I decided to start taking apart my 392 last night so I can check the wear and plan my rebuild out. The motor is from my old 58 New Yorker and had about 70k on it. It's never been torn down beyond the head gasket I replaced when I started driving the New Yorker in 1999. I pulled the motor after a year and it has been parked under the bench since. Edit: My master plan is to redo the motor to hit 400hp at the crank to power a 57 desoto. Originally i posted this for a truck... but changed my mind. It's nasty inside, the sludge flowed like lava and hardened in the head and I'm sure I'll find more suprises along the way. So my goal at the moment is to get it apart and clean the block, heads and rockers out of this old sludge. I'll post up my measurements as I get them. For now, some pictures!
Ok got the heads off tonight and I was able to get my bore gauge in the block. Measured 4.002 as low in the bore as I could get with the piston in it. Showed 4.007 up top. Would a re-ring be ok here? It seems a shame to bore it out to 4.030. Also trying to keep this refresh at a lower cost. Not cheap, but not doing things that don't really need to be done. More pics, lots more sludge and quite a bit of loose carbon in a few of the votes from sitting. I also found a dimple in one of the exhaust rockers. It left the missing metal on the valve head when I pulled the rocker ***embly, I ***ume that one needs to be replaced.
.005" taper is a fair amount.From your pics it doesnt appear to have much ridge.It all comes down to how much money you can spend.If you do a valve job,hone the cylinders and put rings and bearings in it(***uming the crank is within spec) the engine will certainly run but you need to realize the rings wont last as long as they should.We used to do this sort of thing routinely if the customers wallet wouldnt let us do the whole job.Up to you.
The ridge isn't bad at all, it measures 4.001 with some gunk on the unworn portion above the ridge. I may be slightly off as this is my first use of the bore gauge, but that shouldn't change the differential top to bottom for the taper adjustment.I find myself wishing I had taken compression numbers when I took the motor down but I was young (21) and didn't know. As for longevity... I realize it wouldn't be as long. It's a matter of getting the most out of it. The truck won't see 10k miles a year as far as I expect and I do need to get the rest of the project done. I'm not scared to go back later. I took a video of the gauge readings, I'll get it up on YouTube and post the link to the thread for you to see.
The ridge left is what hammers new rings...so even with you bore taper, you'll lose a bit of performance, but the ridge will hammer on a new compression ring, and shortly you will be right back to where you started. (enough commas)? At least have a buddy cut the ridge out, suggest you don't run out and get a ridge reamer and "just do it", takes some know how to set it up. Off my backyard-rebuild-refurbish soapbox
I deal with budget-oriented engine builds all the time So my $0,005 (that is value of my country equivalent to $0.02) - if there is a ridge - get oversize pistons. If there isn't - hone and re-ring and it will be fine. Just as Budget36 has written. Ridge will kill new top ring in no time and you risk breaking that ring, which could do nasty things to cylinder walls...
You had a "70k-mi '58 New Yorker" and You're moving the motor in "a 1950 Dodge truck"..??? Aesthetically speaking, that's like dumping a "Victoria's secrets" -model on the side of the road in favor of the cashier of a russian bomber plane.
Late night epiphany, I think I read my scale on my bore measuring tool wrong It's 4.001 down low and 4.0035 up top. I'll get the vid up in the morning. Saul that car was rough, it didn't see a lot of mile but it sat for a long time, the Interior was completely smoked and the body wasn't in great shape. I could have brought it back but I got a solid offer for the car and got to keep the motor. My 4dr sedan New Yorker was used for a 300D resto. I was also 21 and i didn't really think it through. Now I'm older and I have this motor and my dad has this truck and the truck was modded to take a 392 back in the day. Why not combine them? Hell I still have the 58 Plymouth in my sig too, it needs a lot of work to come back too as I was dumb and stripped it to the shell and then left it outside like that for way too long. I can't really afford to dump the 15k it will take to bring that one back to life. I'm going to sell that and do this truck for a lot less. Then I can be driving something.
Well, I convinced my old man to give up a project he's been holding onto for a long time.... This is going in a 1957 desoto fire sweep 2dr hardtop.
***uming your new measurements are right, you have about 0.0025 inch of taper. That is certainly within re-ring spec territory. You should eliminate the ridge and hone the cylinders obviously. I've seem worse sludged up engines, yours is not as bad as could be. The new 57 DeSoto engine swap candidate sounds like a good choice.
So now that this is going in a car I'm going to replace the cam. Any suggestions? Going to put an a518 behind this along with a 3.23 to start and the jump to a 3.73 sure grip down the road ($$). I'd like to hit 1hp per cubic inch or close to it. Car will be around 37-3800 lbs.
Bumping this, looking at the hot heads .485 238 duration 112LSA cam grind. I want to hot this thing up a bit and hope to score a set of truck manifolds or make some headers work in the desoto. That ch***is is hard to get headers into thought, so it may be a while. Any cam suggestions are appreciated.
