpsyyqmmdmb.jpg.html][/URL]
 
That location would not be the reason for water in the cylinder that is wet. But it might have been leaking also. Notice how clean the piston is? Sure sign of burning coolant.

It is junk. Go BBC.:burnout:
 
ktmoutfront said:
That location would not be the reason for water in the cylinder that is wet. But it might have been leaking also. Notice how clean the piston is? Sure sign of burning coolant.

It is junk. Go BBC.:burnout:
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The cylinder for sure had water in it. When I removed the spark plug, it poured right out. Just wondering how/why the water got in there if the gasket isn't bad.
 
I was looking at the one with the water still in it as the bad one you were referring to. What does the other side of the gasket look like? Could also be a cracked cylinder wall or head. That gasket has been pushed into the cylinder. Reference the flat spot. But usually see staining on the gasket.
 
ktmoutfront said:
I was looking at the one with the water still in it as the bad one you were referring to. What does the other side of the gasket look like? Could also be a cracked cylinder wall or head. That gasket has been pushed into the cylinder. Reference the flat spot. But usually see staining on the gasket.
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The one with water in it was because water leaked in there when I removed the head. The bad one is way at the back of the motor. The top of the piston is all clean. I do see that the block doesn't have a water passage there, but the head does, so it looks like water in the head must have seeped past that spot in the gasket and into the cylinder.
 
cracked cylinder wall... enjoy the bbc. I had exactly the same issue with the motor that was in the vehicle that's my avatar (that picture is of the last day that motor was in the vehicle - I towed it home from that spot). I run TBI with vortec heads.
 
superbuickguy said:
cracked cylinder wall... enjoy the bbc. I had exactly the same issue with the motor that was in the vehicle that's my avatar (that picture is of the last day that motor was in the vehicle - I towed it home from that spot). I run TBI with vortec heads.
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Any way to confirm a cracked wall with pulling it?
 
Here's a closer picture of something weird in the cylinder wall I found after rotating the crank a bit. The crosshatching stops and there's an odd textured area you can see on the left side of the picture. That's the lower area of the cylinder.

What is up with Photobucket his week

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4FC76F93-1F7E-43A4-ADC6-39A192ACB5F6_zpsh63mmtvw.jpg


http://i1105.photobucket.com/albums/h360/bperryrm/Mobile Uploads/4FC76F93-1F7E-43A4-ADC6-39A192ACB5F6_zpsh63mmtvw.jpg
 
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Never seen a crack in that spot, but I haven't seen a lot of cracks either. Any advice for the closest bolt on big block option? I'm told the 8.1 is drop in, probably easier to find a whole truck with one and pull it out.
 
I think the 8.1 is over rated - but there are some who swear by them. (and I can already hear the little feet of Larry coming to dispute me - and I'm not getting into a dispute, it's my opinion).

It's always less expensive to buy a running donor then sell the skeleton when done.

As for cracking in that spot - you Californians :cautious: annoy me with your constantly sunny weather and lack of knowledge about how to properly crack a block by having too little antifreeze in the mix. Not saying that's what happened with you, but that's the classic spot they crack. Some blow out, others compress and push out the weak point. That is where the sleeve casting meets the bottom of the water jacket - it's thinnest there and ice freezes from the coldest point out (usually the middle) - as it expands it hydraulically splits the seam to create enough room for the ice.... for you, probably simply a defective casting and/or someone didn't change the antifreeze enough and it rusted out at the weak point... that's also a favorite spot for turbo motors to go poof since that's where heat is most concentrated by the action of the piston going down then up there.
 
I have pulled many SBC apart to find that same crack.

Don't get the "this engine is the best" debate started.
 
superbuickguy said:
I think the 8.1 is over rated - but there are some who swear by them. (and I can already hear the little feet of Larry coming to dispute me - and I'm not getting into a dispute, it's my opinion).

It's always less expensive to buy a running donor then sell the skeleton when done.

As for cracking in that spot - you Californians :cautious: annoy me with your constantly sunny weather and lack of knowledge about how to properly crack a block by having too little antifreeze in the mix. Not saying that's what happened with you, but that's the classic spot they crack. Some blow out, others compress and push out the weak point. That is where the sleeve casting meets the bottom of the water jacket - it's thinnest there and ice freezes from the coldest point out (usually the middle) - as it expands it hydraulically splits the seam to create enough room for the ice.... for you, probably simply a defective casting and/or someone didn't change the antifreeze enough and it rusted out at the weak point... that's also a favorite spot for turbo motors to go poof since that's where heat is most concentrated by the action of the piston going down then up there.
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I'm not super knowledgeable or care all that much, only thing I really would like is a bit more low end torque. The 8.1 was recommended as a drop in replacement. Looks like a 454 would be cheapest to find locally. Just want it set up for fuel injection and the least likely to leak oil (more modern the better). Those are my two big requirements.

As for why it cracked, it had 50/50 anti-freeze in it. Though I did run it for a while with straight water but it rarely gets below freezing here so I wasn't super concerned about it.
 
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