Engine Compression test kit

Engine Compression test kit

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Discussion

cornflakes2

Original Poster:

230 posts

79 months

Tuesday 15th December 2020
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I'm looking to buy a compression test kit. Can you recommend any?
I don't know if it's a one size fits all and if they can be used to test other pressures such as fuel pressure and injectors or
do all of them require a separate pressure test kit?

I want to test my engine compression, fuel pressure, and injector pressure.


Also a random question:

If your coolant level is the same (not losing any coolant whatsover) does that mean it's safe to rule out a blown head gasket?


gazza285

9,864 posts

210 months

Tuesday 15th December 2020
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cornflakes2 said:
Also a random question:

If your coolant level is the same (not losing any coolant whatsover) does that mean it's safe to rule out a blown head gasket?
No, that just means the head gasket hasn’t failed into the cooling system.

tapkaJohnD

1,952 posts

206 months

Tuesday 15th December 2020
quotequote all
'flakes,

If you want a pressure kit that will test all those, you will have to make up your own!

Cylinder pressure guages are cheap and readily available. They may come with adaptors for different sizes of spark plugs, so check that they fit what you have. The technique for using one needs learning - look it up. But such guages, being cheap, are not precision instruments, nor are they calibrated. You cannot take a reading and compare it with someone elses. They are ONLY for comparing across the block, cylinder by cylinder. You should also be aware of the secondary oil test, that will discriminate between ring and valve or gasket leaks.

Fuel pressure guages need to have very secure connections - you do not want fuel sprays! Many fit them permanently, either within the engine compartment or next to the fuel pump, on a T-connecter on the fuel line.. An electric guage, with a sensor in one of those positions and a readout on the dash, is the only safe way to read fuel pressure on the go.

Injector pressure? That should be the same. The function of an injector may be assessed by pulling it while the engine runs. This must be done with something to catch the fuel spray in and in the open, with a fire extinguisher to hand, preferably held by someone else! Look for a good cone of spray, without missing segments.
Good luck!

Edited by tapkaJohnD on Tuesday 15th December 10:20


Edited by tapkaJohnD on Tuesday 15th December 10:22

cornflakes2

Original Poster:

230 posts

79 months

Friday 18th December 2020
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Thanks for the replies!