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PostPosted: Sun Nov 20, 2005 12:47 am 
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Joined: Sat Nov 19, 2005 11:52 pm
Posts: 39
Location: Redding California
Hi guys, I would like to thank you in advance for your generous input.

I just bought a LUV last week, my first one! The engine was in the bed
of the truck, so now its in the garage. I've torn the engine down to the
head...

The previous owner of this truck said that the head gasket blew out on
the exhaust side. There is no water in the oil, its clean. I'm not
entirely green to engine work, but I am unexeperienced.

My question is: what should I do? I'm about to take the head off,
contious of the timing chain of course. But what after that? I don't know
where to look for these problems claimed by the previous owner.

I obviously need to replace the head gasket. Should I get the heads
pressure tested and milled?

What exacltly are these procedures; (tested and milled?).
As I said, I'm not brand new, but am inexeperienced with this line of
work, and am very willing to learn. I really do appreciate any and all
of your guys' input. Thanks Again.

I'm a new member by the way, and I look forward to the community.

_________________
"Experience is a hard teacher, for she gives the test first, and the lesson afterwards."

1978 Chevy LUV - 2WD - [Work In Progress]
w/1976 1.8L 1815cc Stock Isuzu Motor

http://forums.luvtruck.com/viewtopic.php?t=8843


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 Post subject: Head
PostPosted: Sun Nov 20, 2005 10:17 am 
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da LUV masta

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Location: NE Washington, USA
First, get yourself a manual from your local parts house. Haynes, Clymer.
Next, run a compression check after pulling the plugs. If the pressure is way down, then your info is right. If it reads low on 2 or 3 or both, the head may be warped. This happens if the head wasn't kept torqued down correctly. The sequence is in the manual. A clue to this is oil leaking down the block from the head to the oil pan behind the carb.


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PostPosted: Sun Nov 20, 2005 1:08 pm 
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I have the manual for the truck, (good thing too).
The engine isn't leaking oil, and I have pulled the spark plugs.

Is the sequence for the compression test in the manual?
What should the pressure be for the cyclinders? (1,2,3,4)
I will look in the manual as well.

I've seen the sequence for bolting the head down, so I've got that
taken care of when I get to it. This is my first time working on an
engine by myself. Your help is appreciated. Thanks again.

_________________
"Experience is a hard teacher, for she gives the test first, and the lesson afterwards."

1978 Chevy LUV - 2WD - [Work In Progress]
w/1976 1.8L 1815cc Stock Isuzu Motor

http://forums.luvtruck.com/viewtopic.php?t=8843


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PostPosted: Sun Nov 20, 2005 1:47 pm 
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da LUV masta

Joined: Mon Aug 11, 2003 2:35 pm
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Location: NE Washington, USA
The LUV engine has been known to blow the head gasket between cylinders. I'd recommend doing a compress check first. I've got an '80 with 100k on it. When I checked the compression, at about 90k, the readings were between 135 and 140psi. What year is yours? And how much mileage?


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PostPosted: Sun Nov 20, 2005 2:10 pm 
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If the gasket blew to the outside, it should be a fairly easy fix. I would run a compression check like robertcda suggests, before you tear it all apart, because that is info you just can't get once the head is off. The procedure is fairly simple, just pull the coil wire and all four plugs, test each hole cranking with the throttle open (foot on the floor). The last one I did was low on 1 and 3, turned out to be cracks in the head around those exhaust valves.

The one best tip I have for pulling the head off is to use wire or zip ties around the timing chain through the top sprocket. This locks the chain in the right place on the sprocket, then you unbolt the sprocket from the camshaft and leave it with the block. The book will say to lock the tensioner back on the timing chain, but you won't need to do that. The bottom gear will stay in place, the top will stay put because of the wire/ziptie, and you just bolt it back on when the head goes back on.

The other tip would be to leave the rocker arms off when putting the head back on, this ensures the valves will all be closed and can't get damaged or damage the gasket as you set it down.

