ok to do Top End?, rings/heads only? |
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ok to do Top End?, rings/heads only? |
tat2dphreak |
Jun 17 2003, 07:43 AM
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#1
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stoya, stoya, stoya Group: Benefactors Posts: 8,797 Joined: 6-June 03 From: Wylie, TX Member No.: 792 Region Association: Southwest Region |
ok, as you all know by now I have a burnt valve, and I think that's it.
however, I'm catching a lot of grief from people saying I should split the case, do everything!!! I understand that if I want this 1.7 to last another 100k miles I do need to do this... however, if I only need to fix what's wrong until next summer/spring... is it ok, to just do the top-end(rings/heads) now? I plan to completely rebuild next summer, or next winter(2004) at the latest, put 96mm pistons with a 71mm(or 78mm) crank, new cam...the works!!! at most I will put 1-3k miles on the engine between now and then. I hardly drive it in the winter... no heater b/c of headers... so, can you do the rings and heads without cracking the case and checking main bearings, rod bearings and everything that will be replaced in a year anyway? I just didn't want to to all of this and have to do it all again when I trick out the engine... (IMG:style_emoticons/default/confused24.gif) |
need4speed |
Jun 17 2003, 06:03 PM
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#2
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Member Group: Members Posts: 339 Joined: 11-April 03 From: Arroyo Grande, CA Member No.: 564 |
Just to pass on an argument in favor of doing the rings (and pistons and cylinders).
Disclaimer: I'm a type 1 guy, don't have a 914 yet, so I don't know how expensive these parts are for a type 4, nor what kind of tolerances they're manufactured to. I did a top-end rebuild of my type 1 (1600dp) in the Ghia, including pistons and cylinders. I balanced the pistons - ie. I ground some of the back-edges off until the pistons all weighed with in .1 gram of eachother. The new pistons shipped and the heaviest was 4.9 grams heavier than the lightest. Factory spec is within 5 grams. When I got it back together and running, this engine ran like no other type 1 I'd ever driven before. It's strong, and smooth, idles well. This is with only the pistons balanced, I didn't balance the rods, or the crank or the flywheel or anything else. Prior to the rebuild - well, I guess it could have been the valves in the old heads - they were CRAP, but my top speed was about 75 mph. After the rebuild, I was pleased to find that I could get up past 90 and change. (now that I've replaced the transaxle with one that doesn't have as tall a 4th, top speed is in the 80-85 mph range). On the other hand, Type 1 pistons and cylinders were about $120. So if Type 4 pistons and cylinders are cheap, and if you're reasonably certain that what you have is not balanced, it may be well worth your while to do this. |
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