High Comp 120cc Build

samIam

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8ad-f85

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OK, I did see the gasket failure pics... :)
The heads are being cleaned and skimmed as a precautionary measure, right?
I'm guessing the costs of checking the surface closely is the same as a light cut?
The block is perfect too?
I know that area is a weak spot for HG's.
Why did it fail and what can be done next time?
Did they suggest making sure the threads are really clean and going through a re-torque after running?
I'm trying to understand what the difference would be after they clean up and skim your heads and how THAT would prevent it if things were fine to begin with.

If it's a detonation related failure from over heating at the track, I'd be looking at your bearings.
Either shiny spots towards the piston end or that they don't fall out when the rod is separated.
Better to catch it now than have it dismantle itself at the track later. :D
 

8ad-f85

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Do you have a possible solution in mind?

Belt problems can be as simple as a worn belt or bad dampener/pulley/water pump to the extreme, such as a cracked main cap or crank.

Just re-reading it.
I think you are way over-revving the engine.
I would definitely look at your bearings over winter and try to determine if anything major is damaged.
This is the time to be extremely thorough and learn from what your engine is trying to tell you.
 
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samIam

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I'll probably get the MTS bracket for the alternator and a deep grove pulley, hoping that will hold it still and line up right. I have to run shims behind the alt brackets to keep it lined up correctly. I may pull some bearings but I can't pull the motor out again right now.
 

samIam

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Seriously thinking about testing the big intake. I may get them both flow tested if possible. Heads are done, shop said they look good coming apart and going back together. I also like how the top end came apart. Rockers making great contact, no signs of pushrods jumping around and no additional wear marks in the cylinder. My exhaust needs to be redone and I'm looking for some different headers if anybody has some.
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samIam

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So.... Been a while and I've changed some things. Forest and foremost is the headers. I had some custom long tube headers and 3" exhaust ran to the back. Notched the crossmember for nice clearance. The headers are 4-2-1 headers phased 180 degrees apart. It sounds crazy now. To see people clothing move when you start the car is cool. It's loud now, borderline police problem loud. I love it. I have the test headers and we built the exhaust on the car using them. The finished headers will be done later this year. I got an MTS alternator bracket and it moved the alt down and out the way, new throttle cable and ignition components. And thats where I am now, figuring the timing curve.

Trying to figure what curve I need. My convertor stalls at 3200, car weights 4000 lbs at the track and I have 390 gears. I've searched the forum but need some advice. Do I use the heavy springs and limited the timing to 12/14 degrees from initial? Or the lightest that give 20 degrees of mechanical? I do plan to get lower gears, mid to low 4s.
 

8ad-f85

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Can't toss out easy numbers without more data...
Total timing determined yet or staying with 34* or so?
Does the engine have a happy initial timing setting?
Is there a separate power switch for the ignition, cut-out or start-retard?
Those things can get you around minor annoyances and issues tailoring the curve exactly how the engine likes.

I'd start with 34* total around 3000-3500 and work backwards, with whatever initial it will tolerate and play with it from there. Initial somewhere between run-on when shutting off, destroying your starter at start-up and doesn't heat up things at idle :D . 14-20* initial?
See what it doesn't like starting hot and plan on occasional crappy gas.
 

samIam

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Glad to report my car survived this year without anymore big problems. Went to the eighth mile track once but could only make one good hit against this poor Camaro, Did 8.3 sec at part throttle. I'm still scared to rev this motor close to 6k. My alt belt is still flying off so I'm playing it safe to not overheat so I'm keeping the R's down. I did buy some SBC electric water pump adapters from Cadco and will be converting when I get it from storage next year. The headers and exhaust that Tony made for the car is just so loud, I'll probably go to a quieter muffler and use the cutouts I have.

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Darius

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It many be "loud" but it sure is pretty!!

Any idea what it weighs??

bro. d
 

Cad Man

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Are those procar seats ?

I know they kept taking weight out of them each year ...but unless your scale is off you must have gutted alot of crap..? Even with aluminum top end no air no heat and stupid front bumper shocks removed. Welded solid.. hehe.. mine still weighs around 4200 empty..
 
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samIam

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I'm not sure. The scale at brainard international speedway said 3800. I think it goes in increments of 5 pounds. Full interior and no mods made to lighten the car and 44" sunroof added. Suppose I could take it to the interstate battery scale.
 

Cad Man

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Something ain't right. That would make your car lighter than my 81 title said with a v-6... and th200 junker..

They have 2 very expensive elaborate truck scales where I work that I've weighed mine on.. it's been a while since I've weighed it but I figure even though I've pulled off alot if crap most of the weight has been replaced by added or heavier equipment etc..

The older Cads were weighed minus things like air conditioning, starter all fluids etc... at some point they change the factory that the weights were taken from ..from Cadillac main to New Jersey...


If you look closely at this sticker it says gvw is 5654. With max of 1100 lbs load..
5654 minus 1100 is 4554. That's almost exactly the weight I got when I weighed it with less than 1/4 tank fuel
and no spare.. 20181019_190152.jpg
 
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Cad Man

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I have a feeling your into detonation that's why you loose the head gaskets. ..

Try backing the timing off ..
If your running a mechanical advanced and haven't had it on a distrib machine you really dont kneo what you've got

We should have went another 10 degrees bigger on that cam hahaha

Get a starter retard they are like $80
Lock that distributor out ..it will love you for it

If its predetonation it's only a matter of time before if eats the bearings
 

samIam

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I do need a starter retard. The distributer is locked out. I was in the middle of adjusting the timing at the track when the belt blew.

My car is in storage but I plan on turning the MTS alt bracket upside down to put the alt at the bottom to shorten up the belt. If I don't like that, you'll be hearing from me.

How many GPM you think the stock/MTS belt driven pump does?
 

Cad Man

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Of course it changes with rpm..
At low rpm not much..
I really dont know would just be a guess

All I can tell you for sure is the 507 ran much cooler last year then the year before with the flow cooler pump
 

Roy Heisenberg

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What vehicle(s) do you drive?
472 Caddy in a ‘75 Jeep J-20 TH-400 Dana-60 100LL
Ok, so I am starting to wonder. Is the Flow-Kooler pump really good? Does anyone know of a better pump that bolts into the stock location. ?
 
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