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#16
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look at em do they line up All the way around or does onke or more have a hole or gap next to it.
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86 GMC Jimmy Blue and Silver- R.I.P. 87 Integra RS ~228k miles R.I.P. 92 SVX LS-L Perly ~186k R.I.P. 89 240sx se red ~165k miles Gone and unknown 89 240sx se Black~185k R.I.P. 85 Toyota pickup ~205k R.I.P. 85 BMW 325e ~ Gone and unknown 85 Ford Mustang getting engine swap now! 05 Colorado ~108k Daily Driver |
#17
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Well, again, that's really hard to tell. The top of that combustion chamber, including the valves, is really, really crusty. I'm just going to take the head to somebody who actually knows something. I'm tempted to just buy a new head, but I want somebody to look at it and be able to tell me that the head is the cause of my compression loss. Until I eliminate the bottom end or head gasket (though both are looking less and less likely) as the problem, I don't want to just order a new head.
Thanks!
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2005 RX-8 Grand Touring 2005 Outback 2002 Mercedes-Benz E320 wagon END OF LINE |
#18
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Some photos of the head, gasket and block.
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2005 RX-8 Grand Touring 2005 Outback 2002 Mercedes-Benz E320 wagon END OF LINE |
#19
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One more.
I've found that the head is severely warped. The head gasket doesn't seem totally blown, although the water jacket and oil passages are clearly compromised, right where the head is warped. It would have blown eventually. I don't think the shop that replaced the head gasket for the previous owner back in April machined the head like they claim. I've also found a big difference in clearance between the valves and the cams. The #4 intake valves have a clearance, when closed, of only .003" or so. The other valves are all closer to .010".
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2005 RX-8 Grand Touring 2005 Outback 2002 Mercedes-Benz E320 wagon END OF LINE |
#20
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A lot of things can happen to an OHC head when it overheats. You definitely need to take it to a machine shop for inspection. It could not only be warped but twisted as well. Don't forget, whatever happens to one side usually happens to the other - the cam journals may be affected as well. Some heads can be straightened and machined to take care of that, some can't.
Food for thought: since you have the head off, and the engine may have suffered other issues, you might consider dropping the pan and pulling the pistons. This will allow you to check the bearings and rings. Before you pop them out check for ridges at the top of the cylinders where the ring travel stops. If there is much of a ridge there you'll want to rent a ridge reamer and remove the ridges. Not doing that may cause the rings to catch and ruin the ring lands on the pistons. I don't know how many miles you have on the engine but if it were me, and the miles were over 80k or so, I'd give it consideration, especially if you're going to be thrashing it.
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ASE Certified Master Automotive Technician w/L1. ASE Certified Master Medium/Heavy Truck Technician. Certified EVT (Emergency Vehicle Technician) |
#21
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Rather than taking theh ead to a machine shop, since I'm finding so many things out of spec I think I'm just going to replace it. A rebuilt will set me back $150, and I could easily spend that on an autopsy for this head.
I understand what you're saying about the bottom end. I am definitely considering dropping the bottom end, but I'm also considering leaving it for now, replacing the head, and seeing where that leaves me. The bores are very clean and show no signs of damage or ridges. That doesn't tell me if the rings are worn out, but it eliminates some problems. But you are right - I'm going to be thrashing the engine and it has 108k on it. Not a lot for a Toyota, but still. If I do drop the bottom end, what kind of non-reusable parts am I going to be into just for looking?
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2005 RX-8 Grand Touring 2005 Outback 2002 Mercedes-Benz E320 wagon END OF LINE |
#22
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replace all gaskets and seals bearing are typical and I figure the rings are garunteed replacement...do your pistons have the floating pins? if so the retainers for those might be a good idea
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86 GMC Jimmy Blue and Silver- R.I.P. 87 Integra RS ~228k miles R.I.P. 92 SVX LS-L Perly ~186k R.I.P. 89 240sx se red ~165k miles Gone and unknown 89 240sx se Black~185k R.I.P. 85 Toyota pickup ~205k R.I.P. 85 BMW 325e ~ Gone and unknown 85 Ford Mustang getting engine swap now! 05 Colorado ~108k Daily Driver |
#23
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Somebody on the MR2 site just replied with a very interesting story. He said he removed his head for the same symptoms - zero compression on #4. He also said that his HG shows the same discoloration. He claims a new HG solved his problems and the car's been fine, since. Good to hear.
