Yes, go ahead and do an inspection of the lower end- - - -look for whether or not the crankshaft has been reground, and what condition the connecting rod and main bearing journals are in. If the crank isn't scored or ground way undersize, that's information you'll need to know before some machinist starts adding up figures on his calculator at warp speed. Most professionals don't like to regrind cranks more than .030" undersize. Cylinder bores usually max out at .060" oversize, although some people are willing to go to 80 over. You'll also be wise to get the big ends of the connecting rods reconditioned to assure good bearing fit and the proper oil clearances.
If you're planning to do any serious engine building, here's a handy tool. It's how the pros check for cylinder taper instead of doing the ring and feeler gauge trick, plus it's handy for checking bearing bores and reconditioning connecting rods, etc.
Along with a good set of inside and outside micrometers, you'll be able to "test, not guess" where engine dimensions are concerned. Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
But I will likely look to a professional regardless.
If that's that, then perhaps in the meantime I can look to get some advice on what changes I need to make to the engine to make it a compatible swap with my 216.
Some things I need to look at: Front plate - I have one with the center mount holes to put in Fuel pump - keep 261 one in place? Carb - which to use? Was thinking one with manual choke so that I can keep my dash knob Clutch/flywheel - I think use one off 216 Waterpump - buy low profile? Or adapter plate? What about the by-pass for coolant? Rad - original sufficient? Trans - engine came with an automatic, but from what I heard, it's two speed and not worth using, plus I prefer standard....
So I will be making some calls to figure out where to go for my next steps. In the meantime;
I'm going to assume that I should be keeping the bowl-less fuel pump and putting a filter after it, before the carb? The 261 currently doesn't have a filter plumbed in...
Spoke with my local machine shop today, who was suggested to me from a mechanic friend and their quote was about half of the numbers I was originally provided. In reading through other threads, one of the big concerns with having heads machined is that the exhaust valves can potentially hit the pistons. Are there any other issues that I should bring up to make sure there are no surprises down the road?
Intake valve to piston contact is only a concern if the head is milled a lot, or a non-stock camshaft is used. The Elgin E-293S camshaft is an exact duplicate of the solid lifter cam used in the 261 truck engine, except for a slightly different lash specification. There is also a cam made by Melling (CCS-1) that has slightly more exhaust duration than the Elgin cam that would also work with a 261 engine without any piston to valve clearance issues. The exhaust valves simply cannot touch the piston because of the angle they're installed in the cylinder head and the shape of the combustion chamber. One thing your machinist might not know is that stovebolt exhaust valves are identical to the ones used on small block Chevy V8 engines, and good quality stainless steel valves are available for very low prices. Given that fact, it's not practical to regrind exhaust valves- - - -just replace them with better than new quality stainless valves. It's also NOT necessary to install hardened exhaust valve seats unless you're planning on running Propane or natural gas instead of gasoline, or doing a lot of full throttle operation with maximum gross weight loads. Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
Making notes of all these things, thanks. The cam in the Canadian Pontiac 261's is the same one used in the early Corvettes. I have one in the shop, I will see if I can get some #'s off it.
Hmmmmm- - - - -better re-think that- - - - -Corvette used the same cam as the 261 medium/heavy truck engines, which was a solid lifter cam. The Canadian Pontiac used a hydraulic lifter cam, which may, or may not have the same duration and lift as the truck cam. It will definitely have a different lobe profile, as hydraulic cams don't have the same acceleration and clearance ramps as solid lifter types. Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
That's a cast iron cam- - - - -forged steel ones would have a stamped number, if they have any ID at all. Also, the same casting can have all sorts of different lobe shapes ground onto it. You're much better off with a new cam and the correct lifters to match it than making some sort of a SWAG about which used part you have. If you have a few decades of race engine building under your belt, dig out the degree wheel and a dial indicator, and plot your own cam duration and lift curve on a piece of graph paper. Then you'll know exactly what you have. Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
Fuel pumps are not to expensive ,for piece of mind maybe new would be good idea ,fuel filter good idea ,I am planning on one under tank and one after fuel pump.
The one on the left came with the last 261, on the 848 head. The one on the right might be from a 235. I think the one on the left is newer and might have a larger intake, but it has a autochoke and I would like to use my manual knob. Any chance I could remove the auto and add a linkage?
