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If anyone seen my chevelle at the Sharonville show you seen I was sporting a new intake and some dress up items.
I also changed my heads over the winter and put on a set of double hump heads that I had laying around and removed my "power pack" heads.
It ran, post tense, very well. Maybe too well. I now have have a bent push rod and blown head gasket. The heads are back off to check for any bent valves.
Mike
-------------------- 67 Malibu 67 El Camino waiting for restoration. Tri-State Chevelle #27 ACES #2886 Posts: 366 | From: Clarksville | Registered: Jun 2005
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Mike are sure these did not happen at different times. It seems kind of odd to have both of those happen at the same time unless you had a backfire possibly.
Mike are you running stock pushrods and rocker arms?
Do you have screw in studs for the heads?
The pushrod that bent, did the stud pull out of the head??
Did the valve spring retainer hit the valve guide boss to bend the pushrod???
Did you float the valves @8500 rpms??
Those are a couple thing that can bend a pushrod.
I am inclined to think the blowed head gasket is a different issue. If you got steel shim gaskets I would ditch them and use the Felpros.
-------------------- Larry Grigsby Founding Member # TSC-010 ACES Member #3635 69 SS 396 (454) (Cloned) Posts: 1042 | From: Huber Heights, Ohio | Registered: Aug 2004
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Valves will float waaay below 8500, Like at 6000 if the valve springs weren't up to the task. Did you blow the head gasket because of detonation or running the fuel mixture too lean? How did it blow between cylinders or out the front/side?
-------------------- 1970 SS454 Chevelle cloned 1970 SS396 El Camino for real 2003 SS Silverado I NEED MORE SUPER SPORTS!! Posts: 877 | From: Cincinnati, Ohio | Registered: Oct 2004
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Comp push rods with screw in studs. To answer one.
OK. This what I think happened.
It appears I leaked water into #4 and liquid locked it. Valves couldn't open so push rod gave in. I did a compression check and while doing it anti-freeze was spraying out #4 plug hole.
When I was removing the heads I noticed the head bolts did not seem as tight as I thought they should be. I know I torqued them to spec. I am now thinking my 30 year old torque wrench was way off. At least that is the leading theory now. I know there was green liquid in the oil.
I am pulling the engine and inspecting the rest of the rotating assembly. Hopefully I did not bend a rod.
I did have new springs and they were strong enough that the machine shop said we should go to screw in studs.
I had revved it a little on the way home, but not anything like I had in the past! I heard it when it bent, it sounded like someone had dropped a bunch of money on the floor$$
Mike
-------------------- 67 Malibu 67 El Camino waiting for restoration. Tri-State Chevelle #27 ACES #2886 Posts: 366 | From: Clarksville | Registered: Jun 2005
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Did little $$$ signs come falling out of the tail pipes? If you hydro locked a cylinder then chances are you hammered a rod bearing out too. Time to build a 383.
-------------------- 1970 SS454 Chevelle cloned 1970 SS396 El Camino for real 2003 SS Silverado I NEED MORE SUPER SPORTS!! Posts: 877 | From: Cincinnati, Ohio | Registered: Oct 2004
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You might have got lucky and the valve bent before the rod. I filled up my 454 with gasoline one time and tried to turn it over and it made just a whining noise. I got lucky, I pulled the spark plugs & drained the cylinders. Replace the plugs and ran fine.
I don't like the sound of money dropping anytime. Mike that would explain why a valve would bend with a blown head gasket. Never thought of that one. Almost everytime it is a valve train problem.
-------------------- Larry Grigsby Founding Member # TSC-010 ACES Member #3635 69 SS 396 (454) (Cloned) Posts: 1042 | From: Huber Heights, Ohio | Registered: Aug 2004
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It appears the valves are ok, just the push rods bent so far.
I will have the rest of the engine out on sunday and begin an inspection.
The machine shop guys seem to think the rods will be ok. I will see. The push rod bent at idle, (I think), and I shut it down after I heard something and it started poping out the carb.
Dave, I do have a nice four bolt main 350 that would a good canidate for that. If I did not want to drive this car soon I might consider that. It sounds like a fun build and I never tried that before.
-------------------- 67 Malibu 67 El Camino waiting for restoration. Tri-State Chevelle #27 ACES #2886 Posts: 366 | From: Clarksville | Registered: Jun 2005
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Break out your credit card...you can buy a rotating assembly and have that puppy done in 2 weeks. There's a 502/502 on Cincy Craigslist for $4800.
-------------------- 1970 SS454 Chevelle cloned 1970 SS396 El Camino for real 2003 SS Silverado I NEED MORE SUPER SPORTS!! Posts: 877 | From: Cincinnati, Ohio | Registered: Oct 2004
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Mike how many pushrods are bent? Is it just one cylinder or multiple. I can maybe see an adjacent cylinder leaking through to the other one but not others.
-------------------- Larry Grigsby Founding Member # TSC-010 ACES Member #3635 69 SS 396 (454) (Cloned) Posts: 1042 | From: Huber Heights, Ohio | Registered: Aug 2004
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383=350 block, crank, rods, pistons usually available in a kit. You can get them internally or externally balanced. They used to take 400sb cranks and turn them down then use a 6 inch rod with custom pistons. Now they make 383 specific cranks. You can buy kits on ebay for $600-up
-------------------- 1970 SS454 Chevelle cloned 1970 SS396 El Camino for real 2003 SS Silverado I NEED MORE SUPER SPORTS!! Posts: 877 | From: Cincinnati, Ohio | Registered: Oct 2004
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I do remember the 400sb cranks were involved.
I seen kits in jegs and summit. Those kits are around $600 too.
I also remember you have to grind out some interference in the block for the crank or does the kit with a 383 specific crank make that go away?
What is your take on internal or external balance?
What are the pros and cons of a 383? I am probably on the fence right now as far as cost and time goes. I plan to re-use my intake/heads if I go 383 or is there something I am missing here.
On another note I finished my disassembly on my 327 and the cam was gone. Lobes for 3 and 4 are round now. The rest looked ok. Rod bearings looked ok but did not measure them. Rods look ok but they will need checked if I reuse them. Main bearings had more scoring than I thought should be there, in fact a lot more. The crank would surely need polished if not ground.
I guess I will hitch a ride with Tanya for awhile.
-------------------- 67 Malibu 67 El Camino waiting for restoration. Tri-State Chevelle #27 ACES #2886 Posts: 366 | From: Clarksville | Registered: Jun 2005
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Sorry to hear about all the damage. I am really starting to worry about flat tappet camshaft wear. I think my next cam will be a roller for sure.
-------------------- Larry Grigsby Founding Member # TSC-010 ACES Member #3635 69 SS 396 (454) (Cloned) Posts: 1042 | From: Huber Heights, Ohio | Registered: Aug 2004
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You could always call Big John and see what he wants for a used 350. You could do a Krylon rebuild on it and go.
-------------------- 1970 SS454 Chevelle cloned 1970 SS396 El Camino for real 2003 SS Silverado I NEED MORE SUPER SPORTS!! Posts: 877 | From: Cincinnati, Ohio | Registered: Oct 2004
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