Mustang5l5's Progress Thread - Frame rail repair

Steel1

Mustang Master
Aug 18, 2017
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Verify with Playdough first but that's awful close.
I believe exhaust side is even more crucial because piston is chasing valve.
 
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Mustang5L5

A little massaging and it went right in
Mod Dude
Feb 18, 2001
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Haven’t checked exhaust side yet. Will do in a bit.

Playdough method to follow



Edit: exhaust side has way more clearance. Easily over 0.150” so I didn’t tske a specific measurement

Gotta clay it next. Could be radial interference on the intake
 
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Mustang5L5

A little massaging and it went right in
Mod Dude
Feb 18, 2001
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Ok. Wife put the kiddos to bed so I had more time to properly set it up and measure using dial indicator

873531B8-08AB-4628-8014-1F4FD1CA4647.jpeg


Exhaust side clears by a mile so I only ran those numbers once.

Intake side I set up three times and got repeatable results. Looks like closest approach is around 10 ATDC at roughly 0.060”

I’m off technically 0.015” but I’ll through some fudge factor in so call it 0.020”

I still need to clay it. Also, I’m running my old factory HG under the head. I’ll have to measure it’s thibkness compared to the 9333pt1.

But what to do over 0.020”? Thicker head gasket?
 

HotFox

10 Year Member
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Your sure that soft spring is not hanging open or not following the cam profile? Have had that happen in the past, that is reason why those mock up springs are a bit stiffer.
 

HotFox

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Also you sure that cam is degreed right? I'm suprising Ed would not have that exhaust valve opening sooner which would create more clearence on the intake side.
 

Steel1

Mustang Master
Aug 18, 2017
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Forged or hyper pistons ?
I would put the 9333pt1 gasket and regular springs on it and measure again.
Also do you know your quench number , thicker head gaskets could make that less than desirable.
 

Mustang5L5

A little massaging and it went right in
Mod Dude
Feb 18, 2001
32,478
8,664
224
Massachusetts
Your sure that soft spring is not hanging open or not following the cam profile? Have had that happen in the past, that is reason why those mock up springs are a bit stiffer.
Thought crossed my mind. I’ll rerun it with the correct gasket torqued down, the stiffer springs, and mock solids. It’s a good point considering I measured 0.030” during my quick check earlier that evening. I only need 0.015” to feel better, but I’ll likely check other cylinders as well

Also you sure that cam is degreed right? I'm suprising Ed would not have that exhaust valve opening sooner which would create more clearence on the intake side.
I degreed it twice, breaking it down in between. ICL was to be 107 and I got 106.5 And all the events lined up fine. But now I want to check a 3rd time. Just need to fabricate something to mount degree wheel on crank.

Forged or hyper pistons ?
I would put the 9333pt1 gasket and regular springs on it and measure again.
Also do you know your quench number , thicker head gaskets could make that less than desirable.
Stock ‘88 forged pistons, so 0.010” in the hole? The 9333pt1 is 0.047” compressed so if anything I really should go thinner? But the stock gasket is 0.040” so is quench that bad from the factory?
 

Steel1

Mustang Master
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Stock ‘88 forged pistons, so 0.010” in the hole? The 9333pt1 is 0.047” compressed so if anything I really should go thinner? But the stock gasket is 0.040” so is quench that bad from the factory?
Not uncommon for older smog engines to have a lousy quench, so I wouldn't be surprised.
Going with a thinner gasket would only make your ptv clearance issue worse.
Calculate your quench as it sits now just for reference.
I believe good quench rule of thumb for a street motor with steel rods is 0.038"-0.043", I ended up at 0.039".
 
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Mustang5L5

A little massaging and it went right in
Mod Dude
Feb 18, 2001
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Best estimate is that pistons are equal to deck height. I measured three and found them around 0.000”-0.003”. I found published data suggesting 0.008-0.0013” below was typical, but I’m not seeing it here. I see less.

Original head gasket measured out around 0.045”. I’ll need to sacrifice one of the 9333s and torque it down when i measure next. I need to be 100% sure.

Quence with the 9333s would be 0.047” + 0.003” giving me 0.050” quench which might be a tad high.