I would like to make sure I have all the parts I need for when this goes to the machine shop. From many opinions, it seems that the 216 pump, pulley and balancer should be moved to the 261, with the adapter plate. Before I pull the trigger on pre68dave's adapter plate, is this the best way forward? I'd rather have the shop drill and tap the block, since it's going there anyway. Thanks!
Do you have the original Canadian Pontiac 261 with hydraulic lifters?
As you most likely know, the hydraulic lifters (used in Canadian Pontiac 261s) and the mechanical lifters (used in all USA and Canada truck 261s) are adjusted differently.
Tclederman - do you bring this up for me to remind the machine shop? I will add ot to my notes for them if so. I have the manual for the engine, so when the time comes to do maintenance, I will double check it. It is a true Canadian 261.
Kevinski - one looks like it's bigger than the other, when looking down the barrel. Is there a big performance difference between them?
In regards to the carb ,did they come off of the 261 engines that you got .not the spare one that was with the 216 head.Look from the bottom the top is bigger on the one with the auto choke for a different air cleaner.the carb that came with the 216 head is basically the same but the base is smaller so keep it for parts although some internals may be different but can be switched .
One carb off the Pontiac 261, the other off a 261 with I expect a 235 head. So, as long at it's not a 216 carb, there shouldn't be much of a difference? I would prefer the 235 carb, as it has the manual choke and should fit the original air cleaner. BUT I didn't want to miss out if the other carb was something special
I am no expert and am learning also ,the 261 carbs have possibly a bigger jet in the internals ,the car carb from the 261 may have that jet and may or may not be the same as in the Manuel choke carb ,also the 216 carb is the same with exception to the base (the two big bottom slotted screws ) the top of the 216 carb should be the same with the exception of the jet as stated above .I am shire somebody will correct me if I am wrong but you have a good selection of parts to make up a good carb for you engine
My research lead me to the conclusion that the 235 carbs are 210 cfm and the 261 are 250 cfm. I recently installed a fresh 261 but used the carb of my 235 for initial start up as I knew it worked . I've managed to do about 1,500 miles since and will install the 261 car over the winter at which time I might be able to tell how much of a difference there might be . The 261 carb came with a auto choke , but the top was changed to accommodate the manual choke .
Thanks for the details, I would very much be interested to hear how this works out for you. On the 261 carb that you changed the top on for manual choke, any chance it would also allow for ise of a 235 air cleaner?
I have a factory oil bath filter on it now and plan to use the same filter with the 261 carb. The top part of the carb should be inter changeable to accommodate your original filter . I see you live in Ontario , I live in Whitby and have a number of carb. cores if you need something .
If its a true pontiac 261 then the block is drilled for hydraulic lifters. That means you have your choice of using hydraulic lifters or solid lifters. If you want the motor to be quieter, then order a hydraulic grind cam and dig up some nos gm lifters. A 55-58 block, use 55-58 GM 235 hydraulic lifters, and a 59-62 block uses a slightly different lifter so use the 59-62 GM 235 hydraulic lifter. These lifters can be a little bit of a bear to find so be patient but real GM, or aftermarket nos that are at least 30 years on the shelf. If you decide to use mechanical solid lifters, use the solid lifters from a 56-62 261 truck. Do not use the milk bottle style lifters, they are a different design, for a different cam and cam material and an earlier motor (54-early 55). Also, you have to have the cam ground for mechanical lifter use. The cam lobe design is different depending on the lifter so you want to use a cam made for the type of lifter you will be using.
Actually no but that would be a logical description. the lifter on the left is what is commonly called a milk bottle lifter. Completely flat sides, looks like a milk bottle or milk can. The lifter on the right is a solid lifter for the 56-62 261 truck motors. I have seen the lifter you have once in a while. Its aftermarket (I think, but only because I have never pulled one from any of the motors I have ever taken apart, only seen them as sealed power lifters) and I have never used that style myself so I cant opine on whether you should use it or not. I never liked the design so I never used it. I always used the version that mimicked the hydraulic lifter design when I was retrofitting solid lifters into a hydraulic lifter motor.
I know it's been several posts since this went by but do not use the fiber timing gear. Use an aluminum one. Fiber ones will shred suddenly leaving you stranded. In the process it will take out a cam lobe or two costing you a cam.
