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| What do to to the lower end while the head is off. https://slantsix.org/forum/viewtopic.php?t=67517 |
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| Author: | CraziFuzzy [ Sun Nov 26, 2023 7:33 am ] |
| Post subject: | What do to to the lower end while the head is off. |
I've got a new to me 170 in my daughter's recently acquired A100. I don't have any history on the engine, but am going over things to make sure it'll be as reliable as reasonable for her. I know the engine isn't original to the van (1967 van, code on the block is 1965), and there are signs that some work has been done over it's life. In any case, it was missing consistently, so I ran compression test and #1 had nothing, and an even 150psig across the others. Checked, and lash was gone on #1, so I figure the valve's receded. Also observed some oil weeping from the rear end of the head gasket, so pulling the head for a valve job was a no brainer. No real ridge on the cylinders to speak of, and no signs of any scoring, so I'm going to keep the lower end in place. Is there anything else I could potentially do that might be just some 'just-in-case' things to the bottom end while the head's being rebuilt? I'm thinking maybe soaking something on the rings or similar to make sure they are nice and free when this thing comes back together? |
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| Author: | Charrlie_S [ Sun Nov 26, 2023 8:03 am ] |
| Post subject: | Re: What do to to the lower end while the head is off. |
I don't think the 170 was available in the Vans as original. If it is really a transplanted 170 I think you might be disappointed in the performance. One thing I would suggest, while the head is off is to mill the head for some additional compression. Take some measurements, and shoot for about an honest 8.5 to 1 CR |
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| Author: | CraziFuzzy [ Sun Nov 26, 2023 9:06 am ] |
| Post subject: | Re: What do to to the lower end while the head is off. |
Quote: I don't think the 170 was available in the Vans as original. If it is really a transplanted 170 I think you might be disappointed in the performance.
The 170 was the standard engine for most of run of the A100. Optional was the 225, or a 318. In any case, this van was a 170 with an A745 from the start (based on the info plate). But yes, I was going to have the shop cc the head and mill as appropriate.
One thing I would suggest, while the head is off is to mill the head for some additional compression. Take some measurements, and shoot for about an honest 8.5 to 1 CR |
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| Author: | Charrlie_S [ Sun Nov 26, 2023 9:21 am ] |
| Post subject: | Re: What do to to the lower end while the head is off. |
Quote:
The 170 was the standard engine for most of run of the A100. Optional was the 225, or a 318. .
OK Thanks. I was just thinking being a "truck" that the 225 would be standard. Like the 170 was not available in the early Barracuda. The 225 was the base engine.PS: remember the factory head gasket was a thin stamped steel gasket. Most aftermarket gaskets are at least .020 thicker. You need to compensate for the gasket thickness. |
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| Author: | SlantSixDan [ Sun Nov 26, 2023 9:29 am ] |
| Post subject: | Re: What do to to the lower end while the head is off. |
The risk is that medium-tired rings and bearings that worked okeh with a medium-tired head will not stand up to the increased stress of a nice, fresh head. Then you're back to taking the engine apart again. On the other hand, you probably don't want to put in unnecessary effort, money, and time. On the other-other hand, there's no verified history on this engine, so it's kind of an unknown. Take off the head and have a careful look at the cylinders. How much ring ridge is there at the top? What do the cylinder surfaces look like? You might also remove the oil pan and have a look at how much/what kind of crud you find down there. This will also afford you the opportunity to, if nothing else, clean the oil pickup. And while you're down there, It will also be a good idea to service the oil pressure relief valve to make sure it's doing its job, as described in thread 1, thread 2. If it all looks close to perfect, that's a decent argument for redoing the head (with hardened exhaust seats, etc), measuring/adjusting the compression ratio as Charrlie describes, and putting it all back together. If it looks old…probably best to just go through the whole engine—or find/build a 225; a 170-powered A100 is going to have difficulty safely keeping up with modern traffic on level roads, let alone up hills. Speaking of safety, see this post. |
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| Author: | CraziFuzzy [ Fri Dec 01, 2023 9:15 pm ] |
| Post subject: | Re: What do to to the lower end while the head is off. |
Well, the unknown condition head didn't pan out. Multiple cracks at the seats, so now I'm in the market for a head, preferably 67 vintage or so. If anyone's got a line on one, ideally in the so cal area, please let me know. |
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