You should have the head checked for flatness, milled/straightened only as much as needed, and also pressure checked. When you get it off look for cracks around the exhaust valve seats, they will be obvious if there, and that would save you from paying to test an obviously bad head. Sounds like yours will be ok though, might even still be pretty much flat if it just blew out the side


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PostPosted: Mon Nov 21, 2005 8:05 pm 
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Thanks for the info. My engine is actually on an engine stand in my garage. Today I took the head off, and it turns out that the head gasket was blown on the inside, (between cyclinders 3 and 4). I will look at the head tonight. I've already got a gasket on the way (mail). Do i have to have the head checked for flatness or can i do that myself? how would i? Thanks. Aaron.

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"Experience is a hard teacher, for she gives the test first, and the lesson afterwards."

1978 Chevy LUV - 2WD - [Work In Progress]
w/1976 1.8L 1815cc Stock Isuzu Motor

http://forums.luvtruck.com/viewtopic.php?t=8843


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 Post subject: Flatness
PostPosted: Mon Nov 21, 2005 9:02 pm 
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da LUV masta

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You can check the head if you have something absolutely flat to place it on. Like a table saw top. There's a tolerance for allowance measurable with a feeler guage. I forget what it is. Call a engine machine shop.


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PostPosted: Mon Nov 21, 2005 9:08 pm 
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Thanks, I'll check the head right now, I don't recall seeing any cracks
around the manifold mounts on the head; but I will check that too.

The previous owner just said that he thought the head gasket was blown.
And apparently he was right. But I was wondering; what are the symptoms
of a blown head gasket? -more for future reference but I would like to understand how this problem can be identified. Thanks Again. Aaron.

_________________
"Experience is a hard teacher, for she gives the test first, and the lesson afterwards."

1978 Chevy LUV - 2WD - [Work In Progress]
w/1976 1.8L 1815cc Stock Isuzu Motor

http://forums.luvtruck.com/viewtopic.php?t=8843


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PostPosted: Thu Nov 24, 2005 7:17 pm 
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The book says that the head can differentiate to the MAX of (0.2mm)
Anything above (0.2mm) is bad and the head MUST be refinished.
Anything below this measurement is acceptable.

On my head I took a square and measured from end to end.
I can't really tell if it is o.k. or not.
But there aren't any cracks around the exhaust or inlet manifolds;
so thats good.
The gasket blew on the inside, between (cyclinders 3 and 4).

About how much should it cost to get it milled; does anyone know?
Thanks.

_________________
"Experience is a hard teacher, for she gives the test first, and the lesson afterwards."

1978 Chevy LUV - 2WD - [Work In Progress]
w/1976 1.8L 1815cc Stock Isuzu Motor

http://forums.luvtruck.com/viewtopic.php?t=8843


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PostPosted: Thu Nov 24, 2005 11:05 pm 
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If it blew between two cylinders you will want to look at the space between those cylinders on the head and the block. If left go for too long and run with the blow out it can eat out metal in the head and even worse, the block.

It is fairly tough to measure the runout on a head yourself. I've got an old cylinder head straight edge from my Dad's old tool shelf that was built for the job and I still don't really trust it. When you are talking differences of tenths of a mm you need better precision than most of us do it yourself types have. If it looks good to you, that is a really good sign, but it is worth having it checked out at a shop. It is also good to get a pressure check, which will tell you for sure that there are no cracks anywhere in the head.

Look in the yellow pages under automotive for machine shops. Around here many of the NAPA parts shops have a machine shop in the back, or you could ask whatever parts places you have around where they recommend. Price can vary, resurfacing would probably be something like $40, and a pressure check around the same or a little less. Its hard to say what you will find in your area though, could be less.


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PostPosted: Mon Nov 28, 2005 7:47 pm 
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Great! Thanks for the information. I will call a machine shop tommorrow.
I *tried* to figure out if the head was warped myself; but I don't trust my instrument's nor my skills with such precision. Better to have it worked on then to have to tear the whole thing apart again. :roll:

I'll keep the forum updated with the news. Hope to have it runnin' soon. It'll be my first engine tear-down. It will also be my first LUV!

Thanks. Aaron.

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"Experience is a hard teacher, for she gives the test first, and the lesson afterwards."

