What to do with intake off? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

engrdean · 07-16-2007, 01:17 PM

In order to remove a broken bolt out of the block, I've removed my intake manifold. While I was at it, I went ahead and removed the valve covers. So, my question is, while I have the motor opened up, what sort of cleaning can I do? My plan is to degrease, sandblast, and repaint the intake manifold and valve covers. Anything I can do to clean up the block or the valve train without (any more) major disassembly? It's a 1970 350 with everything original as far as I can tell, and it hasn't been driven in about 15 years. It has spent most of its life on a farm and it is in desperate need of some TLC. I have started it recently, so I know it will run. Other than cleaning, if there are any other suggestions for routine maintenance or potential problems I can check for while I have things apart, I would appreciate it.

RACINJASON22 · 07-16-2007, 02:05 PM

If you are not planning on going any farther in the disassembly I say leave it be unless there is some thing very bad. The more you mess with the internal sludge build up the more will end up in the pan and inevitably the oil pump pick-up.

RJ22...

rlm316 · 07-16-2007, 02:14 PM

You could also possibly clog an oil passage and that would be alot worse than closing up a dirty motor.

engrdean · 07-16-2007, 04:20 PM

So when you guys say leave it be, do you mean the intake manifold as well? Could sandblasting the manifold potentially cause problems? This is the first time I have taken a motor apart to this extent, which I know isn't much, so any advice is great. I am afraid that if I do any more disassembly, I will be opening a big (expensive) can of worms. I have time, as this isn't my daily driver, but not more than a few hundred dollars in my budget right now. I wouldn't say anything looks particularly bad, but then I don't really know what to look for. It is hard to resist the urge to clean things up though. I appreciate the advice, keep it coming.

Musclerodz · 07-16-2007, 04:27 PM

If your like me it starts with the intake manifold. Well while that is off, might as well do the heads. Before I know it, the motor is out and getting stroked or completely replaced with something else.

Anyways, you can clean the manifold no problem, just be careful cleaning the other stuff that can't be removed from the engine.

Mike

Fred T · 07-16-2007, 05:08 PM

I have a hard time recommending sandblasting an intake. The reason is that it's tough to keep the sand out of the air passages, and even tougher to clean all of the sand particles out. You don't want any of the grit going into the cylinders.

A can of easy-off oven cleaner will help getting the gunk off, combined with a scraper and brush. It will also take to paint off.

As for cleaning inside, about all that I can recommend is sopping out the gunk with some rags. I would do that, then lay an old tee shirt in the valley and plug all the holes with rags or paper towels. Stuff things in so that when you pull them out, any junk will go down into the tee shirt. Then clean the intake gasket surfaces. A can of Permatex gasket remover will help a bunch. (the off-brands don't work as well). After its all clean, start pulling rags, finishing with folding the tee shirt so nothing goes into the engine. Then re-clean the valley.

While the intake is off, check the vacuum tap on the rear, and clean out any carbon or blockage. Also, if there is manifold heat passage, it should be cleaned. It also will plug with carbon, and need hammer and chisel treatement if it's plugged.

When you put things back together, throw away the rubber gaskets for the manifold ends. Lay down a bead of rtv about 1/4" thick. Ultra-blue, black or grey work pretty good. Also a thin layer around the end ports that is connected to the beads you just layed. After setting the manifold in place, check the back with an inspection mirror to make sure the sealant fills the gaps. If not, you can lift the manifold and add more sealant before it cures.

One thing I learned years ago was that if you pull the oil pan, plan on rebuilding the engine. You won't be happy with what you find, even though the engine could easily run another 50,000 miles as it is.

RACINJASON22 · 07-16-2007, 06:01 PM

You can clean the intake and covers as well as you want while they are off.

Fred T is correct about the sand blasting IMO to a point but I have donr it many times just make sure all is sand free before reinstallation.

Ultra Gray sealer is the best IMO also but others work as Fre T stated.

I just don't like disturbing sludge build up too much as there is always that possibility to make things worse

but, if you are carfull you can do it.

RJ22...

ChevLoRay · 07-16-2007, 10:39 PM

Just go ahead and put a new intake on it. Then it won't matter about the cleaning/painting of the part.

