Ok, Need some engine help...?
Thread Starter
Burning Brakes
Joined: Nov 2003
Posts: 990
Likes: 0
From: North Texas
Ok, Need some engine help...?
Here's the situtation.....
1970 Matching numbers block with 122,xxx miles. Wife brought it home last Friday and it was leaking coolant. Turned out to be a cracked head - right along the casting at the #5 and #7 cylinders.
Ran the compression check tonight - dry. Here's the average numbers:
1-#175, 3-#195, 5-#185, 7-#190 - Side with the issue
2-#180, 4-#180, 6-#180, 8-#180
Not sure what a 1970 10.25 to 1 engine should have.
Oil pressure is 20 psi range at idle and 38-40 at cruise.
The engine has definitely been out of the car at some point because the block is very clean. Previous owner wasn't very car savy and didn't know anything about it and I definitely believe him.
Here's what I think are my options:
1 - Don't mess and drop in a Crate motor - probably AR Racing.
2 - TrickFlow package - Heads, Cam, gaskets, rockers, and everything else I need. Plus I'd drop the pan and install a new oil pump since I'm there.
3 - New Vortec Heads and intake - Cam...?
4 - ????
Recommendations and thoughts?
I've already spend more this year (Brakes, Wheels, Ignition, Interior pieces) than I really wanted to and now I have this to deal with.
[Modified by 1970-Bronze, 7:54 AM 4/28/2004]
1970 Matching numbers block with 122,xxx miles. Wife brought it home last Friday and it was leaking coolant. Turned out to be a cracked head - right along the casting at the #5 and #7 cylinders.
Ran the compression check tonight - dry. Here's the average numbers:
1-#175, 3-#195, 5-#185, 7-#190 - Side with the issue
2-#180, 4-#180, 6-#180, 8-#180
Not sure what a 1970 10.25 to 1 engine should have.
Oil pressure is 20 psi range at idle and 38-40 at cruise.
The engine has definitely been out of the car at some point because the block is very clean. Previous owner wasn't very car savy and didn't know anything about it and I definitely believe him.
Here's what I think are my options:
1 - Don't mess and drop in a Crate motor - probably AR Racing.
2 - TrickFlow package - Heads, Cam, gaskets, rockers, and everything else I need. Plus I'd drop the pan and install a new oil pump since I'm there.
3 - New Vortec Heads and intake - Cam...?
4 - ????
Recommendations and thoughts?
I've already spend more this year (Brakes, Wheels, Ignition, Interior pieces) than I really wanted to and now I have this to deal with.
[Modified by 1970-Bronze, 7:54 AM 4/28/2004]
Melting Slicks
Joined: Jan 2003
Posts: 2,804
Likes: 1
From: OKC Oklahoma
Re: Ok, Need some engine help...? (1970-Bronze)
Those compression numbers actually look good. Are those the stock heads? Pull them off and see if you can see what the actual malfunction is-why is the head cracked? Personally, I'd probably rebuild it, but most people would say that if the block looks good, you are fine. If the head is cracked, there is a possibility that the block is warped.
EDIT: I just looked at the numbers again....The numbers are acceptable...
[Modified by 79VetteMike, 9:19 PM 4/27/2004]
EDIT: I just looked at the numbers again....The numbers are acceptable...
[Modified by 79VetteMike, 9:19 PM 4/27/2004]
Thread Starter
Burning Brakes
Joined: Nov 2003
Posts: 990
Likes: 0
From: North Texas
Re: Ok, Need some engine help...? (comp)
Well, it's leaking externally right on the casting between the #5 and #7 cylinders. When I start it up, I can see it leaking.
No oil in the water and no water in the oil.
Oh, and the engine doesn't smoke at all. I really can't say anything about oil consumption since I've only put 350 miles on it since I bought it in November.
No oil in the water and no water in the oil.
Oh, and the engine doesn't smoke at all. I really can't say anything about oil consumption since I've only put 350 miles on it since I bought it in November.