Speaking of cams, there are steel ones used on early engines and cast iron used later on. You must use lifters compatible with the cam you have and I don't mean just solid or hydraulic. The material must be compatible. Plus if you use a cam with a taper ground on the lobes the lifters must be radiused to match. Hopefully the cam grinder will tell you. Dave Crower offered to do this for free if I sent him the lifters but I developed a way to do it myself. I had bought the custom grind cam from him. Just so you know. I have been told this isn't an issue on our Stovebolts as the lifter bores are off-center to the cam lobes so tapered lobes aren't necessary. You should check on this issue. It could save you a bunch of grief.
1951 3800 1-ton "Earning its keep from the get-go" In the DITY Gallery 1962 261 (w/cam, Fenton headers, 2 carbs, MSD ign.), SM420 & Brown-Lipe 6231A 3spd aux. trans, stock axles & brakes. Owned since 1971.
Thanks 1Ton, the fiber gear cam was used in Canadian Pontiac 261s. What would be different in the truck that would cause it to fail? I am documenting your suggestions for when I get to that point. Thanks
What 1Ton is saying is excellent advice. US 235 motors used a fiber cam gear. It was used to reduce noise. The problem is that the fiber gears would let go, self destruct so to speak, and take some of the gear teeth off. Depending on the position of the cam at the time to gear let loose, you could end up with bent intake valves, among other damage. The repair is a big pain. Valve job and You either pull the motor and the cam, and replace the gear, or do the job in the chassis which was also a big giant pain. See the early Chilton's car manual (the blue version) wherein they lay out the procedure for replacing the gear in the vehicle.
On the other hand, because noise was not so much of an issue for the trucks, GM used an aluminum cam gear on the 261 Chevy truck motors. Now, you have a Canadian Pontiac passenger car block. That motor got a fiber gear for noise reduction. As it turns out, there is no discernable difference, at least that I have ever been able to hear, between the fiber gear and the aluminum gear. On the plus side, the aluminum gear is way stronger then the fiber gear. So for many many years now, the common wisdom is to use the truck gear set in a 235 or 261 rebuild. I am not even sure that you can get a new manufactured fiber gear set.
On your camshaft, 1Ton is also 100% correct. If you don't know what the material is, you will need to find out, or better yet, just get a new cam. They are not that expensive. If it turns out you have a cast cam, send it out and have it reground. Nice fresh cam and lifters. The other thing is, you should not (I would say you cant) mix the lifters up if you are going to be using a used cam and lifters. Each lifter must go back to the exact same cam lobe from which it was removed. Way too much risk in taking out a cam lobe by mixing them up. If in doubt, regrind. Also, and I have never done this myself, but at least one of the small cam grinders will also regrind solid lifters.
Lots to consider here. I have two sets of cams/lifters that I'm going to bring to the machine shop to deal with. Any advice on where to find an aluminum gear? Would any 235/261 be compatible?
Head is good! Mentioned to the machine shop about the smallblock exhaust valves and that hardened seats weren't necessary. Sounds like they know what they're doing. Guess it's time to look into the waterpump adapter and new gear for the cam sooner than later...
The Melling CCS-1 solid lifter cam has a slightly more radical grind than the 261/Corvette cam, without cxreating any loss of low end torque or a choppy isle. It's also less expensive than the Elgin clone of the 261 cam that we used in John's engine buildup. I'll be machining the bearing journals down on one of thosr cams to fit into the block of the "sleeper 216" I'm building. It's also possible to sleeve the lifter bores down a little and use the MOPAR/AMC/Ford V8 solid lifters that are lighter weight, more available, and cost a fraction of what the stovebolt lifters do.
Don't even consider putting a used cam and lifters into a fresh engine build- - - - -trash 'em and buy new. If even one lifter gets installed out of its former position where it ran on the camshaft originally, it will wear out the lobe in a very short time. Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
Jerry, I know you've mentioned the Melling cam before, but I must be missing something. Looks like the Melling CCS-1 cam is milder than the Elgin 261 cam (E-293S) based on duration specs at 0.050" and lower total valve lift. Images are captures from the Elgin and Melling websites. I should add, when I've used the 261 cam which opens a bit late, perhaps, I have advanced it using a 4 degree offset crank key, and that seems to make good low end power.
