Compression tester

Post by **iddy** » Wed Sep 14, 2005 12:32 pm

I've just been reading the threads on the Engine topic and have a few questions.
Do you test the compression on a cold engine?
How long do you let the engine turn over for. Does the compression reading get higher the more the engine turns, or does it reach a peak after turning over once or twice?
A guy in work is lending me a tester this afternoon, so I'd like to know I'm using it properly.
Talking of which it's time to get off my butt and off to work.

Idris.

Post by **Alec** » Wed Sep 14, 2005 1:20 pm

Hello Idris,

a warm engine would be better, and the pressure does build up but normally it is very quick, a quick burst is sufficient, especially if you take out all the plugs first. I always hold the throttle fully open as well.

Alec

Post by **iddy** » Wed Sep 14, 2005 11:10 pm

Thanks Alec, I'll have a bash at it tomorrow afternoon when I finish work.

Idris.

Post by **iddy** » Thu Sep 15, 2005 2:54 pm

Just finish testing and had readings of 175,175,175,180, so I'm happy with that

If everything else about the car is up to the mark then Ihaven't bought a pig in a poke (phew).

Idris.

btw I've just noticed that if you change your signature in your profile it changes the profile on your previuos posts as well

Post by SR » Thu Sep 15, 2005 3:21 pm

iddy,did u do it cold,ive got too do mine and its out of the car ,steve

Post by **bmcecosse** » Thu Sep 15, 2005 11:10 pm

These are excellent figures - is it a standard engine ?

Post by **iddy** » Fri Sep 16, 2005 4:53 pm

Yes, I did it when the engine was cold - it hadn't run for about 12 hours.
If your engine is out of the car I assume you can do a compression test with the starting handle.
Yes, it's a standard engine - 1098.

The story behind my doubts about the car's reliability is that I bought it while on holiday in Torquay. When I saw the car for sale there was no one at home, so I put my phone number through the letterbox - I was returning home the following morning. I bought the car over the phone and caught the train a few days later. After parting with my cash I then broke down 5 times before I got to Taunton, eventually getting home at 2am on the back of a breakdown truck.
The car has been fine since I changed the coil, but I was told by the AA the breakdowns were fuel related!
In fairness to the guy who sold me the car, he was pretty open and honest. It could just have been a pure coincidence.
Anyway, I chuffed to bits with the car, and that's all that counts.

Idris.

Post by SR » Fri Sep 16, 2005 5:09 pm

thanks mate ,im hoping to connect to my battery wiyh jump leads and do the test,steve

Post by **rayofleamington** » Fri Sep 16, 2005 7:35 pm

I just did another compression test this evening on an engine kindly donated by our sponsor

. I got readings of 120 on all 4 but realised the hose had a hole in it getting progressively worse

I had to wrap my hand round the hose to get the readings, so they probably should be higher.
The worst thing is that it's not my compression tester and it was fine when I borrowed

Ah well - it's only money, and I'm sure they'll be happy to lend it to me again when i've bought them a new one

Post by **iddy** » Fri Sep 16, 2005 7:48 pm

The guy at work who loaned me the compression tester actually gave me his "box of tricks". It also contains a vacuum tester and some sort of timing gun with a fistfull of wires attached to it. It's a pity I don't know how to use them

He owns an original Mini, a Mini cabriolet and a Minivan - he's about 6 foot 4!!

Idris.

Post by **bmcecosse** » Fri Sep 16, 2005 9:06 pm

Plenty of room in a Mini - I am almost as tall and have loads of room - but there is even more room in my Minor Traveller.

Post by **rayofleamington** » Fri Sep 16, 2005 10:34 pm

Anyone know of a really good deal on compression testers?

Post by SR » Sat Sep 17, 2005 5:54 am

i paid £7 for a hi-guauge from ebay,only used once ,still in packaging

Post by **iddy** » Sun Sep 18, 2005 8:21 pm

Ray,
There's quite a few on ebay, ranging from "£2 to £15. There's a guy selling new ones for £8 plus p&p which have two thread fittings. I think I'll buy one myself!!

Idris.

Post by **bmcecosse** » Sun Sep 18, 2005 9:18 pm

I stupidly walked away from one at £ 5 on an autojumble stall because I thought my mate was buying it - I went off to look at something else - asked him later for a look at it and it turned out he had decided not to buy - went back but too late !! He who hesitates etc.

Post by **Packedup** » Sun Sep 18, 2005 9:24 pm

I didn't have one till a couple of years ago, then I bought two in a couple of months. Ran one over breaking the glass on the dial, and never used either until earlier this year. Although the non-broken one is starting to give odd readings, and won't hold the needle in place, they're very useful tools. And the best bit is I paid bout 50p for one, and a quid for the other at the local car boot