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scheides
10-02-2007, 10:44 PM
Ok guys, the 6-bolt on my bro's 90 talon had 0 compression on cyl #2 (full results: 100-0-100-110). The block has 190k miles on it so we figure its time to do new rings and bearings, maybe new pistons a bore, not sure.

So tonight we yank the head off (thanks for the help Allan!) and sure enough the head gasket is blown out on cyl#2 and the head has a good gouge out of it. The spark plug from that cyl had a chunk missing from it, so it could have been caused by that, or possibly an overboost (ebay mbc FTL!) So we're pretty sure the head is crap, not a big deal as we have a rebuilt head ready to rock.

The cyl walls look pretty good all the way around, plenty of cross-hatching and the tops of the pistons look to be in decent shape. Cyl #1 either has a weak injector or something as it looks like it has been running a little hot. Other than that everything looks good.

So my question is, is there a way to check and see how good of shape the rings are in w/o pulling them out? The cyl wall clearance on all cyl's looks identical to the naked eye, all pistons in decent shape. We're considering putting on a new head gasket, a set of arps, and a rebuilt head and seeing how she runs. Is this a bad idea? Any other ideas?

b00stcreep21
10-02-2007, 11:13 PM
I can't really think of a way to check out if the rings are fine w/ the head off, w/o pulling everything apart and measuring gaps. I'd toss the new gasket and head on, do a comp/leakdown test, and rock it

JET
10-03-2007, 02:36 AM
Yeah, toss the new head on and turn up the boost to make up for the lower compression :D

Goat Blower
10-03-2007, 09:25 AM
Cup your hand around the cylinder and blow as hard as you can into your hands, if you hear whistling through the dipstick hole, your rings are bad. :nod:

Or just slap a good head back on and you're on your way. Rings rarely go bad in just one cylinder unless you had a massive injector leak washing down that cylinder. Sounds like everything's fine.

MustGoFaster
10-03-2007, 12:16 PM
Put it together and run it. Back in the day John made his 309 FWHP with 105 compression and an 18G type thing.

AJ
10-03-2007, 12:52 PM
Chris, we talked last night and I think you got the back-up here. Get the goodies for the new head on and we could have that beast back on the road next week.

scheides
10-03-2007, 01:02 PM
Sweet! Thanks for the input guys, we're gonna take a closer look at they cylinder walls today in the daylight, but I think for the moment we're gonna do a full timing belt job on it (water pump et all) and put together a new head...we have one machined and ready to go, just need to yank the springs and retainers off of the old head...the old valves look like junk, can they be cleaned up? Going to get new valve-stem seals and toss in a set of comp cams I picked up from swifty back in april, then we'll see if this thing moves again! Maybe we'll have it ready for the dyno day.....

I actually have high hopes that the new head will actually bring compression up to 130-ish across the cyls....

niterydr
10-03-2007, 02:20 PM
I already told you guys the answer to this question yesterday on the phone with allan.

LET ER BUCK.

turbotalon1g
10-03-2007, 02:26 PM
low and uneven compression rocks, i have nothing good to say.

scheides
10-03-2007, 03:23 PM
I already told you guys the answer to this question yesterday on the phone with allan.

LET ER BUCK.

I know, just looking for more opinions, and I definitely have them! Thanks man!