Hey Jeb,
I ain't none too smart, so I ain't got no good advice fer ya...
Udder 'n... "Don't you take that Duster apart!!"
I sent you a PM that might help.
| Slant Six Forum https://www.slantsix.org/forum/ |
|
| Advice needed on engine rebuild (teardown pics added 8/9) https://www.slantsix.org/forum/viewtopic.php?t=49484 |
Page 1 of 3 |
| Author: | Jeb [ Sat Aug 04, 2012 7:07 pm ] |
| Post subject: | Advice needed on engine rebuild (teardown pics added 8/9) |
In a nutshell, something went horribly wrong inside the #6 cylinder of my truck and now it's skipping, fouling plugs on that cylinder, and has tons of blowby. I really didn't need this to happen right now but with 230,000 miles on the engine I guess I should have been planning for it. So, it looks like I've got a rebuild in store. I've got a 74 engine in my Duster that I plan on pulling and getting rebuilt so I can still use my truck. I plan on doing a pretty much stock rebuild (for quick turnaround) except for shaving some off the head and maybe a better cam (hydraulic lifters). Anybody have any advice or pointers on what to have done and what cam to get? I'm not looking for a road burner, just something reliable and torquey. |
|
| Author: | Fopar [ Sat Aug 04, 2012 7:21 pm ] |
| Post subject: | |
Biggest and cheapest gain would be to raise compression cut block or head. Richard |
|
| Author: | hantayo13 [ Sat Aug 04, 2012 7:31 pm ] |
| Post subject: | |
74 engine is solid cam/lifter..many choices ...cut head /block ...bigger valves ....roller timing chain ... 340 valve springs...super six/four bbl ...duta duels/ larger exhast...improve ingition system kepp on roddin' |
|
| Author: | ceej [ Sat Aug 04, 2012 7:33 pm ] |
| Post subject: | |
So your going to move all the hydraulic stuff over to the 74 engine. Head, cam, and all the valve train stuff? The mechanical profile cam won't be ideal with hydraulic lifters. Don't forget to mark which lifter comes out of which lifter bore if your going to run the old cam. Better yet, since the lifter bores are unlikely to be identical in the '74 block, plan on new lifters, and full run in. There are some better performance slushy cams, they are limited however. If your that stuck on not adjusting valves every ten thousand miles or so, that's OK. There are advantages to the hydaulic arrangement. When you cut the head, you need to account for where the hydrualic lifter is going to run. It needs to be set up correctly, or it won't function right. Maybe Reed will have some input for you. Adjusting valves in a van is a royal pain in the putukus, so he's done a lot with them. I think Duster Idiot was building a slushy for performance. Probably others as well. I would install the '74 engine as is with the mechanical valve train. Tear down the old engine, fix whatever has gone wrong, and reinstall if you wish to stay with hydraulic valve train. It should work fine with the existing stack and ignition in the truck. CJ |
|
| Author: | Rob Simmons [ Sat Aug 04, 2012 7:43 pm ] |
| Post subject: | |
Hey Jeb, I ain't none too smart, so I ain't got no good advice fer ya... Udder 'n... "Don't you take that Duster apart!!" I sent you a PM that might help.
|
|
| Author: | Jeb [ Sat Aug 04, 2012 8:07 pm ] |
| Post subject: | |
Sticking the 74 engine "as is" in the truck is not an option, as it is in much worse shape than the current engine in the truck. It was parked because of rod knock and extreme blowby. If it wasn't for the 3-4 month turnaround at the local machine shop I would go ahead and pull the truck engine and get it redone. Anybody know of some good machine shops in GA that are familiar with slants and can get my short block done and heads spiffed up in about a months time? What are thoughts on just keeping the stock hydro cam and cutting a little off the head to get the compression into the 8.5 range? I'm pretty happy with the way it ran before, just needed a little more oomph to push that brick down the road at 60 MPH. Plus I have an Offy 4v intake on the way and I plan on purchasing a set of Dutra Duals from Doc. I really don't have any budget constraints on this build, just time constraints. Rob I appreciate your help, but I think that engine is just a little too hot for truck. |
|
| Author: | Reed [ Sat Aug 04, 2012 9:28 pm ] |
| Post subject: | |
If you want a quick turn around, try and find a good used motor. If you want tips about building up a hydro motor, I will tell you what I know. A while back, a member spent a great deal of time researching various hydraulic cam profiles expressly for the purpose of building a torquey but fuel efficient slant. I don't have the link handy, but I will try and find the thread. My recollection was that the best combination for low RPM torque and economy was the stock hydraulic cam with the compression raised through head or block milling. In a 200+k motor, I would assume you need at least a rering if not an overbore and head rebuild. The only way to tell is to tear it down and start measuring. Take the time to calculate your target dynamic compression ratio and figure out how much material must be removed from head head or block to get you where you want to go. The only tricky part is remembering that if you shave the head or block beyond the free travel in the hydraulic lifter you can end up bending pushrods. However, I think the benefits of the hydro motor in a daily driver is worth it. The hydro motors were lighter and no adjusting lifters is a nice bonus (I'm lazy, and adjusting lifters in a van is a PITA, especially cylinder #1). My recommendation would be to pull the motor, find out what needs to be done, do the measurements and calculations to maximize dynamic compression and still run regular gas, then do the calculations to see if you need to get shorter pushrods. Keep the stock cam. When it comes to building daily driver truck or van motors, smaller cams and carbs are usually better. |
