I used the Moates.net BCC spreadsheet to find the V8 '427 PCM Memcal part numbers. I used the part numbers at an online GM parts supplier. According to the research I've done the 18 Memcals I have a screen shot of are still available from GM. Depending on the GM parts supplier, some of the part numbers were listed as low as $33.50!Who knows, next week GM might make some / all these part numbers obsolete.
dave w
Last edited by dave w; 05-25-2012 at 10:05 PM.
I was thinking about ordering one of these Memcals, but the shipping seemed excessive to me!
dave w
Holy cripes!! Are they serious or you think its a glitch/typo on their part?
I would like to get a 7427 7.4L memcal, I dont care what is on the prom, as long as the esc in it is for a 454. I am really curious to know if it might get along with my engine better than the 5.7L esc I am using now. Just dont want to pay some crazy price for one only to find out its no better.
79 Jeep Cherokee, AMC 401, T-18 manual trans, hydroboost, 16197427 MPFI system---the toy
93 Jeep YJ Wrangler, 4.0L, 5 speed, 8.8 rear, homebrew hub conversion and big brakes, hydroboost, 2.5in OME lift, 31x10.50's---the daily driver
99 Jeep WJ Grand Cherokee limited, 4.0L, auto, 2wd, leather and power everything, 99% stock---the long distance highway ride.
Here is the correspondence I had with GM Parts Direct:Originally Posted by JeepsAndGuns
My Question ~ Why is there over $410 in shipping charges for part # 16248381?
THAT IS THE TRUE DEFINITION OF INSANE!!!!!!!!!!!!!!!!!!!!! OR STUPIDITY ~ YOU DECIDE??
The Response from GM Parts Direct:
Hi David,
Please accept my sincerest apology for your inconvenience. Part number 16248381 has been discontinued and is no longer available from General Motors.
Thank You,
F Norton
GmPartsDirect.com
On the topic of using a 454 Memcal on a 454, well I think it might be best to go that route. The reason I'm searching for a new Memcal is because I'm troubleshooting what appears to be a faulty Memcal. The Memcal in question is almost always retarding timing, sometimes with the ignition in the "on" position the knock counts go to 255 without the engine running.
dave w
If they cant get it, why even list it on their site...lol
Actually its a AMC 401, not a 454. I just know the 350 knock filters hate it, just curious if the 454 filter gets along with it any better.
79 Jeep Cherokee, AMC 401, T-18 manual trans, hydroboost, 16197427 MPFI system---the toy
93 Jeep YJ Wrangler, 4.0L, 5 speed, 8.8 rear, homebrew hub conversion and big brakes, hydroboost, 2.5in OME lift, 31x10.50's---the daily driver
99 Jeep WJ Grand Cherokee limited, 4.0L, auto, 2wd, leather and power everything, 99% stock---the long distance highway ride.
I'm thinking the knock filter of the '427 PCM for both SBC / BBC are the same part. I think maybe the 4.3 has the same knock filter. I think this because all three types of engines use the same part number for the 4K ohm knock sensor. I'm figuring the main reason for the different Memcal part numbers is mostly for the PROM programming.
dave w
the knock sensors being similar is not a surprise... the 2.8/3.1/3100 60V6 uses the same knock sensor as the 4.6 Northstars....
i would be almost 100% certain that the filter is significantly different between the two applications.
1995 Chevrolet Monte Carlo LS 3100 + 4T60E
Correct me if I am wrong Robert, but as I understand it the actual detonation frequency produced by each engine is relative to the bore size and thus the knock sensors are designed to be "sensitive" to that particular frequency/bore size. The filter is more relative to the engine design/configuration and is there to "filter" out any "noise" from other sources such as valvetrain components etc...
The bore of the 2.8/3.1/3100 was the same at 89mm. The bore of the Northstar is ~93mm. I'm not sure of the bore "range" that a particular knock sensor is effective, but there has to be some kind of range as there are way more different bore sizes in various GM engines vs. the amount of different knock sensors available. Given that my statements are correct, then the AMC 401 would fall right in between the 350 and 454. The 350 has a 4" bore and the 454 a 4.25" bore with the AMC 401 being 4.165. I would definitely want to give a 454 memcal a try. After giving a quick glance at a parts catalog for an earlier TBI truck, the 350 and 454 use the same knock sensor but a different ESC module which definitely piques my curiosities. I am working today so I will run into the parts dept. and attempt to locate a 454 memcal part # that is still available.
