In-truck Head Removal - need advice

[Rippin-J]

Howdy all. I'm learning the ropes when it comes to diagnosing and repairing motors. I have had some trouble with one of my cylinders (only putting out 20 psi), and after doing all of the standard tests, talking to MANY people (thanks NC Goofs!) and doing some extensive research, the best guess is that there is an issue with the valves.

I need help because I would like to remove the heads WITHOUT removing the entire motor from the truck. All of the manuals I have found and read give plenty of detail about disassembling the motor, but always with the motor fully removed. Thus, there are not any notes about things to do or not to do.

I guess my hope is to save some time and some $$ by not removing the whole thing and just having to redo the top-end vs the entire motor. If fixing the valve issue makes the motor run like a champ, I will be very, very happy.

- is this poor thinking on my part?
- has anyone performed this before?
- any suggestions, advice, or things to be extremely cautious of?
- anything else I should consider?

Otherwise, I am going to just go for it and hope for the best.

Thanks!!!

[Jim_PA]

Take a bunch of pictures with your digital camera during disassembly.

don't use the china-wall gaskets on the front and back of the intake during re-assembly--

If you don't have a book to follow on putting it back together, I recommend getting one, or just go to the Edelbrock website, and print out the instructions for installing the intake and heads.

It isn't rocket science, but it gives you piece of mind when you follow someone else's instructions.

[El Jay]

I've pulled heads in frame before without any problems.
Be sure to drain the cooling system first to keep from losing to much coolant into the crankcase.
Then change the oil & filter after you are done with the heads.

[Blazer1970]

Overall it is A LOT easier to R&R a head with the motor out of the truck. If you don't have a crane and an engine stand and you are (hopefully) only doing one head, it will be easier to just do it in the truck.

[BluTrukker]

I agree, try to keep as much coolant as possible out of the crankcase. Change your oil before you even test fire. Even a little coolant is hard on bearings. Also, make sure to lay rags in the valley and distributer hole while you are cleaning up to keep all the debris out of the engine. Other than that it is the same as doing it on a stand, except you will be leaning over the fender. I recommend haynes manuals if you need help. Good luck

[68C15]

it works the same in-frame as it does on a stand. they just do it that way so they can get better pictures for the book.

get a quality torque wrench, do not rent one as they probably have been abuse and are out of calibration

[mrein3]

I've had the heads off my truck with the block still installed a couple of times. And my truck is a 4x4 - which leaves not much room in the back to work on those bolts back there.

I would NEVER remove an engine if I'm pretty sure I have a valve issue.

Like others have said:
Drain the coolant.
Lay rags in the valley.
Clean everything REALLY good before assembly.
When you think you've cleaned up enough, clean again.

I've used a shop vac in the valley. It works really well.

Change your oil & filter after you reassemble - before running the engine. Then take a page from the vortec intake gasket re-do book and change your oil and filter again 50 miles later. Oil is still cheap compared to a rebuild.

[Rippin-J]

appreciate all of the feedback and input.

if I have isolated the problem to just one side of the motor, is it necessary to take both heads to the machine shop?

I had been advised to go ahead and get both redone at the same time.

[Rippin-J]

scratch necessary ...is it recommended?

[monte0185]

Are there alot of miles on your truck? My expeience has been when you have alot of miles and you go to rebuilding heads your going to add pressure to everything else which in turn is gonna take your bottom end out shortly afterwords. If the bottom end has been rebuilt recently then just follow the above instructions and good luck. But if it were me and I knew I had valve problems with alot of miles the I would just go ahead and pull it and rebuild the whole thing. Doing it once right is generally cheaper then doing it two or three times cheaply.

[mrein3]

Originally Posted by Rippin-J

appreciate all of the feedback and input.

if I have isolated the problem to just one side of the motor, is it necessary to take both heads to the machine shop?

I had been advised to go ahead and get both redone at the same time.

I would advise you the same way. What ever valve issue you have on the one side is probably happening or getting ready to happen on the other side. Pull them both, take them to a reputable shop, re-install, and don't look back.

While your heads are in the shop you can prep and paint your intake. Prep your valve covers if they are painted steel. When you get your heads back they should be all cleaned up. Put the prepped covers on them and paint them before installing.

When the paint is dry and you get it all back together it will look AND RUN like a million bucks.

[Sport/Truck]

This is what I’ve learned on doing intakes (applies to heads too). Drain radiator as mentioned, and then drain the oil in a clean pan. Leave the plug out and put another pan to catch drips / water. Right away use rags soak all the water you can in the lifter valley.

