FrontEngineDragsters.Org Forum
Technical => Matt Shaff's Engine Shop => Topic started by: GlennLever on June 17, 2017, 08:54:31 PM
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Went up for our first round of eliminations.
Started fine, then it sounded like the starter was hung up in the flex plate, revved it up and the sound did not go away.
Shut it off and started it up, started fine. What the heck try a burn out to see if it would shake it free.
Half way through the burn out it shut off.
Pulled over to the wall, and got out.
Opponent made his run.
Got back in and was pushed back, and went to the pits.
Starter strains to turn the engine over.
Drained the oil, no metal, but little tiny bits of red, looks and feels like RTV. No red RTV was used building the engine only black and silver.
I have a System 1 remote filter, dumped it and no metal. Found one ore two of the tiny red bits.
Put new oil in, new starter and it still strains to turn it over.
Pulled the blower belt, blower is not seized.
Pulled one valve cover, all looks normal, I forgot to turn the engine over to check to see if the rocker arms were moving, Think they are ok as there are no strange noises. This will have to be checked when I get home.
There are no strange noises from the bottom end when turned over with the starter.
Pulled all the plugs the front two were the hottest, discoloration all the way around the end of the plug, but not into the treads.
Used a bore scope in those two cylinders, tops of the pistons look brand new, cross hatching on the cylinder walls still look new.
I'm perplexed. Put it all back together, and put it in the trailer. When I get home the first thing I will do is pull the torque converter bolts.
Next would be to pull the pan and see if the rods will move, then maybe pull the main caps.
I'm open to ideas.
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Thought---- possably the ring gap closed up and the expansion stuck the pistons??? I dont know if you did anything from the last time you ran it
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Glen we tore up the convertor and did some damage to our trans at BG a few years ago. Acted the same as yours is acting now.
Heavy drag until I un bolted the convertor. Engine fired up fine.
Hope for something easy......
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It will be in my garage tomorrow, hope to have some answers tomorrow night.
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A Blower test's the parts.
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The Crankshaft is broken, working on getting it out.
New one will have to be balanced. Hopefully the rod and piston weights were recorded.
If need be will pull # 8 rod and piston.
Problem may be the rod if it cannot be saved and new one needs to be ordered. Will also order the narrow bearings
http://www.competitionproducts.com/Eagle-Forged-4340-Steel-Crankshaft-Pontiac-400-Main-4250-Stroke-6700-and-up-Rod-Length-2200-Journal/productinfo/EAG440042506700/#.WUm0Q_8YzFI.email
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Ouch....
That's not as easy as a trans issue...
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And it did not break clean thru??
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Is that an OEM crank ?
Jon
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That will cause it hard to turn! Your going to pull the engine apart to put a crank in it, it will be easy to measure the bob weight at that time of it wasn't recorded
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Is that an OEM crank ?
Jon
Eagle
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And it did not break clean thru??
Yes, I had the rear cap off when I rotated the engine and the back piece fell out of the engine.
New crank is ordered, new rods are coming from Venolia
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FWIW it looks as though the crack started at about the 10 O'clock position on the last photo. Maybe use a smaller journal lightening hole. And nitride. And more generous cheek radii.
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FWIW it looks as though the crack started at about the 10 O'clock position on the last photo. Maybe use a smaller journal lightening hole. And nitride. And more generous cheek radii.
Crank was supposed to be good for 1,500 hp.
No lightening holes on the new crank.
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Do yourself a favor and go through the whole motor and check EVERYTHING! Breaking a crank is about as bad as it gets. Check the main webs in the block for cracks and check the main line too. Good luck
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Do yourself a favor and go through the whole motor and check EVERYTHING! Breaking a crank is about as bad as it gets. Check the main webs in the block for cracks and check the main line too. Good luck
All parts have a life cycle and you exceeded it. Worst part is finding when that life cycle is
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The first pic was confusing because you had rotated the crank and by shear luck lined back up to the rod journal.
By the discription of your first post, the thought of a broken crank never would have been in my thought process. Completely broken and you were able to start it, no noise and do a burnout????
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Do yourself a favor and go through the whole motor and check EVERYTHING! Breaking a crank is about as bad as it gets. Check the main webs in the block for cracks and check the main line too. Good luck
All parts have a life cycle and you exceeded it. Worst part is finding when that life cycle is
Fairly new motor as I understand it. Have a $2500 billet Valasco in my motor going on 25 years now
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Yes, I've been racing my 36 lb Crower crank for 9 years, at 10,000rpm, in my SBC.
I also keep track of all runs on my crank, and rods. I keep track of it on my RacePak, and on my run sheets.
Yes all parts have a life cycle, but don't get confused with Big Show blown Nitro, where they only get 2-4 runs on a crank, breaking at a rod journal, but they are making 10-11k HP
Glenn, I assume your Eagle crank was not a cast crank, but forged.
Any signs of pre-ignition, that can hurt a crank, & rods too. IE. black spots on the plugs.
Jon
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No pre-ignition, running 30 degrees of timing.
Forged 4340 crank, four years, at the most 600 runs, aluminum rods
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Glenn, what did your crank company think caused the failer ?
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I did not ask them.
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No pre-ignition, running 30 degrees of timing.
Forged 4340 crank, four years, at the most 600 runs, aluminum rods
Wow you make 150 passes a year in your FED!!
I would have never guessed you had a broken crankshaft either the way it was described. My thought was spun main or ballooned converter