To pull heads or not, that is the question...

[platoribs]

Whether tis nobler to pull the heads completely off and send out for reconditioning or leave them on and just do the valve stem seals in situ?

Obviously if the heads come off and get reconditioned there will be additional cost, I guess the question is what benifits are associated with the more expensive plan.

The engine is out of the car, has new rod bearings and recent 60K, now @180,000 miles is exhibiting a little smoke on first start up. The goal is to reassemble and get another 100K griefless miles.

We're leaning toward leaving the heads on, but I wanted to get a few other EXPERIENCED opinions.

:thankyou:
Plat0

 

[jimtash]

If the engine is already out then take the heads off and have them cleaned and all the valves inspected especially the exhaust valves. With a 180,000 miles, you might want to at least get the carbon off of them. Then replace all the seals including the three camshaft seals. Make sure you apply RTV to the outer camshaft caps too or they'll leak and then install the heads back onto the block and be done with it.

I replaced the heads with the engine in my car FYI and although it went easier than I expected, with the engine out it's a no brainer. I purchased a set of used ported and polished heads, took them both apart, cleaned all the valves, replaced all the seals and am totally pleased with the results.

 

[Eric VerValin]

I had mine done by a machine shop, partially because I didn't want the hassle of messing with the heads... but also for the new 3 angle valve grind they did. Supposedly worth a few hp, and I can't say for certian.. but she sure felt stronger than ever when I first fired it back up.

Plus they should be able to tell you if you need new valve guides or not

 

[93rev2sev]

FFY (For Forum's information):

The headwork was just quoted to me by Rays Precision Engine at ~ $400.

Ray's is known as THE place in the Down River Detroit area to take your mill for reliable, trustworthy re-dux. Everyone at Milan Dragway that I've spoken to says "Ray's knows what they're doing". And the experiences I've had with Ray's confirms that (had a couple of SBF heads rebuilt there, years ago).

I'm sure I could get a basic cleanup/valve re-lap done for $300, but whats a hundred bux at this point?

It would include:

Disassembly
Inspection
Cleaning
Surfacing
Valve grind
Assembly with customer supplied seals

The other option is to save $500 and leave the heads on the engine. ($100 for head gaskets, $400 for valve job).

 

[jimtash]

FFY (For Forum's information):

The headwork was just quoted to me by Rays Precision Engine at ~ $400.

Ray's is known as THE place in the Down River Detroit area to take your mill for reliable, trustworthy re-dux. Everyone at Milan Dragway that I've spoken to says "Ray's knows what they're doing". And the experiences I've had with Ray's confirms that (had a couple of SBF heads rebuilt there, years ago).

I'm sure I could get a basic cleanup/valve re-lap done for $300, but whats a hundred bux at this point?

It would include:

Disassembly
Inspection
Cleaning
Surfacing
Valve grind
Assembly with customer supplied seals

The other option is to save $500 and leave the heads on the engine. ($100 for head gaskets, $400 for valve job).

If you really wanted to save money, you could do a lot of that yourself. For example, the $500.00 you spend at the machine shop for most of the work is more than I paid for the set of ported heads, 2 valves needed to replace two bent one's, all the seals, gaskets, belts, and valve shims. The labor was free because I did it myself.

I cleaned the heads myself.

I polished the combustion chambers and removed all the leftover gasket material with a drill and fine wire brush. I even polished the outside of the heads themselves and made them look shiny.

I took a drill and a coarse wire brush to scrape all the carbon off all the valves. The intake valves had lots of buildup around the base of the stem. The exhaust valves had lots of buildup on the face. You can inspect the valves around the seat yourself and lap them at the same time if you want to but do not grind the valve stems.

I have the OTC service kit for the SHO engine so I did all the valves and seals myself.

Personally I'd take the bare heads to the shop, have them hot tank them and inspect the guides. The rest I'd do myself and that's mainly because I know I'll do a better job because I have more at stake.

 

[Phoenix]

On my opinion , if this was my DD : i would replace the stem seals and call it a day.

If this is your sunday baby , pull the heads. While you are at it you can do a little porting job....

