[wbnapier]

In April, I started building an engine, and today was the first real drive other than around the block and in running in the driveway for tuning purposes.

Downshifting while exiting the interstate, I lost power and needed to be towed home. I thought I had an electrical issue or something, but after going over the engine this afternoon, the worst is apparent. In nuetral, spark plugs out, dizzy out, I am unable to rotate the motor with a breaker bar.

A couple of the spark plug gaps had completely closed, indicating detonation or something weird.

It is a 0.040" over 455, 4.25" stroke. Butler rotation assembly, Stump Puller II cam, etc., etc., Pistons were dished for 91 CA gas. Tri-Power, medium ported #48 heads, etc. Everything redone, no expense spared. Block, heads, etc. all prepped by a really good machinist. Not a single leak.

I will have to sell the car as is. No more time or money. '65 GTO, 4 speed, 3.55 gears, PS, no AC. Not a stock, car, but a good mild restomod. I don't know what I can sell a non running GTO for, but hopefully cover my loss on the engine. Not a good Labor Day.

[tom s]

No noise,knocking nothing?Closed gap would sound like interference of something hitting them.Tom

[i82much]

you would be better off putting a len williams 400 on a credit card and selling the car with a running engine.

also, take a break, let the car sit for a few weeks. don’t do anything rash. you can sell it easier in the spring anyway. you may change your mind in the interim.

[Chris65LeMans]

My condolences. +1 on what i8 said - you’ll easily recover your investment by putting an engine in and selling a running car.

Who assembled the engine for you? I’d ask them to tear it down and diagnose. Somebody screwed up somewhere.

[jarretts70]

I agree with i82much.....take a breather, Walk away....come back in a couple days (or weeks) with a clear head. Then start with the basics - drain the oil & look for metal. Buy/borrow/steal a scope you can stick in a spark plug hole to look for debris or other carnage. (they are cheap on amazon if you don't have one). Crawl under it to make sure it's actually in neutral - there is always a chance there is a issue with a new clutch / pilot bushing / throwout bearing causing the trans to hang in gear.

I has similar feelings as you a couple years ago - freshly rebuilt 428 in my Trans Am began to run like crap, smoke, misfire.....I assumed the worst & was getting ready to pull the motor when a member here suggested 2 things: 1 walk away for a could days. 2. Check the valvetrain. Sure enough, a rocker had backed off...tightened it up & everything was just fine. You might not get that lucky, but there's a chance it's not as bad as you fear.

[wbnapier]

No noise. Just a weird feeling in the clutch when I downshifted then lost electrical power.

I tried to restart, but the starter was unable to turn the engine. This was burning up the starter, which resulted in an electrical burn smell. So, my first thought was that I fried a wire.

When I got home, I pulled the spark plugs, drained the oil, and cut open the filter. Nothing bad / abnormal in the filter.

I'm able to push the car around the garage in neutral, so I'm pretty sure it's safely in nuetral. I'll verify later.

I was the one who assembled it. It's likely some error I made. I know I didn't do a perfect job, but I can't think of anything that would have resulted in a seized engine. Every bolt torqued to spec. Every clearance checked. Rings gapped, cam degreed, pre-load set, etc. I didn't cut a corner on any part. ARP, Butler, Ross, forged crank and rods... I rebuilt the carbs, changed jets, idle circuit, rebuild MSD, the list goes on and on.

I'll pull a valve cover, who knows, maybe something simple.

As for spark plug gaps closed, what could cause that? I thought physical intereference from a bad timing event would be impossible?

Yes, I need to walk away and reassess. Unfortunately, my logical mind tells me that I simply don't have the time. Between work and family I was already pushing it on this project.

[Half-Inch Stud]

Best case scenario: Trans stuck in 2- gears?
Worst-Case Scenario: Crank broke.

You know, the worst-case scenario is not so bad: Block might be okay. Bores probably okay, cam probably okay. Heads probably okay but a couplea valves may need checking.

[tom s]

Mike and I both have bore scopes if you need to borrow one.Tom

[mgarblik]

The smashed plug gaps tells me something happened very quickly. It would have had a miss driving around with gaps closed. So something happened coming off that ramp and downshifting. First guess would be a dropped valve or a valve timing failure, timing chain, something like that. No metal in the oil indicates it happened quickly. No water in the oil is good news for sure. Even if it dropped a valve, the damage may not be as horrible as you think. Need to just relax and as others have said, evaluate the situation and then make good decisions. Selling it with damaged engine would be great for the buyer, but not you. Also, you want the car to be fixed and working like it should. Hope it's not too bad.

