Need Prestolite pump help
 

I am restoring a 76 cig 28ss and am having a problem with the trim sytstem. the drives will trim up/out normally, together and sound fine. the problem is trimming in / down. the pumps sound like they are under heavy load and the drives are moving very slowly. I never ran the system before the restoration so I dont know if this is what they were like before. I feel like it is a valving / pump issue. I checked the pressure on the up and down side and they are to specs at I believe 2200psi up and 600 psi down.

the only other thing I think could be a problem is that I have 2 cylinders with solid pistons and 2 with valving. I installed them 1 and 1 on pt and stbd.

any insight into this would be greatly appreciated.

thanks guys

Chris

Are you running the same size diameter lines on the down side? If not you could be restricting the volume...

There are also newer pumps & rams that will move up & down faster.. However yours should be about the same speed both ways amd if anything many times the drives go down a little faster as gravity or load usually is an assist..


J:cool-smiley-027:

Very common for the shock valves to come apart inside the cylinders.

I had everything apart - cleaned and reassembled - so there is no "mechanical" issue with what I have. both sides have the same size lines.

I think there may be a mismatch problem?

doe anyone know the reason for having solid and valves pistons? and do they serv any function other than overpressure relief?

I have also seen other prestolite pumps with different pump/ valve housings is there a difference?

Thanks for your help

Chris