Newly rebuilt carb, same problem...UPDATE
- Thread starter Fish Guts
- Start date
- Joined
- Jan 1, 2000
- RO Number
- 2006
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- 359
Don’t just repair one head, do them both!
Oops! Yeah, just got a look at the pix. I'm surprised it ran at all.
The pistons being that clean means it's been ingesting water for a bit to have 'steam cleaned' them like that. That one head that's so rusty probably hydrolocked which is why so many push rods bent.
How many hrs on the engine? Trying to determine how much wear on the bottom end. Might have to do the complete engine.
The pistons being that clean means it's been ingesting water for a bit to have 'steam cleaned' them like that. That one head that's so rusty probably hydrolocked which is why so many push rods bent.
How many hrs on the engine? Trying to determine how much wear on the bottom end. Might have to do the complete engine.
pdecat, when I click on the url it shows the pic... Don't know any other way to post it.
Charlie, there's a little over 300 hours.I knew the exhaust was bad at the end of last year, all new now.
Turned the engine by hand and everything seems to move... pistons, lifters, the other side seems fine. All the plugs on the other side look like they're firing fine...
When I was knocking out the valves, this happened, hoping it will be okay.. what do you all think?
Thanks,
Richard
Charlie, there's a little over 300 hours.I knew the exhaust was bad at the end of last year, all new now.
Turned the engine by hand and everything seems to move... pistons, lifters, the other side seems fine. All the plugs on the other side look like they're firing fine...
When I was knocking out the valves, this happened, hoping it will be okay.. what do you all think?
Thanks,
Richard
try deleting the stuff and only use the [img] code
when I click the url code I see larger pix. There looks like a head gasket leak between the two center cylinders. As Charlie sadi the pistons are too clean. That usually means steam from water ingestions.
Charlie: Is there any reliable way to measure piston to deck height to check rods? I would use a straight edge and feeler gauges to look for variation but I don't know what is reasonable.
Charlie: Is there any reliable way to measure piston to deck height to check rods? I would use a straight edge and feeler gauges to look for variation but I don't know what is reasonable.
If I could re-title this thread:
"Ridden Hard and Put Away Wet - A Case Study in Exhaust System Failure"
First a glance and BE History - I joined around 2004 and was asking questions about our 350 SBC MerC and Charlie was the first reply I ever had on this forum. Since then I've learned that if you ask Charlie what's wrong with your SBC you need to have Pen and Paper in hand. When Charlie answers, you might as well order parts before you put a wrench to it. In this case, Failed Joint, Between Exhaust Manifold and Riser, in this case Starboard Side.
I've lost track of the progression of this issue but I think:
1. Boat was out of service for months, maybe winterized. This allowed time for trouble to brew to full strength.
2. Vacuum and/or Compression and/or Blow-Down Cylinder testing was suggested. Doing this would have moved the Carburetor, Base Gasket and Fuel Pump to the bottom of the suspect list.
Seems water got to the valve guides in both center cylinders, exactly what Charlie mentioned. Most likely source is wasting away of the gasket surface between Manifold and Riser. Or "Spacer Block" if your boat uses those. (Ours does, so add $200 to cost of Exhaust Job...) Then the Valve Stems rooted themselves to the Guides with rust and the running engine bent the pushrods till they broke.
From the pix (great pix, clicking on the photos' URL's displays them full screen) I don't think the Pistons are damaged, and all the Valves look like they aren't bent or missing pieces. If the wettest (from water) cylinder bores aren't rusted, my guess would be the Block is salvageable. Heads too, but it might be cheaper to get Rebuilt or even New ones. The pre-Vortec heads are cheap!
Yes, you CAN go to Vortec heads and get more power but now you're adding an Intake Manifold to the mix. I've heard but can't confirm that Vortec heads are prone to cracking, so I'm not as sure I want to upgrade as I used to be. Wondering if anybody can confirm that...
I'd suggest cleaning up the Block's Head Gasket surfaces, the tops of the Pistons, and carefully inspect the Bores. IF they're all OK, then my worries turn to the Camshaft. If you go with the your present Block, I think you'll find you need a Cam and a set of Lifters. It's my belief you'll find the pressures it took to break those pushrods damaged the rubbing surfaces of the Lifters and Cam Lobes. Those parts have only a surface hardness, so if they look marred, it means they will wear very fast. That'll create valve lash that you can adjust out because the SBC has adjustable rockers, but the wear will continue till you have parts of lifter and camshaft in your oil filter and you'll be back to a miss.
For me, the keys to this are Pistons, Cylinder Walls and Head Gasket Surface. If that Block has to come Out, Apart, and/or Machined, my opinion is get a reman long block.
And I'm pretty sure you'll find, if you haven't looked yet, that the "wet joints" between exhaust manifold and riser are shot. So an Exhaust Kit too.
Hate to be Bearer of Bad News, but I've also learned Bad News only gets Worse with Age.
