400 rebuild help

[BSB67]

Yes, have a Melling high volume pump coming tomorrow, and appointment to do just that on Wednesday. That could be all this is, but I know it usually isn't. Pumps don't create oil pressure, and I have none!

But, motors don't go from having fine oil pressure to zero oil pressure instantly without you knowing something went sideways in a big way. If your motor took that big of a crap, you would not need your oil pressure gauge to tell you.

With the little discription you gave, I would guess maybe a oil pick-up failure, or oil pump drive failure.

Seems a bit early to talk about tires, gear and converter for a motor you don't know if you'll build.

 

[451Mopar]

Our '71-74 Chargers are big heavy cars. The stock 14" rim/s tires really don't handle the cars weight very well. I originally put 15x7's with 255x50x15 on the car and they were pretty good along with larger 0.96" Mopar performance T-Bars and sway bars. When I started drag racing the Charger, i put 15x10 on the rear, and some skinnier fronts (don't recall, but they might be 15x5"?)

I would get the 440 source 512" stroker kit for a mild street engine that may only see 6,000+ RPM
For a hot street/bracket race build the 470" stroker is nice if you don't want the real short piston of the 500" kit.
I did the 451" stroker back around 1991 and it was good, but back then there were no affordable stroker kits like today so it was re-used 440 crank and rods.

My Charger now has a 500" stroker kit, but the engine was built to rev 7,000 RPM, and is 12.4:1 compression. Not really what you need on the street. The 512 piston is actually a bit longer than the 500 piston because the 512 kit uses a shorter rod (same for the 470").
Also, the 512 and 470 kits have right about zero deck height which makes getting quench distance pretty easy with a 0.040" head gasket.
With the 451 or 500 the piston sits about 0.020" below deck, so either a thinner head gasket or milling the block to get good quench distance between the piston and cylinder head.
I would get the cylinder head cc volume for the heads you plan to use, and the cam specs to figure which stroker crank, rod length, piston dish gives the best compression ratio for your combination. I guess you want to run pump gas, and a mild cam so you might want to keep compression ratio around 10:1?

The 440 kits I have used were pretty good, but not a drop-in kit. I'm not sure any aftermarket kit is? You will want to inspect all the parts and trial fit them before final assembly. The engine balance can vary slightly on how the pistons and rods are matched up (were talking maybe 3 grams worst case?) If you have a gram scale you can weight match the pistons and rods to get a good average for the balance.

On my current 440 based 512 stroker, I chose to try a less expensive un-balanced kit so I could have my machine shop balance the assembly, but there is not much if any cost savings. I also already had rings and coated 743HNK bearings, so I only needed a crank/rod/piston kit, not the full kit with the rings and bearings.
I might even try a set of gapless rings, but they are expensive, over $300 set.

 

[747mopar]

I found an old similar thread but figured best to start a new one. I'm currently experiencing no oil pressure on a manual gauge in my 74 Charger SE. I'll cross my fingers and have an oil pump put on next week, but need to prepare myself for the more likely motor failure. I'll have someone else doing the rebuild but will be able to supply my own parts. I would probably want to do new bearings, pistons, rods, lifters, possibly cam, etc. Curious as to any good kits or if it's best to buy it all separate. This is not a drag car, so cruising capability is a must.

Car has duel plane intake, TTI headers, 3.23 posi, rebuilt tranny with just over stock new converter, and more. Not sure what hp it's putting out but if I did a stroker kit I would probably need to keep it on the mild side, like the 451. The car is still running stock 14 inch tires. I think I would need to change that just to keep them on the ground. All thoughts and advice are appreciated. I'll update Wednesday after the oil pump install.

You say no oil pressure on a mechanical gauge but didn't mention any rattling, ticking or any other symptoms? If you have zero pressure you should definitely be hearing other signs, I'd put another gauge on it before going through the trouble of changing anything else.

 

[66Satellite47]

Sorry, never built an engine and not always up on the lingo. 3.91 or 4.15? At first I thought gear ratio but there wasn't a 4.15. I dealt with 440 source before when I put CVF racing brackets on the car. I had to change out the water pump. They were very helpful, quality parts and good price. I've also heard nothing negative so far about the kits. Thanks!

Sorry, that's the stroke. 3.91 stroke gives you the 470" & 4.15 stroke gives you 500" cubic inches.

 

[66Satellite47]

A starting point is to pull the valve covers & see if all the pushrods & lifters are in place. On my 426W drag motor, car slowed down during the run, stalled on return road a couple times before seizing up entering the pits. Pulled valve cover, #1 intake pushrod bent laying in the valley along with the lifter. Chiseled the rod bearings off the crank.

