Muffin

OK guys, I'm kinda lost here. I am building a 383. Today was fit the oil pump day. My Kevko pan came with a matching pick up with 5/8th tube. My Melling pump is an M155HV, NOT an M55HV. It has a 3/4 inlet like the 10552 and looks like the 10552 except the relief spring is pinned rather than a screw retainer. Does anyone have knowledge about the 155, so far I have drawn a blank. BTW the packing box says "New Generation".

BLOCKMAN

Here is a link with some info. http://www.mellingselectperformance..../OilPumps.aspx So far all the 383 engines we have built for street a strip whave used the 10553 with no problems.

Make sure the pick up is for a high volume pump or it amy end up to close to the bottom of the pan.

Good luck with your build

85vet

If you are building a high performance engine - DO NOT USE A NEW GENERATION OIL PUMP. There should be a note with the oil pump that it should NOT be used in a high performance engine.
The new generation pumps are not as strong as the original pumps and have a history of cracking or breaking off.

Buy a melling select if you want piece of mind.

Slalom4me

The reason for this is that the gears and hence the body of HV pumps
are longer. The increased length of the pump body moves the inlet
for the pickup downward from the mounting point on the main cap,
placing it closer to the bottom of the pan.

85vet played a central role in threads about oil pumps two years ago.

If anyone would like assistance locating the Melling threads, post
again or PM me.

.

Muffin

Thanks guys. I am beyond the racing age so there will not be any trips down the track. The M155HV should do for a grocery getter. Make that a high powered grocery getter.

Slalom4me

There was enough uncertainty caused by photos of cracking that
occured in mild applications that the opinion is to just go to the
M-Select version.

.

lltrevino

JAKE

Jake

Orr89rocz

first time i've heard of oil pump problems. I forget what i have in my 383. I think its a high volume standard pressure melling, and i want to believe its the 155HV pump. Working good for me, but i dont know if my gauge is accurate or not but my pressure stays jacked even at warm idle. Its 60 psi most always

JAKE

Melling changed the casting. They claim it was at the request of the companies (GM and others I suspect).

This change made the casting thinner in certain critical areas and as a result there have been a lot of casting cracking and breaking.

That's the way the story came to me.

Jake

rodj

http://forums.corvetteforum.com/c4-t...disasters.html

Slalom4me

My vote is that the gauge is essentially accurate.

The pumps are shipping with a high pressure spring. Certain models
were advertised as having both HP & SP springs in the carton but
when polled, respondants indicated they had not received the SP.

A standard pressure spring is available from Melling on request. There
are at least two different methods of retaining the spring in the cap
of the pump (taper/split pin & threaded plug). This affects spring
diameter and length, so be certain to get the correct replacement.

Excessive pressure is undesireable.

.

JAKE

Not only "undesireable" but, contrary to what Melling says, excessive pressure will kill the drive gear on the distirbutor shaft (L98) or the stub shaft (LTXs). Ask me how I know.

On the LTXs that is particularly dangerous because even if the oil pump drive gear dies, the engine will continue to run as if nothing was wrong; that is up until the time the engine seizes because of NO OIL PRESSURE. Hopefully you'd see the CHECK GAUGES light before that happens, as I was lucky enough to see.

Jake