Pay particular attention to properly cleaning the rocker shaft ***emblies. Do one side at a time and do not mix the parts up. Clean is not good enough. http://www.hemihaines.com/Early-Hemi-Engines-6-146.html tr waters here also had an excellent article about this same thing.
As said, your current numbers aren't all that bad so clean the pistons and inspect them very closely. There are plenty of rings for a 4" bore. If you are truly on a budget then consider a regrind on your cam and buy a set of adjustable pushrods. Compare prices with the new cams. Inspect the rocker shafts for ANY signs of galling. Best to also make sure they are still round...same with the rocker arm bores. .
There used to be ring sets for engines with a little more taper than usual and also a little out of round cylinders. I haven't seen them in years but sure they're still out there. Regardless it should be honed and then measured up. A trip to the machine shop for at least a hot tanking and general once over is a good idea. Most shops have a standard basic rebuild service.
I've got the budget for proper re-ring refresh so a new cam/lifters/springs/adustable pushrods/rod and main bearings and hot tank and hone are ok on the pocket book. My thought on this build was to avoid the overbore for now to get the most out of the block before i have to punch it out to .030 over. If i could get .010 pistons outside of customs i would probably do it, but going 30 over for this wear level seems a waste. Im going to be spending some quality time with the rocker arm set soon. We have another full rocker arm set that i can use for parts from another 392, as of now ill be ******ing 3 intake rockers from the set due to pitting on the intake rocker arm surface of my original set. Do you have any thoughts on the cam selection? i've been modeling various shafts and have kicked the PAW and Thumpr **** to the curb, The Hot heads 485 cams need more RPM's than I want to spin this guy up too. With the exhaust restrictions i have the Hot Heads .465 221 112 cam is actually looking pretty strong with a very strong torque curve from 2k (as low as my software goes) up to 5k rpm with a nice roll off to 6k rpm (my planned max engine speed). Also looking at the howard cam 731231-08 which hits harder down low but falls off over 4500 pretty hard. Still looking around for more grinds to play with. Im taking your advice and staying around .480 max lift. Also, thank you for all of your posts here and over on foward look, i've been running across them everywhere and find them very helpful. (i'm chrispy over on FL.net).
where you're thinking of getting a HH cam, call Bob & talk to him about what you're doing. There are 4 bolt ex man re-pros out there.
My dad called him up yesterday and Bob was talking up the 465 as his go to cam, the 485 is "quicker" but he gets 25mpg on the 465. With that torque curve i can see how, its pretty happy pushing the car around at just about any rpm by the look of it.
.465 x 221 (at 050) is fairly docile and should pull pretty well. Not all of the 'big' cam companies have 392 cores so if your shopping around you may fine some lacking. One of my favorite profiles (for everyday cruising) (similar to above) is an older Crower split pattern grind: 267HDP. http://www.crower.com/media/pdf/2008b/109-120.pdf Catalogue page 111. This basic grind has been available for most Mopar engines. .
Hmm docile will work, but going a step further could be fun. I'll check out that crower grind. Today i've been looking at 2 howard cams grinds. the 731141-10 which is .506 lift and 220 duration and the 730991-10 which is .470 lift and 221. Both are 110LSA and 106 centerline. I like that howard says they do their grinds to take advantage of the larger lifter diameter. As it is, they all seem fairly close. the .470 wouldn't require mods on the guides and would be nicer to the rocker arms, seems like a good choice. page 154 http://www.howardscams.com/howards2015.pdf Also, i really need to find a way to fit headers in this car.
It is not uncommon to see rocker tips like those shown. It is caused by a lack of oil through the shafts...to the rockers... to the valve tip. Generally speaking, due to sludge buildup inside the rocker shafts. As Gary stated, check the shafts and the rocker bores for galling. DO NOT SKIMP WHEN CLEANING THE ROCKERS. PULL THE END PLUGS IN THE SHAFTS. (I cant stress that enough)
I wish I had known back when I got this motor, I drove it for a year back in 1999 all sludged up. I'm going to pop the end caps off, check the shafts and clean the good rockets and the stands with an ultrasonic cleaner and brushes for the oil p***ages. I want it to oil correctly.
Glad you are heading in this direction.Can you post pics of the firesweep? No reason,just an old favorite.
FWIW in 1958 Chrysler had to say this about p***enger car cylinder taper requiring boring, and cylinder cleaning .
If all else is still in decent shape then run a drill bit through the oiling holes in the rocker arms to make sure that they are clear. Do not rely on a hot-tank or ultra-sound to clean the **** from these small p***ages. Do not use a drill motor, just your fingers..... .
Did you take your cylinder measurements on the piston pin sides or the thrust sides? Typically the thrust sides will have more wear.
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