Relay timing modification
Relays in automotive use the 87 designation to indicate the terminal of the Normally Open (NO) contact. DIN 72552 specifies the numbering. https://en.wikipedia.org/wiki/DIN_72552 (which is not entirely consistent with what is actually being used, see first comment below) 



Here is a link to an adjustable timer relay for automotive type relays. 

http://hellahd.com/index.php/default/electrics/flasher-and-timer-modules/electrics-category-11/electrics-product-12/

12V, 10A Adjustable Delay Timer Relay (Delay ON or OFF)

https://www.polevolt.co.uk/acatalog/12-volt-Timer-relay.-Configurable-time---delay-on-or-off.-74205.html#SID=78

or

https://www.12voltplanet.co.uk/adjustable-delay-timer-relay-delay-on-or-off-12v-10a.html

or 

https://www.amazon.ca/HELLA-152-131-0-900s-Delay-Control/dp/B003C508XO/ref=sr_1_fkmr0_1?s=automotive&amp;ie=UTF8&amp;qid=1544366749&amp;sr=1-1-fkmr0&amp;keywords=HELLA+delay+time+relay

These are special (expensive). 

https://www.arc-components.com/0-742-12-durite-12v-adjustable-programmable-timer-relay.html

https://www.arc-components.com/12v-pre-programmed-delay-off-timer-relays.html