Race Director
Joined: Apr 2000
Posts: 17,676
Likes: 201
From: Who says "Nothing is impossible" ? I've been doing nothing for years.
Re: Ok, Need some engine help...? (comp)
Can you see a crack or do you think it is cracked because it is leaking there? Take your time and try and fiigure out what is wrong first might just be a gasket or a bolt that needs a little Permatex to seal it.. Compression is acceptable :D
Thread Starter
Burning Brakes
Joined: Nov 2003
Posts: 990
Likes: 0
From: North Texas
Re: Ok, Need some engine help...? (MotorHead)
No, it's definitely leaking there because the water is spraying out when the engine is rev'ed up and it's right in between the cylinders. I suspect it's a water jacket.
What else should I check cause I'm drawing a blank?
What else should I check cause I'm drawing a blank?
Le Mans Master
Joined: Aug 2000
Posts: 9,662
Likes: 7
From: Semper ubi, sub ubi
Cruise-In VI Veteran
Cruise-In VII Veteran
Re: Ok, Need some engine help...? (1970-Bronze)
I was pretty much in the same position as you with my 69, I went as far as buying everything to replace heads, cam, intake, etc. then decided to go with a crate engine.
I put in a ZZ4 and have been very happy with it, although I sort of wish that I'd looked at other options.
I didn't use the heads, cam and other stuff I bought, because I was worried about the other parts of the rest of the engine and the added strain on them made by the increased power. I couldn't see spending $2K plus to rebuild the old engine. So I went with a brand new engine.
Good Luck on what ever you decide.
I put in a ZZ4 and have been very happy with it, although I sort of wish that I'd looked at other options.
I didn't use the heads, cam and other stuff I bought, because I was worried about the other parts of the rest of the engine and the added strain on them made by the increased power. I couldn't see spending $2K plus to rebuild the old engine. So I went with a brand new engine.
Good Luck on what ever you decide.
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer
Brett Foote
10 Things Every Corvette Owner Needs (2026 Edition)
Michael S. Palmer
8 Most "Only Corvette Owners Understand" Quirks and Problems
Pouria Savadkouei
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years
Joe Kucinski
How Much Horsepower Every Corvette Engine "LOST" in 1972
Joe Kucinski
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!
Michael S. Palmer
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Racer
Joined: Apr 2004
Posts: 271
Likes: 0
From: Alpharette GA
Re: Ok, Need some engine help...? (1970-Bronze)
Take the head off and inspect it before making a decision. You said you think the previous owner might have had the motor out, if he had the heads off he might not have got it torqued back on right or even thread sealed the right head bolts.
Good luck
Opps sorry did not see motorheads post before I posted
:iagree:
[Modified by checklst, 6:35 AM 4/28/2004]
Good luck
Opps sorry did not see motorheads post before I posted
:iagree:
[Modified by checklst, 6:35 AM 4/28/2004]
Thread Starter
Burning Brakes
Joined: Nov 2003
Posts: 990
Likes: 0
From: North Texas
Re: Ok, Need some engine help...? (MotorHead)
Motorhead, Is there anything else I can do with the head on? Once I remove that head, moving the car is going to be a real problem.
I originally thought it was the gasket, but I removed the shields and cleaned it up to get a better look. It sprays out right at the casting. Not at the gasket or at the bolts.
I originally thought it was the gasket, but I removed the shields and cleaned it up to get a better look. It sprays out right at the casting. Not at the gasket or at the bolts.
Racer
Joined: Apr 2004
Posts: 401
Likes: 0
From: IL
Re: Ok, Need some engine help...? (1970-Bronze)
Get access to a coolant PSI tester or use a PSI regulator tapped into a coolant port or heater hose. Be carefull not to exceed 15 PSI. This way you can better isolate the leak area.
Compresion numbers are awesome!
Compresion numbers are awesome!
