I have to say first everyone here is so nice to help, even with guys like me who only pop in every once in a while and only when i need help. That said, all the advice and know-how here is priceless - and I do appreciate it.

Well I started communting to work with the Vista Cruiser, with the new rebuilt engine, got the tires worked out, got the vibrations tamed and was just started to enjoying the ride. Its an hour each way at highway speeds - its a really great way to enjoy my classic car.

Well I got an exhaust leak. I thought it was at the flanges, but it turns out the RH manifold loosened just slightly and burned out the gasket at the back of the block. As I investigated, my shop manual says THERE IS SUPPOSED TO BE LOCKING TABS!

This is correct right? He didn't even use lock washers. I am pissed, because that was a really hard job changing that gasket. (It took me 6 hours to do, because well I'm a novice and very cautious.

I ordered the locking tabs from Original Parts Group, but the are on back order for over a month.

So here is my question: I put the new gasket on with some high-temp copper silicone, and put the bolts back in with some lock washers, and I did not overtighten. My question is - is this safe/good idea? Can I drive it like this?

Any input would be helpful and greatly appreciated.

And on a side note, with the air conditioning you can't take out the manifold without removing the freakin' upper control arm?!?! Aaarrgghh! So with the shroud over the manifold, getting that center bolt in was like an act of houdini being helped by sorcery and black magic.

 

you can get those locking tabs on ebay or from fusick or supercars, if you hunt around there was some stainless ones availible too.

 

The proper locking tabs would be the way to assure the problem will be corrected according to factory specs...

 

I was never a big fan of the lock tabs. I chose to use stainless bolts with flats and lock washers. To each their own I suppose.

 

For myself, I do prefer the lock washers as long as there is a flat behind it... My other post was more from a factory spec standpoint...

 

I hear ya John. From a factory stand point it was probably way cheaper to
fabricate a gazillion tin locks rather than using flats and locks.
Gotta keep the bean counter happy.

Atomic, keep in mind those old steel bolts have been through many heat cycles.
They have been known to snap if you look at them wrong.

 

You will be fine as is.

 

If your using flats get the SAE sized flat washers, they are smaller in diameter. They look and function better. I prefer black oxide bolts gr5 or 8 over SS as they are stronger and won't gall. Use a high heat thread compound.

 

I bought these and they prevent exhaust leaks great:

https://www.summitracing.com/parts/p...ake/oldsmobile

Granted, I run headers. The OE locking tabs are just what you need though if you want to keep it stock.

 

Galling is a huge issue with stainless especially bolt to but. At least the solution was shown in the pic, antiseize. Every stainless bolt needs a bath in that stuff.

 

And they don't rust.

 

Oh man, I did not put any flats behind the lock washers! My gut told me to do it, but I didn't do it. When I get the tabs and install them I can throw in the flats. Man, I am pissed. I paid the engine shop to rebuild the motor so I wouldn't have to do this. you would think that a competent engine guy would have seen the issue. F*%#!!

Anyways, after waiting the 24 hours for the copper silicone to cure, i fired it up and there were no leaks. However, the LH side is leaking too. I couldn't hear it over the other side. At least that side is easy to swap in and out!!! HAHA!!!

Thanks for the tips guys!

 

If your using the lock tabs, no flats or locks are required. Before taking the other side apart, try tightening all the bolts but the center. If that does not clear it, tighten the center one just a smidge, don't over tighten.

 

I tried giving them a re-tightening. They all turned a quarter turn, very easily. It did not do anything, so I think the gasket is shot.

 

I think the builder may have reused the old bolts, they look a little weathered. They came out clean and I put anti-seize on them. Should I swap them out for some new ones?

 

I would but that's me. Your call.

 

The original installation of the exhaust manifolds require no gaskets, its metal to metal. You might remove them clean both surfaces and install the manifolds without them.

 

X2, no gaskets

 

In the shops we used gaskets only if the manifolds started leaking, no doubt due to corrosion or warpage.

 

The gaskets can cause manifold warpage.

 

I never use lock tabs on any of my builds ( all different makes),. I've always heard that due to the heat, lock washers dont' work right, either. The most important thing I do, is to retighten the bolts after a few days running. Gaskets can shrink, which makes the bolts seem loose. Maybe do it twice. then forget about it. Just use flat washers, and if using SS, anti-seize.

 

Don't install the manifolds without a gasket. Oldsmobile may have omitted gaskets from the factory but that was 30+ years ago with true, newly machined parts. Here are some gaskets offered by Percy's that I've used before, they work great:

https://www.summitracing.com/search/...rder=Ascending

If you are going to omit the gaskets at least get a true bar and measure the warpage of the manifold with feeler gauges. If it's not true then have a machine shop mill it.

 

This is my feeling about that as well, that they are used and probably not true. As for being milled - they were - and was the reason I paid to have it built. Which really make me mad.

I ordered the fuslick tabs and should have them by the weekend. As for the bolts I think i might change them out.

I'm a big guy and always have a problem with over-tightening bolts. The chop manual says that the exhaust manifold bolts only get 25lbs. Not really sure how I'm going to get a torque wrench down there, but i'll try!