Last edited by pmkls1; 05-27-2012 at 03:52 AM.
Ok, so I did a part # cross reference and ran a dealer locator on the two 7.4 memcal part #'s listed in the spreadsheet above. Those part #'s are not superceeded by another number and have been completely removed from the dealer locator system. I also checked in the parts catalog and none of the numbers I found for a '95 C/K truck memcal were available anymore. So, no luck there. There could be a dealer or multiple dealers out there with old stock still on their shelves, but since GM has removed those #'s from their dealer network program you would have to literally call each dealer individually. I do know of a company that buys NOS parts from GM when they become discontinued and they may very well have some of these memcals. I would have to make a call on tuesday to see as I do not know if this company sells to the public or not and the only contact info I have is an 800 number listed in the GM parts catalog.
The markup on parts from Rare Parts seems astronomical but if you need something, you need it. Partsvoice allows the general public to search subscribers' inventory although the two 7.4 part nos above are not successful. I'd look for memcal and sensor from a medium duty 366 truck engine RPO LS0 which has a 3.95" bore. The modified BCCFind search produces a pile of hits for that engine. For example BCC BSBD part no 16229536 from a non governed closed loop 1997 truck is available from a dealer in Oroville, WA.
HTH
It seems I remember reading that the knock sensors are mostly the same, and its the esc's that diffrent.
I did a google search on the two 454 memcals above, and found this site for one of them.
http://www.gmpartsgiant.com/parts/gm...-16248381.html
I googled the other number and had a hit too, but it was like 160-something dollars.
79 Jeep Cherokee, AMC 401, T-18 manual trans, hydroboost, 16197427 MPFI system---the toy
93 Jeep YJ Wrangler, 4.0L, 5 speed, 8.8 rear, homebrew hub conversion and big brakes, hydroboost, 2.5in OME lift, 31x10.50's---the daily driver
99 Jeep WJ Grand Cherokee limited, 4.0L, auto, 2wd, leather and power everything, 99% stock---the long distance highway ride.
I haven't really seen too much info regarding knock sensors and esc modules or the filters in memcals and pcm's as I haven't delved that deep into custom efi and whatnot. I thought that I had stumbled across info regarding knock sensors stating what I posted above somewhere on an efi site, but I'm not 100% sure by no means. As far as the pricing goes, there is a huge variance from one part # to the next and one of the numbers I looked up was something close to $160. I do know that there are multiple companies that deal with NOS inventory and when it comes to pricing you are pretty much at their mercy. I have seen some very reasonable pricing on NOS items that just don't sell very often though. I recently had a convertible C5 'vette that had ruined the electronic suspension control module due to a massive water leak and that module had already been discontinued. We could not find a module anywhere including salvage yards using their nationwide network. The owner had to locate one himself and actually bought it from an online vendor selling on ebay. The list price for that module was well over $1200 and he got it for around $400 shipped. Anyhow, I would still like to look further into the vendor that is referenced in the GM parts catalog for many discontinued parts for myself just as much as anyone else. I get the feeling that they keep some sort of record of what they have purchased as only certain discontinued parts have a notation with their phone # attached. Other discontinued parts simply say discontinued in the catalog.
Phil
http://www.vpartsinc.com/ this is who buys gm and acdelco old stock. I dont think they sell to the public but I was able to get a account in the early 90's .
During the bankruptcy and following dealer shutdown there were plenty of dealers looking to get out from under inventory. Scoggin Dickey Chevrolet purchased quite a bit from dealers that were closing up.
I had confused Vintage Parts linked above with Rare Parts Co. I have a feeling those guys are connected with GM in some other way like maybe it's owned by former employees or it was started as a spinoff company right before the bankruptcy. No one else is able to get their name listed in the GM parts catalogs and no one else (for parts retailers) does business with dealers through the GM network.
Last edited by 1project2many; 05-28-2012 at 03:04 PM.
Here are some screen shots of the "Internet Research" I did on the Memcals. It's possible some of the Memcals are for knock sensors that are 100K ohms, not 4K ohms. I'm seeing different part numbers for Auto / Manual Trans.
dave w
Last edited by dave w; 05-28-2012 at 05:36 PM.
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