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Why Can't I Read English?
by
rs899
on 29 Sep, 2009 16:39
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OK, so I picked up the 91 Jetta NA with 140K miles that was the victim of somebody else's timing belt error.
http://www.vwdiesel.net/forum/index.php?topic=21204.0I got all the pistons out and everything looks OK, except #1 has an s-shaped rod and a really messed up piston. The top end has been rebuilt and is ready to go.
I was going to re-ring and re-bearing the rods after honing the bores.
I read somewhere that Goetze made much better rings than Grant. I put together a nice order for Arizona Autohaus. It came in today.
I goofed. I only bought one piston's worth of Goetze rings. ( website is kinda misleading- the pricing is for Grant Rings in sets for 4 pistons- the Goetze is price per piston. The price is $25 for ONE Goetze piston set and $22 for FOUR Grant piston set
)
I opened the package, so I don't think AZAH will want to take them back, so I either have to buy $75 more of Goetze rings, $22 of Grant rings, or just use what I have on the other 3 good cylinders.
Unfortunately, I have no idea of what this engine was like. If I knew it burned little oil and had good compression, I would probably just fix #1.
Being cheap, had I read the website properly, I would have just bought the Grants from the get go. I hate to put $75 more in an engine that probably will need a rebuild in 100k miles anyway.
Opinions?
Rick
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#1
by
macka
on 29 Sep, 2009 16:50
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jeez it needs a rebuild now, you might as well just drop the coin while its out and apart.
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#2
by
Rabbit TD
on 29 Sep, 2009 17:55
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Get a set of 4 for sure I wouldn't be afraid of the Grant ones and believe me there is nothing wrong with having a spare set for 1 piston on hand. But also do't get disgusted after you rebuild it and it uses a little oil even after it's broken in. These things all use a little oil no matter what you do, I've had 2 of them bored with new pistons and both used at least a quart in 3,000 mi. but it runs 70-75 on the interstate everyday. $22 does seem awfuly cheap though for a set of rings though
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#3
by
maxfax
on 29 Sep, 2009 18:51
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I've been running a set of grant rings in both my cars now.. THey seem to be working just fine.. Actually great for the price.. THe top line rings they replaced were definitly more costly, and complete garbage.. AS Rabbit TD mentioned though, don;t be too disgusted if it does still use a bit of oil not matter what rings you opt for.. ..
Both my Bunnies went from burning a quart every 400 miles to a quart every 2-3K miles after changing rings..
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#4
by
rs899
on 30 Sep, 2009 03:47
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Thanks guys, maybe I'll get the Grants as long as your experience isn't too bad. I am sure it is going to burn some oil anyway with the mileage it has.
Looking at the 3 good pistons, though, I was surprised at how clean they were. The rings on those were very free and there isn't much , if any, coking of the ring lands ( unlike most of the pistons in my parts collections that are really coked up). That's one reason I was just thinking of leaving those alone at this point.
Macka- no the engine is not out. I would certainly do the whole thing right if I did have it out, but its more a question of not wanting to take the time to do it at this point
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#5
by
macka
on 30 Sep, 2009 04:17
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OK, but IMO if you mangled a piston, you may have other damage. I'd either swap out the engine with a known working engine, or do the rebuild. I don't like guessing if the motor will last for 50 seconds or 50 years after a catastrophic failure like that. If you do swap out a known working keep the block for a spare and rebuild it.
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#6
by
rs899
on 30 Sep, 2009 04:30
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What "other damage"? With the possible exception of the crank, ( and I will look at the main bearings at least) I am willing to gamble that investing about $100 in rings/rods/bolts (and a day's work) will get me 50 to 100K miles vs investing closer to $1000 (and a couple of weekends) to get 200K. I just don't get a sense that this engine is that close to worn out based on a lot of 1.6 NAs that I have seen over the years ( including the one in my Rabbit Pickup).
That must also have been the opinion of the deceased machine shop owner who owned this car. The car came complete with a head that he rebuilt and a used piston/rod ( I had a better one). He could have pulled the engine and reworked it himself for nothing but new parts costs...I am just following his lead.
Rick
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#7
by
arb
on 30 Sep, 2009 05:15
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What "other damage"? With the possible exception of the crank, ( and I will look at the main bearings at least) I am willing to gamble that investing about $100 in rings/rods/bolts (and a day's work) will get me 50 to 100K miles vs investing closer to $1000 (and a couple of weekends) to get 200K. I just don't get a sense that this engine is that close to worn out based on a lot of 1.6 NAs that I have seen over the years ( including the one in my Rabbit Pickup).
No way did your crank get damaged from the piston eating the valve... maybe your cam has a crack that might fracture at any time (Did you test it for cracks ? Magnaflux or the chemical crack detection?) I would do the rebuild too, but don't discount your rebuilt engine so much... The last one I rebuilt did not use oil after break-in and went on for another 100K miles until I sold it - still running like new.
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#8
by
rs899
on 30 Sep, 2009 05:22
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Unfortunately (or fortunately) I am going to have to use a mechanical cam on this hydraulic head (unless someone has definitive evidence that it won't work). The original hydraulic cam was left in the leaky trunk for about a year, and several of the lobes are pitted beyond salvage.
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#9
by
arb
on 30 Sep, 2009 05:50
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Unfortunately (or fortunately) I am going to have to use a mechanical cam on this hydraulic head (unless someone has definitive evidence that it won't work). The original hydraulic cam was left in the leaky trunk for about a year, and several of the lobes are pitted beyond salvage.
Great ! So there is no worry about the cam cracking then. All of my IDI's have had mechanical lifters so I have no idea what the differences are for the hydro - Provda.
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#10
by
lord_verminaard
on 30 Sep, 2009 07:45
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Won't work, the lobe circles are completely different for mechanical vs. hydro.
Brendan
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#11
by
rs899
on 30 Sep, 2009 07:59
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Won't work, the lobe circles are completely different for mechanical vs. hydro
Please educate me further. My rough measurements indicate the lobe (non-contact part) are maybe .050" thicker on the mechanical. Is that going to contact the lifters?
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#12
by
Dakotakid
on 30 Sep, 2009 08:52
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I have been running mechanical cams in hydro. heads for literally thousands and thousands of miles...certainly NOT a problem.
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#13
by
rs899
on 30 Sep, 2009 09:01
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I am glad to hear that, DK. I am willing to confirm your experience, but I was hoping somebody can tell me more about hydraulic lifters and cam theory and why having a slightly different cam will matter.
I have 11 vehicles and so far only this one and my old F-100 have hydraulic lifters. I would just as soon use a solid lifter head with any of a pile of good solid lifter cams I have, but the late PO has already reworked this hydraulic one , and it seems a shame to "waste" it
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#14
by
lord_verminaard
on 01 Oct, 2009 09:53
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Welp, I can be wrong. I didn't think you could get a thin enough shim to make the clearances right if you were putting a hydro cam on a mechanical head, but you're going the other way around so I have no idea how that would work.
Brendan