Compression testing and timing question

Hello again one and all,

Two very simple questions

1. Is it best to carry out compression tests when the engine is hot or cold (type 1)?

2. Just got a VW Beetle as a first car for the son and going through various bits, we have a cheap strobe timing light, i know i connect the main lead to HT lead 1, connect the other to earth, but what can i connect the positive lead to, to get power? In the van i simply connect to the battery but the battery is under the rear seats, confused and obviously i don't want to look to dumb in front of boy wonder.

 

put he timing light pos on the coil feed

 

Thanks for that MorkC

I thought that might be the way, I thought I would check on here first instead of making a fool of myself in front of son No1. Thanks for reply

 

...and the throttle fully open...

 

Hello @snotty, forgive my ignorance.

I'm doing the compression test tomorrow, if the main lead from the coil is removed what difference does having full throttle make. My thinking is the engine will not fire just turn over regardless of throttle position.

My knowledge is still very limited and every day is a school day

 

full throttle to let the air in

 

Thanks @matty will give that a go tomorrow and post up the results to see if engine us fubar.

Xfingers

 

Instead of disconnecting the +ve connection to the coil (which'll burn out your ignition wiring if it shorts to the block), just disconnect the green wire from the breakers to the other side of the coil. This'll stop the engine running and the free cable can flop where it likes.

Open throttle ( and choke open) gets rid of any restriction to airflow, as matty said.

 

And take all of the plugs out, as this will take the compression load off the engine and make it spin faster on the starter

 

And...change your pants every day!

 

Everyday??

 

Yep. None of these turn them inside out tricks...

Also:
- avoid drink and loose women
- however windy it is, never nail your hat to your head

 

Staple gun ok??

 

I normally use Tiger Seal

 

bit gloopy if you get it on your hair!!

 

I was doing this test last year and wondered why my results were low. once I opened up the throttle and took all the plugs out the results were fine. The instructions with my compression tester said nothing about these things.

 

Hair?? Oh yes, I remember.

 

Best not show you the length of mine then!!

Hair people, hair!!