anyone ever spun over a petrol by hand to measure compression?

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ThomasLRNL

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I dont have a petrol starter for my spare petrol 2,25 engine, but I do want to verify if the block is worth refurbishing. the tops of the cillinders have a noticable groove.

I hand spun the engine by the crank bolt dog it had on it.

Dry: 30/35 psi
Wet: around 50 psi

Anyone who has ever done this and still knows their results? Or better yet, someone who has done both! And may be able to say: X psi by hand equals Y psi while using starter.

Let me know, thanks!
 
I will need to buy a seperate starter for this engine, since the engine in my car right now is a diesel. They arent compatible. That is why i would like to measure before i spend tons of money :)

But i guess ill have to find one on the cheap then according to your experiences! Thanks :)
 
Ok , so can you whip off the head look for wear ridge at top and perhaps measure bores that will give a good indication of condition, then you could remove pistons check rings and bearings etc
 
steve2286w said:
Ok , so can you whip off the head look for wear ridge at top and perhaps measure bores that will give a good indication of condition, then you could remove pistons check rings and bearings etc
Click to expand...
Yep, will do.

The wear ridge is definately there. No doubt. I dont know if i have the proper equipment to measure the bore.

Can be done with a caliper? Or better equipment needed? Will post pics soon
 
caliper will just do the top, i borrowed one of these, an internal micrometer. very accurate, but on my 2286 i also took block to a machine shop for them to double check , i had a wear ridge that you could feel with fingernail but was only about 3-5 thou , i still decided to get a rebore to start from new




1724506335614.jpeg
 
steve2286w said:
caliper will just do the top, i borrowed one of these, an internal micrometer. very accurate, but on my 2286 i also took block to a machine shop for them to double check , i had a wear ridge that you could feel with fingernail but was only about 3-5 thou , i still decided to get a rebore to start from new




View attachment 324473
Click to expand...
Great, will check it out thanks
 
This might be totally irrelevant, but apparently the modern way to do a compression check, or rather, a compression comparison between the cylinders, is to simply monitor the starter motor current while cranking the engine.
I've just replaced a two and a quarter diesel, and I could actually feel the one duff cylinder just by turning with the starting handle.
I could also feel the starter motor surging as it spun past the low compression cylinder
 
grewth said:
This might be totally irrelevant, but apparently the modern way to do a compression check, or rather, a compression comparison between the cylinders, is to simply monitor the starter motor current while cranking the engine.
I've just replaced a two and a quarter diesel, and I could actually feel the one duff cylinder just by turning with the starting handle.
I could also feel the starter motor surging as it spun past the low compression cylinder
Click to expand...
You can get a surprisingly good feel for a duff cylinder or two just pushing something over the plug hole. I use a valve grinding stick if I can find it, something similar if not.
 
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