 

[Coronet67guy]

But, motors don't go from having fine oil pressure to zero oil pressure instantly without you knowing something went sideways in a big way. If your motor took that big of a crap, you would not need your oil pressure gauge to tell you.

With the little discription you gave, I would guess maybe a oil pick-up failure, or oil pump drive failure.

Seems a bit early to talk about tires, gear and converter for a motor you don't know if you'll build.

Agree, at this point going at it like it's an intermediate shaft failure or pump failure. But great to get educated on the plan B if the motor is shot.

 

[Coronet67guy]

You say no oil pressure on a mechanical gauge but didn't mention any rattling, ticking or any other symptoms? If you have zero pressure you should definitely be hearing other signs, I'd put another gauge on it before going through the trouble of changing anything else.

New gauge, but yes will be putting another one on it to make sure. Excessive knocking heard, like you would expect from low oil level or no pressure. Thanks.

 

[747mopar]

New gauge, but yes will be putting another one on it to make sure. Excessive knocking heard, like you would expect from low oil level or no pressure. Thanks.

If it's knocking than you definitely have a problem, good luck.

 

[Curiousyellow71]

If its knocking I don't think I would ruin a new pump by installing it in the engine with metal filings in it. First take the oil filter apart and see what's in there. Valve covers off next if there is no filings.

4.25 stroker is a good combo. On the 451 or 470 w a oem crank.. you either have to have the rb counterbalances turned down to b or grind out the block so the bigger rb counterbalances clear. The exception is the early 72 400 block has more room.

 

[66Satellite47]

My Satellite was built as a street cruiser with fairly mild 500" motor. 440 block 4,15 stroke crank, low .500 lift 236/[email protected] A 400 block will be the same thing. My street 500" motor could easily obliterate the 325/50-15 drag radials on the street, but I have 4.10 gears & power lock.
I still would go with the 3.91 stroke, 6.535 rod, low .500 lift cam combo. Try 3.23 gears with a 28" tire. The 470" motor can move the car fine with 3.23's. You will need a limited slip diff though. The 470" with the 3.91/6.535 has a really nice durable piston & good L/R (stroke to rod length) ratio, spins up quick, hopefully not too hard on the tires. Just my opinion.

 

[Coronet67guy]

My Satellite was built as a street cruiser with fairly mild 500" motor. 440 block 4,15 stroke crank, low .500 lift 236/[email protected] A 400 block will be the same thing. My street 500" motor could easily obliterate the 325/50-15 drag radials on the street, but I have 4.10 gears & power lock.
I still would go with the 3.91 stroke, 6.535 rod, low .500 lift cam combo. Try 3.23 gears with a 28" tire. The 470" motor can move the car fine with 3.23's. You will need a limited slip diff though. The 470" with the 3.91/6.535 has a really nice durable piston & good L/R (stroke to rod length) ratio, spins up quick, hopefully not too hard on the tires. Just my opinion.

Thanks for the opinions. I have the limited slip diff, installed that when I went to 3.23 from stock gears. Seems if I just moved to some 15 inch wheels I would have many tire options at 28 inch diameter.

 

[66Satellite47]

Yes, many 15" tire options, you'll likely need them especially if you go with the stroker.

 

[m79ded]

I also did a 451 with TF240 and I really like it, Easy to drive great street manners and plenty of power. Made 625tq and 612 HP. If I had to do it again I would do the 470 combo with a 6.70 rod because it uses the same 1.32 CH piston as the 451, Makes a very light rotating assembly and amazing power

 

[Coronet67guy]

If its knocking I don't think I would ruin a new pump by installing it in the engine with metal filings in it. First take the oil filter apart and see what's in there. Valve covers off next if there is no filings.

4.25 stroker is a good combo. On the 451 or 470 w a oem crank.. you either have to have the rb counterbalances turned down to b or grind out the block so the bigger rb counterbalances clear. The exception is the early 72 400 block has more room.

Great idea, I went ahead and picked up a Wix filter just in case we tear the one on the engine apart to inspect.

 

[Coronet67guy]

You’ll probably want some more gear, 3.55 or ideally 3.73 with the cam I used and around a 28” tall tire, I have 3.54 which acts nicely with this combo, but for bracket racing or more time at the tracks 3.7 or 3.9 gear would be ideal, just not the best on the highway for cruising. The ideal thing would be a 3.91 or a 4.10 gear with a gear vendor over drive giving you a final drive ratio of 3 - 3.2

10 to 11 on the compression. You’re builder can help you with this



He is referring to the stroke of the crankshaft. Stock 440 stroke is 3.75”

Keep in mind the larger 500 + cubic inch engines benefit well from bigger heads like Indy etc.... you already have the tti headers, I assume 1 7/8” primaries, so like 1 wild R/T says I’d probably stick a 470” or like me, a little less, a 451”motor.

