Rusty Scout
Member
Are 304 exhaust manifolds same as 345?
350 Buck Truck Project engine revival
- Thread starter Rusty Scout
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Michael Mayben
IHPA Tech Moderator - Retired & No Longer Online
All I-4 and sv exhaust manifolds are basically the same as far as the mounting pattern/port location on the heads. There are some detail differences regarding whether a hot air choke was incorporated, an air compressor (medium duty app with air brakes) mounted, etc.
For rear dump manifolds, there is of course a distinct passenger side and driver side orientation, not so for center dumps. That is why the rear dump units are more difficult to deal with,...the production numbers were very low as compared to center dump.
Then the last generation center dump manifold were done with a three hole mounting flange for the headpipe, that was after the light line production ceased and these would have been installed oem on many medium duty and school bus chassis.
Rusty Scout
Member
I procured a costly passenger side rear dump in great condition. Ka-ching! Just in case.
Rusty Scout
Member
The moral of the story is if your gut feeling is that you might break a rare hard to find part you will.
I got the original manifold back from my welder for $30 bucks worth of welding and it looks like it May just work. If not then I got a backup on hand. Plus I know where a complete set is sitting in a yard for 66 bucks total but I got to pull it myself. They look good too.
Getting closer. Today the water pump housing and water tubes went on. Orings slathered in hylamar.
Still having fun but this engine May have to go in a museum cause it might get dirty in the truck.
I got the original manifold back from my welder for $30 bucks worth of welding and it looks like it May just work. If not then I got a backup on hand. Plus I know where a complete set is sitting in a yard for 66 bucks total but I got to pull it myself. They look good too.
Getting closer. Today the water pump housing and water tubes went on. Orings slathered in hylamar.
Still having fun but this engine May have to go in a museum cause it might get dirty in the truck.
Rusty Scout
Member
A little closer.
Which fan is better and should be used? The aluminum fin fan that came with the 1975 150 (more fins , probably not stock, with a spacer, no clutch) or an original I just scored from the wrecking yard off a 1974 200 with a 345 no a/c built 9/73 (no clutch, no spacer, slightly larger diameter than the one I got, steel fins, less blades, and seems like I was first to ever remove it).
Which fan is better and should be used? The aluminum fin fan that came with the 1975 150 (more fins , probably not stock, with a spacer, no clutch) or an original I just scored from the wrecking yard off a 1974 200 with a 345 no a/c built 9/73 (no clutch, no spacer, slightly larger diameter than the one I got, steel fins, less blades, and seems like I was first to ever remove it).
Rusty Scout
Member
Michael Mayben
IHPA Tech Moderator - Retired & No Longer Online
I like the rusty fan steve...goes with the big picture!
I do not like those aftermarket fans, my history with that stuff is not good.
The offset to the oem fans is a methodology for reducing fan noise, it's certainly not a detriment to air flow whatsoever.
Since you aren't using a viscous fan clutch (I have no problem with that, one less item to fail), just install an appropriate spacer to set the fan in the shroud so that approximately the front two-thirds is inside the shroud, the rear one-third is outside the shroud. The spacer/hub must fit the center hole in the fan snugly and the rear side of the spacer must fit the nub on the water pump hub firmly also, that is what aligns the assembly so that it runs true.
I have all kinds of fan spacers here, they can be "stacked" together if needed to achieve proper distance, but there is a limit to the stickout of multiple fan spacers though, don't try for more than abut 3". Let me know if ya need one or several, I collect this stuff and have a great source for many more (boxes full!!!).
Another tip...when you install the pulley stack on the waterpump hub, discard the oem phillips head screws and use allen head capscrews instead. Much easier to deal with if ya ever have to remove the pulleys later with the engine installed.
Good pics of the true "side mounts" used on the '74/'75 fullsize stuff! I had a dude asking about those justa few days ago and I had no pics for him! That illustrates the significant difference between that mount system and the semi-side mounts used on Scout II, and the block must be machined for those mount adapters, which is bit of a workaround if using an earlier block in a late fullsize vehicle.
I do not like those aftermarket fans, my history with that stuff is not good.
The offset to the oem fans is a methodology for reducing fan noise, it's certainly not a detriment to air flow whatsoever.
Since you aren't using a viscous fan clutch (I have no problem with that, one less item to fail), just install an appropriate spacer to set the fan in the shroud so that approximately the front two-thirds is inside the shroud, the rear one-third is outside the shroud. The spacer/hub must fit the center hole in the fan snugly and the rear side of the spacer must fit the nub on the water pump hub firmly also, that is what aligns the assembly so that it runs true.
