Broken manifold bolts

[stutaeng]

Well at this point, use whatever you have at your disposal, even if just a 120V flux welder.

I think the oxy acetylene torch will work . I'm not sure what tip size though. There's a joke that that says something like a bolt can't be stuck if it is a liquid, LOL.

 

[Erik the Awful]

If you're already drilling, carefully drill out the center, as straight as you can, as big as you can, as deep as you can without getting into the threads or the bottom of the bolt hole. Eventually you can either use an extractor, or you'll be able to use a center punch and get the bolt threads to cave in to the hole in the center, loosening it.

 

[dakotabman]

well since this thread is still going i will give a update, and also a few questions. so i did try the harbor freight welder, but as several people mentioned it did not work for whatever reason not being powerfull enough i geuss. or possibly my lack of welding skills. the nut just broke off with very little force. so after days of trying i figured it was time to pull the head. so i got the head off now i have a few questions.

1.) should i replace head bolts?
2.) what are the best head gaskets to use?
3.) should i pull other head and do gasket as well?
4.) anything else i should replace while i have easy access too?

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[Schurkey]

1.) should i replace head bolts?

Are they corroded? Bent? Twisted?

IF (big IF) they look good...re-use them. If they're damaged, get new ones. There's nothing wrong with the GM bolts if they're in good condition.

2.) what are the best head gaskets to use?

How far below deck are your pistons? Typical is approx. .025. The engine was designed around .020-thick steel shim gaskets which went out-of-style when Fido was a pup. Anything thicker than .020 head gaskets increases the quench/squish distance, reducing turbulence in the cylinder. This makes for a slower, lazy burn needing excessive spark advance, and THAT leads to detonation. GM and the aftermarket have .028 compressed-thickness head gaskets, I would not use anything thicker than that. "Ordinary" composition head gaskets are typically .040 thick.

3.) should i pull other head and do gasket as well?

I probably would. Depending on mileage and wear, you're probably looking at a valve-job with guide work anyway. You'd know for sure when the first head gets cleaned and inspected. Once the valve springs are off, it'll be easy enough for someone to rattle the valves in the guides, look at the valve faces and valve seats, and generally inspect the heads for wear.

You're gonna pull the springs off to replace the valve stem seals anyway.

4.) anything else i should replace while i have easy access too?

If that were mine, I'd shitcan the flat-tappet camshaft and lifters in favor of an OEM-style roller cam, the thrust plate, timing chain 'n' sprockets, roller lifters, dogbone, spider, shorter pushrods, and have a good look at the rocker arms, 'cause there's about a 50/50 chance they're totaled, too.

Be sure the gear on the bottom of the distributor is in good condition.

All the roller-cam parts can come from a Treasure Yard short-block except--maybe--the timing chain and sprockets, and the thrust plate (which come as a kit from ACDelco) When it was me, I pulled the used lifters apart one-at-a-time to clean and inspect them. Or buy a hardware kit that has the dogbones 'n' spider, a cam, and the timing set with the thrust plates and bolts. There's more than one way to get the roller-cam hardware to install in your block.

So this is a TBI engine? The swirl-port heads are not much for performance. I get the sense you don't want to replace them, though. I suffered-through swirl-port heads on my K1500 for a couple of decades; they work but they don't make power. Last time the engine had to be re-done, I got rid of the swirl-ports in favor of aftermarket aluminum heads. You'd be looking at another thousand+ dollars--minus whatever you DON'T spend fixing the heads you've got. I'd rather have QUALITY aluminum heads than valve-jobbed swirl-ports.

 

[dakotabman]

Are they corroded? Bent? Twisted?

IF (big IF) they look good...re-use them. If they're damaged, get new ones. There's nothing wrong with the GM bolts if they're in good condition.


How far below deck are your pistons? Typical is approx. .025. The engine was designed around .020-thick steel shim gaskets which went out-of-style when Fido was a pup. Anything thicker than .020 head gaskets increases the quench/squish distance, reducing turbulence in the cylinder. This makes for a slower, lazy burn needing excessive spark advance, and THAT leads to detonation. GM and the aftermarket have .028 compressed-thickness head gaskets, I would not use anything thicker than that. "Ordinary" composition head gaskets are typically .040 thick.



I probably would. Depending on mileage and wear, you're probably looking at a valve-job with guide work anyway. You'd know for sure when the first head gets cleaned and inspected. Once the valve springs are off, it'll be easy enough for someone to rattle the valves in the guides, look at the valve faces and valve seats, and generally inspect the heads for wear.

