|
By Whitey - 15 Years Ago
|
G'day All,
I have a 272 fitted to a ski boat that has become my project and seek some knowledge as it'smy first v8. She was bought last Sep after being neglected in a rear yard for 7 years and she definately appeared that way when picked up. The owner stated that the motor was sound and was not the reason he stopped using her but we have all heard that before.
I had the motor out to clean up and fix the hull, but did not pull it right down due to funds available, only removed the manifolds and rocker covers and turned it over with the starter only after a good lube and made sure all moved as it should with all valves etc moving as they should. All of the oil was removed and changed with a new filter fitted and no pieces of metal were found in the sump. I have had her running in the front yard with no worries at all, idling away happily and some sharp revs to piss off the whinging neighbours.
I dropped her in a River today for a last check as I planned to go to a dam for her first trip this weekend.
After a few minutes it all went very bad!! She started to make a metal on metal clanging noise from the block (like hitting it with a hammer). The strange thing was it was sporatic. Like bang....bang..............bangbang.........bang..................bang if you get my drift. It wasn't a constant bang like with every stroke. It seemed louder through the intake when the air cleaner was removed. The motor continued to idle away happily and she was not missing or anything. One side of the exhaust appeared to be a bit steamier than the other if that helps, as the water is dumped into the exhaust just after the manifold to be blown out the back. The oil pressure gauge was reading a steady 70psi with no fluctuations at all.
My dad was with me and he is very mechanical and thinks she may have thrown the top or part of a piston due to possibly being a bit rusty which was now getting knocked around the bore. Looks like I will be pulling the heads off for a look and see what I'm up for.
Any tips or advice is greatly appreciated as I have never worked on a y before now. Does anybody know where a good source of parts, eg pistons etc is as I might be needing them soon, preferably in australia but not necessary if the freight isn't too bad. From a quick look on the net 292 pistons seem cheaper and more readily available so has anybody bored out a 272 and used them instead? Does anybody know of some basic checks I can do while running to problem solve before I pull it down to narrow the problem?
Thanks for any replies.
Geoff the broken hearted ski boat owner!!
|
|
By Hollow Head - 15 Years Ago
|
|
http://www.cussobills.com/cussobills/?page_id=23 Might be the right place. AussieBill might know better....
|
|
By Ted - 15 Years Ago
|
|
Welcome to the site! Pulling the valve covers and simply looking for anything out of place would be on the top of the list. Be sure to look at the valve springs closely for broken coils. Then perform a compression check with all the spark plugs out of the engine and the throttle blocked wide open. And look at the plugs while you’re removing them and keep them in the order that they were removed. They may provide a clue in their appearance or coloring.
|
|
By crenwelge - 15 Years Ago
|
|
I'm not sure of your definition of banging. While you have the valve covers off as previously suggested, check for valve movement. You could have valves sticking. I suppose you have gotten rid of all the 7 year old gas. It will turn to varnish. Something like Marvel Mystery Oil will usually dissolve varnish.
|
|
By MarkMontereyBay - 15 Years Ago
|
If your motor is idling well; not misfiring, as you described, and the banging is sporadic and coming from the engine block, I don't think there is a valve train problem. Unfortunately, to me it sounds like something has gotten in to one of the cylinders. I mean something like a piece of metal (lost nut or screw, carb nut or washer, or possibly a big chunk of carbon.) I would be hesitant to run it again if it was idling ok and not missing. Not even for a compression check. If there is something in one of the cylinders and you haven't damaged a piston or cylinder wall best to leave it be. I would be thinking seriously of pulling the heads to see what is up unless you have access to a boroscope that you can insert into the spark plug hole on each cylinder and have a look around.
Mark Hebard
|
|
By Bob's 55 - 15 Years Ago
|
This may or may not be your problem but I thought I would throw it out there...
I was once given a '64 Corvair that ran real strong but made a noise in the engine. Being a LOT younger I figured since it was free I would abuse it until it broke. After a couple of months I 'll be danged if the noise didn't go away but it started running like it lost a cylinder and popping back though the Carburetor. So I pulled the head on that side and found a small bolt that had been dropped down a carb? stuck in a intake valve and holding it open. The piston and head were beaten all to hell. Replaced the piston and cleaned some of the divots in the head, lapped the valves (in that cylinder only) and I was on my way back to practicing my power shifting (it was a 4 speed).
Sorry for the long story but I feel the best bet is the check the valve train as suggested and then pull the heads.
Good Luck.
