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-   -   Scope pics of the motor, time to rebuild? (https://67-72chevytrucks.com/vboard/showthread.php?t=809846)

rechinca 07-30-2020 01:06 AM

Scope pics of the motor, time to rebuild?
 
5 Attachment(s)
So I have the motor on a stand while I am going through my rebuilding of the front end. I finally took the time to run my scope through the cylinders. Granted it was kind of spur of the moment change in plans to pull the engine/trans so no compression or leak down test. HOWEVER...I am not encouraged by the pics you will see. Lots of carbon, what looks like a way too clean cylinder (head gasket issue I think), another with a possible burnt valve and some scoring. What do you think?

rechinca 07-30-2020 01:12 AM

Re: Scope pics of the motor, time to rebuild?
 
And for info, the block checks out to a 1972 A-body 165 HP 350. Best guess from the info on the block, it’s a 1972 2 bolt main from a Monte Carlo with an Edelbrock Performer I take and a 600cfm Edelbrock carb.

Ironangel 07-30-2020 06:20 AM

Re: Scope pics of the motor, time to rebuild?
 
Run it!

Davidf 07-30-2020 08:29 AM

Re: Scope pics of the motor, time to rebuild?
 
LS time

rechinca 07-30-2020 09:44 AM

Re: Scope pics of the motor, time to rebuild?
 
Iron, I like your style. If it were still in the truck it would definitely get run!

David, I want to do an LS and have that OD, but something about the old school 3 OTT makes that hard to do. That is why I went with this truck as it was the color combo I wanted AND 3OTT. Although doing it now would be a huge advantage. Easy to explain to the wife for sure.

Ol Blue K20 07-30-2020 09:49 AM

Re: Scope pics of the motor, time to rebuild?
 
How did it run before you pulled it?

68 P.O.S. 07-30-2020 09:54 AM

Re: Scope pics of the motor, time to rebuild?
 
I love 3OTTs too. I'd get one if I could. I'd really like to run a 5OTT like my old Nissan shop trucks had.

HO455 07-30-2020 01:17 PM

Re: Scope pics of the motor, time to rebuild?
 
I'd run it. Borescope pictures can be deceiving unless you have used one a lot. It your concerned do a leakdown check. Then you'll have more information before putting the squeeze on the wallet.

gmc684x4 07-30-2020 01:47 PM

Re: Scope pics of the motor, time to rebuild?
 
Have you ran this motor any smoke does it use oil ?
Did it run good ?

I have done this several times and drove it like i stole it for several years

If it ran good run it and start saving up for a ls upgrade and drive your truck in the mean time

I am more likely to rebuild a ls motor now then a gen 1 350

In my two trucks i am working on i am putting gen 1 rollercam 350s because i have them and they run well

weim55 07-30-2020 01:56 PM

Re: Scope pics of the motor, time to rebuild?
 
All of the pictures you posted of that cylinder look excellent actually. But that is just one cylinder. If you were satisfied with the way it ran before it was pulled do a quick compression check and if it passes reseal it so it doesn’t have any oil leaks, put it back in and go. As rebuild parts in the supply chain become more and more iffiy, and good machine shops becoming more and more difficult, I advise people to stay away from rebuilds if it all possible these days.

Steve weim55 Colorado

rechinca 07-30-2020 03:40 PM

Re: Scope pics of the motor, time to rebuild?
 
Thanks for the info guys. I should have specified a bit more. There were across several cylinders. As far as how it ran before I pulled it, it’s been sitting stationary for about 2 years! (Truck abuse and neglect I know!). As I recall, it started and ran decent but I bet I had 150 miles or less on it when ****e repair jobs by idiots made it a safety concern. Think I am going to just clean it up, new rear seal, oil pan gasket, timing chain/cover gasket and send it. I have the gaskets on hand in a trade with a friend so for that stuff I am not out money. Trans is getting new bearings and seals while it’s out.

Just to add insult to injury, found the starter had a broken ear, one bolt tight, one just laying through the bellhousing into the broken ear, and the third was missing because the bottom ear in the bellhousing was broken. Did have an almost new clutch but it was a smoked flywheel. That is at machine shop hoping to be found usable after a little grind. Just one more thing to repair.

Good news is I have a complete bellhousing attached to a 3 speed with a Hurst Indy floor shifter attached and another bellhousing with the fork attached still in my shed from a parts score last year.

AllGoNoShow 07-30-2020 04:29 PM

Re: Scope pics of the motor, time to rebuild?
 
Last year I replaced the top half of a 350 in my camaro (rebuilt 20 years ago) that had been sitting for several years (has about 25k on it). Your cylinders and carbon deposits look better than mine did and once I got mine all back together and running it didn’t smoke or leak or anything.

You won’t know for sure until you run it, but everything looks pretty good to me. SBCs are remarkably resilient.

57taskforce 07-30-2020 04:54 PM

Re: Scope pics of the motor, time to rebuild?
 
Run it. The bores in mine are ridged pretty good and it still runs good, no oil consumption. I pulled the heads and had a ridge deep enough to hook with my finger nail. I didn’t touch it other than a complete reseal because my longer term project is a 6.0 swap. I don’t regret my decision at all. If the compression/leak down are decent and it’s got oil psi, send it.

BigBird05 07-30-2020 08:26 PM

Re: Scope pics of the motor, time to rebuild?
 
As a daily driver just drive it. Anything more and it needs a rebuild.


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