I friend brought his 69 Vette to my place to give a looking over after he could not get it started, When I got the car I went to start it and found that the starter just spun, so I went under the car to see what was going on and found that the nose of the starter had broken off and that while I was under the car saw a constant drip coming from the rear of the pan(car was nose up on stands) It was oil but so thin, I thought to myself and wow heavy on the gasoline smell. So went up top pulled the dipstick and it was way up on the stick. Pulled the drain plug and filled my 9 litre (9.5 qts) drain pan to the brim just a hair more and it was over the sides. Here is the question: How does this happen and where should I start looking? It's a holley spread bore with no float adjustments that I can see,(not much of a Holley guy) 350 cid all stock restored except the spread bore from what I know of the car. Thanks.
sounds like either the fuel pump ..if its mechanical..may have blown the diaghpram..or the floats are stuck , and needle valve in the carb(s) have stuck and its dumping raw fuel into the cyl.. the pump problem could dump directly into the crankcase
Just guessing here but maybe the inlet valves on the carb stuck open, flooded the cylinders, it hydraulically locked the engine causing the starter to break when cranking, engine then sat and the gas drained past the rings into the pan. Hopefully others will chime in.
Could be a ruptured diaphram in the fuel pump, but with a busted starter I'm gonna guess that the carb dumped enough gas in the engine to hydraulic a cylinder and break the starter. I hope it wasn't bad enough to bend a rod, I've seen them do it. If it were mine I'd check the carb, pull the plugs and oil up the cylinders and see what's going on. Another thing to check would be to make sure the gas cap is vented. I've seen changes in temperature pressure up gas tanks enough to push fuel by the needle & seat in the carb. At least one intake valve will be open while the engine is sitting there and it would fill that cylinder with gas. Larry T
i forgot to add..if its been letting fuel in by way of the carb being the issue , be careful not to run it without flushing the engine very well..the fuel can wash down the cyl. and the bearings and ruin the engine..I have run across this with one of my sbc's and its near shot..very low on compression..so i will need to re-ring it, and hone the cyl. before i put it in anything , this fuel will also wash your cam of any oil and ruin it too.. I will be taking the top end off this engine and checking it over very well and flushing it down with oil.. if you get it flushed well, and find your problem,, do a compression check to see what the health of the engine is as far as the rings and cam,rods etc. and crank if you feel its been run this way
just a novice here ,but isnt it a good thing the nose broke off the starter so it wouldnt of fired off? never heard of an engine exploding but seems like that would do it if it got fired up. or would a gas fouled plug even light?i had an injector hose inside the manifold on a ot blazer crack open and spray fuel into the cavity,it was so violent it sheared all the bolts off the upper manifold.scared the **** outa me but didnt keep burning.was told if i didnt turn the key off it could of been nasty.
Thanks all, that's what I was thinking about the fuel in the cylinder and the starter breaking. I did a compression check a couple of weeks ago for him and it's 130 to 150 all around. Low oil pressure not much power. I am suggesting a rebuild, he wants to drive it before winter gets here. I pulled all the plugs and some were very wet, I let it sit all night with plugs out will squirt some oil in before turn over. I am going out to shop to install starter and look over the fuel system, the suggestion about the fuel cap sounds interesting, it was in the 40s C here a few times last couple weeks while it sat. hmmmm. Thanks again all.
Make sure you pull all the plugs before you crank it again. Von Rigg Finks first comment is right. Check all those things.
When a cylinder hydraulics it is common that a connecting rod bent too. It'll show up if you redo a compression test with all plugs out, i don't think i'd start it until you did that. Bummer.
If it were me, I'd drain the pan (already done), change the oil and filter. Replace the starter, keep the plugs out and spin it to build oil pressure. It'll lubricate the bearings without a load on them and give you an idea if it's hurt. Listen for odd noises when cranking, and look down the carb to see if there is fuel going into the engine (shouldn't be without compression). Maybe pull the fuel pump and look for signs of fuel from a ruptured diaphragm. If it all checks out, put the plugs back in and fire it. Worst case is you have trashed SBC..... no big deal. Build another.
I have the compression specs from first test, when i redo the test, if rod is bend i should find a large/small drop in compression?
I have the specs from first compression check. When I redo the compression check will I see a large or small drop in compression on the bad rod? If there is one.
I would **** can the spread bore carb for now also just use a 600 or 650 , also as someone else said prime the oil pump with the spark plugs out first before you do any testing.
Yep on both of those wetatt4u, I'll do the prime spin then I'll do a compression check. I have to hunt down a carb and intake as well. Starter is back in, I'll let you all know what the comp check is.
There'd be quite a drop in compression, when you bend a rod the rod gets shorter and the piston will stay down in the hole a ways.
Ditto, but for another added reason. I have heard and read about more than a few cars going up in flames when someone had the plugs out, plug wires dangling (they still spark), and then cranked the engine with a bit of fumes or fuel spitting out of the plug holes. People rarely think of that possibility until the one day their fire extinguisher is a little too far away....
Hot thought on the spark issue I disconnected the coil. Bummer on the priming, I only have Mopar equipment at my hands right now. Think it's time to close the door open a beer until I get what I need.
I had adventures with gas in my oil from the carb loading up with gas & the sbc flooding drastically. You could smell it on the dipstick. This happened twice until I got the carb straightened out. As stated, this is not a good thing as the cylinder walls get washed & you could have resultant problems. Each time it happened, I changed the oil & filter & cleaned the plugs. I don't seem to have any problems, as result.
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