Need opinion about choice of Early Hemi oil pump for 1953 Chrysler 331. Choice #1 -- Rebuild original pump assuming housing is in good shape. Choice #2 -- 340 oil pump with adapter from Hot Heads Choice #3 -- 392 oil pump with modified rear main bearing cap
i have used the hh pump the titan and missile pumps with good results. it depends on what you want to do with this engine.
Here's a link should tell you what you need to know. http://www.hothemiheads.com/oiling_system/hi_volume_340_oil_pumps.html
I realize this thread is over 10 months old. Before you make any decision, You really need to read the oil section in Hemi Tech here on the HAMB. There are some different opinions about Hemi oil pumps that have NOT been covered on this page.
we put a 340 small blk Chrysler pump in our engine masters engine. it revved to 7000 rpms (required) and put out 660 h.p. with a 1050 cfm holley. it's a bored and stroked 1956 354 to a 396 cubic inch. the pump works great ! we made our own adapter, but hot heads is good, just a little pricey. make sure you disassemble the entire rocker shafts and CLEAN them super good if using the originals.
you can use the stock shaft that goes to the distributor, the after market ones are a little short and can lift up off the male end of the cam gear and you will lose oil pressure. it happened to us.
First, I don't want to say anything negative about anyone. If you are in the market to buy an oil pump for a Hemi read, "HEMI Tech: Oil systems- filters, pumps, pans." It is here on the HAMB. I've read all of it several times, Page #4, Post #99 really got my attention. Decide for yourself, . . . My choice, original pump, if it's useable or a new M50 with the rear main cap modified. There are two members here on the HAMB that do the main cap modification, they are 73RR and TR Waters.
I did not had any luck with my aftermarket oilpump in my dodge 53. Allmost cost me my new restored engine. Put back the stock one and never looked back.
I just ordered the M50 for my 354, Gary said he had posted how to modify the rear cap so we'll see how difficult it is.
ive been running the 340 small block pump in all my hemis (4), drag racing, street, haven't had one problem. good luck out there hemi guys !
Hey Zeph! I'm coming to the end of building a 1965 Dodge D100 with a 331 hemi in it. I fired it up for the first time - I have a temporary mechanical oil pressure gauge installed under the hood so I can monitor during tuning etc. - All of a sudden the oil pressure dropped to 0 psi ... (not a slow decline) - Obviously I turned it off immediately and went into research mode The engine has the 340 pump but I dont know about the shaft. (I took this build over from my father when he got sick to finish it for him .... and he passed away recently) I have the distributor a LITTLE bit loose to set the timing. Is it possible it has raised up just enough to disconnect from the drive gear? Do you have more information? Thanks so much!!! Luke
I would think the stock one would be fine for a rebuilt engine without large, sloppy bearing clearances.
So heres a sketch of my set up .... I have contacted HotHeads and this is the reply: Luke, I don't have a 331 or 354 block here to I can measure but I measured the lengths of the int. shaft and the oil pump shaft and distributor shafts and they all show to be correct. I have a longer shaft that we use for our chevy distributor adaptor that I can send you that is longer than stock( 7.060 length) and you can use it to make a custom length shaft and cut it down to match your engine and re pin it. Like we discussed before factory engagement was around .120-.130 on either side but you can go deeper if you want. We have seen some industrial versions that needed this done before but not car engines. Thanks, Eric Can anyone confirm the dimensions? Also does this plan make sense: 1) Press the intermediate shaft up slightly to fully engage the distributor (redrill the set pin) (I think this is going to be easier than cutting and extending the distributor shaft 2) Press the oil pump shaft to fully engage the intermediate shaft (This means the end of the shaft will NOT be flush with the bottom of the oil pump drive gear .... but I dont see that being a problem. I'm scratching my head why I have to do this though!!!! I measured up the old oil pump and it would have the same problem .... And I dont agree with what Eric said about the 0.100 engagement being enough .... that seems like a recipe for disaster
Luke; Did you find the actual cause for your Oil Pressure to drop to zero before deciding to dive into pump drive and sub pieces?
I run HH hi volume pumps in my dodge and Chrysler... pan mods are needed.. will not fit as stock pan. As for the pumps.. they really deliver...solid.
