How much would an overhaul help?

pookster

Well-known member
I am in an autoshop class and we have the opportunity to overhaul our engines, if we want to. I recently did a compression test on my 6 and they read about 90. Isn't it suppose to be around 140? So I was wondering how much power am I losing, and is it worth the time and money to do it? If I want to overhaul it has to be this year so I have the equipment and knowledge of a mechanic. Another question is, I have heard a lot about people overhauling engines and it never runs quite as good as it use to. Is it because they aren't careful enough or what?
Thanks for your thoughts.
 
yup, i do believe that it should be higher than 90, did you do it with your shop teacher looking over your shoulder to make sure you did it correctly?

what do you want from your six? just a stock rebuild?
if you could toss in a new cam, and some better internals, better ignition, possibly a Aussie 2V head, and upgrade the exhaust, then i'd do it, even if you could only get the cam and internals i'd do it, the rest can be added later

as for people having problems, usually it takes a while to work out the bugs in a system, a few have persistent problems (Jimbo springs to mind), while some get them to work just about perfectly even with an untried, brand new system (the Crossflow also springs to mind)
some people just get dealt a crappy hand, but if you are careful, and have someone that can guide you well, then you can minimize how bad your hand is, and even negate it completely*

if you prepare well for it, and don't rush, then you should do well

*not to imply that Jimbo is a crappy mechanic or anything, he's just the first person that sprang to my mind
 
Northern Auto Parts has a master kit that includes: cam, lifters, timing set, pistons, piston rings, rod/main/cam bearings, oil pump, frost plugs and a gasket set all for around $327. I think I can use the credit from the cam and upgrade to a better one. I am planning on doing exhaust, better head and other upgrades. I just wonder if it is worth the money to do the overhaul along with my eventually other upgrades.
 
If you are going to rebuild, I would make sure I get a kit from a "reptable dealer". I would not go with a Auto Zone, or JC Whittney, or a place like that. Make sure they do not read "Made in China", etc. Just as always, you generally get what you pay for. Don't forget about a good machine shop also! :lol:
 
When you say the compression test turned up 90psi...Was that on ONE cylinder or all of them? So long as they are all within 10% of each other the engine is doing OK, no NEED for a rebuild.

Different testing procedures will give different results.
 
A duff choice of head (unmilled) can also be a culprit in terms of low but consistent compressions. A lip over about 6 thou in #1 would have me plan in the 18-month timerframe for a rebore.

Regards, Adam.
 
Doing the test with all otehr spark plugs in and the throttle blades closed will give low readings also. Thats why I asked how he did the compression test. If he simply took one plug out, and cranked it over, I doubt he got a true reading.
 
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