Ok i just put the motor in the car and its running..but i also just found out that melling is having stress fractures in some of their pumps because of thinner castings...********....most of the stuff i have seen is on the m55...i put in a m155...is this model having the same probs as the m55....cause it has me worried sick about my new $4500 engine..can someone shed some definite light..i read one post on corvetteforums where the m155 had the thicker castings...i sure hope so

 

noone knows

 

Where are you seeing this 155 number? I'm looking at the catalog and I don't see that particular number for SBC/LT1's.

 

Measure the thickness of the casting with a dial or digital caliper. The new ones are .80", the good ones are 1.25". If yours measures out to 1.25" or greater then you're good to go.

 

What year did they thin it down? I'm not gonna take my pan off and check it. I've had my M55HV since 2002.

 

the box says m155...there site lists it..i cant exactly measure it cause its in the motor and in the car...i have seen several sites list the m55 m155 and m55hv...let me find the link

 

http://www.chevelles.com/forums/show...hlight=melling

here is the link that had the most info...there are several on the net

 

Nevermind, someone said it was Jan 2004 in another thread.

 

Stock the lt1's have a 3/4" dia pickup tube (Melling M155), but your older SBC's had a 5/8" dia pick up tube (Melling M55). You have the correct replacement oil pump with the M155. I will measure the thickness of a couple of the M155's that I have on the shelf for you tomarrow.

 

thank you please do..im getting mixed words from several people and cant decide what the deal is..just seen that some folks were running the m55 and it was cracking and they were having problems with them..cant get a definite on the m155..does the years affect it..i just bought mine in february and it had the infamous "warning note" in it..i have factory motor mounts and it only see the strip maybe twice a year..and no circle track stuff.

 

The sites mention other qualifying issues besides just solid motor mounts. Whether the bolt head was lubricated, whether a washer was used under the bolt, whether a stud with washer was used, the insert being a different metal and the expansion rates of the two metals caused a crack. I went ahead and ordered/received the Melling "M" select pump #10555 and bolt on pickup 12557. As soon as it quits snowing here (Upstate NY-Global Warming my a**, Al Gore) I'll pull the pan and install it. I'll be able to examine the current M55HV and see what, if anything has occurred. I've spun the motor to 7,000 a few times and plan on racing it quite a bit this Spring/Summer/Fall. I don't want some evil surprise in the oil pump to kill this brand new motor.

 

yes but from the testimonials i have read the people with the problems are the ones who are heaily modded cars with solid mounts and who do alot of racing

 

I got you the measurement on the two M155 pumps that I have on the shelf. From the machined surface to the oil pump mounting bolt face they bolth measure 1.321". However they do come with the solid motor mount advisory to go to the Melling select series oil pump.

 

awesome...but when were they produced..are they the old one or is it a new one like mine

 

I just bought these oil pumps a week ago from my supplier. They didn't have any on the shelf there and ordered them straight from Melling.

 

wow thats a big relief..im not gonna worry about it so much now..especially since you measured them and everything..i sure do appreciate you taking the time to do this,..that was the extra step i needed to see what the deal really was

 

Glad I was able to help out!!

 

Just an FYI.....I just got my Summit oil pump today. It is stamped on the side with M55HV. The thickness with the pump (SUM-121155) is a little over 1.25". So that makes it the good M55HV right? For $20.00, if it is the good one, I'll be pretty happy. Thanks.

 

Oddly enough, it seems like no one has found a pump with this thin casting.......