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Discussion Starter · #1 ·
Hi
I bought a F code 1300 engine secondhand. My plan was to rebuild it so I have a decent engine for my (soon to be daily driver again!) beetle. However, it seems a decent engine. Correct endfloat, no nasty noises when I turned it over by hand. So I thought to throw caution to the wind and start it up.
I set the tappets, fitted the correct carb and dissy, checked the oil and went for it.
It seems to run great, very little if any smoke and sounds nice. I haven't driven it yet as the rest of the car isn't ready yet.

Today I have borrowed a compression tester and leak down tester. Tonight I've recorded the compression test results.

1 - 100
2 - 100
3 - 105
4 - 105

I like the closeness of the figures, but I have no idea if the values are OK. All the figures I find online are for the higher compression ratio 1600, where 100 would be a concern

Anyone know if these figures are concerning?

I will do the leak down test tomorrow and let you know the results
 

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It all sounds fine, nothing to worry about there. Around 125 or so would be ideal but they'll probably increase some when you've run it a bit.
 
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Discussion Starter · #3 ·
I did the test with the engine cold, I assume that's right
 

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Discussion Starter · #5 ·
Thanks chaps. (Yes throttle wide open)

So, leakdown test results. ....


Throttle open, oil cap off, plugs out, piston at top of compression stroke.

1 - 36
2 - 48
3 - 34
4 - 36

Numbers are a percentage of pressure loss.

Below 10 is a great engine, below 30 is only just ok but worn. ......

Looks like I'll be doing a rebuild!
I could hear (and feel in the case of number 2!) the air coming out of the oil filler, so rings at fault. No noise from exhaust or carb, so valves probably OK. On number 3 (it had to be number 3 lol) I could hear it coming from the head area suggesting possible crack or not seated to the cylinder.
Not good!
 

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I'd be happy to run it as-is but a set of rings and a quick valve grind would get it singing for not much $$$.
 
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Discussion Starter · #7 ·
But if I'm doing new rings and valve lap, may as well get the bottom end checked and fit new bearings. I recon under £150 and a few hours. Unless the case needs aline boring, crank replacing, cams knackered and both heads are cracked...... lol
 

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It's up to you of course and it all depends on the use you want to put the engine to.

If it were me I'd never dream of splitting an original engine with negligible end float and presumably good oil pressure. No one can build an engine like VW did.
 
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Do you really know how long it has stood for? Now you have had it running, give it an oil change, let it do 100 miles or so and then test it again. You might be surprised by how much the compression comes back by. If it doesn't then give it a rebuild then!
 

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Really depends how in depth you want to go. If the engines not in the car then getting the barrels off is pretty easy and then you could give them a quick diggle ball hone, new rings and that's that. Heads, well the exhaust guides are always the ones to wear quickest but gotta remove springs to test and then have seats and valves re-cut.
Doing new crank bearings could be worthwhile but it's the conrod I've found get out of spec quicker. My early 1200 only needed the crank journals to be polished yet both big n little ends needed resizing. If the rods aren't checked then tightneing up all the other tolerances with new bearings will exacerbate the wear in the area not checked ;)
 
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