Finally when you have everything going back together, just before you install the intake, pour some of the oil into the lifter valley to flush out any water that may have got by.
You might not want to dump it all in depending on how much crud is collected at the bottom of the pan, if the oil is clean no problem.
s/t

[Matt_ks]

Ok so here is my two cents worth.....

Valves are just one of many things that could lead to a weak cylinder..
hopefully it is just a valve or two.. but here are some other things to consider
#1 Piston rings
#2 Flat Cam lobe
Now im sure that these item have been mentioned some where in this post or at some point they where brought up, i just didnt see them here in this post.

As far as doing just one head.... Dont u have the top end tore down that far you might as well do them both!!!!! A head job is only going to run you about 200-250 bucks and that is with buying the head and intake gasket from the machine shop, ( at least thats what I paid for myu Aluminim Heads and Gaskets) As everyone has already said, take your time, CLean up real well, and CHANGE THE OIL another thing to think about is stuff sum rags into the cylinders this will soak up the coolant and keep a good bit of the gunk out.

hope this helps.

[Rippin-J]

Heck yeah, all great input. I am getting pretty excited about tearing into it ...hopefully on Sunday.

Matt_KS - to your other two suggestions, would a flat lobe on the cam result in the valve not opening and closing (ie, not moving when I turn the motor)? AND, I have considered the piston ring (and pray that isn't the problem) but was told and have read that if the compression doesn't go up after adding oil directly to the cylinder before doing the test, then it's a valve issue. I tried that a couple of times and the reading never got any better. Is there another test I can try that would specifically target the piston rings?

couple more questions:
- what is 'the valley' you all are referring to? I assume it's the valley-like area between the heads beneath the intake. never seen one freshly opened so not exactly sure where to look for (and later to add) the oil/water mentioned above.
- what parts do I need to be sure to bring with me to the shop other than the heads? pushrods, etc?
- when everything is at the shop getting serviced, should I use a garbage bag or something to keep the block wrapped in to prevent stuff from getting into the cylinders?
- finally, is there any cleaning, inspecting or servicing that I can do myself on the pistons/cylinders while the heads are off?

Thanks again everyone, very helpful.

[berencam]

Originally Posted by Rippin-J

Heck yeah, all great input. I am getting pretty excited about tearing into it ...hopefully on Sunday.

Matt_KS - to your other two suggestions, would a flat lobe on the cam result in the valve not opening and closing (ie, not moving when I turn the motor)? AND, I have considered the piston ring (and pray that isn't the problem) but was told and have read that if the compression doesn't go up after adding oil directly to the cylinder before doing the test, then it's a valve issue. I tried that a couple of times and the reading never got any better. Is there another test I can try that would specifically target the piston rings?

couple more questions:
- what is 'the valley' you all are referring to? I assume it's the valley-like area between the heads beneath the intake. never seen one freshly opened so not exactly sure where to look for (and later to add) the oil/water mentioned above.
- what parts do I need to be sure to bring with me to the shop other than the heads? pushrods, etc?
- when everything is at the shop getting serviced, should I use a garbage bag or something to keep the block wrapped in to prevent stuff from getting into the cylinders?
- finally, is there any cleaning, inspecting or servicing that I can do myself on the pistons/cylinders while the heads are off?

Thanks again everyone, very helpful.

Your correct on the lifter valley. I used duct tape when i did my truck to cover the valley and cylinders, I purchased a set of remaned heads for 375 so i didnt have to take them in to be worked on. You can inspect the cylinder walls for scoring. Also while your in there to tell weather or not it is a flat cam lobe, turn the engine by hand and watch the lifters in question in the lifter valley. I have pictures of the same brake down and rebuild in the truck just like you want to do, so you can see what your getting yourself into, links in my sig. Its my 1970, first or second page.

[truckdude239]

just replace the push rods and rocker arms cost me 20 buxe for all 16 rods and rocker arms

[Matt_ks]

Yes a flat lobe will cause the valve not to open!! If u have tried the oil in the cylider trick and the pressure didnt go up!!! then that my friend is a very good indication, that you are going to have to replace some rings, there is a couple ways of doing this, you can just fix the cylinder that is down, but heck u have it tore down this far, and rings are sold in a set so might as well do the other 7.
One other thing I forgot to mention on the cam lobe is that you may just have a collapsed lifter, this is where the hyd lifter nolonger holds its pressure and while the lifter may be riding the full travel of the lobe, because the lifter is collasped it will not open the valve!

As far as you other questions ie bagging the block yeah it wouldnt hurt it will keep it cleaner, the only thing you will need to take the the shop is the heads now even if it is a ring, or cam issue it still wouldnt hurt to have them redone cuz if it a ring issue your going to have to rebuild the rest of the motor too, kinda sounds like it may be a little wore out as it is?

