TBucket Engine Project (Dart SHP)

Indycars said:
I did this, checked the pushrods and they have plenty of clearance. I can feel them both with plenty
of slop. There was NO change, still no compression !!!

So to make sure I knew what to expect, I move to cylinder #3. There is no doubt in my mind now,
there is NO compression on cylinder #1 !!!

I wanted to compare the valve retainer heights from the intake to exhaust on cylinder #1 .... I get 0.060
inches lower on the intake valve. To make sure I had a valid comparison, I moved over to the cylinder #3
intake took the same measurement across to cylinder #1 intake. Guess what I got the same clearance
within 0.002 inches.

My guess is the intake valve is bent, which keeps it from closing completely. But when did it happen, it's
been since May 2016 that the motor has seen anything over 5000 RPM. Since then I have been on another
6 hour drive to the Lake of the Ozarks in September. When I parked it at the end of the 2016 summer in
October, I had not noticed any changes in the engine behavior.

Grumpy needs to get away from the kids and wife and move to Oklahoma, then this would be a fun problem
to solve, just hope it doesn't cost too much !

View attachment 9374

View attachment 9373

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Click to expand...
You must have Floated the Valves at your Hometown Street Race Nationals.
Its been 3-4 years now.
 
Does not make much sense Rick.
The Crower cam is not a Race grind.
Unless there is alot of Toss Weight.
Stainless valves are kinda Heavy in grams weight.
 
don,t guess deal in verified facts,
its rather a simple operation to verify if there is or is not damage to the head,
by removing and inspecting the cylinder head.
once your dealing with fact vs guess work you can proceed,
based on the info verified, I wish I was local, too you rick, with your permission,
we would have already removed and inspected the cylinder heads
 
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Why the smaller damper?(i think the bigger is needed for a stroker?)
Did you use a piston stop(inserted into the sparkplug hole)? maby you bennt a valve there(or it was bent before and is the source of your engine problems).
You could remove the rocker and do a leak down test.
but anyway just pull the head. its not a big deal. you can probably just change that one valve and get the seat repaired(see if it damaged the piston, am positive it will be perfectly fine).
 
mathd said:
Why the smaller damper?(i think the bigger is needed for a stroker?)
Click to expand...
I assumed that Fluidampr knew more about it than I did, and this was the best they had.

mathd said:
Did you use a piston stop(inserted into the sparkplug hole)? maby you bennt a valve there(or it was bent before and is the source of your engine problems).
Click to expand...
Yes I used a piston stop, but was gentle when approaching TDC

mathd said:
You could remove the rocker and do a leak down test.
Click to expand...
I don't have a leak down tester, but I should be able to apply air pressure to the cylinder and tell
easily if I have a leaky valve. I should do that to all cylinders.

Thanks for the input!
 
Just checked cylinder #1 with air pressure and it's definitely coming from the intake valve.
Listening to the air escape thru the carburetor, as compared that with the exhaust which had
nearly zero noise. Both pushrods had plenty of clearance, so nothing holding the valves open
there.

Just to make sure, I used the steel block in the photo and hit the valve with a 2 lb hammer to
see if that changed anything. Put air pressure to the cylinder again and there was NO difference
in the sound coming thru the carburetor.

Have already placed my order thru Amazon for a Fel Pro 1206 gasket set and a tube of Right Stuff
Permatex sealer.

FP01_BentValveDiagnosis_00243.jpg

This adapter I made many years ago. This is how I applied 100 psi to the cylinder to check for valve leakage.

FP01_BentValveAirAdapter_00244.jpg

I sure wished there was another explanation to this problem. But it will give me a chance to check for
any damage from Detonation or maybe confirm that I'm just hearing things.

.
 
