1985 V8-S10 Blazer

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TireSmoker
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Re: 1985 V8-S10 Blazer

Post by TireSmoker »

These are newer centerbolt valve covers. I dont have any crappy ones. The mess would be annoying, but I could deal with it if it fixed the issue.

Dont think I cracked a plug -- they didn't go in till after the engine was installed. As mentioned, all 4 on the driver's side look very consistent, which I think is good. I'll try to post a pic tomorrow. Upon further inspection, the gap might be a little tight judging by eye. I'm gonna check that tomorrow.

Intital timing is somewhere around 15-18. Running around 22 with vacuum advance (at idle). I unhooked the vacuum advance, spun it up over 3000 and made sure the timing was in the low-mid 30s. I put 5k miles on the engine last year with this distributor, and it was good enough for mid 13s in Tony's motor a couple years ago. Mechanical advance is good and free -- verified when I changed cap/rotor this afternoon.

I need to get a vacuum gauge hooked up and see if the needle is bouncing.

-Dave
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Re: 1985 V8-S10 Blazer

Post by Maverick »

https://www.summitracing.com/parts/cal- ... /chevrolet

Cut the tops and set the idle as low as possible. No mess no mas.
Maverick
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Re: 1985 V8-S10 Blazer

Post by TireSmoker »

No compression in #3. I backed off the exhaust valve a little bit, and it registered maybe 10 psi. #1 read around 85, and #2 was 90 (other head). I guess I won't be driving it to Carlisle. Bummer.

-Dave
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Basement Paul
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Re: 1985 V8-S10 Blazer

Post by Basement Paul »

Major bummer.

-BP
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Re: 1985 V8-S10 Blazer

Post by MostMint »

I was hoping for something simple. Can you tell if this is the cam, lifters, valves or rings?

I'm guessing from the tone here the cam is #1 followed by a lifter at #2
[quote="Basement Paul"]Is that a mint rocketship on the hood?? :shock:
-BP[/quote]
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Re: 1985 V8-S10 Blazer

Post by Maverick »

Smoker,

Hate to beat a dead horse, but I'd check the easy stuff first. The fact that you got some compression when you backed off on a lifter makes me think it could be just valve adjustment. Really think you should try adjusting the valves with the engine running.

Or, if you have a nipple for the spark plug hole-to-air quick connect you could find the leak. We found the tight valve on the Lincoln by using WXO's tool. Put a cylinder with low compression at TDC between compression and power strokes. Put air pressure on the cylinder and listen for air escaping out the carb, tail pipe, or oil fill. You'll then know where the compression is going.
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Re: 1985 V8-S10 Blazer

Post by TireSmoker »

I'm doubtful it is the rings. This thing ran just fine all last year. I've put around 5k miles on it since I bought it. When I was doing the compression check, I had the driver's side valve cover off -- I can see the #3 valves opening and closing. I haven't measured their lift, but I see them moving. After I got 0 the first time, I did back the valves off, wondering if they were still tight, to just a hair beyond 0-lash (ie-- just ever so slightly loose), thats when I got the 10-ish reading. I

I should probably be clear about one thing, not sure if I mentioned it earlier in the thread-- I don't know much about these heads. I bought a Vortec 350 a year or two ago for these heads. I got the whole thing for $100, but it was cheap because the bottom end was bad. The heads looked fine, visually, but I never had them checked out. I never saw them run. I installed new springs and valve seals on them and that was it. In hindsight, I should've had them inspected.

I guess I should head out and drain the oil to see what I can.

-Dave
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Re: 1985 V8-S10 Blazer

Post by TireSmoker »

A little bit of debris. Looks like a couple wires from a wire brush?? But overall, not bad? I should cut open the oil filter, but my tin snips aren't getting the job done.

Got one of these on its way (been wanting one since troubles with my old 406)
https://www.summitracing.com/parts/sum-900510

-Dave
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wxo
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Re: 1985 V8-S10 Blazer

Post by wxo »

Hey Dave, if you decide to follow Maverick's advice to adjust the lifters while running, (and I encourage you to try it), I have a tip that should help you contain the oily mess. I've used it in the past with some success. The idea is to make a larger lip on the bottom of the head below the rockers to help the oil drain back into the head as it overflows the lower lip. Remove your valve cover and get some aluminum flashing and cut a length to fit across the bottom and part way up each side of the head lip. Tuck the strip of flashing inside the bottom lip on the head and it will direct any splashed or overflow oil back into the head. I've done this on the older style four bolt valve covers, but not on the center bolt style, but the concept is the same.
We really would like to see this project in Carlisle, so get crackin'. :mrgreen:
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Re: 1985 V8-S10 Blazer

Post by TireSmoker »

I probably will try to do the running valve adjustment -- its easy and there's nothing to lose at this point. I'd *really* like to drive this thing to Carlisle and I have a couple other options to get it back running, but the clock is ticking.

-Dave
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Re: 1985 V8-S10 Blazer

Post by GMJohnny »

I'd try the valve adjustment like mentioned above. When we diagnose machines
at work, we ALWAYS do the easy stuff first, and work our way to the most difficult.
I've seen valves stuck open on small machines, broken rocker arms, rocker arms off of
push rods, bent push rods, bent valves, etc., etc.... You can always rip the heads off and have them
checked or whatever, but you owe it to yourself to do this step before going to that drastic
step. One step at a time. You never know what you might find. Maybe something stupid
will show up while you are working.

GM
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Re: 1985 V8-S10 Blazer

Post by TireSmoker »

Well, I did the running valve adjustment -- no real change. I haven't redone the compression test, but I can still feel the same puf-puf-puf on the drivers side exhaust and it's still not smooth.

I guess I'll pull the intake first and see if I see anything obvious with the #3 lifters. I don't expect that I will. If the problem lies with the heads, I will probably pick up a set of these: https://www.summitracing.com/parts/sum-151124/overview/ They are only $20 more per head than the stock Vortec heads (https://www.summitracing.com/parts/nal- ... /overview/) and already have upgraded springs to accomodate my cam.

On the plus side, my filter cutter showed up and I cut open the break-in filter and I see nothing in there.

The one thing I do like about this truck, it's easy to work on. All the plugs are pretty easy to reach, the header bolts aren't bad. Also, since the engine compartment is so small, everything is an easy reach.

-Dave
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Basement Paul
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Re: 1985 V8-S10 Blazer

Post by Basement Paul »

Yeah, by the time you pay for a valve grind on your existing heads, these will already be installed, and not a lot of cost savings. I guess once you realize your push rods are all straight, your lifters look good, and your cam is still lifting them all up and down the right amount, it's time to order them up. Seems like a bargain for 1.94 vortec heads that are built with real tornados inside.

-BP
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Re: 1985 V8-S10 Blazer

Post by TireSmoker »

Pretty sure I checked the pushrods for straightness before I assembled it. Rolled them along a piece of glass.

Drained the water out of it tonight. I'll get some disassembly done tomorrow and/or Friday. I'll probably end up skipping the TRP opener on Saturday.

Basement Paul wrote:Seems like a bargain for 1.94 vortec heads that are built with real tornados inside.
I hope they are 13 second tornados. :lol:

-Dave
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Re: 1985 V8-S10 Blazer

Post by Basement Paul »

Since they're closed on Saturday, I could lend a hand on Saturday AM if you're not doing house stuff.

-BP
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