Broke a valve.

Five0 · 05-28-2001, 01:02 PM

As some of you know I hade a little car trouble. Well I got the head off and the problem was I broke a valve. It put a couple of dents in the piston but did not seem to do anymore damage than that.

Do you think the piston will be ok or will I have to replace it?

The dent is about 1/8" deep (about the depth of the fly cuts in the piston) and about a 1/4" wide.

The heads appear to be fine but I will have them checked to be sure.

------------------
James Cox
nochevy@hotmail.com
1991 Mustang LX
12.565 @109.38mph 1.764 60ft

red82gt · 05-28-2001, 03:03 PM

I'd just de-burr the spot on the piston to make sure you don't get a hot spot, they're pretty tough (yours are forged, right?).

------------------
GT-40 heads (ported, polished, + milled), B303 cam, 1.7rr's, JE pistons, Offy intake, Carter AFB 625cfm carb, Flowtech 1 5/8" shortys, Flowtech X-pipe, MAC Flowpath exhaust, MAC pulleys, 373's, subframes, Eibachs+Tokicos, B&M ripper, FMS Clutch, Zoom Quadrant+cable, 17" CSA Ultra rims, 235/45ZR17 Yokohama AVS S4's, MSD 6A ignition+coil, FMS 9mm wires, Carbed, Naturally Aspirated, and Nasty!

Five0 · 05-28-2001, 06:34 PM

Yes they are forged.
How much do you think it would cost to replace the pistons with some better ones with a higher compression and maybe lighter weight?

------------------
James Cox
nochevy@hotmail.com
1991 Mustang LX
12.565 @109.38mph 1.764 60ft

Five0 · 05-28-2001, 06:36 PM

And do you think it would be worth the time and money?

How much difference do you think it would make?

The motor has about 100,000 miles on it.

------------------
James Cox
nochevy@hotmail.com
1991 Mustang LX
12.565 @109.38mph 1.764 60ft

red82gt · 05-28-2001, 06:55 PM

With that many miles you probably wouldn't want to do just a piston and ring change, you'd want to measure the wear on the block and probably have it bored and fitted with oversize pistons. I would wait until the short-block needs a rebuild, you'll need to do the bearings to change pistons and rings.

Five0 · 05-28-2001, 07:54 PM

How much do you think all that will cost and will it make a difference in performance?

------------------
James Cox
nochevy@hotmail.com
1991 Mustang LX
12.565 @109.38mph 1.764 60ft

dinomite · 05-28-2001, 08:06 PM

Quote:

Originally posted by Five0:
(about the depth of the fly cuts in the piston)

Interesting way to do it....

red82gt · 05-28-2001, 09:23 PM

For good aftermarket forged pistons-$500, $80 for rings, $60 for gaskets, etc. Then whatever your favorite machine shop charges for boring.
I'll cost about $800-$900 (total)and a streetable bump in compression (<11:1) will get you maybe 25hp.

Five0 · 05-28-2001, 11:14 PM

Thanks for the help red82gt.

I don't know what I am going to do yet, I may use this as an excuse to get me a 351w installed; but I may be without a car for a while as this is my daily driver.

Can someone tell me why the headers I have on my 302 won't work on the 351w?

------------------
James Cox
nochevy@hotmail.com
1991 Mustang LX
12.565 @109.38mph 1.764 60ft

red82gt · 05-29-2001, 01:53 PM

I think the main problem is the alignment of the H-pipe since the headers sit higher up, I think it doesn't clear the transmission or something.

