timing belt and modded oil pumps
 

ok,

so im having a new timing belt fitted on monday to my 93 wrx.
ive asked the garage to check the tentioner and pullys at the same time as i get a knock when the car is cold which goes when hot. i also asked that they check the water pump.

is there any thing else i can ask them to check/replace for peice of mind? Other than the cold knocking, the engine appears strong and i want to keep it sweet.

ive read something about a modified oil pump which some people go for as the oe one fails often. can anyone explain?

Here you go:

https://www.scoobynet.com/general-te...oil-pumps.html

thanks for that. any other advise?

You can sometimes find on the earlier cars the backing plate on the oil pump becomes loose over time. This plate houses the oil pump gears, the same gears that the pump uses to draw the oil from the sump. This can result in a gradual loss of oil pressure often going unnoticed over time and ultimately causing damage.

Depending on your mileage it may well be worthwhile getting the oil pump checked while everything is accessible, it shouldn’t add too much onto the job.

“Modified” pumps have had a small modification made to the pressure relief valve chamber minimising the chances of the pressure relief valve sticking.

“Uprated” pumps are pumps that increase the flow rate. You find them used on or fitted standard on cars fitted with AVS, pistons squiters; crank modifications and so on 10mm 11mm 12mm pumps are available. Although you don’t have to have any of the above to fit the up rated pumps.

thanks mate, ill ask them to check the oil pump backing plate too.
changed the gearbox oil today with sucess. castrol syntrax 4 litres. :)
couldnt get 2nd gear untill car was warm so i hope that will sort that.
car has only done 40k miles.