who knows what happens when....?
12-23-2002, 09:47 PM
#1
Safety Car
Thread Starter
who knows what happens when....?
who knows what happens when heads have been planed (sp) .020"-.030" and they are bolted on to an engine without planing the intake manifold or using thicker intake gaskets?
12-24-2002, 07:10 AM
#5
Safety Car
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Re: who knows what happens when....? (76 Red)
Sorry can't help with your Q. Is that you getting ready to jump out of that balloon???
12-24-2002, 09:15 AM
#6
Racer
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Re: who knows what happens when....? (SIGNGUY)
If it is in fact only .020-.030 then you should be ok.I have a chart we used at the machine shop when I worked there years back.I will see if I can put my hands on it and will post the info. :crazy:
12-24-2002, 10:41 AM
#7
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Re: who knows what happens when....? (SIGNGUY)
According to a HOW 2 in Summit for every .010 milled off the heads you need to mill off .0123 from the manifold or head sides and .0173 off the manifold bottom or block ends. This is assuming you have 64 cc heads which I believe came on the L82. If 76cc then you still mill the .0123 but the other is not required.
12-24-2002, 02:32 PM
#8
Safety Car
Thread Starter
Re: who knows what happens when....? (Fevre)
According to a HOW 2 in Summit for every .010 milled off the heads you need to mill off .0123 from the manifold or head sides and .0173 off the manifold bottom or block ends. This is assuming you have 64 cc heads which I believe came on the L82. If 76cc then you still mill the .0123 but the other is not required.
heres the deal...the heads that i obtained for my engine rebuild ended up being 1971 truck heads...76cc
it is my understanding that everytime their shaved however they get smaller in cc...correct? so their now probably like 68cc...?
they have 2" stainless steel valves and medium springs...
the engine smokes bad and is burning 1 qt of oil every 10 miles...
come to find out, they have been shaved at least .020" that we know of, maybe more...aparently they arent ligning up with the intake precisely...
i have heard that if you shave .010" your still cool...nothing changes...
.020" and you use special intake gaskets...
and at .030" you have to shave the intake manifold...
how does this sound to ya'll???
[Modified by SIGNGUY, 2:50 PM 12/24/2002]
12-24-2002, 05:31 PM
#9
Le Mans Master
Re: who knows what happens when....? (SIGNGUY)
If you have an aluminum manifold you CAN crack becuase it tries to bend. This would be rare but it can happen. Somtimes a gap will form at the ports under the plenum and you will have a vacuum leak that is VERY difficult to find and/or it can pull oil into one of more cylinders. Again a difficult thing to diagnose. It is important to match the ports for good flow also. Even if you get no leaks you may be hindering the intake/exhaust flow and thus engine performance may be affected.
12-24-2002, 05:35 PM
#10
Le Mans Master
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Re: who knows what happens when....? (silvervetteman)
If you have an aluminum manifold you CAN crack becuase it tries to bend. This would be rare but it can happen. Somtimes a gap will form at the ports under the plenum and you will have a vacuum leak that is VERY difficult to find and/or it can pull oil into one of more cylinders. Again a difficult thing to diagnose. It is important to match the ports for good flow also. Even if you get no leaks you may be hindering the intake/exhaust flow and thus engine performance may be affected.
Milling the head does decrease the volume. The only way to be sure how much is to CC them.
Todd
12-24-2002, 06:17 PM
#11
Le Mans Master
Re: who knows what happens when....? (72rdstr)
Yes.... Coolant leaks. A serious problem. Again they are usually on the underside and go un-noticed until you find that you have 9 quarts of milky oil. :cry
12-25-2002, 08:56 AM
#12
Safety Car
Thread Starter
Re: who knows what happens when....? (silvervetteman)
ive done a couple of oil changes already and there dosnt apear to be anything foriegn in it...ie coolant etc...
who knows exactly how to measure how much head was shaved off without removing the heads?
who knows exactly how to measure how much head was shaved off without removing the heads?