I have all kinds of fan spacers here, they can be "stacked" together if needed to achieve proper distance, but there is a limit to the stickout of multiple fan spacers though, don't try for more than abut 3". Let me know if ya need one or several, I collect this stuff and have a great source for many more (boxes full!!!).
Another tip...when you install the pulley stack on the waterpump hub, discard the oem phillips head screws and use allen head capscrews instead. Much easier to deal with if ya ever have to remove the pulleys later with the engine installed.
Good pics of the true "side mounts" used on the '74/'75 fullsize stuff! I had a dude asking about those justa few days ago and I had no pics for him! That illustrates the significant difference between that mount system and the semi-side mounts used on Scout II, and the block must be machined for those mount adapters, which is bit of a workaround if using an earlier block in a late fullsize vehicle.
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Rusty Scout
Member
One more thing about my fans:
the rigid fan that was installed by the previous owner with the 6 aluminum blades measures 17" while the IH 200 fan I scored from the yard and looks to be factory measures 18". I would assume that correct fan diameter is as crucial as position in the shroud opening.
Is there a rigid fan out there that will provide better cooling than the stock 5 blade fan? Like say the all steel rigid flex a light racing fan or a derale rigid race steel blade fan. Both of these units are in the $30 range.
The reason I ask is rather than spend the time restoring a rusty 5 blade stock fan engineered for noise reduction, I would rather buy a fan that looks and works better. If there is nothing to gain on buying a newer rigid fan I will restore the rusty one.
Also I came across an interesting file on IH cooling specs...see attached
the rigid fan that was installed by the previous owner with the 6 aluminum blades measures 17" while the IH 200 fan I scored from the yard and looks to be factory measures 18". I would assume that correct fan diameter is as crucial as position in the shroud opening.
Is there a rigid fan out there that will provide better cooling than the stock 5 blade fan? Like say the all steel rigid flex a light racing fan or a derale rigid race steel blade fan. Both of these units are in the $30 range.
The reason I ask is rather than spend the time restoring a rusty 5 blade stock fan engineered for noise reduction, I would rather buy a fan that looks and works better. If there is nothing to gain on buying a newer rigid fan I will restore the rusty one.
Also I came across an interesting file on IH cooling specs...see attached
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Michael Mayben
IHPA Tech Moderator - Retired & No Longer Online
I've posted that extraction from an ihc sales engineering letter on other sites over the years steve, glad you found it. But it does not tell the whole story by any means.
There is nothing wrong with that oem fan other than it's looks. I'd have that cleaned up and ready to mount in under an hour!
There is no way to improve an oem cooling system that is certainly not under-capacity! The only way to improve a non-maintained system is to start from scratch and clean everything. You have already done that! The cooling systems on these vehicles was far from "broke" when they left the factory.
On the other hand, installing non-standard parts like that pos "flex fan" will create issues! I have no idea why folks do shit like that, I don't care what any smokeblow on "summit" or "jegs" claims, there is no way those fans can out perform a stocker. None of this "drag racing" or "performance" shit has any place on these vehicles designed and intended for use in daily service as trucks working under a full load continuously.
And obviously the 17" fan was a total fookup from a po, no way it can work with an oem shroud if it's diameter and pitch is not matched! Typical...typical. That's about as effective as those unknowledgeable folks who claim that a shrouded radiator system is not needed. I gayrondamteeya, if the shroud was not needed, there is no way a manufacturer would bear the cost of installing a shroud on every vehicle produced just so folks could remove 'em!
There is nothing wrong with that oem fan other than it's looks. I'd have that cleaned up and ready to mount in under an hour!
There is no way to improve an oem cooling system that is certainly not under-capacity! The only way to improve a non-maintained system is to start from scratch and clean everything. You have already done that! The cooling systems on these vehicles was far from "broke" when they left the factory.
On the other hand, installing non-standard parts like that pos "flex fan" will create issues! I have no idea why folks do shit like that, I don't care what any smokeblow on "summit" or "jegs" claims, there is no way those fans can out perform a stocker. None of this "drag racing" or "performance" shit has any place on these vehicles designed and intended for use in daily service as trucks working under a full load continuously.
And obviously the 17" fan was a total fookup from a po, no way it can work with an oem shroud if it's diameter and pitch is not matched! Typical...typical. That's about as effective as those unknowledgeable folks who claim that a shrouded radiator system is not needed. I gayrondamteeya, if the shroud was not needed, there is no way a manufacturer would bear the cost of installing a shroud on every vehicle produced just so folks could remove 'em!
Rusty Scout
Member
Ok well that rusty stock 18" fan has been restored: beadblasted and painted.
