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71ROUTE66
04-02-2010, 10:25 PM
On my '71 - 455, I have an exhaust leak between the drivers side exhaust manifold and the head. I know I can expect to break off a couple of bolts. Would it be more practical to remove the head with the exhaust manifold and just take the assembly to a machine shop since they will need to be refaced anyway. Has anyone done this? And since I will be into it that far, with 115,000 miles, does it make sense to re-build the engine? The engine appears to run fine otherwise. Also, I do have an oil leak at the rear seal as well.

Thanks

Bruce

Smartin
04-03-2010, 07:17 AM
If you think you can lift that combo out of the engine compartment by hand, then go for it. I did it with my convertible years ago when I rebuilt the heads...and it's heavy!

I wouldn't bother with the whole engine if it seems to run fine otherwise. I would have both heads gone through, though.

centurion 455 ragtop
04-03-2010, 09:18 AM
I feel the pain. For about 3 years now I fought with myself on an exhaust leak on.... the ac side manifold. I know the bolts will come out as I rebuilt the engine 5 years ago and used anti seize. But its going to be a royal pain in the rear doing it on that side. Maybe this year I'll do it. As with yours I would agree with Adam. But first being its the driver side I would try spaying some nut buster on the bolts for a few days and letting it soak and then heat the crap out of them. You have more room to work with on that side. But keep in mind if one bolt feels funny then stop and remove the head with the intake.

EEE
04-04-2010, 12:02 PM
Take it easy, and see if the bolts come loose without applying crazy torque, you might get lucky. If they don't come out, you're just back to square one. You shouldn't have to turn it into an engine rebuild because of an exhaust leak.

71ROUTE66
04-04-2010, 05:03 PM
Since I intend to rebuild the heads and re-machine the exhaust manifold face, I might try and remove it as an assembly first.

Bruce

73 Centurion
04-05-2010, 12:10 PM
If you're going to have the head worked on you don't have too much about snapping bolts. You certainly want to avoid breaking the bolts if possible, but the shop can deal with it if it happens.

Broken bolts are a nightmare if you want to leave the head on the engine, but if you're going to pull the head it's much easier to deal with the problem on a bench.

Separating the exhaust manifold from the pipes will probably prove to be a pain as well. They get hot from the exhaust but hang out in the open where they get splashed and coated.

If you can take the time soaking with liquid wrench or equivilant for days can help. Heating the bolt helps by causing the bolt to expand and crushes the rust that is holding the threads. You can apply liquid wrench let it work for a couple of days. Heat the bolts and reapply the liquid wrench. The heat cycle in the middle can open passeges for the penetrating oil.

If you have a friend with an impact wrench they can be useful for loosening bolts without breaking them. They are also good at breaking bolts so it's always a matter of luck.

Let us know how this works out for you.

John

71ROUTE66
04-05-2010, 09:11 PM
I had the exhaust replaced maybe three years ago. The bolts from the exhaust pipe to the manifold should come off OK. after soaking and heat, I'll try a couple of bolts to see if they cooperate. If I snap one or two, I'll take it in since it will have to be machined anyway.

Thanks

Bruce

71ROUTE66
05-31-2010, 08:34 AM
As stated previously, I have an exhaust leak. Is it true that no gasket is used when mounting the exhaust manifold? I have read that there was no factory gasket. However, there are gaskets for sale for this purpose. Any recommendations?

Thanks.

Bruce

71ROUTE66
05-31-2010, 08:34 AM
As stated previously, I have an exhaust leak. Is it true that no gasket is used when mounting the exhaust manifold? I have read that there was no factory gasket. However, there are gaskets for sale for this purpose. Any recommendations?

Thanks.

Bruce

Smartin
05-31-2010, 08:39 AM
When you pull your manifold, have a machine shop mill the surface of the manifold flat. Make sure the head surface is clean as well. Then spread a light layer of red RTV on the surface. Install with no gasket. I've done this on several cars, and have never had a problem with leaks.

Yes, it it true the factory used no gaskets.

71ROUTE66
05-31-2010, 09:36 AM
do I need to machine the head surface as well?

Thanks.

Bruce

Smartin
05-31-2010, 09:48 AM
Typically, the head surface remains much flatter due to the rigidity of the head. I've never milled the head surface. The RTV should help seal any imperfections still remaining.

71ROUTE66
05-31-2010, 10:47 AM
Thanks for the advise.

Bruce

EEE
05-31-2010, 01:14 PM
I've used the gaskets with no problems previously.

If the only thing bothering you is an exhaust manifold leak, I suggest you try to carefully remove that manifold and just try a new gasket, or as Adam suggested above, use the RTV silicone. If it was me I would leave it at that to see what happens once re-installed.

Removing the head and machining the manifold etc. kind of takes it to a level you might not have to go to.

I've also seen exhaust manifolds crack, so take a good look at it once out, since this will be the best time to do it.

71ROUTE66
06-13-2010, 11:15 AM
Well - Yesterday I finally found the courage to address my exhaust manifold leak on my 455. I soaked the bolts with PB blaster (several times over the past two years). The first couple of bolts cooperated, but finally broke one - decision time! I decided to tear down the top half of the engine. Since the car has 115,000 miles, it thought it was time anyway.