This has nothing to do with what we a discussing but believe it not when the Corvair was given to me it had a complete set of, now get this, 13x6 MAGNESIUM Halibrand "Kidney Bean" wheels on it. Still have them ~35 years later.
|
|
By aussiebill - 15 Years Ago
|
|
With many years of expeirence with new y block boat owners, there seems to be a breaking in learning curve period and lots of money spent both wisely but generally unwisely trying to take every shortcut known to mankind to fix the problems. This is NOT meant to be unkind to anyone but with 40 yrs of trying to educate boat owners, 9/10 spend more money on shortcuts instead of commiting to doing it properly once. That aside i would read the plugs, check the tappet settings, rotate the engine looking for anything to indicate which cyl area the noise may come from. Not hearing the actual noise is hard to be accurate on suggesting noise source but Things that come to mind; is the dip stick hitting the crank, could there be a loose valve seat, or something fallen into engine. next step is off with the heads to rule out top end problems and check piston tops for integrity or foreign object. I guess its just inspecting everything slowly with medical precision and preferably with someone else with mechanical prowess, 2 minds are better than 1. Just aside for a moment, here in Aust there were thousands of short 17' wooden clinker speedboats with y blocks, they were 1st cheap powerfull V8 here and replaced the sidevalve V8 and flathead dodge 6 cyl, nearly all were bored out 272 to 292, hence everyone here then having 292 engines in everything!!, they were mounted back the front or opposite and were combinations of locally made marine manifolds and car type parts, next generation came along and fibreglassed the old hulls and they go again! I often recite this story as i know it; a relativley young guy with limited funds buys his 1st cheap skiboat, encouraged by his buddies to go sking but no money to buy fuel, knows nothing about the engine and old timber deck peeling off but is commited to fixing it, a few years later the hulls right, lets hit the engine, bang, pop and thats strange? the pushrods are bent and fallen into valley, or it went off the key and first trip is overheating, then its 2 or 3 replacement heads, 6 head gaskets, another 12 months of frustration and disappointment each trip to water, maybe then they,ll listen and rebuild it properly to stand the constant high rev range use, never looking at temp guages till it,s too late. At last and thousands of $ later the boats good and much fun is had, wage rises and they move on up the boat price range and buy a newer used boat, the y block boat sits in the yard under a canvas sheet, if lucky, and years later a new young guy comes along looking for cheap 1st boat and you guessed it, turn key, bang pop, thats strange! oh! Some of the pushrods have fallen into valley and;;;;;;. regards bill.
|
|
By aussiebill - 15 Years Ago
|
|
Whitey, after rereading symptoms, could one of the exhaust manifolds be corroded and letting water into cyl causing sound, hows the engine oil color now. keep us informed of any updates. Prop coupling tight?
|
|
By Whitey - 15 Years Ago
|
|
Thanks for suggestions guys, they are all helpful. I have to admit Aussiebill, that when reading yours it definately gave me a smile. I am trying this on a very tight budget, but haven't tried to cut too many corners. Even with little cash I have done everything methodically and replaced with new when possible. My boat is all fibregalss and needed a replacement stringer and some glassowrk obviously. I would have liked to pull down the whole motor when it was out and inspected it but just didn't have the cash. I have bought a complete gasket kit from the US as I needed exhaust manifold, rocker cover and timing cover gaskets and anticipated I might need some more. My dad's first car was a 55 customline with a 272 and he has been drooling over her since I bought it to my place and is always keen to help out, reliving some memories I think. As previously stated since buying her I have a sourced a 55 customline manual which I have read and done lot's of research here. I saw that they may stick valves if not used for a while that's why she was totally lubed and turned over, first by hand then starter with the plugs out and watching all valves etc to ensure all movement. Th oil that was in her was old, but not milky at all and only a bit of sludge in the bottom and no metal parts found. The dipstick is definately clear of all moving parts, but I can't rule out a corroded manifold as the previous owner only used her in salt water and the clutch manifold water tubes were completely eaten away and required extensive repair work. When the exhaust manifold were off I filled them under tap pressure and sealed one end and they both stayed dry internally, but as stated the right (really left as she's in backwards) was definately steamier. I have a friend coming over today who has been involved with old cars, especially chevs for a long time and will let her idle over for a while so he can have a listen and give his thoughts. Please keep them coming all and I will let you know how we go today and what she looks like if pull her heads off tomorrow. Cheers Geoff
|
|
By Whitey - 15 Years Ago
|
|
Well Gentlemen, you won't believe this as I still don't! She's fixed and purring away again happily. I went down and pulled off the rocker covers and the pushrod for no2 exhaust had slipped out. Didn't even get bent or anything. Marked the nut and wound her out, replaced the pushrod and went back to where it was and obviously too loose. Adjusted correctly as with the others and now she is running perfectly. My friend (really big into chev's) who came for a look even said he was impressed how smooth she's running. Stated "you could even sit a can of coke on the air filter and it wouldn't spill a drop!" Thanks for all of your advice and tips and I plan to try again for a run in the river tomorrow, hopefully I'll let you all know that she went like a trooper. Geoff
|
|
By MoonShadow - 15 Years Ago
|
Tell your friend you can do that on a scrub engine too, just don't pop the top! Glad the problem was a simple fix. Check back on that push rod again soon. The adjuster could be backing off on it. Probably be a good Idea to set all the valves soon. I think 19 thousandths will do it. Just follow the firing order and do one cylinder at a time. Never hurts to recheck! Chuck in NH
|
|
By aussiebill - 15 Years Ago
|
|
Whitey, glad you found it and hope you have some more fun in that y block boat.
|
|