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Intake have to be on for a compression check?
#1
The intake manifold doesn't have to be on in order to do a compression check right?

I just tried to do a compression check on the #8 cylinder and the gauge never moved!  Stuck or bent valve not closing???

Thanks!
Wade
1972 Mach 1 351 cj 4speed
"We confide in our strength, without boasting of it; we respect that of others, without fearing it."--Thomas Jefferson

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#2
Intake manifold does not need to be on. Pull the valve cover, if the valve is stuck open that rocker arm will be loose when the valves should be closed on #8. It really doesn't matter now what is causing it, the head will have to come off. A bore scope may show you what the problem is.

I assumed you checked for bent push rods, already.



“If you can't explain it simply, you don't understand it well enough.”
--Albert Einstein
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#3
(11-10-2018, 04:54 PM)Don C Wrote: Intake manifold does not need to be on. Pull the valve cover, if the valve is stuck open that rocker arm will be loose when the valves should be closed on #8. It really doesn't matter now what is causing it, the head will have to come off. A bore scope may show you what the problem is.

I assumed you checked for bent push rods, already.

Ive decided to pull the whole motor.  Im still going to do a compression check on all cylinders to get some baseline numbers.  Im betting that #8 has had water sitting in it for a while.  Hopefully the cylinder isnt pitted and I can just hone it out.  Going to inspect the bearing and rings and may replace them too.  How do I tell what size the rings and bearings are?  Are the sizes stamped on them?

Thanks!
Wade
1972 Mach 1 351 cj 4speed
"We confide in our strength, without boasting of it; we respect that of others, without fearing it."--Thomas Jefferson

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#4
Bearings will have a stamp on the back side. Rings are determined by piston and bore size. Oversize pistons have the oversize stamped on the crown. such as " + .030 ". You may need to wire brush the to of a piston to find it.

If you have never taken apart or rebuilt a V-8 before, stop where you are and get this book. It'll guide you through the disassembly process.

https://www.amazon.com/Rebuild-Big-Block...rd+Engines


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#5
(11-12-2018, 09:02 AM)Hemikiller Wrote: Bearings will have a stamp on the back side. Rings are determined by piston and bore size. Oversize pistons have the oversize stamped on the crown. such as " + .030 ". You may need to wire brush the to of a piston to find it.

If you have never taken apart or rebuilt a V-8 before, stop where you are and get this book. It'll guide you through the disassembly process.

https://www.amazon.com/Rebuild-Big-Block...rd+Engines

+1 good guide. Also take plenty of pics and bag and tag everything!!! Even if you are going to replace that with new still bag and tag as it can make a good reference when reassembling. Also CLEAN CLEAN CLEAN work area is a must!

73 Grandé H Code. Headman long tube headers, T-5 Transmission, 3.70 Traclok, Lowered 1" all around, Aussie 2v heads w/ 2.19 intake, 1.71 exhaust, screw in studs, full roller cam 608/612 lift 280/281 duration LSA 112, Quick Fuel 750 CFM double pumper, AirGap intake.

- Jason


[Image: 082-hot-rod-power-tour-2017-1970-1970s.jpg]
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#6
I have tried to replied to this thread "suggesting" that the rings on 8 are probably stuck! NOW that I see you are pulling - my guess is that is best and hopefully all you will have to do is clean up (if indeed just rebuilt) even pads, ATF and moly lube will work. HOPEFULLY you didn't break a ring - but if all you have to do is get rings and bearings you got off easy

Mark
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#7
(11-12-2018, 09:02 AM)Hemikiller Wrote: https://www.amazon.com/Rebuild-Big-Block...rd+Engines

Thanks!  I bought the book this morning.  I have built a BB chevy on my own so as long as its the same premise I will be fine.

Thanks!
Wade
1972 Mach 1 351 cj 4speed
"We confide in our strength, without boasting of it; we respect that of others, without fearing it."--Thomas Jefferson

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#8
(11-13-2018, 11:32 AM)scgamecock Wrote:
(11-12-2018, 09:02 AM)Hemikiller Wrote: https://www.amazon.com/Rebuild-Big-Block...rd+Engines

Thanks!  I bought the book this morning.  I have built a BB chevy on my own so as long as its the same premise I will be fine.

they are not quite the same as there are a couple nuances that differ in the clevo, plus if you plan to rev it high, you should consider doing the oil mods and maybe lifter bore mods.
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#9
(11-14-2018, 12:25 PM)barnett468 Wrote:
(11-13-2018, 11:32 AM)scgamecock Wrote:
(11-12-2018, 09:02 AM)Hemikiller Wrote: https://www.amazon.com/Rebuild-Big-Block...rd+Engines

Thanks!  I bought the book this morning.  I have built a BB chevy on my own so as long as its the same premise I will be fine.

they are not quite the same as there are a couple nuances that differ in the clevo, plus if you plan to rev it high, you should consider doing the oil mods and maybe lifter bore mods.


What oil mods and lifter bore mods?  I doubt it will ever see over 6500 rpm's but the oil mods may be a good idea anyway.  Is there an article on how to do the mods?

Thanks!
Wade
1972 Mach 1 351 cj 4speed
"We confide in our strength, without boasting of it; we respect that of others, without fearing it."--Thomas Jefferson

  Reply
#10
(11-15-2018, 12:13 PM)scgamecock Wrote:
(11-14-2018, 12:25 PM)barnett468 Wrote:
(11-13-2018, 11:32 AM)scgamecock Wrote: Thanks!  I bought the book this morning.  I have built a BB chevy on my own so as long as its the same premise I will be fine.

they are not quite the same as there are a couple nuances that differ in the clevo, plus if you plan to rev it high, you should consider doing the oil mods and maybe lifter bore mods.


What oil mods and lifter bore mods?  I doubt it will ever see over 6500 rpm's but the oil mods may be a good idea anyway.  Is there an article on how to do the mods?


i will post it as soon as i can . they also have it on the pantera site and maybe tim meyers site. i posted it on this site a while ago but you might not find it with the search engine.

i would also consider a 1 piece rear main seal if you want to be guaranteed that the rear seal will not leak at all.

http://351c.net/board/index.php?/topic/4...main-seal/

https://www.youtube.com/watch?v=GWnrgKM_wBo

.
[Image: rear_seal.thumb.jpg.1d893d8dd8020439bdaf...542d51.jpg]

.
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