- Joined
- Jan 1, 2012
- Messages
- 8,520
- Reaction score
- 1,387
- Location
- Eugene, OR
- My Car
- 1971 Mustang Sportroof M code
It's been a while since I participated in forum discussions. I would look in once in a while to see how things were going, though. We moved last year and the place we moved to needed quite a bit of TLC, nothing major, just a lot of it. Between moving, COVID, doctors, etc. I haven't taken the time to get back on board. Kilgon sent me a PM yesterday, and it gave me the impetus get back on board. I'm looking forward to the discussions and camaraderie.
I also thought I would update you on how things are going with my Mustang, with a little history about it thrown in. I've titled it:
My Trip Down the Rabbit Hole
Otherwise known as “How one thing leads to another”
My wife found our ’71 Mustang Sportsroof when we were living in Reno, on a side-street shortcut with a for sale sign on it. It was in decent shape, no rust to speak of, on small crease in the driver’s door, and with a 351C M Code with a Holley 750cfm vacuum secondary and C6 and a 3.73:1 Detroit Lockered rear end. She knew that I almost had one once and would like to have it. When I was in the Army, in Germany, and getting short I ordered a ’71 Mach 1 with a 351C and 4-speed that I was going to pick up in New Jersey and drive it home to Nevada, Well, 3 months before my discharge Dad passed away and I had to cancel the order.
The P.O. had dropped a valve, due to the worn out shifter bushings and lack of a kick down rod. The only way he could downshift it was manually. He was in 3rd gear want to show a Corvette what was up, pulled the shift lever down, missed 2nd and hit 1st and over-revved it.
He was asking $1,250 for it, my wife (loves horse trading) talked him down to$750.
Got it home, pulled the heads, the one valve was slightly bent, no piston damage. I was surprised, though, that it still had hone marks on the cylinder walls. The turkey pan intake gasket had a puddle of oil in it, so it had been leaking. I took the heads to a machinist had new guides with positive valve seals and hardened valve seats installed, along with the new valve. Got it running, but it smoked some. The exhaust pipes had oil residue in them and I thought it would burn out, got better, but never went away. I kept thinking it was the intake manifold gaskets, tried every trick I could think of, could get the smoke completely cleared up. It had really good compression on all cylinders. It was very fast, though, drove it around some on the temporary license. Took it up to Virginia City, wife said she would never ride with me again in it.
Anway, we moved to Las Vegas, and took the Mustang with us, never had a chance to work on it a lot. Three moves late and I’m finally getting back to working on it. Two moves ago I decided that I would put a better cam in it, which was going to also require a different torque converter. Pulled the engine and found out why it still had hone marks in the cylinders, it was a service block, no partial VIN on the back of the block. I pulled the transmission with the engine. Next, I pulled the camshaft and my trip down the rabbit hole started. There was a ¼” chip out of the corner of one of the teeth on the distributor/oil pump drive gear. Not really a big deal, but I wondered where the chipped off piece had gone. Pulled the oil pan, couldn’t find anything, pulled the pistons, what the bleep is that? There was a place at the bottom of one of the cylinders, where someone had take a die grinder and ground off part of the lower cylinder. I could also see some slight scoring on the cylinder wall. Hit it with the hone and there was one spot that stayed shiny. You can see the ground off area and the shiny spot in this picture. The cylinder at the shiny spot was about 0.005” bigger then the rest of the cylinder. My theory, someone didn’t double check the torque on all bolts, that one rod wasn’t tight enough, came off and banged up the bottom of the cylinder. Grinding off the bottom of the cylinder allowed the piston to rock due to not enough skirt support and caused the worn/ shiny spot. Because the bad spot was at the bottom of the stroke it still developed good compression readings, just 5 psi less than the average of the rest of them, which was 148psi. Enough oil would still get by, though, to cause it to smoke a little.
I went ahead and checked the rest of the engine over and noticed something strange on the rear cam bearing bore plug. Another what the bleep moment. This is what I saw:
Now, what would somebody do that? I popped it out and this is what it looked like on the other side:
It had been rubbing on the end of the camshaft, were they using it to adjust the end play???
I thought about having that cylinder sleeved, but didn’t know how the ground off area would affect the sleeve seal.
So, I started looking for a block, found a Q code 3 hours away. Our last move was last year and I have a decent sized work shop, and now I’m starting to rebuild the engine. It appears to be in very good condition, not even any ridge at the top of the cylinders. I finally found a local machinist that I’m confident can do the job and do it right. I’ll have him bore it, new valve guides machined for Vitron seals and hardened valve seats.
