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Rebuild heads or new heads

  • Thread starter Thread starter Funwithfox
  • Start date Start date Aug 31, 2020
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General karthief

wonder how much it would cost to ship you a pair
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#21
  • Sep 1, 2020
  • #21
Is the bottom end of this engine in good shape? Did you do a compression test before you took the heads off?
 

General karthief

wonder how much it would cost to ship you a pair
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#22
  • Sep 1, 2020
  • #22
It boil down to a plan with accurate info.
 

Funwithfox

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#23
  • Sep 1, 2020
  • #23
2000xp8 said:
You guys should stop with the flywheel talk.
In 99.9 percent of cases it's not provable.

gt40 iron heads with a cam and gt40 explorer intake will make 250-265rwhp. That's really not opinion, it's been done thousands of times.

TFS kit will make 290-310rwhp. Again, i consider this to be fact.

It goes up from there, custom cam's, better intakes, afr heads you can stretch it all the way to 359rwhp (which is the best i've personally seen from any stock 302).

Electric fans should not be any type of priority on a gt40 iron setup, if you have an extra $400 it should goto the heads long before that. You have the best parts already? Go ahead, just don't expect a lot of return for your money.

For the OP, what makes you think the heads are the problem and the engine isn't burning oil?
Click to expand...

Again, I am new to getting this deep in an engine. #8 plug looks like I dipped it in mud. You can see the #8 valves in the pic above look pretty bad and #6 is starting to get that way. The rest of the plugs are pretty lean. Maybe I am overlooking something else?
 

Funwithfox

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#24
  • Sep 1, 2020
  • #24
General karthief said:
Is the bottom end of this engine in good shape? Did you do a compression test before you took the heads off?
Click to expand...

I did. All were around 135 or so and #8 started at 120 and dropped down the 2nd and 3rd tests.
 

General karthief

wonder how much it would cost to ship you a pair
20+ Year Stangneter
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#25
  • Sep 1, 2020
  • #25
The compression is at the bottom level of ok, not really good but ok. I would throw some bearings and rings at it.
 

Adieu

Easy there, this ain't a dating site.
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#26
  • Sep 1, 2020
  • #26
General karthief said:
The compression is at the bottom level of ok, not really good but ok. I would throw some bearings and rings at it.
Click to expand...
Low-ish compression isn't necessarily rings.
 

General karthief

wonder how much it would cost to ship you a pair
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#27
  • Sep 1, 2020
  • #27
74stang2togo said:
Low-ish compression isn't necessarily rings.
Click to expand...
I agree but we don't know the miles, it was just my opinion.

General karthief said:
I would throw some bearings and rings at it.
Click to expand...
 

Funwithfox

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#28
  • Sep 1, 2020
  • #28
General karthief said:
I agree but we don't know the miles, it was just my opinion.
Click to expand...

I have just under 100k on the car. Not sure if anything was ever done to lower end. here are some pics of #8
 

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Funwithfox

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#29
  • Sep 1, 2020
  • #29
Just spoke with previous owner. It had new rings and bearings less than 20k ago.
 

2000xp8

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Aug 8, 2003
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#30
  • Sep 1, 2020
  • #30
Funwithfox said:
Just spoke with previous owner. It had new rings and bearings less than 20k ago.
Click to expand...
Which would beg the question, why did an 80,000 mile car need new rings and bearings, when they typically last at least twice (sometimes triple) that?
I'm guessing at this point you are thinking it's the valve seals which is why you are considering heads or head work.

Couple things, valve seals are rarely the culprit and the compression is unilaterally on the lower end.
Next, i rarely trust any rebuilt 302. I'd rather have a factory explorer shortblock than one that is home rebuilt.
Just one of those things that is never the same the second time around especially since nobody has a clue usually about the builder.

Right now, i'm not thinking heads are not your solution.
Edit: I added NOT, it's hard to see this forum on my phone since the keyboard covers the bottom of a long post, so i missed it my proofreading.
 
