When Stroker Motors Go Bad.... - Page 4

turnpike boy · #61 (**permalink**) 10-15-2007, 06:48 PM

Quote:

Originally Posted by RedBarchetta

I never said that.

Let's both agree to agree that the clearances on this particular motor were a tad tight.

Mmmm.....yeah, sure, ok.

Agreed. So long as you don't machine my blocks for me

.

turnpike boy · #62 (**permalink**) 10-15-2007, 06:49 PM

Quote:

Originally Posted by scottj

In the machining trade numeric values less than one are expressed in "thousandths", i.e., .010 is read as "10 thousandths", .100 is read as "100 thousandths" (not 1 tenth), whereas .0001 is read as "1 tenth" ( as in 1/10th of a thousandth).

HEY! Stop giving away those secrets, willya?

RedBarchetta · #63 (**permalink**) 10-15-2007, 07:06 PM

Quote:

Originally Posted by turnpike boy

Agreed. So long as you don't machine my blocks for me

.

Deal.

But let's first put (at the top of the list) the shop name of the builder that tweaked this one.

turnpike boy · #64 (**permalink**) 10-15-2007, 07:38 PM

Boy, agreed, big time.

AK1234 · #65 (**permalink**) 10-15-2007, 07:58 PM

My 2 cents is ... the piston to valve clearance was OK, its either a efective valve OR the valve was too tight in the guide AND OR your running too hot of a spark plug and that caused the valve to become too hot and too tight in the guide ....causing the valve to hit the guide. Been there done that.

Ron

AK1234 · #66 (**permalink**) 10-15-2007, 08:00 PM

....causing the valve to hit the Piston ...

BDR561 · #67 (**permalink**) 10-15-2007, 08:01 PM

Wayne Partridge Sr.
Newton, KS

His clay was Plat Dou
Here's his last claim:

"Mark, what you see there is some of the blue dow that simply came off with the head and stuck on the valve. In a situation like this the complete valve area would be crushed, not two small holes. I remember the material when I removed it and it was setting in the studio. It had set up and was hard and the complete intake and exhaust ports were almost 200 thousands thick. That cam was not that big, under 700 lift, nor was the rocker ratio over sized. All normal and well below critical standards".

I did see the gauge on the video stating .2100, but again that was not in the relief. The still shot will amaze you all. The video also shows him applying oil on the clay so the material wont stick to the valve!!

BDR561 · #68 (**permalink**) 10-15-2007, 08:04 PM

AK1234,

Not a defective valve, unless there was 8 of them. Every Ex. valve had hit it's piston. A/F was perfect and actually running a little rich.

You need to see the video/still shot to see... I do have someone working on that for me so I can post. Now I just need to order the replacement parts and rebuild....

LMH · #69 (**permalink**) 10-15-2007, 08:36 PM

I might have missed it in the thread but how many miles are on the engine when this occured?
Larry

BDR561 · #70 (**permalink**) 10-15-2007, 08:45 PM

400 easy miles

DAVID GAGNARD · #71 (**permalink**) 10-15-2007, 09:07 PM

I use Play Doh to check the piston/valve clearance and have had no problems with it.........I always degree the cam first, then bolt on the head with NO gasket and run thru the cycle twice, remove head, check notch in Play Doh.........if the clearance is within specs, then you have extra clearance with the head gasket thickness..........

With all 8 exhaust valves hitting the pistons, it's obvious that the piston to valve clearance was NOT correct from the start and I'm suprised the motor lasted 400 miles.........

If the Pay Doh was all pushed out of the valve notch and you could see the valve after checking the clearance, then your builder screwed up big time!!!!!!!!! the whole purpose of the check is to see that what happened on your motor DOES NOT happen!!!!!!!!!!

The valve springs had nothing to do with the valves hitting the pistons.........

The failure was simply not enough piston to valve clearance on the exhaust valves, something any engine builder should have seen and corrected before going any futher with the assembly of the engine........

David

CHANMADD · #72 (**permalink**) 10-15-2007, 09:38 PM

So much ado about what is obviously like david say's ,poor assembly with not enough clearance,or someone changing rocker ratio's without thinking.

LMH · #73 (**permalink**) 10-15-2007, 11:29 PM

Quote:

Originally Posted by BDR561

400 easy miles

400 miles!!! Yep, this is an build problem for sure.
Larry

Excaliber · #74 (**permalink**) 10-15-2007, 11:58 PM

You know I love the title of this thread. Kind of like, "When wild cam's attack".

BDR561 · #75 (**permalink**) 10-16-2007, 08:19 AM

OK guys...

Here's the still shot. I have about a 30 second video I will post shortly..

blykins · #76 (**permalink**) 10-16-2007, 08:30 AM

What's weird is that the side with the aluminum showing through is the intake side. You would think you would have had problems with the intake valves hitting as well.

It's really hard to distinguish the thicknesses from a 2D picture though.

BDR561 · #77 (**permalink**) 10-16-2007, 09:13 AM

That is the intake side (there goes my theory)!! Time to break out the clay and see what the clearance is now, then check the crank key, etc...

blykins · #78 (**permalink**) 10-16-2007, 09:15 AM

What was the seat pressure on the valve springs?

Excaliber · #79 (**permalink**) 10-16-2007, 10:14 AM

Looks like the PlayDoh doesn't lay down well on the piston and some of it stuck to the intake valve, which is the bare metal you see. I think I will stay with clay, seems to leave a better impression and stays put more securely.

blykins · #80 (**permalink**) 10-16-2007, 10:26 AM

There are a lot of variables in this one....I would carefully examine each component....even the timing chain. If something happened and the cam timing retarded enough, it could pull the intake valves away from the piston and shove the exhaust valves down into it.