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No compression on 6,5,4 or 8

jamesroney

Contributor
Sr. Member
Joined
Sep 11, 2007
Messages
1,667
Loc.
Fremont, CA
I threw $3,500 at it to rebuild recently. Not gonna toss it out unless the block is trashed. I can fix it up just under $800 methinks.
Where are you located?
If you can get to the Wild Horses show this weekend, I will give you a fresh rebuilt 1978 302 long block. (28 oz imbalance, double row timing chain, fresh heads. It was running great in my bronco before I did the Explorer swap.
 
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chuzie

chuzie

Bronco Guru
Joined
Jul 21, 2006
Messages
2,697
That's very generous of you James, but I'm totally stuck on making this one work for now. I'm running explorer too and love it.

Thanks bud. Most appreciated though.
 

phred

Contributor
Bronco Guru
Joined
Aug 25, 2006
Messages
3,432
Loc.
Earth
Mike, your already elbows deep into this. Knock the pistons out and replace them. Why risk it later. Knowing you’re never afraid to use the skinny pedal a set of pistons is cheap insurance.
 
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chuzie

chuzie

Bronco Guru
Joined
Jul 21, 2006
Messages
2,697
Yep, y'all are right. Might as well get it over with and not risk it down the road. Finding that C9 351w block was hard enough; would be silly to risk destroying it because I'm lazy and impatient.

Looks like I can't get pistons till the end of May. Guessing they're made of Chineseum.

Oh well, I'll order valves and lap em into heads and clean and prep as much as possible.
 

bax

Contributor
Old Member
Joined
Aug 22, 2005
Messages
14,491
Pistons will be fine. Looking at the pictures the impact was not bad. The cam needs to be replaced, you already know that. check the valve stems. they are often cracked after a valve bending at 4K rpm. You should be able to see any damage. So cam, timing set, lifters, valves, springs, pushrods, rockers? and check the rocker studs. Good times.
 
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chuzie

chuzie

Bronco Guru
Joined
Jul 21, 2006
Messages
2,697
Pistons will be fine. Looking at the pictures the impact was not bad. The cam needs to be replaced, you already know that. check the valve stems. they are often cracked after a valve bending at 4K rpm. You should be able to see any damage. So cam, timing set, lifters, valves, springs, pushrods, rockers? and check the rocker studs. Good times.
Troublemaker! PM sent.
 
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chuzie

chuzie

Bronco Guru
Joined
Jul 21, 2006
Messages
2,697
Have a few buggered up bronze valve guides in my aluminum heads. Is this a machine shop job or a DIY? I've never done it before.
 

lars

Contributor
Been here awhile
Joined
Jun 29, 2001
Messages
3,041
Loc.
NorCal flatlands
Let me help you spend your money. Convert to a roller cam, with better cam choices :cool: As a bonus, no cam break-in, so you get an extra 20 minutes of driving your Bronco!
 
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chuzie

chuzie

Bronco Guru
Joined
Jul 21, 2006
Messages
2,697
Let me help you spend your money. Convert to a roller cam, with better cam choices :cool: As a bonus, no cam break-in, so you get an extra 20 minutes of driving your Bronco!
I knew I never liked you Lars! First you try to coax me into expensive experimental aircraft and now this. I'm trying to retire at 55! Don't you have a plane to fix or something?

I much prefer to add a crap ton of overpriced high zinc oil and sweat it out at 2500 rpm for 20 minutes because that's seems to have worked out so well for this cam... NOT!

Honestly, I feel the small circle cams have fewer choices if my recollection from 2019 serves me correctly. That said, still waiting to hear back from Lunati for options since my current cam is no longer available.

Hey, at least that badass synchro spacer is working like a charm. Many thanks for the for that my friend. I still owe you beer.
 

bax

Contributor
Old Member
Joined
Aug 22, 2005
Messages
14,491
Have a few buggered up bronze valve guides in my aluminum heads. Is this a machine shop job or a DIY? I've never done it before.
I let the machine shop do it. Mostly because if the new valve is tight the shop will make it correct. But yes you can do it yourself.
 
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chuzie

chuzie

Bronco Guru
Joined
Jul 21, 2006
Messages
2,697
I let the machine shop do it. Mostly because if the new valve is tight the shop will make it correct. But yes you can do it yourself.
Thanks Bax. No sense in me screwing it up. To the machine shop I go.
 
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chuzie

chuzie

Bronco Guru
Joined
Jul 21, 2006
Messages
2,697
Running like a champ. Machine shop rebuilt my heads and I pulled the motor to swap in a new cam, lifters, pushrods, rear main seal (2 piece), timing set and distributor gear and massaged the impact marks on my pistons.

Had to halt break-in procedure when the damn nylon seal on the Explorer pump pressure line started leaking. A Lee Power Steering adapter fixed that issue. Break-in went perfect after and now I'm back on the road. I actually like the new cam selection; runs much better and even changed my pushrod length because it was incorrect from the last rebuild.


Huge thanks to everyone for the thoughts on the situation. Still crazy how one stupid little bolt caused a cascading catastrophic failure, but $hit happens.
 

1970 Palmer

Full Member
Joined
Mar 2, 2020
Messages
455
I'd run the pistons! BUT......I would pull all of them first and inspect them visually. I would want to look very closely at the top ring land, make certain the valve head depression at the outer edge of the piston top did not pinch the top ring. It needs to rotate freely.
 

DirtDonk

Contributor
Bronco Guru
Joined
Nov 3, 2003
Messages
47,355
I think you missed Page 2 Palmer (I did too at first)!
Good advice, but he's already up and running.

Paul
 
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