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 Post subject: Why is Darth still sick? :(
PostPosted: Mon May 02, 2011 9:30 pm 
Haha, I just built a W24 Octo-Turbo, now what?!
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Joined: Wed Dec 21, 2005 7:14 pm
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Location: Missing my garage in Sunnyside
:(

Finally got the 945 running on the weekend. I'll post up the epic tale when I have more time. For now, i need your collective noodle power to help me figure this out.

Before:

Blown head gasket (#1 fire ring toast)
Used coolant, lots of blowby (crankcase pressure), lack of low end, bumpy idle.
vacuum at idle: ~16inHg
Compression:
1: 125
2: 135
3: 155
4: 155

After:

New head gasket, rebuilt head, V-cam, block mount distributor.

Not using coolant (yay!), still blowby (wtf), lack of low end (worse!), bumpier idle. Ok, I know the v-cam won't help low end, or idle necessarily, but shouldn't be that much worse...
Vacuum at idle: 11in HG
Just did compression test:
1: 128 (yay!)
2: 140 (ok, v-cam probably)
3: 140 (ok)
4: 100, ONE HUNDRED. W-T-F.

carbon in the rings when i cleaned the pistons? what else? HEEEELLLPPPP!!!

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 Post subject: Re: Why is Darth still sick? :(
PostPosted: Mon May 02, 2011 9:54 pm 
Haha, I just built a W24 Octo-Turbo, now what?!
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Joined: Wed Dec 21, 2005 8:40 pm
Posts: 3492
Location: Calgary, Ab
Ugh.

Blowby ain't gonna change due to a head gasket change - you did nothing to the rings, and that's the only thing between you and blowby.

Cranking compression is a result of IVC position. V and T are apples and oranges. Also, a couple thou valve lash means lots and lots of difference in IVC. In my measurements of the B280, each thou was something like 2 degrees of IVC. Be sure you've got your valve lash right before trusting a compression test. Try a leakdown to know if/where it's leaking.

I say put the T back in and see how it runs. Compare apples to apples.

Edit - what springs did you end up using?


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 Post subject: Re: Why is Darth still sick? :(
PostPosted: Mon May 02, 2011 11:56 pm 
Haha, I just built a W24 Octo-Turbo, now what?!
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Joined: Wed Dec 21, 2005 7:14 pm
Posts: 1875
Location: Missing my garage in Sunnyside
I used the aftermarket springs I got from you.

Valve clearances all set 15-16 thou, rechecked after a couple of heat cycles.

I realize you can't compare T and V, but the numbers should still be consistent.

Cyl one came up, as expected without a broken fire ring. I expect some blowby from there, as its probably had a coolant wash for some time so the bores won't be great.
Cyl two came up, even with 3, probably where they should be if 3 was healthy at 155 with the T cam.
Cyl 4 used to be identical to 3, so I would expect it to be 140, but it's 100. Blowby seems to be as bad, or worse, so it's mostly coming from 4 now.

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 Post subject: Re: Why is Darth still sick? :(
PostPosted: Tue May 03, 2011 7:11 am 
Haha, I just built a W24 Octo-Turbo, now what?!
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Joined: Wed Dec 21, 2005 8:40 pm
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Location: Calgary, Ab
Well if you want to, bring it over this weekend and we'll blow into the cylinders & see where it comes out. Were the piston tops all carboned up when you cleaned them? It might be possible that you jammed a a ring full of it, since I presume you don't have a compressor to blow them out afterwards. Not much to be done about it now.

I would still pop the T cam in to see if that tightens up the compression, though. The V might be worn all funny (I don't remember if you used it before) and is holding open #4 intake a bit longer than the others. Don't suppose you spun all the valves after they were tipped, to see if one got dropped & bent, did you?

If you say it's got more blowby than before, then yes you may have clogged a ring or something like it. I suppose the remotest chance exists that your head gasket is leaking, bypassing all the coolant passages around #4, and going right to the oil return hole, but I sure wouldn't lay money on it.


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 Post subject: Re: Why is Darth still sick? :(
PostPosted: Tue May 03, 2011 7:13 am 
Haha, I just built a W24 Octo-Turbo, now what?!

Joined: Wed Dec 21, 2005 8:03 pm
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Location: T2C
Throw a can of Restore in it and go on a road trip to Edmonton or somewhere...somewhere where it will be up to operating temperature for a couple of hours. Provided it's bores that are the issue, it can't do any (more?) harm...

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 Post subject: Re: Why is Darth still sick? :(
PostPosted: Tue May 03, 2011 8:33 am 
Haha, I just built a W24 Octo-Turbo, now what?!
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Joined: Wed Dec 21, 2005 7:14 pm
Posts: 1875
Location: Missing my garage in Sunnyside
The pistons weren't carboned up too bad. Just a thinnish layer that I gently scraped and wiped off. I'm sure some chunks got down around the rings, but I soaked the bores with wd40 several times, carb cleaner, cycled the pistons and wiped them down to clear up as much as I could.

Appart from the cam noise the first time I fired it up, the car is running the same, same vaccum, etc, so unless I buggered up both head gasket swaps the same, I'm putting it down to something else.

Now you're getting me paranoid that it's a valve not sealing...didn't spin the valves no, but didn't notice anything funny when I kept pulling and inserting them when doing the springs.

Was thinking about doing the restore thing too, but ya, leakdown next.

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 Post subject: Re: Why is Darth still sick? :(
PostPosted: Tue May 03, 2011 11:44 am 
Haha, I just built a W24 Octo-Turbo, now what?!
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Joined: Wed Dec 21, 2005 7:14 pm
Posts: 1875
Location: Missing my garage in Sunnyside
Further thoughts.