You want it to look better, right? It's just money.....go ahead and spend it. If you don't, your kids will just be fighting over it after you're gone and that's just not right.

pharcydekm · 07-16-2007, 11:18 PM

Quote:

Originally Posted by ChevLoRay

Just go ahead and put a new intake on it. Then it won't matter about the cleaning/painting of the part.

You want it to look better, right? It's just money.....go ahead and spend it. If you don't, your kids will just be fighting over it after you're gone and that's just not right.

Too funny on the kids fightingfor it!!

I agree on the new intake too. You can get an edelbrock 2101 pretty cheap and I'm sure you will enjoy the power gain. If it were me I would replace the valve guide seals and adjust the valves while I had it apart.

Probably be a decent time to replace the timing chain too. Well gues syour doing the pan at that point and while its off do the oil pump. A damn it here i go again yank the engine rebuild. Thats how it all starts for me!!!

nplocoman · 07-17-2007, 01:10 AM

The valve guide seals are a must do

rlm316 · 07-17-2007, 07:25 AM

There is nothing wrong with blasting the intake as long as the right precautions are taken. I always use duct tape on the gasket surfaces, both the carb side and the head side. When you are blasting just stay away from these as you don't want to do them anyway. The only other problem areas are the threaded holes. If you screw in some old bolts into the threads the media won't be able to enter. If some does get in all you need to do is put a small ammount of grease on the correct size tap and run it in. When you do, it will collect the media and trap it in the grease ( may need to do it more than once till it comes out clean), and blow it out with compressed air. This is the same thing that I have done many times with nice results. Works great when you are careful and take your time. Good luck.

07-16-2007, 01:17 PM	#1
engrdean Registered User Join Date: Dec 2006 Location: kansas city, mo Posts: 30	What to do with intake off? In order to remove a broken bolt out of the block, I've removed my intake manifold. While I was at it, I went ahead and removed the valve covers. So, my question is, while I have the motor opened up, what sort of cleaning can I do? My plan is to degrease, sandblast, and repaint the intake manifold and valve covers. Anything I can do to clean up the block or the valve train without (any more) major disassembly? It's a 1970 350 with everything original as far as I can tell, and it hasn't been driven in about 15 years. It has spent most of its life on a farm and it is in desperate need of some TLC. I have started it recently, so I know it will run. Other than cleaning, if there are any other suggestions for routine maintenance or potential problems I can check for while I have things apart, I would appreciate it.

07-16-2007, 02:05 PM	#2
RACINJASON22 GEARHEAD Join Date: Jan 2007 Location: CENTRAL,PA Posts: 2,284	Re: What to do with intake off? If you are not planning on going any farther in the disassembly I say leave it be unless there is some thing very bad. The more you mess with the internal sludge build up the more will end up in the pan and inevitably the oil pump pick-up. RJ22... __________________ 72 SWB 2WD MY PROJECT 72 LWB 4X4 FUTURE PROJECT SUBSCRIBE HEREBOARD VENDORS HERE NORWOOD MEET SURVIVOR!

07-16-2007, 02:14 PM	#3
rlm316 Registered User Join Date: Aug 2006 Location: Woodstown, NJ Posts: 669	Re: What to do with intake off? You could also possibly clog an oil passage and that would be alot worse than closing up a dirty motor.

07-16-2007, 04:20 PM	#4
engrdean Registered User Join Date: Dec 2006 Location: kansas city, mo Posts: 30	Re: What to do with intake off? So when you guys say leave it be, do you mean the intake manifold as well? Could sandblasting the manifold potentially cause problems? This is the first time I have taken a motor apart to this extent, which I know isn't much, so any advice is great. I am afraid that if I do any more disassembly, I will be opening a big (expensive) can of worms. I have time, as this isn't my daily driver, but not more than a few hundred dollars in my budget right now. I wouldn't say anything looks particularly bad, but then I don't really know what to look for. It is hard to resist the urge to clean things up though. I appreciate the advice, keep it coming.

