In the same vein of Eric's post, it looks like I have a misfire in the #5 cylinder... I was driving to work the other day and it started getting a bit salty (low vacc., feeling like I lost a cylinder)... Teched it down a bit on
weds. when I had time, valve lash looked good, have spark to the cylinder, though if I pull the plug wire for #5 the idle speed doesn't change/barely changes...)

So when I get some time it looks like I'll be doing a leakdown test, and seeing if I lost the rings, or ??? on that hole...

Talk about rotten timing... I know some people wanted an Hpak ride today too....



I guess if I have to take the head off, now would be the opportune time to have it redone with O/S valves...

Nuts!


-D.Idiot

Guess those hardened seat aren't to hard, eh? Good luck with your lower back while pulling the head...

grand timing indeed.. good luck on fixing it. and those arent all that heavy.. well atleast i think so nah j/p i know those are a back breaker lol. good luck with the fix. maybe people will settle for a not so hyper pack ride lol lol

Looks like...

Dry comp test:
cyls 1-6

165
165
180
178
40
180

Wet Test:
Cyls 1-6
180
180
200
195
40
210


looks like I've got some slightly worn rings, and one cylinder to leak test....

If it's the valves, and I'm pulling the head... it's time to put those O/S valves in....


-D.Idiot

It's interesting that this showed up kind of all of a sudden. I've had rings break and show up suddenly, but the valves usually go a little at a time. Look on the bright side. The head is an easier fix than the short block overhaul, and you got two pistons with perfect rings. And, you can now put in those oversized valves. At least you can leave the manifolds on until the head is off. You won't have to practice the sorcery usually needed to get the manifolds off and on.

Get some help lifting that head off. It just might be the heaviest passenger car head ever made. A think the Buick straight 8 was a flat head, which would have made it much lighter. Most of the other inline heads I can think of are aluminum. Maybe an old I-6 Ford, or I-6 Chevy is as heavy. Anyway, don;t be a hero, take care of your back, and good luck.

Sam

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hook an engine lift to it. I used mine the other day to change blades on my riding mower.

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'72 Duster 198 stock cam, 3:23's Hookers on jack stands for 8 years in the driveway
'79 Maxivan 360 Offy Qjet Comp RV cam/rusting in the driveway.
93 D350 160HP Cummins Auto Dually Clubcab needs a injector pump
2005 Golden Couch Buick

I can't say on that, but I will not pull a intake manifold off a Ford FE (332, 352, 390, 428, etc) motor by hand. Always with a hoist.

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Charrlie_S
65 Valiant 100 2dr post 170 turbo
66 Valiant Signet 170 nitrous
64 Valiant Signet
64 Valiant 4dr 170
64 Valiant 4dr 225

I remember reading a performance article comparing the 383 to the 390... it was interesting to see in stock cast iron form the 383 was about 65 lbs lighter than the 390... and when they went to tear it down and compare weights... a fair amount of the difference in weight was the intake manifold...


Having pulled the head and stack wholesale at a wrecking yard and huffing the assembly up to the desk... I think a buddy or using the hoist is the key... I have to get my buddy over anyway since he has the leak down tester, and the valve grinder...



-D.Idiot

That's because the intake makes up half the heads too. The heads are pretty light though.

I used to help a buddy race a 427 Fairlane. He took almost 100 pounds off the nose by switching to an aluminum intake.

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Official Cookie and Mater Tormentor.

It doesn't sound too bad....

So far it looks like the #5 exhaust valve is the culprit... leakdown test was very audible through the rear bank tailpipe, no leak in the intake or crank case....

so head has to come off, and we'll also get to see if anything else got blow torched (probably unplated the tin on the piston... actually while checking for tdc on that piston the probe came back out of the hole with some nice black carbon on it....)

Time to dig out those O/S valves....

-D.Idiot

They look like the same readings I had in my '78 1/2 ton. Culprit ending up being #5 exhaust valve. Never saw one so badly burned. Did a reworked head w 3 angle valve job. What a difference. And yes that head is heavy and askward even w/o the manifold. Probably easier in a car just due to it being closer to the ground. Mike

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Good gun control is hitting your target repeatedly

Pulled everything off the head (it wasn't as bad as I thought... but I'll put the manifolds back on the head before installing it so I know they are sealed nicely....)... pulling the head wasn't too bad, it was just fun to do it without pulling the rocker bar and leaving the pushrods in place....

Post mortem in the bores... all pistons are intact, the bores are a bit shiny, there is no real ridge, but there is a ring of carbon at the top of the bores... the piston faces are a little black but you can still read plain as day the numbering/overbore size on the faces and no holes...

The chambers are all nice can clean, with some typical discoloring on the valves... this weekend I'll pull the valves to see if any of the seats are toast, and definately look at #5.....



more soon,

-D.Idiot

Progress!

Sam

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post mortem looks like, most of the 'number' problem is due to wear of the seating surface on the valves... all of them show signs of deteriorating, and the #5 was the first to go... the seats are intact and in great shape, the pattern of seating on the valves themselves was not good, and it looks like the keepers are hammered... oddly the bronze guides are in perfect shape (and really tight too)...

Time to pull out those SI O/S valves and redo the seats....abused and 53K on the clock isn't bad for how much this poor thing's been hammered...

-D.Idiot

Do you have hardened seats in those heads? It is suprising that you lost that much compression on # five so suddenly, and there was no burning. Was the valve burned at all?

Sam

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