|
| Author: | Reed [ Sat Aug 04, 2012 10:18 pm ] |
| Post subject: | |
HERE is the thread I was thinking of. Skim the first few posts and start reading in detail around the bottom of page one. A tremendous amount of research was done there. |
|
| Author: | Jeb [ Sun Aug 05, 2012 7:33 am ] |
| Post subject: | |
Thanks for the links Reed, looks like I'm going to keep my stock cam and just do a mild bump up in compression. I'll have to wait until I can get the head off to CC everything and measure how far down in the hole the piston is. I'm curious to know just how bad the factory C/R really is. Also, is there just a generic "be on the safe side" number for shaving the head so the DCR doesn't get too high? I was think .030-.040 off the head or block would do good for a brick with 3.25 gears. |
|
| Author: | DusterIdiot [ Sun Aug 05, 2012 9:49 am ] |
| Post subject: | Not really... |
Quote: I'm curious to know just how bad the factory C/R really is.
You won't know until you measure the deck height and figure out how you are going to 'index' your cam....DCR calculator will determine this once you have the numbers...with a truck I'd shoot for the mid 7's on DCR, close to high 8 or low 9 SCR... Factory SCR once you measure is going to be in the 7:1 range if nothing else had been done to the motor previous to your rebuild.Also, is there just a generic "be on the safe side" number for shaving the head so the DCR doesn't get too high? I was think .030-.040 off the head or block would do good for a brick with 3.21 gears. -D.Idiot |
|
| Author: | Jeb [ Sun Aug 05, 2012 10:13 am ] |
| Post subject: | |
Thanks for clearing that up. I'm going to start removing stuff today and go by the machine shop tomorrow to see how backed up they are. Once I get the engine out I will get all the measurements and report back here. Any recommendations on what brand of pistons? I plan on getting it overbored to whatever it will clean up at. Sure would be nice if my offy intake would arrive in time to be part of this build. I'm sending out a manifold this week for Doug to modify for a Dutra duals. |
|
| Author: | Rick Covalt [ Sun Aug 05, 2012 11:16 am ] |
| Post subject: | |
My 2 cents. It is not possible to do any type of rebuild , even stock rebuild, for 2-4 times what you can buy a decent used engine for. If you can take a week or two and really look you can probably pick up an engine for a couple hundred bucks. Then take your time and do a rebuild the way you want for your truck without rushing it. I picked up a jasper rebuild with just a couple 1000 miles on it for $200. It is currently in my Valiant. There is a mid 70's engine setting in my garage that Ryan picked up complete for $50, with under a 100,000 miles on it. I was offered a 170 at Carlisle a few years back for free. There are plenty of slants out there for cheap. Last time at the strip, I had 3 people come up to me and want to sell me there "old" car setting in the barn with slant 6's in them. You may be able to pick up a rusted hulk of a car with a good running engine in it for $3-500 and pull the motor and get $200 for scrap. Think it through, and you will be fine!! Rick Rick |
|
| Author: | Reed [ Sun Aug 05, 2012 12:23 pm ] |
| Post subject: | |
Quote: It is not possible to do any type of rebuild , even stock rebuild, for 2-4 times what you can buy a decent used engine for. If you can take a week or two and really look you can probably pick up an engine for a couple hundred bucks...You may be able to pick up a rusted hulk of a car with a good running engine in it for $3-500 and pull the motor and get $200 for scrap.
Excellent points. For example, here is a $150 74 Duster shell with a running motor in the Atlanta Craigslist. Looks like a solid shell, so it would be a shame to strip it and crush it, but you gotta do what you gotta do.
|
|
| Author: | Jeb [ Sun Aug 05, 2012 4:53 pm ] |
| Post subject: | |
Thanks everyone for the input. I've decided to stick with this engine and just get it redone for now. Everything will be stock H/D components, with the only performance mods being upping the compression and a mild port job on the heads. I managed to get everything off the engine today. All that remains is to remove the hood, unbolt the trans & torque conv., and remove the engine. Ultra crappy cell phone picture of today's progress: 
|
|
| Author: | Rug_Trucker [ Mon Aug 06, 2012 3:25 am ] |
| Post subject: | |
CNC-dude is in Georgia. PM him for machine work. |
|
| Page 1 of 3 | All times are UTC-08:00 |
| Powered by phpBB® Forum Software © phpBB Limited https://www.phpbb.com/ |
|