07-16-2007, 04:27 PM	#5
Musclerodz Senior Member Join Date: Aug 2005 Location: OKC, OK Posts: 2,364	Re: What to do with intake off? If your like me it starts with the intake manifold. Well while that is off, might as well do the heads. Before I know it, the motor is out and getting stroked or completely replaced with something else. Anyways, you can clean the manifold no problem, just be careful cleaning the other stuff that can't be removed from the engine. Mike __________________ Mike Redpath

07-16-2007, 05:08 PM	#6
Fred T Cantankerous Geezer Join Date: Aug 2002 Location: Bel Aire, KS Posts: 6,264	Re: What to do with intake off? I have a hard time recommending sandblasting an intake. The reason is that it's tough to keep the sand out of the air passages, and even tougher to clean all of the sand particles out. You don't want any of the grit going into the cylinders. A can of easy-off oven cleaner will help getting the gunk off, combined with a scraper and brush. It will also take to paint off. As for cleaning inside, about all that I can recommend is sopping out the gunk with some rags. I would do that, then lay an old tee shirt in the valley and plug all the holes with rags or paper towels. Stuff things in so that when you pull them out, any junk will go down into the tee shirt. Then clean the intake gasket surfaces. A can of Permatex gasket remover will help a bunch. (the off-brands don't work as well). After its all clean, start pulling rags, finishing with folding the tee shirt so nothing goes into the engine. Then re-clean the valley. While the intake is off, check the vacuum tap on the rear, and clean out any carbon or blockage. Also, if there is manifold heat passage, it should be cleaned. It also will plug with carbon, and need hammer and chisel treatement if it's plugged. When you put things back together, throw away the rubber gaskets for the manifold ends. Lay down a bead of rtv about 1/4" thick. Ultra-blue, black or grey work pretty good. Also a thin layer around the end ports that is connected to the beads you just layed. After setting the manifold in place, check the back with an inspection mirror to make sure the sealant fills the gaps. If not, you can lift the manifold and add more sealant before it cures. One thing I learned years ago was that if you pull the oil pan, plan on rebuilding the engine. You won't be happy with what you find, even though the engine could easily run another 50,000 miles as it is. __________________ Fred There is no such thing as too much cam...just not enough engine.

07-16-2007, 06:01 PM	#7
RACINJASON22 GEARHEAD Join Date: Jan 2007 Location: CENTRAL,PA Posts: 2,284	Re: What to do with intake off? You can clean the intake and covers as well as you want while they are off. Fred T is correct about the sand blasting IMO to a point but I have donr it many times just make sure all is sand free before reinstallation. Ultra Gray sealer is the best IMO also but others work as Fre T stated. I just don't like disturbing sludge build up too much as there is always that possibility to make things worse but, if you are carfull you can do it. RJ22... __________________ 72 SWB 2WD MY PROJECT 72 LWB 4X4 FUTURE PROJECT SUBSCRIBE HEREBOARD VENDORS HERE NORWOOD MEET SURVIVOR!

07-16-2007, 10:39 PM	#8
ChevLoRay Old Skool Club Join Date: Jun 2001 Location: Benton, AR "The Heart of Arkansas" Posts: 10,880	Re: What to do with intake off? Just go ahead and put a new intake on it. Then it won't matter about the cleaning/painting of the part. You want it to look better, right? It's just money.....go ahead and spend it. If you don't, your kids will just be fighting over it after you're gone and that's just not right. __________________ Member Nr. 2770 '96 GMC Sportside; 4.3/SLT - Daily driven....constantly needs washed. '69 C-10 SWB; 350/TH400 - in limbo The older I get, the better I was.

07-17-2007, 01:10 AM	#10
nplocoman never finish start another Join Date: Mar 2007 Location: North Platte Nebraska Posts: 432	Re: What to do with intake off? The valve guide seals are a must do

07-17-2007, 07:25 AM	#11
rlm316 Registered User Join Date: Aug 2006 Location: Woodstown, NJ Posts: 669	Re: What to do with intake off? There is nothing wrong with blasting the intake as long as the right precautions are taken. I always use duct tape on the gasket surfaces, both the carb side and the head side. When you are blasting just stay away from these as you don't want to do them anyway. The only other problem areas are the threaded holes. If you screw in some old bolts into the threads the media won't be able to enter. If some does get in all you need to do is put a small ammount of grease on the correct size tap and run it in. When you do, it will collect the media and trap it in the grease ( may need to do it more than once till it comes out clean), and blow it out with compressed air. This is the same thing that I have done many times with nice results. Works great when you are careful and take your time. Good luck.



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