The 1947 - Present Chevrolet & GMC Truck Message Board Network







Register or Log In To remove these advertisements.

Go Back   The 1947 - Present Chevrolet & GMC Truck Message Board Network > 47 - Current classic GM Trucks > The 1969 - 1972 Blazers and Jimmys Message Board

Web 67-72chevytrucks.com


Reply
 
Thread Tools Display Modes
Old 04-09-2010, 09:27 PM   #1
RAB38
Registered User
 
Join Date: Nov 2005
Location: Southern Maryland
Posts: 164
Problems with the blazer

I know I dont post much but thought I would share my frustration. It will be 3 years since I have restored my blazer to the state it sits now. over the past few years i have had several issues to work on and it has not been the most reliable truck in the world. This past winter I decided to pull the engine for several reasons. I had a bad oil leak from the pan and my lifters were really noisy. Being that the truck is so tall it was just easier to pull the engine to do the minor repairs. Anyway, after I pulled the engine I determined the heads were in bad shape. Mind you this was after about no more than 10,000 miles. They needed new seals and the guides were bad and the valve install heights were all different. So as typically happens things snowball.

Had the heads redone, fixed the oil pan gasket, put in a diy 4x4 crossmember, gm perf. part roller lifters, degreed the cam, some other odds and ends.

Put the engine back in and ran it a little loccally. Everything seemed fine. This past weekend I decided to drive it 2 1/2 hour to my grandparents house for a shake down before a car show in OC MD this coming May. Anyway thing runs awesome, no issues whatsoever.

I filled the truck with fuel while up there and then starts the problems. get back to thier house and the fuel pump started acting up (in the tank pump for FI) Would not hold pressure, so I unhooked the line at the filter and bypassed the relay to run the pump and seemed to pump fine (pumped about 2 gallons out). Hooked the line back up started the truck and it ran fine. I thought wierd, maybe I have a vent issue with the tank being full. Drove it around the next day before leaving for home and everything was good.


Start to drive home got about 1/2 hour from my gparents house on the interstate and the truck starts to run bad, I pull over and see that my fuel pressure is erratic and it seems to running rougher than it did the day before. So I turn around and limp the truck back to my gparents house.

Long story short, went back up during the week and trailered it home and tore into it last night. Pulled the valve covers and low and behold the number 1 exhaust valve, the rocker had some how got loose and allowed the pushrod to popped loose. Looked a little closer and realized that the valve spring was compressed at least 1/4".

I am thinking bent valve ( possibly struck the piston )or when I had the heads redone they had the guide set to tight. Hell I dont know all I know is I am disgusted and When I thought I just had a simple fuel pump problem now it looks like the engine will be coming back out... and most likley will be a complete rebuild.

Just had to vent...........
__________________
72 Blazer CST 383 stroker roller, fuel inj, t350,NP205, D60 front, 14b rear, detroit locker, 38 x15.50 mtz's, welds, cross over steering, custom cage,Line X Spray in liner, House of Colors Tangelo Pearl Orange
RAB38 is offline   Reply With Quote
Old 04-09-2010, 10:03 PM   #2
Livrat
Member #1049
 
Livrat's Avatar
 
Join Date: Jun 2000
Location: Troy Montana
Posts: 3,940
Re: Problems with the blazer

I really sucks to have problems like you experienced!! sorry to hear that...

Just a quick thought.. take a close look at your number 1 cylinder valve spring.. the spring itself may have broken which would make the valve sit about 1/4 inch down, that will generally tend make the engine run okay at idle (compression holds the valve closed @ low RPM) and like crap when you step on the gas,
You may not need to pull it all out, just replace a spring.. (it happened to me on the 454 in my 4x4)
Livrat is offline   Reply With Quote
Old 04-10-2010, 12:03 AM   #3
AlaskaMatt
Registered User
 
AlaskaMatt's Avatar
 
Join Date: Apr 2010
Location: AK
Posts: 198
Re: Problems with the blazer

Ouch! I know how you feel. Every time I think things are tip top something else starts to rumble.
AlaskaMatt is offline   Reply With Quote
Old 04-10-2010, 12:35 AM   #4
old man jimmy
Registered User
 
Join Date: May 2007
Location: texas
Posts: 329
Re: Problems with the blazer

Just passing on a tidbit from a lot of years working on small blocks. But When you have the heads off. I'd suggest having a machine shop install umbrella seals. The rubber bands chevy uses are pure junk. For those of you that get the morning first start smoke. That's usually why.
old man jimmy is offline   Reply With Quote
Old 04-10-2010, 08:43 AM   #5
RAB38
Registered User
 
Join Date: Nov 2005
Location: Southern Maryland
Posts: 164
Re: Problems with the blazer

It does not appear that the spring is broken, by looking at it, but I plan on taking the spring off to see if I can move the valve. So if the spring is broke I will see it then.

I have always used umbrella seals, they are a must for oil control.


If this thing is as bad as I think, this engine will not be going back and I need to decide on what to run LSX, Large big block or Duramax. I have wanted to swap out the engine but not right now, I have other things that need my attention and money right now.
__________________
72 Blazer CST 383 stroker roller, fuel inj, t350,NP205, D60 front, 14b rear, detroit locker, 38 x15.50 mtz's, welds, cross over steering, custom cage,Line X Spray in liner, House of Colors Tangelo Pearl Orange
RAB38 is offline   Reply With Quote
Old 04-11-2010, 09:49 PM   #6
Firebirdjones
Registered User
 
Join Date: Oct 2009
Location: Prescott, Arizona
Posts: 2,396
Re: Problems with the blazer

Sounds like a classic valve guide set too tight. Generally happens on the exhaust because they run a bit hotter.

Probably lucky it didn't hang open further and do serious damage. Any reputable machine shop should cover it none the less.
Firebirdjones is offline   Reply With Quote
Old 04-18-2010, 07:59 PM   #7
RAB38
Registered User
 
Join Date: Nov 2005
Location: Southern Maryland
Posts: 164
Re: Problems with the blazer

you were right, the guides are way too tight. I dont know why I cant fine a quality machine shop around here. So now both heads have to come off and all the guides checked.
__________________
72 Blazer CST 383 stroker roller, fuel inj, t350,NP205, D60 front, 14b rear, detroit locker, 38 x15.50 mtz's, welds, cross over steering, custom cage,Line X Spray in liner, House of Colors Tangelo Pearl Orange
RAB38 is offline   Reply With Quote
Old 04-18-2010, 11:34 PM   #8
Firebirdjones
Registered User
 
Join Date: Oct 2009
Location: Prescott, Arizona
Posts: 2,396
Re: Problems with the blazer

The machine shop that did the work should cover that.

You are right, it's hard to find a good machinest that takes pride in their work.
The problem with cylinder heads is they are fairly simple to machine and rebuild. So alot of shops hire what I call "monkeys" (beginers) to do all the head work since that's most of what comes through an engine shop. Quick and easy get em' in get em' out type of thing.

I had close friends that ran a couple of the best shops in the country in my opinion when I lived in Ohio. I worked in there on occasion and did all my machine work and dyno testing.
Now living in AZ I've lost that fringe benefit and I'm now in the same boat as you. Checking around for someone that does quality work,,,ugh....I really don't trust anyone. So I feel your pain.

Hope you get it worked out.
Firebirdjones is offline   Reply With Quote
Reply

Bookmarks


Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -4. The time now is 07:54 PM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
Copyright 1997-2022 67-72chevytrucks.com