I'm a believer... (now) UPDATE!!!

If there is a 'LOT' of valve step play, the most evident thing would be lots of 'blow-by' out the valve cover. Could even show blue smoke out the exhaust. But this all depends on how loose the exhaust valves are...oh, you didn't specify intake or exhaust valve, still, the effects would be pretty much the same.

I'd still check the toothy thingy. I had the same problem and I hashed it out with Geo(GVP). He pointed out the module thingy that the coil and ECM are connected to on the distributor(I think it was the green/white wires).

My boat is a 1978 so the ignition system was the basic points distributor. Switching over to the TBIV had a few connection differences and getting the best ECM was a trial and error but over all, the TBIV has been great over the last 15 years.
 
quote:
Originally posted by Fish Guts

Charlie, I think I remember you saying you rebuild your own heads. When I replaced a few of these valves, there was quite a bit of play between the valves and guides, this is bad, no? Would that kind of valve play cause that type of loss of power (rhetorical question I guess)?

Thanks,

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Many years ago when I was a young guy fresh out of the US Navy, I got a job in a place that rebuilt heads. All day, every day for a couple of years I rebuilt heads.
Loose valve guides are no good. If you were losing compression last time you checked it, that would cause it.
That being said; guides generally go bad because of an oiling problem. If several guides were loose, than you have a bigger oiling problem.
The motor will run with bad guides, but it will run like crap because of bad compression, and fouling of the plugs.
 
Charlie, I do get a bit of blow by out the valve cover, and quite a bit of smoke out the exhaust but only until it warms up. # 4 and 6 exhaust were frozen, I had to pound them out with a hammer then cut the tip off and pound them the rest of the way through. The new ones were very loose. #6 intake was tuliped/sucked. new one was also pretty loose. The toothy thingy and module are brand new, maybe I will try to use some loctite on it, it could be lifting up and down with the spinning?

JVM, When I was adjusting lash with engine running, I was getting plenty of oil through all push rods, so I don't think it's an oiling problem.

Thanks,
 
Sounds like you'll need a rebuild on those heads. They're probably pretty expensive now days. Bronze valve guides are kinda like a rolled up toilet paper roll. The guides are reamed out and the guides are seated. The valve stem have to be mic'd, too, to see if they're worn too much.

You might be needing new heads. I got vortec heads when they first offered them and they were so cheap,like maybe $215 apiece brand new completely assembled. You'll need a vortec intake manifold, though. I have a used cast iron vortec intake for sale cheap in case you go that route.
 
Charlie, can I just change over to vortec heads like that? I mean short from needing a different intake, it should be okay? The company I was looking at, Clearwater Cylinder heads in FL have some good prices, but they ask for the casting #'s to make sure they match. Do I need different lifters and push rods?

Thanks,
 
Used to live in Tampa and several shops I knew used Clearwater Cylinder Head. They had good reports.
 
My engine is a 1971 400ci smallblock chevy. The castiron vortec heads were made for the 1997(?) chev pick-up. My memory is getting bad but I think the GM small-block was the same from 1956 to...? They changed the side for the oil filter mount around 1980-1985 (?). Otherwise, the bolt patterns haven't changed for 50+ years. That's one of the reasons the SBC is so cheap to rebuild and/or find parts for.
 
Charlie, that Clearwater Cylinder Head company website shows year ranges and casting numbers. SBC came out in 1955 with 265CID. Then the famous 283 that Chevy rated (drum roll please) 283HP with mechanical fuel injection.
Back to Richard's heads - Does Casting No 906-062 ring any bells?
 
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