I’ll reset the stiffer checker springs and mock solids and recheck. The light springs didn’t collapse the lifters but the checker springs do

Not gonna lie...a little bummed. But everything can be solved. Just a matter of money and where to throw it
 

Steel1

Mustang Master
Aug 18, 2017
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Best estimate is that pistons are equal to deck height. I measured three and found them around 0.000”-0.003”. I found published data suggesting 0.008-0.0013” below was typical, but I’m not seeing it here. I see less.

Original head gasket measured out around 0.045”. I’ll need to sacrifice one of the 9333s and torque it down when i measure next. I need to be 100% sure.

Quence with the 9333s would be 0.047” + 0.003” giving me 0.050” quench which might be a tad high.

I’ll reset the stiffer checker springs and mock solids and recheck. The light springs didn’t collapse the lifters but the checker springs do

Not gonna lie...a little bummed. But everything can be solved. Just a matter of money and where to throw it
Don't get too down yet there should be some reasonable options to solve it.
I'm going to go out into my freezing garage later...lol and see if I can find what my final ptv was
just for reference.
My pistons were .008" - .009" out of the hole due to shorter deck height and decking of my 69 block
but was able to get good numbers with the correct dish. Also bumped compression nicely.....more powwwaaaa !
 

Mustang5L5

A little massaging and it went right in
Mod Dude
Feb 18, 2001
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Checker springs, solid lifters, 9333hg snugged down...not much difference

Gotta clay it

87E5D100-7E09-4597-ACF1-455542376CC5.jpeg
 
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Mustang5L5

A little massaging and it went right in
Mod Dude
Feb 18, 2001
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Exhaust valve never really gets close. Here’s the intake valve. On my Caliper it measures pretty damn close to 0.080”

EAA2D2A7-9B62-490E-A3A1-7E296F12C7D9.jpeg

FB8C562B-79E8-4447-9720-CE3EFF795E4E.jpeg
 

Mustang5L5

A little massaging and it went right in
Mod Dude
Feb 18, 2001
32,478
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224
Massachusetts
Repeated it. Exhaust way away so I’ll disregard measuring it from here out. Intake close to face.

16BC72E0-AF92-487C-BBFD-A18B9A2D8582.jpeg

32783D65-038D-4EF5-9212-7DE52CD86958.jpeg



Gonna degree the cam again just to be sure. I’ll need to rig something to mount my wheel off the balancer since my front dress is installed (jumped the gun there)
 
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67coupe

Founding Member
Apr 5, 2002
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I’d contact Ed. It’s a custom cam for your combo. He’s probably done 100’s if not 1000’s of 5.0 cams. He’ll know if something is amiss.
 

Mustang5L5

A little massaging and it went right in
Mod Dude
Feb 18, 2001
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Gonna re degree it first. After I degreed it I pulled the timing chain off to mess with something. I’ll kick myself if I installed it off a tooth.

Just need to rig something up to mount my wheel on the crank pulley first since I put that together

I’m 99% sure it’s correct though
 
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Mustang5L5

A little massaging and it went right in
Mod Dude
Feb 18, 2001
32,478
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Massachusetts
Well, after googling all night I’m gonna send it. I’m coming to recheck my cam timing first to make sure that’s on, and clay the other pistons as well. I also got confirmation from Ed that I should be good.

My springs I’ll end up running should be stiffer and cause some deflection in my valvetrain which might add 0.020-0.030 to my clearance. That would put me in the generally acceptable zone. This isn’t a high revving race motor as your know

But like I said, I’ll triple check this all and then button it up.
 
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HotFox

10 Year Member
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Now wonder the intake is so big it does not even come to the original valve reliefs. So in theory you could run a flat top piston.
 

Mustang5L5

A little massaging and it went right in
Mod Dude
Feb 18, 2001
32,478
8,664
224
Massachusetts
Now wonder the intake is so big it does not even come to the original valve reliefs. So in theory you could run a flat top piston.
Your right on the intake side, but it’s a maybe on the exhaust. The exhaust valve does line up with the relief so unsure if a flat top piston would allow the same clearance as I measured.

860CEF54-CD7E-409C-BED1-AAF68261200E.jpeg


It looks close on the left side radially but the depth perception is off in this photo. That side is pretty high up but the pic is deceiving.

I’m going to clay all 8 pistons. I just want to be sure. If this was a GT40 combo with 100k miles on original springs, I wouldn’t be so confident in the clearances I have. Realistically, I’ll prob drive 1-2k miles on some pretty good springs and then stuff this all on a 347 stroker down the road
 
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