That doesn't prove that my car will be fine with a new gasket. I still need to make sure the block is true, and I'm still going to replace the head because it's enough of a question mark. But I was glad to hear from somebody who had the same problems.
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2005 RX-8 Grand Touring 2005 Outback 2002 Mercedes-Benz E320 wagon END OF LINE |
#24
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Well, somebody set me straight and explained that the pistons can't be pulled out through the bottom. That hadn't occurred to me. So now I think I should probably pull the pistons out since I have the head off anyway. I'm just not sure what to inspect or if thre are parts I'm going to have to replace just because I pulled the pistons in the first place.
Argh.
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2005 RX-8 Grand Touring 2005 Outback 2002 Mercedes-Benz E320 wagon END OF LINE |
#25
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Probably just the pan gasket.
You'll want to take a look at the rod bearings for scuffing, deep grooves, etc. and the rings to be sure none are broken and that they float freely in their grooves.
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ASE Certified Master Automotive Technician w/L1. ASE Certified Master Medium/Heavy Truck Technician. Certified EVT (Emergency Vehicle Technician) |
#26
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Quote:
Is there a pattern by manufacturer or by engine as to how much of a ridge normally shows up after a certain amount of miles? (ie: do Fords tend to have more of a ridge than Chevy?)
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David B. SVXipedia @ SVX-IW.COM -- SVX Information Warehouse 2.0 coming...eventually! Ebony 1992 SVX LS-L 5 spd Koni/GC Stebro 187k miles RIP (Rust In Pieces) 1993 SVX 5 spd Koni/GC Stebro Polyurethane bushings still available! |
#27
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I suppose there is. Chevy small blocks have a different rod length to stroke ratio than a small block Ford. This causes a higher piston skirt loading which I would expect to cause the piston to rock and 'dig' in a bit more, creating more of a ridge. It's also why the little Fords wind up higher than their Chevy counterparts. As far as which is more prone to having a ridge I'll be honest and say I haver paid much attention. I'm sure ring construction and the metals involved would also be a factor.
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ASE Certified Master Automotive Technician w/L1. ASE Certified Master Medium/Heavy Truck Technician. Certified EVT (Emergency Vehicle Technician) |
#28
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I wasn't being specific to GM vs. Ford but overall...do you notice certain companies engines are "cleaner" than others?
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David B. SVXipedia @ SVX-IW.COM -- SVX Information Warehouse 2.0 coming...eventually! Ebony 1992 SVX LS-L 5 spd Koni/GC Stebro 187k miles RIP (Rust In Pieces) 1993 SVX 5 spd Koni/GC Stebro Polyurethane bushings still available! |
#29
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For a number of years now the lower end of an engine is the least worry. I can't recall the last time I've worked in the basement, probably in the late '80s. Generally speaking, if something catastrophic has happened the entire engine gets replaced. It's difficult to find a machine shop that can do their job and then buy the necessary parts for a reasonable amount of money vs. buying a crate engine. So, as a result, I rarely see an engine's innards. Most of the time it's just to replace a head gasket, otherwise it's either a reman engine or the heap. Today's engines usually outlast the car's street value. You can thank electronic ignition and fuel injection for that.
So, to answer your question, no, I don't. It's more a matter of maintenance. I can say that my observations while I sold tools (and was in every shop in town) was that Saturn and Mitsubishi cars had more engines torn apart in the dealerships than any other make. Saturn uses low-tension rings that have a horrible reputation for sticking and blowing oil out every conceivable place (poor maintenance is partly responsible.) The Mits' techs said that their cars had very good engines but their customers were mostly punk kids that thrashed the cars and never did basic maintenance. They said the kids always said "It was running great until it didn't." Go figure.
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ASE Certified Master Automotive Technician w/L1. ASE Certified Master Medium/Heavy Truck Technician. Certified EVT (Emergency Vehicle Technician) |
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