I guess what I was getting at in the last post was fan design. Is a 1974 5 blade oem fan going to move more or less air than say a 7 blade 1979 Scout fan? (I would love to understand more about the science behind the optimal number of fan blades and fan blade pitch.)
and another fan science thought: I assume for max air flow ideally there would be zero clearance between blade tip and shroud edge. But that's not possible due to frame and engine mount flexing caused by terrain and engine torque. I measured the 1975 pickall shroud opening and got 19.5" diameter. That leaves .75" clearance for the 18" fan. Better than what was the situation last time I had her running with a 17" fan in a 19.5 shroud but how much better?
Onward: next:
finish touching up engine (couple of minor bare spots)
finish the intake do dads ( kickdown bracket, choke spring housing, vacum fitting etc)
pre-oil engine with drill motor
install tranny linkge and lines
hang engine
I guess what I was getting at in the last post was fan design. Is a 1974 5 blade oem fan going to move more or less air than say a 7 blade 1979 Scout fan? (I would love to understand more about the science behind the optimal number of fan blades and fan blade pitch.)
and another fan science thought: I assume for max air flow ideally there would be zero clearance between blade tip and shroud edge. But that's not possible due to frame and engine mount flexing caused by terrain and engine torque. I measured the 1975 pickall shroud opening and got 19.5" diameter. That leaves .75" clearance for the 18" fan. Better than what was the situation last time I had her running with a 17" fan in a 19.5 shroud but how much better?
Onward: next:
finish touching up engine (couple of minor bare spots)
finish the intake do dads ( kickdown bracket, choke spring housing, vacum fitting etc)
pre-oil engine with drill motor
install tranny linkge and lines
hang engine
Michael Mayben
IHPA Tech Moderator - Retired & No Longer Online
First post from a new computer I got installed at 2am this morning! The old unit is terminal.
The fan blade is actually not even centered in the shroud opening, it's offset. That also has to do with air flow dynamics and reducing noise. There has to be much blade tip clearance to allow for the extreme amount of flex that the IH shit allows in the radiator core support area on both fullsize stuff and Scout II. That is why so many of the shrouds disappeared, the blade tips ate 'em, especially in an off-road situation and aggravated by totally crapped front engine mounts on the fullsize stuff. Same "flex" issue that cracks exhaust manifolds.
But that aftermarket shit you had is not anywhere near optimal! That was a simple scab job to simply fill the hole.
These engines are not difficult at all to cool using the oem parts and a engine block and radiator that is clean! Anyone who says otherwise don't know shit about cooling systems!! The cooling systems are very much "over-capacity", the hd systems for use with hvac are even more so, therefore the thermostat does a wonderful job in maintaining correct engine temp if it's the correct type of stat for the bypass. That is why it's optimal to run the rs 370 pattern stat.
A Scout II cooling system is about 20% "smaller" in heat exchange capacity, therefore they are not "over-capacity"...but rather right at minimum capacity for the application, considering they run the same engine packages as fullsize. You cannot compare a Scout II system with a fullsize system for that simple reason!!
The fan blade is actually not even centered in the shroud opening, it's offset. That also has to do with air flow dynamics and reducing noise. There has to be much blade tip clearance to allow for the extreme amount of flex that the IH shit allows in the radiator core support area on both fullsize stuff and Scout II. That is why so many of the shrouds disappeared, the blade tips ate 'em, especially in an off-road situation and aggravated by totally crapped front engine mounts on the fullsize stuff. Same "flex" issue that cracks exhaust manifolds.
But that aftermarket shit you had is not anywhere near optimal! That was a simple scab job to simply fill the hole.
These engines are not difficult at all to cool using the oem parts and a engine block and radiator that is clean! Anyone who says otherwise don't know shit about cooling systems!! The cooling systems are very much "over-capacity", the hd systems for use with hvac are even more so, therefore the thermostat does a wonderful job in maintaining correct engine temp if it's the correct type of stat for the bypass. That is why it's optimal to run the rs 370 pattern stat.
A Scout II cooling system is about 20% "smaller" in heat exchange capacity, therefore they are not "over-capacity"...but rather right at minimum capacity for the application, considering they run the same engine packages as fullsize. You cannot compare a Scout II system with a fullsize system for that simple reason!!
Rusty Scout
Member
Showtime. I should have mounted the GM starter before I did the rear dump manifolds. Without a curved starter wrench we decided to yank the manifold off and get it done.
Trying to get torque on a standard box end wrench was futile. Forget about it.
Enough already
Front tires deflated about 90 % gave us about 2 inches of clearance. Note to self: work on level ground next time as it would help the engine mounts line up with the frame pads a little easier.