Last edited: Sep 1, 2020

Funwithfox

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#31
  • Sep 1, 2020
  • #31
Spoke to PO (thinking fairly descent engine guy looking at the other stuff he built in his garage) about this. It is the original block. He bought the car from his buddy. His buddy changed the heads, intake and cam. After he changed all that he got mad because it was smoking and sold it to the guy I bought it from. PO figured since he had done the top end, he'd do the bottom end thinking a ring was causing the smoking problem. He took it apart and had the blocked checked at the machine shop and put it all back together with new rings and bearings and it still smoked. He rechecked everything and found that whoever did the heads didnt install the valve stem seals so he put the seals in and it took care of the smoking. PO really thinks its the heads that are giving me issues. He thinks the head guy that they took it to didnt really know what he was doing. The guy has now been out of business for some time.
 

2000xp8

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#32
  • Sep 1, 2020
  • #32
It might be time to do an entire build or rebuild.
Your compression is mediocre all the way around, build up only on a couple pistons and questionable previous work.

This is exactly when people pay more for unmolested cars.
 

Boostedpimp

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#33
  • Sep 1, 2020
  • #33
Just my opinion.. If it were me and my goals were to have a fun reliable car to speed light to light with on the weekends or to work a few days a week while dropping panties all along the way... than I would honestly just get the P heads you already have checked out / reworked by a reputable shop. Upgrade the valve springs if they aren't already and slap on your 1.7 roller rockers you want. After that I would upgrade the rear ring and pinion gears to a 3.73, replace the speedo gear to match the new ring and pinion gears so the speedo is close to accurate and start enjoying the car.

Skip the better heads, cam game it'll become a head ache if your just into a reliable cool car. If you don't you'll be spending on larger injectors, fuel pump, mass air meter, and chasing down little issues along the way while you could have simply been enjoying the car.

Efan conversion is something you should really save for when you've done everything you want and want to free up some revs.. Because you'll need to come up with a mounting bracket setup for the fan of choice you go with. Spend decent money on a solid fan controller or wiring it up with relays etc which most people rigg or do hack jobs. Mechanical fan although loud and not as efficient won't burn out or doesn't require wiring to fittle with. So again if it's just a cruise around stockish reliable car then why bother touching the mech fan.
 
Reactions: Monkeybutt2000, Hoytster and General karthief

General karthief

wonder how much it would cost to ship you a pair
20+ Year Stangneter
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#34
  • Sep 1, 2020
  • #34
I agree with boosted, get the heads checked first,
 
Reactions: KRUISR

KRUISR

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#35
  • Sep 1, 2020
  • #35
Funwithfox said:
If the GT40 heads give me 30hp, what do a set of new heads give me? I know it varies, but a general range would be good.
Click to expand...

Depending on the heads you get, you should see an additional 10 - 40 hp over your GT40's, assuming no other changes. In my opinion, not worth $1100 for that little incremental gain on a street/fun car. If very aggressive driving/racing is the goal, by all means, go for new heads. Every little bit of power helps.
 

KRUISR

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#36
  • Sep 1, 2020
  • #36
I agree with you Boosted on most of what you said. On the efan front... I can teach you how to install used Contour fans with parts from the wreckers, not hacking the wiring and the only not plug and play part is connecting a fan control switch from your favorite OEM. Will need to fabicate a T-connector for the lower rad hose and total cost should be well under $100. You will have OEM reliabilty and electric fans that barely run unless in stop and go traffic and a pair of override switches if you like too.

I just did my '04 F150 using a fan unit from a 2010 and OEM Contour relay system (just like I did my Mustang). My total cost (because I had some left over Contour parts from a 4 cyl DD) were around $70 CDN.
 
Reactions: Monkeybutt2000 and Boostedpimp

Boostedpimp

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#37
  • Sep 3, 2020
  • #37
KRUISR said:
I agree with you Boosted on most of what you said. On the efan front... I can teach you how to install used Contour fans with parts from the wreckers, not hacking the wiring and the only not plug and play part is connecting a fan control switch from your favorite OEM. Will need to fabicate a T-connector for the lower rad hose and total cost should be well under $100. You will have OEM reliabilty and electric fans that barely run unless in stop and go traffic and a pair of override switches if you like too.

I just did my '04 F150 using a fan unit from a 2010 and OEM Contour relay system (just like I did my Mustang). My total cost (because I had some left over Contour parts from a 4 cyl DD) were around $70 CDN.
Click to expand...
I'm good with efans, like I said I end up putting them on all my cars but I don't do it as a first mod or to pickup horsepower
 
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