I’ll be stroking it to a 408 with a balanced kit from Scat, which is supposed to be here the first week in October.
I’ll get into more details on the engine build later, and plans for the body.
I also thought I would update you on how things are going with my Mustang, with a little history about it thrown in. I've titled it:
My Trip Down the Rabbit Hole
Otherwise known as “How one thing leads to another”
My wife found our ’71 Mustang Sportsroof when we were living in Reno, on a side-street shortcut with a for sale sign on it. It was in decent shape, no rust to speak of, on small crease in the driver’s door, and with a 351C M Code with a Holley 750cfm vacuum secondary and C6 and a 3.73:1 Detroit Lockered rear end. She knew that I almost had one once and would like to have it. When I was in the Army, in Germany, and getting short I ordered a ’71 Mach 1 with a 351C and 4-speed that I was going to pick up in New Jersey and drive it home to Nevada, Well, 3 months before my discharge Dad passed away and I had to cancel the order.
The P.O. had dropped a valve, due to the worn out shifter bushings and lack of a kick down rod. The only way he could downshift it was manually. He was in 3rd gear want to show a Corvette what was up, pulled the shift lever down, missed 2nd and hit 1st and over-revved it.
He was asking $1,250 for it, my wife (loves horse trading) talked him down to$750.
Got it home, pulled the heads, the one valve was slightly bent, no piston damage. I was surprised, though, that it still had hone marks on the cylinder walls. The turkey pan intake gasket had a puddle of oil in it, so it had been leaking. I took the heads to a machinist had new guides with positive valve seals and hardened valve seats installed, along with the new valve. Got it running, but it smoked some. The exhaust pipes had oil residue in them and I thought it would burn out, got better, but never went away. I kept thinking it was the intake manifold gaskets, tried every trick I could think of, could get the smoke completely cleared up. It had really good compression on all cylinders. It was very fast, though, drove it around some on the temporary license. Took it up to Virginia City, wife said she would never ride with me again in it.
Anway, we moved to Las Vegas, and took the Mustang with us, never had a chance to work on it a lot. Three moves late and I’m finally getting back to working on it. Two moves ago I decided that I would put a better cam in it, which was going to also require a different torque converter. Pulled the engine and found out why it still had hone marks in the cylinders, it was a service block, no partial VIN on the back of the block. I pulled the transmission with the engine. Next, I pulled the camshaft and my trip down the rabbit hole started. There was a ¼” chip out of the corner of one of the teeth on the distributor/oil pump drive gear. Not really a big deal, but I wondered where the chipped off piece had gone. Pulled the oil pan, couldn’t find anything, pulled the pistons, what the bleep is that? There was a place at the bottom of one of the cylinders, where someone had take a die grinder and ground off part of the lower cylinder. I could also see some slight scoring on the cylinder wall. Hit it with the hone and there was one spot that stayed shiny. You can see the ground off area and the shiny spot in this picture. The cylinder at the shiny spot was about 0.005” bigger then the rest of the cylinder. My theory, someone didn’t double check the torque on all bolts, that one rod wasn’t tight enough, came off and banged up the bottom of the cylinder. Grinding off the bottom of the cylinder allowed the piston to rock due to not enough skirt support and caused the worn/ shiny spot. Because the bad spot was at the bottom of the stroke it still developed good compression readings, just 5 psi less than the average of the rest of them, which was 148psi. Enough oil would still get by, though, to cause it to smoke a little.
I went ahead and checked the rest of the engine over and noticed something strange on the rear cam bearing bore plug. Another what the bleep moment. This is what I saw:
Now, what would somebody do that? I popped it out and this is what it looked like on the other side:
It had been rubbing on the end of the camshaft, were they using it to adjust the end play???
I thought about having that cylinder sleeved, but didn’t know how the ground off area would affect the sleeve seal.
So, I started looking for a block, found a Q code 3 hours away. Our last move was last year and I have a decent sized work shop, and now I’m starting to rebuild the engine. It appears to be in very good condition, not even any ridge at the top of the cylinders. I finally found a local machinist that I’m confident can do the job and do it right. I’ll have him bore it, new valve guides machined for Vitron seals and hardened valve seats.
I’ll be stroking it to a 408 with a balanced kit from Scat, which is supposed to be here the first week in October.
I’ll get into more details on the engine build later, and plans for the body.
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