how do you test hydrualic lifters please help?

 

You do not check hydraulic lifters like you would solid lifters. Hydraulic lifters are set when engine is put together and that is it. The way they are put in when engine is built is to put engine at tdc and torgue all rocker arms to 19ftlbs,that is all there is to it.

 

We havw a problem with a cherokee , car was runing on petrol at idle switched over to lpg the car backfired through air intake violently since then car has made nasty taping sound in top end and miss fires . We have done a compression test which ranges between 120 and 150 psi , also had head off and cant find any faults . we are open to sugestions can you advice please ?

 

Check the pushrods, bet one or several are bent.

 

They appear not to be but we will check again does anybody know could the timeing of moved when it back fired ?

 

Timings not going to move, so long as the distributor is tightened properly. Did you roll the pushrods on a piece of glass? That is the only way to properly check them.

 

Thanks we haven't roled them on glass but we will try that now and get back to you

 

how are you injecting the propane? what are the condition of the plugs?

 

we have rolded push rods on glass they are all perfect , and the gass is enjected through a single point injection into the manifold

 

Then it's possible that a lifter did get pooched. Usually the pushrod/valve will get damaged first.

 

where at into the manifold? IMO it sounds like you are getting a UNEVEN mixture and had a lean backfire........Just my experiance but from nitrous apps...if its a DRY kit it is injected pre-throttle body so that you are sure all cylinders get a even mixture...or a TB plate kit.....simply running a line into the manifold wont work......PICTURES??.

 

it has been proffesional fitted and set up and injected before throtle body , still cant understand why there is a miss fire and knocking noise on petrol or gass

 

with all the lifters off do the valve stem tip all measure out to be the same height? PLug condition?

 

yes they do measure the same , any other sugestions ?

 

Any one else help ?