Sucks about the bearing problems. I'm pretty sure i got mine from Rockauto and i had no issues. There are differences between the cast and forged cranks as already mentioned. As far as getting V8 bearings, the early forged motors actually share some bearings in common with a big block mopar if i remember correctly. It's all in that Doug Dutra book.
As far the cam thrust control, as mentioned the back of the cam gear serves as thrust control going rearward. Thrust control going forward comes from those oil pump gears! The resistance of turning the pump creates a rearward force that keeps the cam from wandering forward.
I think the slant six has a reputation for being a very reliable bottom end, but i dont know how much of it is myth and legend. I have 2 of these motors and both of them had spun #1 rod bearings. One crank had already been welded and one needed to be. As far as just the main and rod bearings the oiling system is perfectly symmetrical front to rear with the oil pump in the exact middle and #1 and #6 are at the ends. But, if i remember correctly the front main bearing intentionally leaks some oil to the front to lubricate the timing chain and the rod gets lubricated AFTER the main bearing, so i think #1 rod bearing is one weak link in the oiling system.
My block was ground on in the cam gear thrust surface to create an oil channel outward, probably to improve chain lube. Is that too much leakage? It correlates with the bearing damage since front cam and main bearing are T'd off the same supply and leaks in either would reduce pressure at the #1 rod bearing, BUT i know for a fact this engine spun #1 rod bearing after being run with no oil after a botched oil change 15 years ago. So I'm not sure where this issue lands between '#1 rod bearing will wear faster' and '#1 rod bearing will definitely fail in a short amount of time' and I haven't put enough time on the motor to find out the hard way! If it fails again or wears fast and i actually notice, I will probably fill that groove in the block.
Rear cam bearing also sends some oil up to the head for the rocker shaft but I believe it's actually less than what's leaked out the front. The design of the system definitely suggests that #1 and #6 rod bearings are most likely to be damaged out of everything.
Yep, mine had the #6 rod bearing come apart when the oil pick-up clogged, all five other rod bearings looked OK.
Mr_Asa said:
Interesting that there are only 4 main bearings in there. The weakest Ford block I know of (post '62) had 5 main bearings, most of them had 7.
Any concerns with the bottom ends coming apart on the Slant Sixes?
Chrysler's strategy was to make the main bearing journals very large to make up for the smaller number of bearings. Between the four bearings and the long stroke on a 225, these motors don't like to rev. Which is why I've opted for boost instead. 
The crank is in the block again, with the upper main bearings and rear main seal in place.
Before I can get the caps in place to check bearing clearances, I need to clean the main bearing caps and rear main seal cap - a lot.
Dealing with the rear main seal with the engine out makes me wonder about an automotive version of "Would you rather?":
- Change a rear main seal with the engine in the car and the car on jackstands
or
- Pull the engine just to change the rear main seal?
More work cleaning the bearing caps, still have a bit of crud caked on. Not sure if I should try a bit more cleaning, or figure that if the solvents I've already tried didn't take the baked-on oil off, that it won't come off.
I wonder if Maslow had a large Makita drill? Because when all you have is a Makita drill, sometimes it seems like all your problems can be solved with the right attachment.
The end result.
Next step, check main bearing clearances with Plastigage before considering the crankshaft finally in place.
Looking cool. Maybe your crush measurement is too small? Something to look into if it isn't fixed this time around!
CatDaddy said:
Looking cool. Maybe your crush measurement is too small? Something to look into if it isn't fixed this time around!
The main problems I've been having with main bearings have been with catalogs that were either off by two cylinders or one decade. I've finally found the correct ones.
Lookin good.
I was super apprehensive about the rear main seal when we put ours together. Turns out that doesn't leak, but the front passenger corner of the oil pan where the oil pan and timing cover gaskets come together does. And i was SUPER fastidious doing the oil pan gasket. So now im remembering to be annoyed about that again.
I got lucky off a CL email alert for possibly the first time in years (pour one out for CL..) and got a FREE 'ran when pulled' 225 from a guy who pulled it to put a v8 in his Dart. The car was gone and guy said it was a 71, but I dont think it is. Its got a factory 2brl intake and the head has the rear coolant port and no spark plug tubes. I seriously have not read the numbers off the side yet but im hoping its a slightly later but still forged crank engine. The style doesn't really matter but I think i have more leftover forged crank parts than cast crank parts. This one will be built for my RV one day, theoretically. The RV came with a bored block and all the rebuild parts to put it back together, but it had all been apart so long that everything was rusted up. The last core i bought for it turned out to have some serious cylinder water damage and also have a 'poorly repaired' welded up crank journal.
Vigo (Forum Supporter) said:
Lookin good.
I was super apprehensive about the rear main seal when we put ours together. Turns out that doesn't leak, but the front passenger corner of the oil pan where the oil pan and timing cover gaskets come together does. And i was SUPER fastidious doing the oil pan gasket. So now im remembering to be annoyed about that again.
Yep, I had a case of the rear main seal being OK and the oil pan leaking earlier too. Hopefully it will be easier to make sure everything's set up corretly with the engine out of the car.
Those corners cam be a bit of a bear to reseal properly on the slant 6 sometimes without first setting the pan and gaskets on, Using a bit of gasket shellac to hold stuff in place, Adding copious amounts of RTV, getting the bolts started but not tight.... let the RTV Flash off over night, then fully tighten the pan bolts down.
I have had some success with this technique.
Greg
Has anyone tried using a sealant (Right Stuff, FIPG, etc.) rather than a gasket for the oil pan? My experience is mostly with Toyotas, but it's typical for them to use FIPG sealant rather than a gasket, and it works very well - far better than the oil pan gaskets that the corner stores sell because customers still assume that all engines use them.