Big cubic inch motors mean big exhaust, big carburation, big everything which also usually equates to more money.

Dollars to donuts, the 451 or 470 will make you very happy.

Yes, 1 7/8. I was going to get the 1 3/4, but they were backordered many weeks and the others were on the shelf, so done. And while I appreciate all the suggestions I'm not wanting to change the gears again, and a 451 or 470 will be plenty of fun. The motor is pretty stock internally now but has all the high performance goods attached, so it would greatly benefit from some new heads and a rebuild. But still hoping it's just a pump and nothing is damaged. Considering those tires and wheels regardless and ditching the 14's. Hell it's Fathers day tomorrow, I deserve it! lol

 

[Coronet67guy]

I also did a 451 with TF240 and I really like it, Easy to drive great street manners and plenty of power. Made 625tq and 612 HP. If I had to do it again I would do the 470 combo with a 6.70 rod because it uses the same 1.32 CH piston as the 451, Makes a very light rotating assembly and amazing power

Thanks. Sounds like a great combo and lots of power. Why the TF240? If buying a kit from 440 source, the 470 has 6.535 rods, whereas the 451 has 6.76 rods. Not sure if they would ship the 6.76 in the 470 kit or not.

 

[66Satellite47]

When I built my 400/451 drag motors in the '80's, the first used the stock low deck 6.36 length rods, second one used the 6.76 440 rods. Short rod L/R = 1.7. The long rod L/R = 1.8. The 470 with 6.535 rod & 3.91 stroke gives a 1.67 L/R. The short rod version will spin up quicker. The added side load on the cylinder from the short rod is not significant, and many intakes will respond well to the short rod piston movement at TDC.
Get a good look at that stock bottom end that's been exposed to no oil pressure.

 

[451Mopar]

Thanks. Sounds like a great combo and lots of power. Why the TF240? If buying a kit from 440 source, the 470 has 6.535 rods, whereas the 451 has 6.76 rods. Not sure if they would ship the 6.76 in the 470 kit or not.

They don't have a 1.263" compression height piston to work with the 3.915" stroke and 6.76" rod.

You might be able to use a GM length 6.700" rod and the 451 pistons with 1.320 compression height. if concerned about rod ratio?

If you calculate the piston position vs rod length, there is very little difference between what we call long rod (6.76") vs. short (6.535") rod, because they is not really that much difference in the actual rod lengths, I think the difference in length is around 3%, and the difference in piston position per degree rotation is small as I recall when I actually looked at it years ago.

 

[m79ded]

Thanks. Sounds like a great combo and lots of power. Why the TF240? If buying a kit from 440 source, the 470 has 6.535 rods, whereas the 451 has 6.76 rods. Not sure if they would ship the 6.76 in the 470 kit or not.

Both the 6.535 and 6.70 rods are great, I prefer to use the 6.70 rod because it works perfect with a 1.32CH piston and with minimal decking it brings it very close to 0 deck. 1.32 CH pistons are lighter, more choices and readily available. The longer rod provides a slightly "Better" rod ratio not that it makes much difference, but for a street engine less side load and heat on engine. TF240 because again i'm doing most of my driving on the street and spend 80% of the time in the 2500 -4500 range and it just works great the port is just the right size. The torque in the 451 is awesome and the 470 is even better, it's a awesome street engine. Easier on parts, heat, fuel. Works great. Keep in mind the Buick 455 TQ monster had a3.90 and 6.70 rods as well.

 

[Coronet67guy]

Both the 6.535 and 6.70 rods are great, I prefer to use the 6.70 rod because it works perfect with a 1.32CH piston and with minimal decking it brings it very close to 0 deck. 1.32 CH pistons are lighter, more choices and readily available. The longer rod provides a slightly "Better" rod ratio not that it makes much difference, but for a street engine less side load and heat on engine. TF240 because again i'm doing most of my driving on the street and spend 80% of the time in the 2500 -4500 range and it just works great the port is just the right size. The torque in the 451 is awesome and the 470 is even better, it's a awesome street engine. Easier on parts, heat, fuel. Works great. Keep in mind the Buick 455 TQ monster had a3.90 and 6.70 rods as well.

Sounds great. I actually have a 73 Rivi with that monster 455. 51k original miles and original paint. Sadly it may hit the sell block if I need funds to get the charger fixed. Fingers crossed for an inexpensive fix.