Busted and I gotta fix it

[critter]

The car: 1974 Trans Am:



This all started several weeks back. I had been to a car show. My sister had invited me over for dinner that night so I planned to drive from the show to her home. I made it most of the way before the car quit running. I was cruising along at about 50mph when it was like someone flipped a switch.

My brother in law, Bryan Blocker of Blocker's Performance and Restoration, came over with some tools and we began to diagnose. We discovered we had no fire to the plugs and when I yanked the distributor we found that three teeth were gone from the BOP composite gear I run with my hydraulic roller cam.



We towed it back to his shop. The building was full with customer's cars and I told him to put it on the back lot, I'd throw my cover over it, no problem. We went ahead and pulled the intake and valley pan to see if anything obvious poked its head up but it didn't. We simply laid the valley pan and intake back on top of the motor, threw the cover on and walked away. I was headed out on vacation the next week so I figured it would set until I got home.

Unfortunately I got home and then the tornado hit Vilonia, Arkansas. That's where Bryan has his shop. He called me that night to say the cover had blown off but the car hadn't suffered any damage he could see. Considering I had family in the path of a killer tornado (4 died that night) I didn't give a darn about the car. So we spent the next 2 weeks cleaning up storm damage.



I decided to put a new gear on the cam, hoping it was a simple gear failure since nothing else was apparent, and see if I could start it long enough to put it on a trailer. I started by draining the oil from the block through a cloth to see if I caught anything. 2 gallons of rain water later we got to the oil. Nothing there. I then poured a fresh 5 quarts of oil through the block to see if I could chase the water out. Then I topped it off, put in new gaskets, buttoned it up and gave it a shot. It fired right up and ran about 4 seconds and died. I pulled the distributor. This time it broke the gear in half.

So the roll back was called and the dropped it at my house. The motor had to come out.




I did that today.

I started tearing it down. One think I was curious to see was how the Keen-sert I put in the block that time had held up. It did well. It's in the lower, center part of the picture. for those who don't know, I tried to re-torque a head bolt prior to NFME back in 2008. The threads stripped out of the block. I made a jig using an old head, drilled it and installed the Keen-sert while the block was in the car. It's still going strong! The other thing you'll see is carbon build up on the pistons. The driver's side head needs new valve guides.



Removing the lifters I spotted this. The #1 lifter had a spot that was galled on one side.



And it matched a spot on the cam lobe. It's hard to see in this picture but it's there.



So all of this to say this thread will be about the tear down, diagnosis on why it did this and the build of a new engine. That engine will probably be a 461ci based on a 400 block and using a stroker kit. Watch for updates.

[Jims78elky]

Bummer about the distributor..ouch!

I Like the updates..Keep it up Critt!

[andrewb70]

Time for a LS3...

Andrew

[critter]

LOL. It was considered. But I love my Pontiacs with Pontiac power so after the tear down it will most likely be a build thread for a Pontiac 400, stroked to make a 461ci motor.

[LeighP]

Go Chris!

[My427stang]

I have started running steel gears on billet cores. You need to talk to the cam manufacturer on what the materials are on their core. Dissimilar materials are bad, but usually steel to steel is an option.

You of course can't run cast iron with billet, but steel to steel is fine, and you dont have to deal with fragile composite or bronze that eventually wears out.

The sacrificial gears are of course good for a racer, but anything that puts a lot of miles on, I prefer steel to steel

[critter]

Crane used to do pressed on steel gears but they went out of business. Of course all their grinds were old technology anyway. If the cause is indeed cam wear I will look into it.

Only a complete tear down, which I'll do over the next few days, will tell but I bet that I'm going to find a worn cam thrust plate.

[critter]

Tonight's continuation of the teardown gave me the apparent cause of the gear breakage and the results of what happens when you don't pay attention to detail.

First thing I noticed after getting the lifters out was the excessive end play on the cam. It measured at .064. WAAAYYY too much. That should be more like .004 - .007.


Removing the thrust plate revealed a lot of wear. The picture doesn't do justice to the groove worn into that retaining plate.


But the real kicker was when I flipped the engine over. Yes, that's the oil pump pickup laying there and yes that's the half a cam gear laying up there, just where it was when I pulled the pan.


The crazy part is that I never had an oil pressure problem. It also shows that, though I thought I remembered tack welding that pickup, I obviously didn't . DETAILS! DETAILS! DETAILS! No one to blame but myself since I assemble my motors myself. I did it. I didn't pull rods or the crank yet but all the cam bearings look great. So my gut feeling is that the cam thrust issue was breaking gears and I was still getting oil pressure because the pickup didn't fall all the way out until I flipped the engine over on the engine stand. I'll know more regarding the pickup issue tomorrow when I pull that stuff apart.