How the other cylinder check? only on cyl #1?
I dont think detonation could bend a valve and a bent valve will make it run bad, apparently it was not a problem last time it was running(so i dont think it floated the valve).
Piston stop can hit piston, but can it hit a valve? i dont think so. especially if it did not come out bent(these things are soft).
Am really curious there(and sad for you)
 
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I have never seen it happen to Brodix Heads.
Known to be the Best for Cheverolet's.
But sometimes The Pressed in Valve Seat Inserts come loose on aluminum cylinder heads.
And can come loose on Cast Iron Heads with replacement valvseats.

Grumpy has a Million Links on the Topic to read as we all know here.

The issue is real.
The Ford Guys Tease all the LS Guys with their Drag Race Street Race engines Blowing up.
#1 issue is the Valve seats come loose in LS engines. They Blow up bad.
#2 I have witnessed is the #3 crankshaft thrust bearing lets go, engine is destroyed.

But Its A SBC with Premium Brodix cylinder heads.

Also E heads or Edelbrock Heads for Pontiac V8 sometimes drop the valve seats, aluminum race heads too.

Just have to get it apart Rick like Grumpy said.
 
mathd said:
How the other cylinder check? only on cyl #1?
Click to expand...
I will have to check, but I'm wondering if it's worth the trouble, since I might as well pull both
heads for a visual inspection.

mathd said:
I dont think detonation could bend a valve and a bent valve will make it run bad, apparently it was not a problem last time it was running(so i dont think it floated the valve).
Click to expand...
I wasn't trying to insinuate that it was possible. But it would give me a chance to check out what
I thought I was hearing for the last 2-3 summers.

mathd said:
Piston stop can hit piston, but can it hit a valve? i don't think so. especially if it did not come out bent(these things are soft).
Am really curious there(and sad for you)
Click to expand...
Right ..... the piston stop could not have bent the valve. Beside I never turned it by hand but
gently when approaching TDC. It would have already have been bent or I would not have
mentioned the problem when trying to find TDC ... before I ever tried the piston stop.

Remember I was using my finger over the SP hole to tell when I had compression before I
used the piston stop.

I'm sorry you lost me there ... what did you mean by "these things are soft" ???

.
 
Indycars said:
All I can say is I sure hope I DON"T get that good ! hehehe !!!
Click to expand...
You have no hood or fenders. Cut that 40 minute time in half.

The .060" difference in retainer heights is common. It is due to the valve lengths.
The depth of the spring pockets might be different on your heads for intake and exhaust.
So those valves were chosen to get the proper installed height without using excessive shims.

Piston stops are usually made from brass. If a piston smacked it too hard, it would bend and be impossible to unscrew - you would have to remove the head and screw it in the rest of the way, assuming that the spark plug threads were not damaged.

Sorry to hear about this problem Rick, but now you know what was probably causing your detonation problem.

If it is not the valves, then you have a hole in the top of your piston.
I'm hoping for the valve, so you don't have to tear into the bottom end.

Edit: as impossible as you think it could be Rick, most likely something fell into the carb and just happened to make it into the #1 cylinder, bending the intake valve on it's way in. Got any neighbors that don't appreciate your hot rod? This alone is a good reason to fit a screen between 2 carb base gaskets at the bottom side of a carb spacer so it won't interfere with the throttle blades.

index.php
 
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Rick, looking at that pic with the straight edge across, it does look to me that the valve locks are seating lower valve on the left one.
 
I have a device similar to this:

51GhC8fSwCL.jpg


It works very well and uses WIFI to connect with my iPhone. Not USB. I think I paid $40-$50 ? GREAT purchase. Very clear video...

You should be able to easily see what is going on via the intake. It is too stiff for the sparkplug hole.
 
I think something happened with a Valve seat coming loose.
Poor Heat transfer is a potential cause.

I recall having a conversation on this topic with Grumpy in the past on his Forum.

Integral Valve seat or Pure cast iron heads are the safest.
Problem is very few good choices for Race Use.
Just the Big Block Chevy like 781 Oval ports or 1970 LS6 454 Retangular ports & 1970 Pontiac RAIV Round Port cylinder heads.

We were talking Beryllium Copper seats & Titanium Valves too Grump & Me.
 
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