Heat/ Exhaust Rise Intake

BobR35

BobR35

Senior Member
So I've been reading about the intake block off for the heat/ exhaust into the intake manifold and tried the easy fix with slipping in shims under the intake first. Well that didn't work for me because the exhaust leaked at that point afterwards and it called for removing the intake and doing it the right way. Upon inspection of the intake I saw that both holes for the heat rise were cracked. I decided to make hole plugs out of thin stainless, recessed in the hole and then using the extreme heat JB Weld to seal the holes. I ground the cracks V shaped and filled the cracks at the same time in order to make one piece seal on the complete job. Im waiting on the gasket to reinstall and try this out, hopefully will be driving by Saturday. I'll post the results next week after I put some miles on her.
 

Attachments

  • 20231004_171014.jpg
    20231004_171014.jpg
    50.2 KB · Views: 291
  • 20231004_171030.jpg
    20231004_171030.jpg
    97.5 KB · Views: 287
  • 20231004_171138.jpg
    20231004_171138.jpg
    56.6 KB · Views: 284
  • 20231004_171310.jpg
    20231004_171310.jpg
    67 KB · Views: 289
  • 20231004_171320.jpg
    20231004_171320.jpg
    58.4 KB · Views: 292
  • 20231005_163841.jpg
    20231005_163841.jpg
    90.9 KB · Views: 289
  • 20231005_120114.jpg
    20231005_120114.jpg
    59.6 KB · Views: 31
Last edited:
BobR35 said:
So I've been reading about the intake block off for the heat/ exhaust into the intake manifold and tried the easy fix with slipping in shims under the intake first. Well that didn't work for me because the exhaust leaked at that point afterwards and it called for removing the intake and doing it the right way. Upon inspection of the intake I saw that both holes for the heat rise were cracked. I decided to make hole plugs out of thin stainless, recessed in the hole and then using the extreme heat JB Weld to seal the holes. I ground the cracks V shaped and filled the cracks at the same time in order to make one piece seal on the complete job. Im waiting on the gasket to reinstall and try this out, hopefully will be driving by Saturday. I'll post the results next week after I put some miles on her.
Click to expand...
527222


527223


527224


527225


527226


527227
 
Bob, Your reading about the subject has not sufficiently educated you before you jumped into action. It's not the intake manifold that you block the heat risers on, it's the engine block itself, and the ideal device to block it with is a wheatstalk penny, (one on each side) as the metallurgy of that vintage penny is perfect for the job. It taps right into place in the block and stays put. Nowadays, the consensus seems to favor the drilling of a ⅛" hole in each of those pennies, to allow a trickle of heat through. I hope that whatever damage has been done to the manifold can be repaired, and that an unmodified gasket can correct the leaky situation.
 
ford38v8 said:
Bob, Your reading about the subject has not sufficiently educated you before you jumped into action. It's not the intake manifold that you block the heat risers on, it's the engine block itself, and the ideal device to block it with is a wheatstalk penny, (one on each side) as the metallurgy of that vintage penny is perfect for the job. It taps right into place in the block and stays put. Nowadays, the consensus seems to favor the drilling of a ⅛" hole in each of those pennies, to allow a trickle of heat through. I hope that whatever damage has been done to the manifold can be repaired, and that an unmodified gasket can correct the leaky situation.
Click to expand...

Thanks and I understand what you're saying. I think the mod I did will have the same effects, hope so, I looked at the penny procedure and didn't like the way it might fall thru into the block and I had to repair the manifold anyways so that's why I went this way. I'll be putting it back together this evening and find out. lol
 
My 40 had a mercury dime in each of the block passages when we rebuilt it so I just left them as they were. and like said above, you block the deck not the manifold. Tim
 
Not the same as blocking the block . Your creating the hi heat in the manifold gasket area . if you want positive outcome from your fix , I would seriously consider using the penny in the block . This will stop the heat before the intake , gasket surface . You stand a risk of burning the gasket .
 
Ggmac said:
Not the same as blocking the block . Your creating the hi heat in the manifold gasket area . if you want positive outcome from your fix , I would seriously consider using the penny in the block . This will stop the heat before the intake , gasket surface . You stand a risk of burning the gasket .
Click to expand...

Thanks for your feedback. I did the block at the intake due to the cracks on the intake area that needed to be repaired, that came out nicely. I understand the the block would have been the proper way to eliminate the issue, but since I'm experimenting with the repair anyways, filling in the hole completely at the intake, I went a head and left the block as is for now. I'm probably going to regret not blocking it at the block in the future but it's back together for now. I usually due everything at least 2 times anyways, lol. It's up and running now, let's think positive!:)
 
I don't think BobR35 was asking for advice,
I believe he intended to show everyone his solution for his cracked intake manifold.


Bruce
 
WHY? The heat will evaporate the fuel better and increase performance on the street with the original carburetor.
 
Terry said:
WHY? The heat will evaporate the fuel better and increase performance on the street with the original carburetor.
Click to expand...

hey Terry, I'm told that you loose horse power with intake temperature. The need for heat rise here in FL isn't necessary (80*-100*), and any increase in power on this old girl is needed. I drove her about 100 miles yesterday, mostly on the highway at 50 mph and she ran great. The intake plugged didn't make any noticeable difference but I'm happy with the change. The running temp especially in town in traffic did drop a bit.
 
All said and done the oil pressure was 5lbs above what it was before at idle and at speed. It was a lot higher cold but as it got warmer it declined but still was better. I guessed at the amount of shim to put into the oil pressure relief spring and didn't want to overdo it so I leaned on the conservative side. I'm good with the results knowing it's not a new engine. I don't think that blocking the heat rise has any affect on the oil pressure.
 
I agree-the heat passage isn't going to raise oil pressure so your increased spring pressure must have caused that relief valve to seal a bit better. That's great!
 
Just what do you expect to gain from this? More horsepower? better fuel economy? We id this back in the 50's because it sounded better. I think??
G
 
Ol' Ron said:
Just what do you expect to gain from this? More horsepower? better fuel economy? We id this back in the 50's because it sounded better. I think??
G
Click to expand...

Well Ron, I'm just trying to do every little thing and anything in order for this old girl to run a little longer. I drive her more than most do and with the lower compression and the hot weather here, if it isn't perfect, there's gonna be some issues. I'd love to rebuild the engine but I'm not quite ready for that yet. Besides, I'm not sure I can physically do it and I am not one to farm things out. It's a love affair making things happen!
 
You must log in or register to reply here.
Back
Top