If there is a problem with the head, it isn't from the springs, or tipping the valves or any of that. I can't say conclusively of course, but given that the car didn't seem to run any differently between the first headgasket, and the second after the extra machining and new parts, i would think the issue must be related to:

1) cam, though it looks ok, it would have to be pretty messed to give 40% lower compression on the one cyl. I will swap back to T though.
2) problem with the head rebuild, valve grinding.
3) something with the #4 rings, or lack of sealing on the #4 fire ring.

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 Post subject: Re: Why is Darth still sick? :(
PostPosted: Tue May 03, 2011 1:14 pm 
Haha, I just built a W24 Octo-Turbo, now what?!
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Joined: Wed Dec 21, 2005 7:14 pm
Posts: 1875
Location: Missing my garage in Sunnyside
aaaaand another update.

Ran home to grab the car with the rain coming in. What's that...a nice big puddle under the car. sweet.

Didn't have the time, or the heart, to investigate further. At this point, with the luck I've had so far, I'm inclined to guess it's the RMS as that's the only one that I haven't had to replace yet.

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 Post subject: Re: Why is Darth still sick? :(
PostPosted: Wed May 04, 2011 8:50 am 
Haha, I just built a W24 Octo-Turbo, now what?!
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Joined: Wed Jun 14, 2006 4:19 pm
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Location: Lethbridge, AB
Wow, sorry I missed all this yesterday. You did mark the valves for each cylinder right? It's sort of hard to know how to diagnose this problem from here over the interwebz. Providing the valves were replaced in the right holes, each valve was hand lapped for that seat and all were sealing when I last had them.

The puddle is coming from the RMS? WTF is up with that - have you had this issue before or is it new? Cleaning the carbon can alter the compression on a compression test, but I agree with Matt, leak it down and figure out what's up. How did the bores look when you had the head off?

Warmer weather is coming...perhaps a set of Deves rings and a bottle brush rebuild is in order (last thing you wanted to hear).

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 Post subject: Re: Why is Darth still sick? :(
PostPosted: Wed May 04, 2011 9:37 am 
Haha, I just built a W24 Octo-Turbo, now what?!
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Joined: Wed Dec 21, 2005 7:14 pm
Posts: 1875
Location: Missing my garage in Sunnyside
See my "further thoughts" post above, I'm 99% sure no problems were introduced by me or the shop I had tip the valves. The car ran crappy with the first gasket I tried, and no noticeable difference the second time (after I'd dis-assembled the head and tipped the valves). No way to be 100% sure of course.

Spent some time under the car with it running last night, and for the life of me couldn't figure out where the oil is coming from. It wasn't visually leaking in the garage, so it must be happening under load. Seems to be spraying from somewhere and dripping down the downpipe and engine. It doesn't seem to be the RMS.

Next step is to clean it up and check again, and do some leak down testing. At this point, yanking the motor and doing a re-ring (and getting the RMS while I'm at it) seems easy compared to the last 3 weeks. Bores *looked* fine, cross hatch still visible.

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 Post subject: Re: Why is Darth still sick? :(
PostPosted: Wed May 04, 2011 5:51 pm 
Haha, I just built a W24 Octo-Turbo, now what?!

Joined: Wed Dec 21, 2005 8:03 pm
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Location: T2C
Sounds like the rear seal on the head is leaking and running down the back of the block. What did you put in there when you took out the distributor?

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 Post subject: Re: Why is Darth still sick? :(
PostPosted: Wed May 04, 2011 6:46 pm 
Haha, I just built a W24 Octo-Turbo, now what?!
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Joined: Wed Dec 21, 2005 7:14 pm
Posts: 1875
Location: Missing my garage in Sunnyside
The stock plug, it's sealing well. Jade took the car for a short drive last night, and there are just a few toonie sized drips today.

I'm suspecting its a pressure related leak, which is sorta good, I guess. I opened it up once on the way home the other night and the next day the puddle was there so it may be the turbo feed, or drain, or something like that, leaks with more RPM.

Man, you and I are having sh!t for luck with our cars lately, eh Dale?

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 Post subject: Re: Why is Darth still sick? :(
PostPosted: Wed May 04, 2011 7:40 pm 
Haha, I just built a W24 Octo-Turbo, now what?!
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Joined: Thu Dec 29, 2005 12:29 am
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Crappy to hear about this Athal. Hope you can get it all sorted soon.

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 Post subject: Re: Why is Darth still sick? :(
PostPosted: Thu May 05, 2011 10:32 am 
Haha, I just built a W24 Octo-Turbo, now what?!
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Joined: Wed Dec 21, 2005 7:14 pm
Posts: 1875
Location: Missing my garage in Sunnyside
Giving it a good clean to check for leaks again, and maybe limping it to Matts or buddy Craigs for leak testing tonight.

Is there some chance there's a problem with the block deck that is keeping the #4 from sealing and allowing oil to leak out the back corner of the head? Can that happen and still have good compression on #3 cyl and not be leaking coolant everywhere at the same time?

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 Post subject: Re: Why is Darth still sick? :(
PostPosted: Thu May 05, 2011 10:52 am 
Haha, I just built a W24 Octo-Turbo, now what?!
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Joined: Wed Jun 14, 2006 4:19 pm
Posts: 3131
Location: Lethbridge, AB
swedishmeatball wrote:
Giving it a good clean to check for leaks again, and maybe limping it to Matts or buddy Craigs for leak testing tonight.

Is there some chance there's a problem with the block deck that is keeping the #4 from sealing and allowing oil to leak out the back corner of the head? Can that happen and still have good compression on #3 cyl and not be leaking coolant everywhere at the same time?


Given the design of the coolant/oil passages I would say that it is unlikely as the pressurized oil comes up between cylinders 1 and 2 and there is no return path past 3/4.

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