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Old 10-06-2024, 04:26 PM   #301
raggedjim
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Re: Previous owner '68

So I decided I would do a leak-down test. I know, the results might be different if the engine was hot and fully oiled, but I did it anyway.

Test psi was 100psi and I did test both at top stroke and bottom of each cylinder.

Results were:

Cyl 1 top - 90%, bottom - 92%
Cyl 2 top - 84%, bottom - 88%
Cyl 3 top - 84%, bottom - 80%
Cyl 4 top - 90%, bottom - 90%
Cyl 5 top - 82%, bottom - 80%
Cyl 6 top - 86%, bottom - 84%
Cyl 7 top - 96%, bottom - 94%
Cyl 8 top - 90%, bottom - 90%

Now this was a long sitting, dry engine. Given the results I am going to replace the valve guide seals and hope for the best. If you think I'm screwing up let me know.
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Old 10-07-2024, 10:29 AM   #302
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Re: Previous owner '68

Looking at how clean the valley is on that one, and your cold test results, I'd say it's a runner.
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Old 10-08-2024, 09:36 AM   #303
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Re: Previous owner '68

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Originally Posted by clay68c10 View Post
Looking at how clean the valley is on that one, and your cold test results, I'd say it's a runner.
Too late, I couldn't resist tearing it down! I'd hate myself if I didn't.

Pics to come...
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Old Yesterday, 07:17 PM   #304
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Re: Previous owner '68

So, I pulled the heads. I decided to go ahead and put new head gaskets, valve seals, etc. Cylinder are pretty clean, no ridge at all, and still some crosshatch on the bores.

Tops of pistons have carbon, she was running a bit rich. The liquid is Marvel Mystery fluid I used to store engine for the last 20 years.
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Old Yesterday, 07:19 PM   #305
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Re: Previous owner '68

Cleaned tops of pistons with Aircraft stripper, not perfect, but it'll do. By the way, they are .030 over.
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Old Yesterday, 07:23 PM   #306
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Re: Previous owner '68

Main bearings and rod caps look good. I put them back with a bit of assy lube and torqued them down.
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Old Yesterday, 07:25 PM   #307
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Re: Previous owner '68

Crank looked good too.
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Old Yesterday, 07:27 PM   #308
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Re: Previous owner '68

Shop is kinda a mess while I'm doing all of this.
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Old Yesterday, 07:35 PM   #309
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Re: Previous owner '68

Wasn't going to pull the cam but I decided to so I could get some assembly lube on it. I also replaced the cam plug. Not sure what cam is in it. The end was stamped B040A and 891344 which I couldn't find anywhere on the web.

No pic of cam but here's one of the timing chain and the rear cam bearing.
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Old Yesterday, 07:39 PM   #310
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Re: Previous owner '68

Starting on the heads tomorrow. If all looks good I'll replace the valve seals, lap the valves, and reassemble them. They are nothing special, I just want a good running truck.
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Old Yesterday, 08:39 PM   #311
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Re: Previous owner '68

you got busy in a hurry ....nice progress
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Old Today, 04:42 PM   #312
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Re: Previous owner '68

Thanks Zicc!

Finished tearing down the heads. I used a lever type spring compressor my uncle made to remove the keepers.

Clamped the heads down to my table and started levering the springs. Also used a magnetic pickup tool and a pick to remove the keepers.

If you're curious, the heads are 333882 on drivers side and 42624 on passengers side. The intake valves are 1.94" and exhaust is 1.5". Not the best heads, but they will work for me.
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'69 ('70?) 2wd Blazer
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Old Today, 04:46 PM   #313
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Re: Previous owner '68

Tried my best to remove this broken exhaust manifold stud. Basically, an hour of dicking around with the welder. No bueno.

I'm going to take the heads to the machine shop to have them cleaned and the broken stud removed. Sometimes you gotta know when to let the pros do it.

Once I get them back I will lap the valves and reassemble.
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'68 Short step - https://67-72chevytrucks.com/vboard/...d.php?t=849675
'69 ('70?) 2wd Blazer
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Last edited by raggedjim; Today at 04:57 PM.
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Old Today, 04:49 PM   #314
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Re: Previous owner '68

Gonna need a new dampener. Unless you guys have an answer for this.
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Old Today, 04:51 PM   #315
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Re: Previous owner '68

I also disassembled the oil pump out of curiosity. Looked good inside, looks like it is a Melling high volume pump.
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Old Today, 05:11 PM   #316
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Re: Previous owner '68

Quote:
Originally Posted by raggedjim View Post
Gonna need a new dampener. Unless you guys have an answer for this.
I have used this repair kit with great success.

https://www.autozone.com/external-en...4121/76828_0_0

https://www.ebay.com/itm/12656266943...xoCy84QAvD_BwE

Last edited by MySons68C20; Today at 05:14 PM. Reason: missing info
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Old Today, 05:16 PM   #317
raggedjim
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Re: Previous owner '68

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Originally Posted by MySons68C20 View Post
I've heard of those, what is the process? Do you epoxy it to the snout?
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Old Today, 05:27 PM   #318
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Re: Previous owner '68

The kit comes with a red Loctite type stuff....If you buy the bare sleeve I would use red Loctite.
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Old Today, 05:33 PM   #319
raggedjim
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Re: Previous owner '68

Quote:
Originally Posted by MySons68C20 View Post
The kit comes with a red Loctite type stuff....If you buy the bare sleeve I would use red Loctite.
Thanks!
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