Yes, Check out the pics attached here ... you can see up into the hole where the oil pump and intermediate shaft "tore up" (sorry about how grainy they are ... snap shot of a video) Also had a lot of metal in the oil pan (I think from the bottom of the intermediate shaft) .... could also be the engine breaking in. Even the pics of the top of the int shaft (gear side) I can see some wear .... looks like its going to skip or let go ... When it was running (before i lost oil pressure) I was having a VERY hard time keeping it running and doing the initial tune ... so its possible the distributor was skipping already? It just seems like 0.050" to 0.100" is not enough to drive an oil pump. it takes a lot of force to develop 60-80psi Yes - I have the Steph's rear sump oil pan and the right pump arm (see pics) ALSO! THANK YOU GUYS FOR THE HELP
I have to agree with .050-.100 is questionable engagement. Seeing your photos is pretty convincing. With metal frag in the pan did you open up your Pump to make sure a frag didn't get in and jamb the gears?
I did open the oil pump. everything seems ok (no scoring etc) and I will be replacing the bolts (grade 8) and using red locktite when i re-install ... (I know some had issues with bolts on this form)
Shouldn’t the male tang on the pump engage the female end on the intermediate shaft. Looks like the oil pump spacer may be too thick and not letting the tang engage deep enough? I can’t tell very well from the pics,,,sorry. Just an idea. Tommy
The pump I used wrecked a fresh done pan... Hemi pans in good shape are worth gold....Dodge ones are worth even more.... after all the hard work of metal finishing a decent one and the expense of plating.... the 340 pump pressed right through the pan upon assembly....... this was 2 nights before Detroit(mad thrash as per usual).... Luckily .... I had a somewhat decent pan and used a stock pan. When i bought the 340 oiler...I was told it was a direct fit.... nothing needed .... I was pissed.
Yes sir.. EXACTLY ... based on my measuring the male oil pump only engages the female intermediate shaft by 0.100" ....... I might investigate grinding down the 340 oil pump spacer ... but i dont have a surface grinder and i think it would be easier to push the intermediate shaft down .... instead of "moving the oil pump up by grinding the HotHeads provided spacer. Its killing me .... i REALLY hope the bit of time it was runnin with out oil pressure didnt screw this engine. things ain't cheap to rebuild!!!! Heard that bruh .... I have measured where the pick up sits in the pan ... and made sure it wasnt dead locked in the bottom..... I will be "drill spinnin' the pump" with oil in the pan to see if it makes pressure once i finish all the mods I'm planning on.... BUT again ... I dont know why i need to do it. 1) push the intermediate shaft UP to engage the distributor fully 2) push the oil pump drive shaft UP to fully engage the intermediate shaft
Do you still have the original pump to measure how far down the pump extends into the main cap? Or at least to compare it to the 340 pump? There must be more tang engagement than what you currently have,,,it will never stay together with what it is now. As far as any damage might be,,,,for my peace of mind,,,,I would remove each rod cap one at a time,,,and give the bearing an inspection look. Then ,,,do the same to the mains. If it only ran a few seconds,,you should be fine. I am assuming you used good assembly lube? Hope it works out for you! Tommy
Hey Luke, You do have the correct distributor in there,,,,,did you check clearance between the distributor shaft and the intermediate gear top? Just a thought,,,,I know the cam gear drives the intermediate down,,,but the pump will also try to screw it back out of the top,,,too much clearance and the tang will disengage. Tommy
I did measure the original Oil Pump: from pump base (mounting point) to tip of pump = 2.910" soooo since the spacer = 0.500" 2.910" + 0.500" = 3.410" The measurement on the 340 conversion = 3.375" (see the drawing i did above) 3.410" - 3.375" = 0.035" which is basically Sweet F*ck All ... and might as well be an error in measurement on my part being under the truck trying to measure with a caliper and a straight edge etc. the way i see it is the original pump and the 340 pump have the same dimensions. Again: THANK YOU GUYS .... for questioning my thought process and bringing these things up ... its helping me work though it!!!
Correct Distributor: TECHNICALLY ... no .... i have a 318 distributor. BUT according to HotHeads it should be "ok with 0.100" to 0.150" of engagement" but it just doesnt seem like its enough And the second part of your statement: "Just a thought,,,,I know the cam gear drives the intermediate down,,,but the pump will also try to screw it back out of the top,,,too much clearance and the tang will disengage." thats my thought also ..... sh*t just has too much variable clearance.