A rebuild if you do it yourself can cost anywhere from 350 to when ever your pocket book says stop. but you can build a good running stout motor for about 600 bucks and be proud to say that you built that to all your buddies.

hope i havent confused u too much! but if I did then dont hesitate to hit me up on here again.!

[72blue]

before you go to the machine shop with them, take off the head in question and inspect the gasket. You may have a bad one and that could be your problem. This may have been said before, but didn't see it. I had this problem b4 and that was the fix.
Now if this is your excuse to go spending some $ then go on ahead, but if you want to do the least and keep on truckin then remove that head first, inspect it and if it looks well, then go right ahead and proceed w the other. Hope you get her runnin soon.
James

[Hutch]

Here is some great reference material on the subject.
David Vizzard has alot of engine books
The first one is a great book to start with it will answer alot of questions and is a step by step book.
Years ago I used one of these to rebuild an engine and I learned alot of things that I still use today.
http://www.amazon.com/s/?ie=UTF8&key...l_8141dab3aj_b

[Hutch]

Oops bad link
Just go to amazon.com and type in David Vizard in the search box

[Average Joe]

This is all great advice but I would like to add if pulling the heads while still on the vehicle drain the block. You will find a small plug at the bottom center of the block abot a half inch above the oil pan flange. These can sometimes be a bear to remove but will get alot more coolant out that would otherwise go in the cylinder.

[tim21391]

i know its not the same but i pulled both heads off my dads 67 mustang and such and had no problems

[brad_man_72]

pulling the heads is a good way to find excessive cylinder wall wear and lead to a 500hp rebuild........

[highperf4x4]

Since you're pulling all the accessories off the front of the motor anyway you can take the 4 bolts out of the water pump and take it off to drain the coolant. That will get your coolant below the head line. That's how I do it when I'm pulling them in the vehicle.

As mentioned before, pull the intake first and spin the motor (take the spark plugs out and it will turn easy). If the lifters for that cylinder aren't moving as far as the others then it's the cam and you need to pull the motor and start from scratch.

If you're going to do one head, then you should do them both. If the engine is old enough that it doesn't have hardened valve seats for unleaded gas then you'll want to have them installed. If the engine is high mileage then you can expect it to smoke after you do the valve job as you've increased cylinder pressure thereby increasing "blowby"

Definitely put some clean rags in the cylinders before you start cleaning off the old head gaskets but I wouldnt' drain the oil until after you've cleaned the gasket surfaces. Whatever falls in the motor will drain out better with the oil. I'd also flush the lifter valley with deisel fuel while you have the drain plug out. Run your finger around in the valley while you're at it to see if you find any copper. Copper is in the "core" of your bearings. If you find any then your bearings are in bad shape and you should pull the engine and rebuild it.

Another thing to check while you have the heads off is the "ring ridge". Your piston rings stop about 1/4" from the top of the cylinders. If you find a pronounced "ridge" there then your cylinders are extremely worn and you should pull the motor and rebuild it.

[Rippin-J]

Originally Posted by highperf4x4

Since you're pulling all the accessories off the front of the motor anyway you can take the 4 bolts out of the water pump and take it off to drain the coolant. That will get your coolant below the head line. That's how I do it when I'm pulling them in the vehicle.

As mentioned before, pull the intake first and spin the motor (take the spark plugs out and it will turn easy). If the lifters for that cylinder aren't moving as far as the others then it's the cam and you need to pull the motor and start from scratch.

If you're going to do one head, then you should do them both. If the engine is old enough that it doesn't have hardened valve seats for unleaded gas then you'll want to have them installed. If the engine is high mileage then you can expect it to smoke after you do the valve job as you've increased cylinder pressure thereby increasing "blowby"

Definitely put some clean rags in the cylinders before you start cleaning off the old head gaskets but I wouldnt' drain the oil until after you've cleaned the gasket surfaces. Whatever falls in the motor will drain out better with the oil. I'd also flush the lifter valley with deisel fuel while you have the drain plug out. Run your finger around in the valley while you're at it to see if you find any copper. Copper is in the "core" of your bearings. If you find any then your bearings are in bad shape and you should pull the engine and rebuild it.

Another thing to check while you have the heads off is the "ring ridge". Your piston rings stop about 1/4" from the top of the cylinders. If you find a pronounced "ridge" there then your cylinders are extremely worn and you should pull the motor and rebuild it.

adding all of the above to my 'things to look for' notes. thanks.