[Formulas]

Possible base screw in carb came lose, they can do some strange migration from cylinder to cylinder.

If you play this game long enough you will get bit somehow the difference is in the recovery.

Bright side is it's just an engine not a totaled car you are alive to fight another day

[Navy Horn 16]

Does your "really good machinist" not warranty his work?

My guy told me to beat the piss out of it and anything I broke the first year he would fix for free.
I've been beating the piss out of it for 3 years now with no major issues...just BS stuff to get down from 12.51 to 11.61....

[wbnapier]

Tom S - Thank you for the offer, my neighbor has one. I'll look to satisfy my curiosity, but the engine needs to come out regardless of what I see in the hole.

mgarblik - Yes, it was mildly misfiring under load, but not idle. This was my shakedown cruise, so I was planning on addressing those tuning issues today. Little did I know.

Formulas - I'll check for loose screws! Who knows, maybe I got grenaded.

Navy Horn 16 - Yes, I am pretty sure the machinist would warranty the work. I haven't spoken to him as this all went down today.

But, let's be honest, who's more likely to have a made a mistake? Me, the first time engine assembly guy, or him whos been doing Pontiac engines before I was born? I also selected and ordered the majority of the parts independently. It's all very tricky. Maybe he'll cut me a deal on a short block. Who knows...

[tom s]

Guys,the shop is the shop I use and did all of Joe Sherman’s work.Would be hard to hold him responsible if he did not supply parts or assm the engine?Tom

[wbnapier]

The machine shop crew were good and knowledgable with Pontiacs.

This is my first rodeo... Many things I would do differently, but I stand by the machinist. Between the machinist, SD Performance, John Wright, Butler, and lot's of you folks, I've had great help...

I've taken tomorrow off work... Depending on the heat and my mental status, I'll start unbolting things.

[Lemans64]

Lets hope for something small and easy to fix.

[Dragncar]

Could you have gotten a rod or two backwards so the chamfer is on the inside ? Did you gap the rigs yourself and get them too tight ? Things warm up and the ends touch and I bet you could seize a engine up.
I know someone who got 2 main caps in the wrong place. Ran, for awhile.
Hope it all turns out well.

[NeighborsComplaint]

Pull the valve cover off on the side with the plugs whose gap closed up. Look for broken valve springs and a valve at half mast. You may have dropped and bent a valve. The motor literally stops dead in its tracks when it happens with no noise, no engine coast-down and no trash in the oil. Usually accompanied by a chirp of the tires before you thrown the clutch out.

[chiphead]

Mashed plug gaps usually mean the engine ate something. Usually a screw or nut. You'll have to pull the heads to confirm what it was. The electrical failure at the same time is weird. Possible starter wiring issue as well?

I agree on pulling the upper valve train first and working your way in. Usually when an engine eats something, It should still turn part way backwards, unless whatever it ate bends a rod. So totally locked up is either starter hung in flywheel or bottom end failure.

[dataway]

Sounds like it ingested something. Rear wheels were driving the engine until you put the clutch in ... engine then probably rotated a few turns and stopped when the ingested part found a foothold. Ingested part includes the possibility of an engine part ... valve.

For a person that infrequently assembles an engine, the valve train usually poses the most opportunities for a mistake.

Not making much or any noise would be unusual though, unless it was a very small part, but even a small part can pound the gaps shut ... do that to a few cylinders and it wouldn't want to idle with the clutch in ... then the part drops to the lower side of the cylinder and wedges between the piston and head and locks it up.

First thing I'd try is turning the engine backwards ... if it turns backwards it's not a piston/bearing seizure but a part stuck in a cylinder.... most likely. Although I guess it's possible a piece stuck in the right place, or multiple parts could lock it up both ways.

Chip beat me to it

[slowbird]

Originally Posted by Dragncar

Could you have gotten a rod or two backwards so the chamfer is on the inside ? Did you gap the rigs yourself and get them too tight ? Things warm up and the ends touch and I bet you could seize a engine up.
I know someone who got 2 main caps in the wrong place. Ran, for awhile.
Hope it all turns out well.

His filter would have tons of crap in it if he put the rods in backwards.