 

[platoribs]

...has new rod bearings and recent 60K, now @180,000 miles is exhibiting a little smoke on first start up.

Did I mention I wasn't having any other problems with this engine when the diff pin was liberated.:wave:

I believe the compression figures are available somewhere... let me look around here...:laugh_ti:

If this is your sunday baby , pull the heads. While you are at it you can do a little porting job....

I take all my babies out on sunny Sunday's...:sun:

 

[St Louis SHO]

With the engine out, seriously Chris, I would just do the valve seals and call it a day. It's a few hours with the engine on the floor and alot less money.

- James

EDIT: Also, Tom, get some GM top engine cleaner and soak all cylinders through the spark plug holes. This will clean the carbon out of the ringlands. Do this in steps:

Pour a cap full in each cylinder, let it sit.
Rotate the engine 1/4 turn, repeat step 1
do this about 4 times.
the top end cleaner will end up in the oil pan, which is ok. Drain oil, start engine, let warm up, change oil.

This is 100000000x better than seafoam, and the engine will love you.

I've done this on a few 180-250k engines, and it raised the comp. by 20%

- James

 

[93rev2sev]

EDIT: Also, Tom, get some GM top engine cleaner and soak all cylinders through the spark plug holes. This will clean the carbon out of the ringlands. Do this in steps:

Pour a cap full in each cylinder, let it sit.
Rotate the engine 1/4 turn, repeat step 1
do this about 4 times.
the top end cleaner will end up in the oil pan, which is ok. Drain oil, start engine, let warm up, change oil.

- James

Thank you:
Ancient St Louis secret?

I imagine this would be even more effective on an engine that was at running temp when the stuff gets dumped in?

If so, it'll hafta wait until it's all back together and running...

 

[St Louis SHO]

Nope, do it cold.

Its a GM service bulletin on the norfstar cadi motors... It works great.

 

[trainguy1989]

With the engine out, seriously Chris, I would just do the valve seals and call it a day. It's a few hours with the engine on the floor and alot less money.

- James

EDIT: Also, Tom, get some GM top engine cleaner and soak all cylinders through the spark plug holes. This will clean the carbon out of the ringlands. Do this in steps:

Pour a cap full in each cylinder, let it sit.
Rotate the engine 1/4 turn, repeat step 1
do this about 4 times.
the top end cleaner will end up in the oil pan, which is ok. Drain oil, start engine, let warm up, change oil.


This is 100000000x better than seafoam, and the engine will love you.

I've done this on a few 180-250k engines, and it raised the comp. by 20%

- James

Good to know! Thanks

 

[lowc]

yea that gm cleaner is one of the best things goverment motors ever made atleast since the 60s

 

[sperold]

I would pull the heads only if I knew the engine had been overheated, othewise they would stay on.
In the overheated case, you could check for cracks, and see if the rings still had tension, and this exercise would put new head gaskets in place, to replace your scorched gaskets.

 

[SHOtimer]

When I rebuilt my 3.2, I had the machine shop pressure test my heads....they said it was fine. I had them swap the valve stem seals. I think I paid around $100.00.

The heads have ~200k on them total, with ~65k on them since I put it all back together.

I take out the same amount of oil that I pour in 3k earlier...and my tail pipes breath clear when she is started up cold.

All that to say....I'd pull the heads and have the stem seals replaced then patch it all back together.

Plus, it gives you a chance to freshen up the head gaskets and all the other stuff in there.

Doug

 

[platoribs]

All that to say....I'd pull the heads and have the stem seals replaced then patch it all back together.

Plus, it gives you a chance to freshen up the head gaskets and all the other stuff in there.

Doug

Just so I'm clear on what your saying... what are you saying?

What all other stuff in there are you referring to?

 

[SHOtimer]

I'm referring to all the easy stuff it is to freshen up when the heads are off...ect: the head gaskets, the knock sensor, the gaskets on the side of the head...

If I had the engine that far apart and out of the car. I would certainly at least replace the valve stem seals, have the machine shop pressure test the head to see how it is holding up, and get a new seal on the head gaskets. Plus replace that knock sensor...and all the other gaskets.

Doug