Start time was about 0830 and we had the engine in place by 1030 even thought the hook was in the front hole of the lifting plate(my bad).
Edit: in hind sight now that I think about there would not have been enough clearance to get that oil pan over the rad support if I had used the center hole on the lifting plate. As it was the water pump pulley was kissing the boom as the engine went over the support. Good thing I left the thermo housing/ neck off before using the engine crane as that would have been another constraint.
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Dealbreaker74
Member
New parts are sooo cool! Let us know how she runs!
Rusty Scout
Member
Michael Mayben
IHPA Tech Moderator - Retired & No Longer Online
Great pics of the motor and erik! Did he have an emt unit standing by in case of any injuries?
That shot of the side mount engine along with the rear dump manifolds will really help other folks who don't have experience in determining what to look for when swappin' engines around.
And another thing...now I know the side mount motor ('74/'75) uses the "short body" fuel pump same as for an sv-powered Scout II. The '73 and earlier pickalls must use the "long body" fuel pump in order to clear the front engine mounts, I would have never thought about that, but your pics illustrates that really well.
That shot of the side mount engine along with the rear dump manifolds will really help other folks who don't have experience in determining what to look for when swappin' engines around.
And another thing...now I know the side mount motor ('74/'75) uses the "short body" fuel pump same as for an sv-powered Scout II. The '73 and earlier pickalls must use the "long body" fuel pump in order to clear the front engine mounts, I would have never thought about that, but your pics illustrates that really well.
Rusty Scout
Member
One other thing that was puzzling was the upper bolt for the power steering pump bracket. The new water tubes of recent production were made slightly differently than the original 304 tubes, it appears so at least on the driver side tube. So off came the water tube so that we could get that upper p/s pump bracket bolt in place.
Now all I have to do is figure out how to choreograph the dance of the initial firing/breakin of the new 304, bleed the cooling system, fill the new tranny while maintaining safe operating temps and 2000 rpms for 30mins for proper cam break in.
Now all I have to do is figure out how to choreograph the dance of the initial firing/breakin of the new 304, bleed the cooling system, fill the new tranny while maintaining safe operating temps and 2000 rpms for 30mins for proper cam break in.
Robert Kenney
Super Moderator
Nice job on your truck. From your position it is phenomenal to see the great outcome. Also congrats to all the helpers you have given props to. 
Dealbreaker74
Member
You'll need some bubbas to help out when you first fire it up. I did the same dance when mine was fresh. Filling the coolant isn't such a tough deal, its getting the trans filled up.
Start by filling the pan up with at least 6 quarts. And hopefully you dumped as much atf into the converter as it would take before you installed it. If not, you'll want some advice from a trans pro. I've never installed a new trans with a dry converter.
The big deal is getting a funnel in a vertical position and high enough to avoid the breeze created by the fan. At 200rpms, the breeze will easily turn atf into a fine mist as you try to dump it into the funnel. I ended up stopping the engine and using heater hose to get the funnel high enough away from the torrent. We then restarted the motor and were able to fill the rig with atf. Man, what a mess. Hope you do better!
Start by filling the pan up with at least 6 quarts. And hopefully you dumped as much atf into the converter as it would take before you installed it. If not, you'll want some advice from a trans pro. I've never installed a new trans with a dry converter.
The big deal is getting a funnel in a vertical position and high enough to avoid the breeze created by the fan. At 200rpms, the breeze will easily turn atf into a fine mist as you try to dump it into the funnel. I ended up stopping the engine and using heater hose to get the funnel high enough away from the torrent. We then restarted the motor and were able to fill the rig with atf. Man, what a mess. Hope you do better!
Rusty Scout
Member
Thanks for all the support. This is all just practice run for when I do the Scout engine next. That 1979 345 has nearly 275k on it. Here she is at soldier meadows, Nevada recently.
Rusty Scout
Member
Well it ran but its being a bastard. After 17 minutes of 2000 rpms it sounds like the lifters are still refusing to pump up. So either the lifters are faulty or wrong or the noise was normal. Anyway I had to shut it down cause the police came a knocking. Loud glass packs from previous owner and small refined town = instant cops any suggestions??????????? How long could it possibly take for the new lifters to pump up????? Lifters were installed with assembly lube only, preoiling with a drill, brad penn 30wt break in oil. I did not soak the lifters in oil prior to assembly and did not manually pump them up on the bench either. The only good news is that it runs like a raped ape.
Below is the box the new lifters came in. I believe that they are repackaged comp cams lifters as comp cams uses the same part number for this application.
Below is the box the new lifters came in. I believe that they are repackaged comp cams lifters as comp cams uses the same part number for this application.
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