Thread Starter
Burning Brakes
Joined: Nov 2003
Posts: 990
Likes: 0
From: North Texas
Re: Ok, Need some engine help...? (Fevre)
Fevre, The TrickFlow package that Summit offers is priced right and has everything. I'm not sure I can get all the part they offer and iron heads for less money.
Melting Slicks
Joined: Mar 1999
Posts: 2,845
Likes: 2
From: Apex NC
Re: Ok, Need some engine help...? (GasketDude)
:iagree: with GasketDude. Get a firm reading on exactly where the leak is. If it really is a crack in the head, the least expensive option may be to take that head off and get the crack repaired. Since the rest of the engine is solid, why start fooling around with it just as the good driving weather arrives?
My own personal opinion is that you should maintain the original numbers matching components in the car. There were very few '70's built to start with, and even fewer retain their original drivetrains 30+ years later. If the head cannot be salvaged, you should be able to find a correct head for the car at a reasonable price, and have both heads reworked with new valvetrain components and reinstall them without going in to the bottom end of the engine.
Shannon
My own personal opinion is that you should maintain the original numbers matching components in the car. There were very few '70's built to start with, and even fewer retain their original drivetrains 30+ years later. If the head cannot be salvaged, you should be able to find a correct head for the car at a reasonable price, and have both heads reworked with new valvetrain components and reinstall them without going in to the bottom end of the engine.
Shannon
Melting Slicks
Joined: Jun 2001
Posts: 2,429
Likes: 14
From: CA
Re: Ok, Need some engine help...? (1970-Bronze)
I agree with the others - clean it up & pressurize the radiator. You can get a pressure tester for $60-$70. Once you find it, you may be able use a 2-part epoxy on it as a temp (or perm) repair.
Thread Starter
Burning Brakes
Joined: Nov 2003
Posts: 990
Likes: 0
From: North Texas
Re: Ok, Need some engine help...? (71coupe)
I picked up the Radiator Pressure Tester at lunch.
I'll post my findings tonight.
Got to take the wife out to dinner for our Anniversary, first - LOL.
I'll post my findings tonight.
Got to take the wife out to dinner for our Anniversary, first - LOL.
Thread Starter
Burning Brakes
Joined: Nov 2003
Posts: 990
Likes: 0
From: North Texas
Re: Ok, Need some engine help...? (1970-Bronze)
Ok well when I start pressurizing the system, the head starts leaking. In fact, it quit because the level got below the crack in the head. I had to add water to the system.
It started leaking around 5 psi and only got worse as the pressure increased.
It's extremely hard to see exactly where it's leaking since it's right on the casting ridge.
It started leaking around 5 psi and only got worse as the pressure increased.
It's extremely hard to see exactly where it's leaking since it's right on the casting ridge.
Racer
Joined: Apr 2004
Posts: 401
Likes: 0
From: IL
Re: Ok, Need some engine help...? (1970-Bronze)
Sorry 'bout your bad luck! Does it look like the previous owner ground on the head to make them look "cooler"? This is one way they leak to the outside. Seen your questions about engine rebuilders and it sounds like your getting ready to "just swap it". Now it's decision time, rebuild or replace?
Plenty of cylinder head choices out there, some will even fool "the experts". Time to get out the check book! Whacha gonna do?
Plenty of cylinder head choices out there, some will even fool "the experts". Time to get out the check book! Whacha gonna do?
Drifting
Joined: Sep 1999
Posts: 1,411
Likes: 1
From: Wylie TX
Re: Ok, Need some engine help...? (1970-Bronze)
If you really want to find exactly where it's leaking, go buy some coolant dye. You will put it in your radiator and it will cause the leaking area to "glow" when using a black light.
The dye can be bought at just about any auto parts store. If you need it, I have a black light you can borrow if you want to save some $$. I've never used it for coolant, but it really helped me with an oil leak.
The dye can be bought at just about any auto parts store. If you need it, I have a black light you can borrow if you want to save some $$. I've never used it for coolant, but it really helped me with an oil leak.