12-25-2002, 08:59 AM
#13
Safety Car
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Re: who knows what happens when....? (J75)
If it is in fact only .020-.030 then you should be ok.I have a chart we used at the machine shop when I worked there years back.I will see if I can put my hands on it and will post the info. :crazy:
12-25-2002, 11:05 AM
#14
Le Mans Master
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Re: who knows what happens when....? (SIGNGUY)
i think its up to 30 you can do without cutting for the manifold,,,,its also a good idea to port out your intake with your heads after this....
if you have 76cc heads and deck 30 thous i think it takes it down to 72.something cc no more than that,,,,
if you have 76cc heads and deck 30 thous i think it takes it down to 72.something cc no more than that,,,,
12-25-2002, 09:26 PM
#16
Re: who knows what happens when....? (SIGNGUY)
You don't.
How close is the intake valve seat to the cyl deck? Usually when removing .030 or more the flat milling will cut into the seat on the shallow chamber side.
How close is the intake valve seat to the cyl deck? Usually when removing .030 or more the flat milling will cut into the seat on the shallow chamber side.
12-25-2002, 11:11 PM
#17
Safety Car
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Re: who knows what happens when....? (Twin_Turbo)
You don't.
How close is the intake valve seat to the cyl deck? Usually when removing .030 or more the flat milling will cut into the seat on the shallow chamber side.
How close is the intake valve seat to the cyl deck? Usually when removing .030 or more the flat milling will cut into the seat on the shallow chamber side.
12-26-2002, 06:07 AM
#18
Re: who knows what happens when....? (SIGNGUY)
It will be kind of tricky to figure out how much was shaved. You can cc the chambers and compare to stock but then you'd still not know exactly how much was shaved, it'd still be guessing.
The reason I said that about the seats is that if you see your seats are cut into on the shallow side, you are pretty sure it's cut .030 or more. It does not work the other way around, if they're cut into they may even be shaved .030", some castings would have the seats cut into at say like .050"or even more.
But WHY don't you know how much was shaved off? Were they previously shaved, did the machine shop forget what they shaved off (bad machine shop!)
Marck
The reason I said that about the seats is that if you see your seats are cut into on the shallow side, you are pretty sure it's cut .030 or more. It does not work the other way around, if they're cut into they may even be shaved .030", some castings would have the seats cut into at say like .050"or even more.
But WHY don't you know how much was shaved off? Were they previously shaved, did the machine shop forget what they shaved off (bad machine shop!)
Marck
12-26-2002, 07:29 AM
#19
Safety Car
Thread Starter
Re: who knows what happens when....? (Twin_Turbo)
But WHY don't you know how much was shaved off? Were they previously shaved, did the machine shop forget what they shaved off (bad machine shop!)
Marck
Marck
the heads are old and probably have had several owners by now...and nobody really knows how many times they have been shaved...
the guy at the machine shop says all he knows is that HE shaved them .010...
not sure about previous...
12-26-2002, 07:42 AM
#20
Re: who knows what happens when....? (SIGNGUY)
What kind of heads are they? 462624 heads or some 882's?
Judging from the high compression, it sounds like they're open chamber smog heads, not really good for making power. I'm not sure what the machineshop cost or what it will cost to have the manifold reworked but if it were me I'd invest in some cheap World Torquers or something like that if the budget is tight.
If they're the 462624 heads I'd throw them away immediately, they are very thin and only a few thousands of the deck could comprimise head gasket clamping on some of them, they are true pieces of poopie.
Marck
[Modified by Twin_Turbo, 6:45 AM 12/26/2002]
Judging from the high compression, it sounds like they're open chamber smog heads, not really good for making power. I'm not sure what the machineshop cost or what it will cost to have the manifold reworked but if it were me I'd invest in some cheap World Torquers or something like that if the budget is tight.
If they're the 462624 heads I'd throw them away immediately, they are very thin and only a few thousands of the deck could comprimise head gasket clamping on some of them, they are true pieces of poopie.
Marck
[Modified by Twin_Turbo, 6:45 AM 12/26/2002]