Mr_Asa
UltraDork
1/25/21 11:55 a.m.
In reply to slantsix :
I've heard from experts in the field that that is basically the way you're supposed to use RTV. Not necessarily the copious amounts, but letting it set for a decent amount of time, then tightening it.
I always tighten till I see it squish out just a hair, then leave it for 4 hours and come back to it.
In reply to Mr_Asa :
Yes that's what I think I mean.
I have had not such good luck when just laying a bead and then bolting together - sometimes the rtv is so slick and slippery i just allows the gaskets to push out / slide out. - Maybe my copious amounts remark is not accurate either.
Greg
In reply to DarkMonohue :
can the right stuff sealant seal gaps 1/2" to 1/4"?
That's what is needed by the corners of the front gasket on this engine's application where the timing cover and oil pan converge.
Greg
In reply to slantsix :
I'm trying to find pics to see what you mean and not having great success.
Just to make sure we are on the same page, I'm wondering whether it is viable to use FIPG, Right Stuff, or similar in place of, not in addition to, the gasket set. I suppose it could also be used as a gasket sealant or adhesive, but it really seems to work well in place of a traditional gasket.
In reply to DarkMonohue :
I will get you a picture of what I am talking about later.
Greg
DarkMonohue said:
In reply to slantsix :
I'm trying to find pics to see what you mean and not having great success.
Just to make sure we are on the same page, I'm wondering whether it is viable to use FIPG, Right Stuff, or similar in place of, not in addition to, the gasket set. I suppose it could also be used as a gasket sealant or adhesive, but it really seems to work well in place of a traditional gasket.
The slant six oil pan gasket is a four piece nuisance. The sides both seal to the block and use thin cork gaskets. The oil pan sealant would work there. But both ends use rubber gaskets - the back seals to a cap over the rear main seal, and is relatively thin - except for thick rubber blocks on the end. But the front of it seals to a curved, stamped timing cover, with a very thick rubber gasket. Here's a picture of what the gasket set looks like. The top one is the front of the oil pan to the timing cover, and the one just below it goes on the back of the motor.
slantsix said:
In reply to DarkMonohue :
can the right stuff sealant seal gaps 1/2" to 1/4"?
That's what is needed by the corners of the front gasket on this engine's application where the timing cover and oil pan converge.
Greg
I've used it to seal a 3/8 gap between an intake manifold and the China walls, on a V8 where the CNC block mill went a little overboard when cutting them to compensate for decking.
Not only did it not leak, but when I had to remove the intake manifold, I was lifting the engine out of the car with a cherrypicker, by the Right Stuff. I ended up slicing the Right Stuff with a long thin knife until I could wedge the manifold out with a prybar.
It's urethane based, not silicone. A lot closer to windshield adhesive than RTV.
Here are some up close pics and measurements of the front Timing cover / oil pan gasket:
20210125_202607 by Hyperpack, on Flickr
20210125_202618 by Hyperpack, on Flickr
20210125_202626 by Hyperpack, on Flickr
20210125_202636 by Hyperpack, on Flickr
20210125_202643 by Hyperpack, on Flickr
20210125_202704 by Hyperpack, on Flickr
20210125_202710 by Hyperpack, on Flickr
For Me that's a lot of solid mass to try to replace with goo.
I suppose it could be done, but i don't think I am ready to try it until I have a buncha time to fail and clean up the mess a few times.
Greg
Kind of a peculiar shape on that front piece. I assume there's a similarly shaped void that the sealant would have to fill if it were to replace that piece, and there appear to be metal collars molded in to act as spacers to prevent crushing it between the pan and block. Is that the case?
I would be tempted to retain those rubber end pieces, but coat the mating surfaces lightly with FIPG (or Right Stuff or Hondabond or whatever your particular religion dictates), and use the same sealant in place of the pan rail gaskets, as Matt mentioned.
In reply to DarkMonohue :
Yes I would suggest to retain it as well, Just coat it the the Right Stuff sealant.
Greg
Plastigaged all the main bearings.
They all measured within spec, around 0.002" or just a little less.
Now, time to install the crank sprocket (it has several keyways to allow adjsuting the cam timing) and degree the cam. I found a very cool printable cam degree wheel generator here:
https://www.blocklayer.com/degree-wheeleng.aspx
You can put in your cam specs and have it mark where everything should be opening.
Unfortunately the crank is missing its key. And the pack of Woodruff keys from the local parts store is way off...
And the local parts stores all seem to be out. So I'll see if I can salvage the key from the spare crank in the picture. First, get a puller and pull the sprocket...
Removing the sprocket was straightforward enough. Unfortunately, the only way I could find to remove a Woodruff key combined two words that don't belong in the same sentence, "carefully" and "hammer". But it's either that or set this back another week...
Fortunately, the key came out intact.
I deburred the edges with a Demel and used a C-clamp to put it into the crank in the engine.
I used an old crank pulley as a makeshift installation tool. It looks like the sprocket is taking too much force to install, though; looks like I'll need to hone it. This is a common complatint on Rollmaster timing chains - on the other hand, nobody else is making a decent performance chain for these motors.
I would coat that with anti-sieze before assembly. It will slide on a little easier, and if you ever have to remove it again it might come back off.
Matt, hone or put a sanding band on a dremel and sand the I.D. a bit.. it will help with the press on the crank.
Greg
Actually, I've found a pipe fitting that looks like it makes the perfect installation tool for that sprocket.