1978 Chevy LUV - 2WD - [Work In Progress]
w/1976 1.8L 1815cc Stock Isuzu Motor

http://forums.luvtruck.com/viewtopic.php?t=8843


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 Post subject: Headgasket Update:
PostPosted: Fri Dec 02, 2005 3:31 pm 
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Well, $35 dollars later, my head is now milled. I have a felpro head gasket for the install and I'm ready to go. I just had one final question; I bought some Permatex "Form A Gasket Sealant." It is non-hardening and is a Gasket Sealant.
Can I use this for the head gasket? It shows kinds of use on valve covers and other gaskets, but isn't the head a little more tempermentle? or will this do fine?
Everyones help has been incredible. Thanks a Lot. Aaron.

_________________
"Experience is a hard teacher, for she gives the test first, and the lesson afterwards."

1978 Chevy LUV - 2WD - [Work In Progress]
w/1976 1.8L 1815cc Stock Isuzu Motor

http://forums.luvtruck.com/viewtopic.php?t=8843


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PostPosted: Sat Dec 03, 2005 12:43 pm 
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Do not use ANY sealer on the head gasket. With the head torqued down, there is more than enough pressure to seal it up. I don't even use any sealer on the valve cover if I can get away with it, just make sure the cover and head are clean of old sealer/gasket. You could use a very light coating on the intake manifold, but even there I usually skip it unless the head or IM are rough looking.

You should also do some cleaning on the block as well. I use a razor blade to carefully scrape all the junk off, then lightly sand the block with some 800+ grit sandpaper to smooth it off. If it is pretty clean you could skip the sandingThen clean it with something that will leave no residue like acetone or (my preference) GoofOff. Before you put the gasket down, wipe it and the block with a tack cloth (available for less than $1 at most hardware stores, anyplace paint is sold) to get any loose bits picked up. Then just before you drop the head back on do the same to its mating surface. Any grit in between things can cause the gasket to fail sooner. You also want to be very careful to not bang the head into the gasket when lowering it in place. Back off the valve adjusters all the way so the valves are almost all closed because the seem to like to hit the gasket when you are getting things in position. A ding in the fire rings on the gasket can make the gasket fail pretty fast. You could also install the head without the cam or rockers on it too, which is probably easier. It also makes lining the cam back up to the sprocket easier as well.

The FelPro gasket says it is "Permatorque" and never needs retorquing, but I'd still go back after the first 1000 miles or less and tighten it back down again. When torquing down the head be sure to follow the pattern, and go in 2-3 steps. Like torque all the bolts to 30, then to 50, then take them up to 72 or whatever the correct number is. (I forget exactly and don't have my book handy) This helps to ensure you don't warp the head putting it back on.

The razor blade can also be used to clean the old gasket off the intake and intake side of the head, but be careful because the aluminum can scratch pretty easy.

The basics are to get things clean, keep them clean, and be careful not to hurt the gasket putting it all back together. Clean and careful should get you back together with the best chance for long lasting repair.

The last one I did I put both manifolds on before putting the head on, but I had help setting it in place. If you are doing it yourself, it would be much easier to get the head on right without the manifolds. The manifolds are tough to get in place on the truck, but it cuts the risk of dropping the head into the gasket. I guess it kind of depends on how burly you are, I'm sure some of the guys here could pluck the block out of a LUV with their hands.


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PostPosted: Sat Dec 03, 2005 10:44 pm 
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:)

Thanks for the tips; I will certainly use them. I'm looking forward to
getting the truck running. So with great anticipation; I'm moving forward.

Once more- I appreciate everyones helpful guidance.

_________________
"Experience is a hard teacher, for she gives the test first, and the lesson afterwards."

1978 Chevy LUV - 2WD - [Work In Progress]
w/1976 1.8L 1815cc Stock Isuzu Motor

http://forums.luvtruck.com/viewtopic.php?t=8843


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PostPosted: Wed Apr 21, 2021 7:07 pm 
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I blew my head gasket in my 75 and I’m having trouble taking my timing chain off. Could anyone explain to me how to get it off?


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PostPosted: Fri Apr 30, 2021 7:27 am 
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Location: Lodi CA
Dylan W wrote:
I blew my head gasket in my 75 and I’m having trouble taking my timing chain off. Could anyone explain to me how to get it off?



I have the book.


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PostPosted: Fri Apr 30, 2021 8:56 am 
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Here goes a picture. If I can remember I think you use a bolt to push against the block and it pulls the sprocket out.


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