"Ridden Hard and Put Away Wet - A Case Study in Exhaust System Failure"
First a glance and BE History - I joined around 2004 and was asking questions about our 350 SBC MerC and Charlie was the first reply I ever had on this forum. Since then I've learned that if you ask Charlie what's wrong with your SBC you need to have Pen and Paper in hand. When Charlie answers, you might as well order parts before you put a wrench to it. In this case, Failed Joint, Between Exhaust Manifold and Riser, in this case Starboard Side.
I've lost track of the progression of this issue but I think:
1. Boat was out of service for months, maybe winterized. This allowed time for trouble to brew to full strength.
2. Vacuum and/or Compression and/or Blow-Down Cylinder testing was suggested. Doing this would have moved the Carburetor, Base Gasket and Fuel Pump to the bottom of the suspect list.
Seems water got to the valve guides in both center cylinders, exactly what Charlie mentioned. Most likely source is wasting away of the gasket surface between Manifold and Riser. Or "Spacer Block" if your boat uses those. (Ours does, so add $200 to cost of Exhaust Job...) Then the Valve Stems rooted themselves to the Guides with rust and the running engine bent the pushrods till they broke.
From the pix (great pix, clicking on the photos' URL's displays them full screen) I don't think the Pistons are damaged, and all the Valves look like they aren't bent or missing pieces. If the wettest (from water) cylinder bores aren't rusted, my guess would be the Block is salvageable. Heads too, but it might be cheaper to get Rebuilt or even New ones. The pre-Vortec heads are cheap!
Yes, you CAN go to Vortec heads and get more power but now you're adding an Intake Manifold to the mix. I've heard but can't confirm that Vortec heads are prone to cracking, so I'm not as sure I want to upgrade as I used to be. Wondering if anybody can confirm that...
I'd suggest cleaning up the Block's Head Gasket surfaces, the tops of the Pistons, and carefully inspect the Bores. IF they're all OK, then my worries turn to the Camshaft. If you go with the your present Block, I think you'll find you need a Cam and a set of Lifters. It's my belief you'll find the pressures it took to break those pushrods damaged the rubbing surfaces of the Lifters and Cam Lobes. Those parts have only a surface hardness, so if they look marred, it means they will wear very fast. That'll create valve lash that you can adjust out because the SBC has adjustable rockers, but the wear will continue till you have parts of lifter and camshaft in your oil filter and you'll be back to a miss.
For me, the keys to this are Pistons, Cylinder Walls and Head Gasket Surface. If that Block has to come Out, Apart, and/or Machined, my opinion is get a reman long block.
And I'm pretty sure you'll find, if you haven't looked yet, that the "wet joints" between exhaust manifold and riser are shot. So an Exhaust Kit too.
Hate to be Bearer of Bad News, but I've also learned Bad News only gets Worse with Age.
j-d, thanks for the post... I bought the boat last year, and basically, short from a couple fishing trips, it was just a vacation home for the wife and I. Just sat at the slip. I knew the risers didn't look good, which is why I didn't take it out much. Was not put away wet, the engine was pulled from the boat and drained,(had to replace the whole transom assembly, due to corrosion). whether there was water in the cylinders, I couldn't say. From what I can tell, this was a pre-existing condition.
Head gasket was good, problem was water intrusion from bad exhaust. Everything now "looks" okay. Gonna put it back together when the gasket set comes in.
I am actually thinking the cam is okay, but we'll see...
Thanks for all the input everyone.
Head gasket was good, problem was water intrusion from bad exhaust. Everything now "looks" okay. Gonna put it back together when the gasket set comes in.
I am actually thinking the cam is okay, but we'll see...
Thanks for all the input everyone.
Hopefully the additional information from Richard will work out that the block itself is OK, maybe even the heads can be reconditioned if this was a long block or major rebuild with recon heads. 300-hour block should show hone marks in the bores of all eight, uniformly, and with those few hours, no ridge.
Bruce has a good eye for this stuff, so maybe it's head gasket not fallout from bad exhaust parts.
And I was wondering about the same idea Bruce set out about putting a straight edge across the block deck at each TDC piston and using a feeler gauge to see if the ones that got water show a little lower, which could be a sign of a bent connecting rod.
This is an ugly mess but I'm starting to feel a little better about it.
Still, look carefully at Cam and Lifters. The force it took to bend those pushrods was way beyond design parameters.
Bruce has a good eye for this stuff, so maybe it's head gasket not fallout from bad exhaust parts.
And I was wondering about the same idea Bruce set out about putting a straight edge across the block deck at each TDC piston and using a feeler gauge to see if the ones that got water show a little lower, which could be a sign of a bent connecting rod.
This is an ugly mess but I'm starting to feel a little better about it.
Still, look carefully at Cam and Lifters. The force it took to bend those pushrods was way beyond design parameters.
j-d, I agree about the force it must have taken to bust the rods. But, I had to really bang these valves out. However, as I mentioned, cranking the engine by hand, everything moves as it should (from what I can tell). I'm thinking if the cam lobes were worn so bad as to bend/break a push rods, I can't see how the lifters would actually move fully. I will put it all back together and see (and hope). Honestly, I don't know how this thing ran so well in the condition that it was in. Anything over 900 rpm's, it ran so smooth. Last year it actually ran great.
