Machinist have any thoughts as to why that valve did what it did????
71 Dart 410 stroker ..
- Thread starter 70aarcuda
- Start date
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Duane
Well-Known Member
I am not an engine machinist but imho the piston hit that exhaust valve.
Remember most piston to valve clearance recommendations want more clearance on the exhaust valve because it will usually get closer than the intake. I see that Tony reported his numbers when he degrees the cam. He then advanced it 2 degrees which again will affect the piston to valve clearance. I know that Tony has said he does not see any marks in the other 7 cylinders but let's look closely at Tony's picture of the beat up piston that I have posted. To my eyes
I see a perfect half moon arc on that piston. To me it looks like before that valve was destroyed it clipped the piston forming that arc.
If it keeps hitting it, it will break a chunk right off the valve. That hardened piece of broken valve becomes trapped in the cylinder and beats up the aluminum (soft) head and piston while it bangs around inside the cylinder.
That one cylinder may have had a slightly weaker valve spring.
The engine may have slightly over revved and floated that particular valve.
But imho that arc that I think I see on the piston is a telling sign.
I will take a second look at that piston went i remove it from the rod...
picked up some Hedman 1 7/8 headers for the 410 once it is all fixed and ready to go back into car.....bolted them on to the other 408 that been on the stand for awhile....
picked up some Hedman 1 7/8 headers for the 410 once it is all fixed and ready to go back into car.....bolted them on to the other 408 that been on the stand for awhile....
j par
Well-hung Member
The exhaust configuration isn't familiar to me. Do the slip connections seal nicely? Is there something required there? Of course it appeals to my taste for something a little different. LOL
Once I toast my cheap Summit headers with this header wrap maybe I can get (make?) something like that.
Once I toast my cheap Summit headers with this header wrap maybe I can get (make?) something like that.
They are hedman race headers...the tubes slip on...the collectors slip on...and number 7 and 8 tubes go out thru the fenderwell....
makes for a easier installation for the big tubes
makes for a easier installation for the big tubes
j par
Well-hung Member
I assume the number 7 goes underneath the break master cylinder? Next question where do I order those?
hedman makes them....summit or jegs would be the best place..i got these from FABO for a great price.
Hedman Husler® Race Headers 75140
Hedman Husler® Race Headers 75140
Those are good headers if you don't mind cutting the inners.
j par
Well-hung Member
Numbers matching /6 ac car, a couple holes in the fenders will match the hole iI'm going to put in the hood for the dual quads 
replacement pistons finally showed up last monday....with all said and done...they are within 1 gram of the original pistons in weight....and that is using my Harbor Freight Digital scale that cost $9.95.
Waiting on block....should be ready this coming week.....
Waiting on block....should be ready this coming week.....
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Hedman Hustlers.... you'll have to modify the two passenger side tubes if you want to run the Milodon "low profile" pan. We actually ran a spacer at the head to move the header out some. After going to the tube K that afforded us room to run a rear sump pan.... which those headers still hit. At that point I had two new tubes made as the spacer was a pita and I didn't have torsion bars to fight around anymore. My custom W8 headers are patterned after the hustlers also.
I don't use the milodon oil pan...I use the moroso. .....The Dart does not have torsion bars anymore...
This afternoon, I was looking for a set of strut rods for Tonya Valiant Wagon...I know I got 3 sets somewhere....Found two more sets of those hooker 5204 headers that are on the cars in deep storage....
This afternoon, I was looking for a set of strut rods for Tonya Valiant Wagon...I know I got 3 sets somewhere....Found two more sets of those hooker 5204 headers that are on the cars in deep storage....
Duane
Well-Known Member
I bought that scale too. I am amazed at the accuracy of it for only $10. Repeatability is excellent too. Perfect for weighing Pistons.
1/10 of a gram accuracy for $10.
Dam...I misspelled Freight....corrected...lol
Thanks Jay...I do have one....but it was a pain in the *** due to hitting the K member....but now cars either have the QA1 K member or I cut and rewelded the OE K member...
I think I got 7 of the Moroso 360 pans...a few of the 340 pans....plus a couple in reserve that are patched...LOL
Thanks Jay...I do have one....but it was a pain in the *** due to hitting the K member....but now cars either have the QA1 K member or I cut and rewelded the OE K member...
I think I got 7 of the Moroso 360 pans...a few of the 340 pans....plus a couple in reserve that are patched...LOL
Picked up the block this morning...got some cleaning to do....need to order some bearing ....I needed two single sets of 4.045 rings.....finally gave up and bought a complete set as two piston sets with 1/2 the cost of a full set....will have spares for the future.
famous bob
mopar misfit
all cylinders should have a chamfer for ring installation.
Yes i agree too. In the picture it looks like a 45* cut, the hole width of the sleeve. I KNOW THAT IT IS NOT!!!! Just thought it was funny. guess i need new glasses or a new monitor....or maybe both
will take a second look at later this week...got a 63 valiant wagon to finish converting to disc brakes on....besides the bearing wont be here until later in the week....something to work on over the xmas holiday
Washed the block...nice outside middle 60s.....Got the Crank installed and torqued....
Should have the short block back together this weekend depending on how much football I watch...
Should have the short block back together this weekend depending on how much football I watch...
racerhog
RacerHog likes his Mopars
Looking good....
Did not get as much done today as I wanted too.....Got camshaft in ...using same setting as before...but will set up degree wheel to double check....and will knock in the odd bank of pistons tomorrow.
Good thing I checked the cam timing as I was way too advance, I advanced the crank sprocket 4 degrees cause the cam is 108 and suppose to be at 104...well the Hughes cams I forgot have the advance built into them....We got 101...7 degrees advanced. Pulled the gear off and reset the crank sprocket at Zero...straight up..and bingo I got 104.5 close enough with my small degree wheel...Love to buy that large one comp makes...
Anyway....we had two new pistons to cut rings for...got them done and knocked in....Need to get timing chain cover, oil pump and pan cleaned up and installed. Short block will be done awaiting the heads. Going to try to get the heads in the shop this coming weekend.
Anyway....we had two new pistons to cut rings for...got them done and knocked in....Need to get timing chain cover, oil pump and pan cleaned up and installed. Short block will be done awaiting the heads. Going to try to get the heads in the shop this coming weekend.
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