Another downer was the cam. When it came out I noticed a lot of "spots" on the cam. They correspond with where the lifters contacted the lobes on the cam and water got under them. Basically, rust. I think the cam is toast and at least one lifter set.

[MrQuick]

surprised that it wasn't tacked on. Was the pump seized?

[critter]

Nat as surprised as me. I'm the guy who should have tacked it. How the heck I missed doing that I don't know. Still, I don't think oil delivery was my problem. None of the cam bearings looked bad. I'll tear down the rods and mains tonight and those bearings will tell me if there really was any oil delivery issue.

The pump was not seized. It turns easily by hand.

[critter]

The root cause was discovered tonight. As much as I wanted to blame it on cam walk, that wasn't it. When I disassembled the oil pump tonight I found this:


Laying on the pump base plate is a small piece of metal. As you can see from the teeth on the pump gears that sucker went through there more than once. I found it up next to the check ball in the pump. It looks like casting flash on one side and is smooth on the other. I have to figure the pickup fell off and sucked that into the pump. Here's a closer look.



I tore down the rest of the block. Here are the rod bearings. A little copper showing on the tops in a few places but for the most part OK.


And the main bearings. Looks like #2 saw some metal at some point. Lots of copper showing there.


Anybody need a set of SD rods with .030 over TRW pistons?


So that's about it. This block is pretty good except for the fact that the ear for the starter mounting is broken off.That make's it scrap metal. So it's time to move on. From here I'll be building a 400 block with a stroker kit. I'll post as I go.

[MrQuick]

I have actually seen this before....the pump will pass metal, increases friction then causes the oil pump housing to over heat and the pickup tube hole expands an the tube falls out.

Finding the weak spot can get expensive.

[mc84_zz4]

Bummer about the sick engine, but nice dissection of the cause/effects...

[critter]

My decision to build a 461 was based on a lot of factors. The primary one being that I'm on a budget and need to re-use my Super Duty #16 heads. So that means I need cubic inches to keep compression up. Another is that the 461 kits are some of the least expensive out there for my horsepower goal, roughly 500.

To that end I had intended to buy a kit from one of the known engine builders. However, a deal popped up on Performance Years forums. A young man had a complete setup, assembeled in a short block. He decided not to go that route after the machine shop misunderstood and put a race fill of hard block in the water jackets rather than the street fill he wanted. So he left the kit in the block while he pondered his situation. Then he had an LQ4 motor fall in his lap. Since he was building a pro-touring car he decided to go with the new technology.

So I purchased all the parts he had in the short block. That included the SRP pistons, 4.155 bore, full floaters, file fit rings, Eagle 6.8 inch rods, a Tomahawk cast crank, 3 inch mains, all bearings, a set of ARP 2 bolt main studs, an SFI rated flex plate from PRW, with bolts, and a Performance Products balancer. He said that they had balanced the assembly but I find no machining marks on the pistons or crank so I'll have to disassemble the stuff and check it. I don't trust them to be good out of the box.

I won't be using that balancer. I have an SFI rated Pioneer unit so it will be for sale. Other than that, I've checked all the parts out and they'll go into this next build. Kudos to Scott for having taken time to mark all the parts and how they were assembled and taking great care when he disassembled it to be sure he didn't damage anything. He was a nice guy and a real car guy. He even met me half way from his home in Oklahoma City to deliver the parts.

Here's a photo of this weekend's take:

[ponchopower69]

Man what a bummer that would be! Im glad to see it getting fixed up even better! Good luck and remember to tack weld the pick-up to the oil pump too lol.

[critter]

I would but I'm going back with a Canton road race pan so that pickup bolts to the pan. NO CHANCE it comes loose!

[ponchopower69]

Sweet choice!! That will fix it for sure lol!

[manicmechanic]

Watch out for that canton pick-up, trouble reported over at transam country...

[LeighP]

Yeah, thats me....I think the pickup I have was a one off manufacturing defect...since I've had it in a box with the RR pan for at least two years...and no one else has reported any trouble.
The pickup tube is welded into the pickup at the wrong angle...won't fit onto the pump. I called Canton and sent pics...they're looking into it.
I couldn't afford to wait on them, I ordered another from Summit, should be here in a couple of days.
I do like the bolt on pickup design.

[critter]

Thanks for the heads up. Leigh, pictures over on TAC?