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Compression test results - Help and advice please

798 Views 5 Replies 4 Participants Last post by  camachinist
Hello everyone.

I have finally got around to doing the compression test on my 1967 289 4v,

To get everyone up to speed, I am getting smoke and oil coming up through the oil filler hole, the dipstick and the pcv. I have replaced the PCV and make sure all the crannies under the carb is clear.

Here are the compression results (by cylinder. I did each on twice and these numbers will be rounded off to the nearest 5)

1 - 130 psi
2 - 80 psi
3 - 130 psi
4 - 130 psi
5 - 140 psi
6 - 125 psi
7 - 140 psi
8 - 65 psi

Now seeing that #2 and #8 are so far out of norm, I squirted some oil in each hole, let it set for a few minutes and tested again. Here are those results.

2 - 190 psi
8 - 160 psi.

Here is where I need help. What should my next step be?

I have a spare motor I can rebuild. I have not done any testing on it but I pulled it out of this car because of some ominous oil burning, piston noises and loud clicking under the valve cover.

There is also a shop near my place advertising a rebuilt 302 with a 7year/70,000 mile guarantee for $855.

I am trying to minimize cost and downtime since this is my only means of transportation.

Thanks so much in advance for your help.
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With a rebuild of the heads and all new bore, pistons, cam, and the other parts required for a total rebuild, you can easily spend 1k for machine shop work and parts, not to mention your labor for putting it together. Is the store engine a long block? If so, jump on it. If a short block, then you still have to deal with heads, etc. Make sure what is new in the engine and go from there.
Does their guarantee mean they do the install, if so your looking at a pile more money, but the 302 does seem like the cheepest alternative.

68 fastback, 390 4V premium fuel
80 5.0 hatch, just finished
91 5.0 coupe, daily driver
84 RamCharger 4x4 extreme mudsliger and winter junker
Sounds like your rings are shot. Time for a rebuild.

'68 Coupe, 289, C4, 3.40 gears, GT-40P heads, TCI Streetfighter stall convertor.
Hi, if the 302 is a long block like mentioned above I think I would go for that then if you wanted to BUILD an engine for later on you could use the 289-4 and do it as money and time were available. John

Opal frost pearl metallic 67 coupe
also have a 95 opal frost pearl G/T BOSS edition convertible belongs to swmbo
Say bye-bye to the rings in your two bad cylinders....the engine will likely run a while longer but oil consumption will start getting embarassing...*G*

I wouldn't buy a rebuilt engine unless the shop installed and fired it and warrantied the installation as well as the engine....

Personally, I'd suggest rebuilding your core at a reputable local shop....ask around at the car clubs and/or race track...they know who's good and who's not...

You'll do the install and possibly assembly but, in the long run, if you pay attention to detail, you'll have an engine and experience you can be proud of.....

If you get all your ducks in a row, the car shouldn't be down for more than a weekend...

Good luck!

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