Does anyone have any thoughts on the last pic I posted about the broken valve "guide" in the head? Should this be okay?
Thanks,
Richard
Does anyone have any thoughts on the last pic I posted about the broken valve "guide" in the head? Should this be okay?
Thanks,
Richard
I had a plug wire off on our SBC and it seemed to develop nearly full speed, just a little slow on the uptake. I pray the Chevrolet Prayer before an outing. "Dear Lord, One Eight Five Three Six Four Seven Two, Amen." So the two center starboard cylinders are 4 and 6 which would mean Hit Hit Miss Hit Miss Hit Hit Hit. Two Miss's in a row would have felt a lot worse.
By "Put Away Wet" I meant being run with the leaky manifold joints then shut down for an extended time. That could well have been prev owner stuff. But you have new manifolds, risers (spacers) now, right?
What boat is this 260 in? Does it call for spacer blocks? I ask about spacers because MerC wants the top of the risers to be at least 13" above the boat's floating waterline. If you don't have that, there's another possibility for water in the valves.
By "Put Away Wet" I meant being run with the leaky manifold joints then shut down for an extended time. That could well have been prev owner stuff. But you have new manifolds, risers (spacers) now, right?
What boat is this 260 in? Does it call for spacer blocks? I ask about spacers because MerC wants the top of the risers to be at least 13" above the boat's floating waterline. If you don't have that, there's another possibility for water in the valves.
Carefully inspect the bottom of the lifters that broke the four pushrods. They should be smooth and convex with no blemishes in the surface. If they're flattened, concave or roughed up, then you can assume the same happened to the cam lobes.
I think you should take the heads to an automotive machine shop for checking and a valve job. They'll check and true the gasket surface, check the guides, and replace what's necessary. They should be able to tell you about that chipped guide edge. My guess is that it'd be OK.
I think you should take the heads to an automotive machine shop for checking and a valve job. They'll check and true the gasket surface, check the guides, and replace what's necessary. They should be able to tell you about that chipped guide edge. My guess is that it'd be OK.
Awwww SH*T!! I just lost my looong reply going back over the pics.
Short version. Don't sound like you'll be doing a lot of boating so burning oil may not be that bad. Pull the valves on those two inner cylinders (keep track of where they went). put some grinding/lapping compound on the seats and rotate to see if there are any high spots or bent valves. That rusty cylinder head don't look as bad as the one next to it with it's stuck valve. If the valves move up and down freely, just lapping them to get a seal should be all you need. Check lifters like JD said and press the center cup down to make sure they're not frozen. New ones cost less than $3.
As far as piston height goes, they're just numbers you gotta look up, but they're for new engine specs. Any wear slowly widens the tolerances. I have to look them up when I do an engine.
Short version. Don't sound like you'll be doing a lot of boating so burning oil may not be that bad. Pull the valves on those two inner cylinders (keep track of where they went). put some grinding/lapping compound on the seats and rotate to see if there are any high spots or bent valves. That rusty cylinder head don't look as bad as the one next to it with it's stuck valve. If the valves move up and down freely, just lapping them to get a seal should be all you need. Check lifters like JD said and press the center cup down to make sure they're not frozen. New ones cost less than $3.
As far as piston height goes, they're just numbers you gotta look up, but they're for new engine specs. Any wear slowly widens the tolerances. I have to look them up when I do an engine.
j-d, It is a 1988 23 foot Regal cruiser. No spacers, just the manifolds and risers, all new. I'll check the lifters, maybe just buy the 4 new ones to match the push rods.
Charlie, won't be using the same valves, had to pound them out. Actually had to cut the tops off two of them because I had flattened them with the hammer. I will seat the valves properly with lapping compound.
So... I know the PO must have done some work to this side, because it had a different valve cover gasket, just don't know what he did.
Charlie, won't be using the same valves, had to pound them out. Actually had to cut the tops off two of them because I had flattened them with the hammer. I will seat the valves properly with lapping compound.
So... I know the PO must have done some work to this side, because it had a different valve cover gasket, just don't know what he did.
Heck, if the valves had to pounded out, you'll probably need a whole new head. It's possible to open up the valve guide and put in larger valves...but machine work could end up costing as much as a used head. There ain't no difference between auto and marine head. Got a friend that knows engines and can get one for you at the junk yard. Clean it up, put in brass freeze plugs and lap the valves.
I bet the PO did what you're gonna do 'cept for not replacing a bad manifold/riser. Inspect the block real good for cracks that may have been another way water got in the heads. No telling what the PO did or didn't do.
Too bad you're not closer, I have a (free)260 sitting in the garage that wasn't powerful enuff. I have a 400 SBC in my boat now and I got 2 or 3 400 blocks in the garage waiting to be built. The 400 engine is the best small block made for marine use. The parts are cheap like the 350 and can easily be made to put out the power of a big block (454 ci).
Too bad you're not closer, I have a (free)260 sitting in the garage that wasn't powerful enuff. I have a 400 SBC in my boat now and I got 2 or 3 400 blocks in the garage waiting to be built. The 400 engine is the best small block made for marine use. The parts are cheap like the 350 and can easily be made to put out the power of a big block (454 ci).