I think it went pretty well. First I removed the hood - this is a must. I disconnected all the linkage and lines to the intake manifold and then removed the manifold. Pulled back the A/C compressor and removed the alternator. Pulled back the power steering pump. Removed the valve covers. Removed the rocker arms. Disconnected the exhaust. Then we rigged a gantry using a rope over my garage roof joist to help lift the intake and exhaust manifold as an assembly - success.

I intend to bring the assemblies to a machine shop in the North Chicago Area to recondition. Recommendations on machine shops welcome.

The cylinder wall look good.

Now, since I am into it this deep and based on the miles driven, I could use some input from your experiences. Here are some questions.

Should I replace the timing chain? Camshaft? Lifters? Push rods? Water Pump?

Should I consider replacing the oil pump to improve lubrication?

Other recommendations?

That's a mouthful!

Bruce

71ROUTE66
06-13-2010, 11:15 AM
Well - Yesterday I finally found the courage to address my exhaust manifold leak on my 455. I soaked the bolts with PB blaster (several times over the past two years). The first couple of bolts cooperated, but finally broke one - decision time! I decided to tear down the top half of the engine. Since the car has 115,000 miles, it thought it was time anyway.

I think it went pretty well. First I removed the hood - this is a must. I disconnected all the linkage and lines to the intake manifold and then removed the manifold. Pulled back the A/C compressor and removed the alternator. Pulled back the power steering pump. Removed the valve covers. Removed the rocker arms. Disconnected the exhaust. Then we rigged a gantry using a rope over my garage roof joist to help lift the intake and exhaust manifold as an assembly - success.

I intend to bring the assemblies to a machine shop in the North Chicago Area to recondition. Recommendations on machine shops welcome.

The cylinder wall look good.

Now, since I am into it this deep and based on the miles driven, I could use some input from your experiences. Here are some questions.

Should I replace the timing chain? Camshaft? Lifters? Push rods? Water Pump?

Should I consider replacing the oil pump to improve lubrication?

Other recommendations?

That's a mouthful!

Bruce

Smartin
06-13-2010, 11:56 AM
Bruce,

At this point, I would not replace any more than you have to, unless you just want to keep going with it.

Rebuilding the oil pump can be a tricky endeavor, and requires some precision measuring...and if it's not right, your oil pressure will suffer. But there is a lot of good information out there to help you get through it.

Did you make sure you kept all your lifters and pushrods in order?

Gum,beest
06-13-2010, 12:46 PM
When i had my engine open this winter
I replaced the timing chain for a double chain http://www.rockauto.com/catalog/moreinfo.php?pk=904136
Replaced the oil pump http://www.rockauto.com/catalog/moreinfo.php?pk=117831 and added a thrust plate to it as well http://www.rockauto.com/catalog/moreinfo.php?pk=117829
A new water pump can't hurt either , complete this all with a gasket kit and your set to go
my Odo meter reads 62000 miles and it was time to replace the timing so i imagine it is time for your engine as well
Know this: If you want to change the camshaft you have to break in the engine all over again

:Brow: p.s. lifted all the stuff out by hand (gantry cranes is for ............. people with more resources then me) :beers:

And all the links refer to 73 stuff

71ROUTE66
06-25-2010, 10:13 PM
I received my rebuilt heads back today. The shop did a great job. However, the exhaust leak I had turned out to be two good size cracks. Does anyone know of a source for a replacement?

Thanks

Bruce

71ROUTE66
06-25-2010, 10:13 PM
I received my rebuilt heads back today. The shop did a great job. However, the exhaust leak I had turned out to be two good size cracks. Does anyone know of a source for a replacement?

Thanks

Bruce

EEE
06-26-2010, 03:31 PM
Should be able to pick one up easily from v8buick.com (parts wanted section), or ebay.

71ROUTE66
06-27-2010, 05:37 PM
Has anyone had experience with a cast iron repair shop on their exhaust manifold?
Bruce

71ROUTE66
07-31-2010, 11:50 PM
Well - six weeks after my decision to correct my exhaust manifold leak, I am proud to say my small project (turned large) was completed this past Thursday. To recap - the cracks in my left exhaust manifold forced me to remove my heads. I proceeded to have my exhaust manifold repaired,heads rebuilt, I changed the timing chain set, changed the water pump, changed the fuel pump, dropped the oil pan and re-gasketed due to leaks, and I cleaned and painted the components.

By the way, the impact wrench was the answer to removing the harmonic balancer bolt.

Yesterday, I decided to make a trek from Chicago to Ames Iowa to visit the BCA National Car Show. Most of the way there, we had the top down - it rained the last hour. Today, we walked the show and turned around and drove back home. On the way home, the weather was perfect, so the seven hour drive down U.S. Route 30 was totally enjoyable.

I am thrilled that our repairs held up to this test. We did not show, since it was our first BCA show visit. There was one Centurion being judged.

I am glad to be driving her again.

Thanks for all the advice.

Bruce

Smartin
08-01-2010, 06:23 AM
Congrats, Bruce! I wish I could've made it to Ames.