You're gonna pull the springs off to replace the valve stem seals anyway.


If that were mine, I'd shitcan the flat-tappet camshaft and lifters in favor of an OEM-style roller cam, the thrust plate, timing chain 'n' sprockets, roller lifters, dogbone, spider, shorter pushrods, and have a good look at the rocker arms, 'cause there's about a 50/50 chance they're totaled, too.

Be sure the gear on the bottom of the distributor is in good condition.

All the roller-cam parts can come from a Treasure Yard short-block except--maybe--the timing chain and sprockets, and the thrust plate (which come as a kit from ACDelco) When it was me, I pulled the used lifters apart one-at-a-time to clean and inspect them. Or buy a hardware kit that has the dogbones 'n' spider, a cam, and the timing set with the thrust plates and bolts. There's more than one way to get the roller-cam hardware to install in your block.

So this is a TBI engine? The swirl-port heads are not much for performance. I get the sense you don't want to replace them, though. I suffered-through swirl-port heads on my K1500 for a couple of decades; they work but they don't make power. Last time the engine had to be re-done, I got rid of the swirl-ports in favor of aftermarket aluminum heads. You'd be looking at another thousand+ dollars--minus whatever you DON'T spend fixing the heads you've got. I'd rather have QUALITY aluminum heads than valve-jobbed swirl-ports.

damn lol thats alot. and i agree about the heads. i have been seriously debating a vortec head swap with the aftermarket intake to match. but in all reality i was wanting to just throw this head back on without doing any machine work to it. just get the broken manifold bolts out, then i would have a truck again and could build a totally seperate engine for it and take my time with it. this truck has 205,000 miles i really just bought for a work truck( not a beat the **** out of it work truck, just a good realible truck to do whatever i need.) the motor ran great before i broke the bolts off. so im hoping i can just throw it back together and it last another 50-100 thousand miles.
on the topic of the heads what did you go with? i see the vortec swap is common. but is there better options for around the same coin?

 

[Schurkey]

I had a pair of the original (Gen 1) Trick Flow Twisted Wedge heads sitting on a shelf in the garage. I bought them "used" on eBay for maybe $600 several years ago.

Aside from the weirdness of the Twisted Wedge design, and the ZZ4-style manifold I used with them, they seem to work out well on my '88. This has been somewhat hampered by the fact that I popped the transmission not long after installing the engine. Both were rebuilt/replaced about the same time, near 20 years ago.

When I finish dicking with the "Plow Truck" which was also down all winter, I'll be digging into the '88 to see if the trans is truly screwed, or if it's maybe just a plugging filter.

 

[Erik the Awful]

The cheapskate in me says, "All the stock head parts will bolt onto this casting." https://www.summitracing.com/parts/drt-10024361/make/chevrolet

I only say this because I haven't heard of issues with dropping valves in these motors. Definitely go to roller cam while you have the heads off.

 

[PlayingWithTBI]

Or, if you want a complete set that bolts right up to your manifold and flow better than the Vortec heads...
https://www.summitracing.com/parts/sum-162108/make/chevrolet

 

[RichLo]

Depends on your budget and ambition.

Bare minimum at this point I would replace both head gaskets and all of the head bolts... I was always told they are torqued to yield which means one-time use.

Next to bare minimum would be valve seals and a simple valve lapping. This is just labor besides the seals, lapping compound and a rented or bought valve spring compressor. And obviously clean, clean, clean some more. Easy-off oven cleaner works well for carbon deposits.

While your in there tings to consider would be 1.6 ratio roller rockers and gasket-match porting the intake manifold and heads.

With anything more you'll also need computer tuning to make it run right.

 

[Schurkey]

^^^ Lapping compound bought from a typical parts store is WAY too coarse. It's useless. When it was me, I bought a small can of "Clover"-brand, 400 grit lapping compound. If I had it to do again, I'd have bought 600 or finer. The 400 works well enough for the few valve jobs I do.

Verify the "Torque-to-yield" head bolts. I would not expect them to be TTY. Just because you're using Torque-Angle to tighten them, does not mean you're torquing them to (or beyond) the yield point. My '97 C-K service manual on DVD does not list the phrase "Torque to yield". It does say to install sealer on the head bolts (new bolts would probably have sealer already on them.)

If you're replacing the rockers on the original heads, you'll need self-aligning rockers. If you're using aftermarket heads with pushrod guideplates, you'll need hardened pushrods. The guideplates will chew-up OEM pushrods.