How a great deal on a throttle body spacer can destroy an engine.

Well boys and girls here's how a cheap 13 dollar tbi spacer from the junkyard can kill an engine. I had gotten this tbi spacer and the longer bolts from my local pick a part for 13 bucks and I thought "what a deal! I hit gold!" Put it on the truck the same day and reused the longer bolts, well what I didn't realize is that one of the bolts was tweaked and when I was sitting at a red light idling, the truck just died. Didn't think anything of it, started it up and it started knocking, then it made a bang and a clatter sound and died altogether. What had happened was that one little bolt had been sucked into the throttle body and was being thrown around in the number six cylinder combustion chamber. Pulled it all apart and I shattered the number 6 piston, took a nice chunk out of the cylinder wall, and blew the head gasket all at the same time. So the engine is being rebuilt as I write this, it's getting bored .060" over, melling M55 high volume oil pump, stock tbi heads but with a little bit bigger valve spring in them, weiand Stealth intake manifold and a Holley 600 cfm carburetor with vacuum secondaries. If you need an idea of what it sounded like, think of putting a bunch of bolts in an empty paint can and then putting that paint can in a paint shaker. I knew I would have to get the engine rebuilt anyway as the number one cylinder had 70 psi of compression and was burning a quart of oil almost every time I'd drive the truck. The motor was wore out to begin with so it doesn't hurt my feelings, stay tuned for updates.

Damn!!!!! that sucks!!!!!

So exactly which bolt broke? One of the bolts that hold the TBI to the manifold? Did the head of the bolt break off?

Ken

To be fair, that's no fault of the spacer, but rather a poor installation. Not to salt the wound because it does suck, but at the end of the day it is what it is. I'd keep the TBI, shove a little more cam in there, and get it tuned with headers before going backwards with a carb. Since you destroyed a head I'm sure, you could look at upgrading those as well.

kenh said:

So exactly which bolt broke? One of the bolts that hold the TBI to the manifold? Did the head of the bolt break off?

Ken

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The bolt that broke was the back right mounting bolt for the tbi (the one closest to the driverside). The head of the bolt came off, but the long stud part was still there like nothing happened.

Supercharged111 said:

To be fair, that's no fault of the spacer, but rather a poor installation. Not to salt the wound because it does suck, but at the end of the day it is what it is. I'd keep the TBI, shove a little more cam in there, and get it tuned with headers before going backwards with a carb. Since you destroyed a head I'm sure, you could look at upgrading those as well.

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Well either way I don’t really care. This motor was wore out to begin with. It had 70 psi of compression on the number one piston and had a ton of ring ridge. I knew it would have to be rebuilt it at some point. It burned 20w-50 motor oil like water. I’m glad it went now rather than going down a freeway far from home. As for the heads, I have to stick with my stock tbi heads as the machine shop wanted 650 dollars for a pair of rebuilt Vortec heads. So I had them rebuild the tbi heads which walked away fine. I already have a comp cams Xe250h cam in the truck and I’m getting headers too. I’m ditching tbi because no matter what, it would run so lean it would backfire through the intake yet run so rich it would shoot black smoke out of the exhaust pipes. I also want to make more than 250 hp.

b454rat said:

Damn!!!!! that sucks!!!!!

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Tell me about it...

dlindsey19 said:

The bolt that broke was the back right mounting bolt for the tbi (the one closest to the driverside). The head of the bolt came off, but the long stud part was still there like nothing happened.

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So the bolt head snapped off and hopped down the #6 runner? What a dick move.

I guess I dont understand how the bolt head got down through the air filter and into the throttle body .....are the bolts inside it?

^yea me too?