05-28-2001, 01:02 PM	#1
Five0 Registered Member Join Date: Apr 2000 Location: middleburg, fl, usa Posts: 1,134	Broke a valve. As some of you know I hade a little car trouble. Well I got the head off and the problem was I broke a valve. It put a couple of dents in the piston but did not seem to do anymore damage than that. Do you think the piston will be ok or will I have to replace it? The dent is about 1/8" deep (about the depth of the fly cuts in the piston) and about a 1/4" wide. The heads appear to be fine but I will have them checked to be sure. ------------------ James Cox nochevy@hotmail.com 1991 Mustang LX 12.565 @109.38mph 1.764 60ft

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05-28-2001, 03:03 PM	#2
red82gt Sober voice of Reason Join Date: Nov 1998 Location: Kelowna, B.C., Canada Posts: 1,514	I'd just de-burr the spot on the piston to make sure you don't get a hot spot, they're pretty tough (yours are forged, right?). ------------------ GT-40 heads (ported, polished, + milled), B303 cam, 1.7rr's, JE pistons, Offy intake, Carter AFB 625cfm carb, Flowtech 1 5/8" shortys, Flowtech X-pipe, MAC Flowpath exhaust, MAC pulleys, 373's, subframes, Eibachs+Tokicos, B&M ripper, FMS Clutch, Zoom Quadrant+cable, 17" CSA Ultra rims, 235/45ZR17 Yokohama AVS S4's, MSD 6A ignition+coil, FMS 9mm wires, Carbed, Naturally Aspirated, and Nasty!

05-28-2001, 06:34 PM	#3
Five0 Registered Member Join Date: Apr 2000 Location: middleburg, fl, usa Posts: 1,134	Yes they are forged. How much do you think it would cost to replace the pistons with some better ones with a higher compression and maybe lighter weight? ------------------ James Cox nochevy@hotmail.com 1991 Mustang LX 12.565 @109.38mph 1.764 60ft

05-28-2001, 06:36 PM	#4
Five0 Registered Member Join Date: Apr 2000 Location: middleburg, fl, usa Posts: 1,134	And do you think it would be worth the time and money? How much difference do you think it would make? The motor has about 100,000 miles on it. ------------------ James Cox nochevy@hotmail.com 1991 Mustang LX 12.565 @109.38mph 1.764 60ft

05-28-2001, 06:55 PM	#5
red82gt Sober voice of Reason Join Date: Nov 1998 Location: Kelowna, B.C., Canada Posts: 1,514	With that many miles you probably wouldn't want to do just a piston and ring change, you'd want to measure the wear on the block and probably have it bored and fitted with oversize pistons. I would wait until the short-block needs a rebuild, you'll need to do the bearings to change pistons and rings.

05-28-2001, 07:54 PM	#6
Five0 Registered Member Join Date: Apr 2000 Location: middleburg, fl, usa Posts: 1,134	How much do you think all that will cost and will it make a difference in performance? ------------------ James Cox nochevy@hotmail.com 1991 Mustang LX 12.565 @109.38mph 1.764 60ft

05-28-2001, 09:23 PM	#8
red82gt Sober voice of Reason Join Date: Nov 1998 Location: Kelowna, B.C., Canada Posts: 1,514	For good aftermarket forged pistons-$500, $80 for rings, $60 for gaskets, etc. Then whatever your favorite machine shop charges for boring. I'll cost about $800-$900 (total)and a streetable bump in compression (<11:1) will get you maybe 25hp.

05-28-2001, 11:14 PM	#9
Five0 Registered Member Join Date: Apr 2000 Location: middleburg, fl, usa Posts: 1,134	Thanks for the help red82gt. I don't know what I am going to do yet, I may use this as an excuse to get me a 351w installed; but I may be without a car for a while as this is my daily driver. Can someone tell me why the headers I have on my 302 won't work on the 351w? ------------------ James Cox nochevy@hotmail.com 1991 Mustang LX 12.565 @109.38mph 1.764 60ft

05-29-2001, 01:53 PM	#10
red82gt Sober voice of Reason Join Date: Nov 1998 Location: Kelowna, B.C., Canada Posts: 1,514	I think the main problem is the alignment of the H-pipe since the headers sit higher up, I think it doesn't clear the transmission or something.