89 Corvette Mostmint #39

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MostMint
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Re: 89 Corvette Mostmint #39

Postby MostMint » Sat Oct 27, 2018 3:43 pm

^ I now have a place to add ballast if needed lol

Tom came over and with some thrashing we were able to get it started today. Still a ways to go before its ready to move under its own power.

Looking for engine pics I came across this so I'll just leave this here for now:

https://www.barrett-jackson.com/Events/ ... UPE-133130

It fetched $19k.
[quote="Basement Paul"]Is that a mint rocketship on the hood?? :shock:
-BP[/quote]

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MostMint
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Re: 89 Corvette Mostmint #39

Postby MostMint » Thu Nov 01, 2018 12:31 am

After getting the car started I went to work to make it actually run. I set the timing. With the electronics for timing advance connected it would start. Without it it would not. So I set the timing cranking with the starter. It worked.

The next problem was the crankcase vent hose was missing. I figured no big deal leaving it to open air it pulls in air anyway but this was totally wrong. After hooking it up the car started idling. Took a while to realize I actually had it so it could be installed.

I also noticed the cooling fan is running when the engine is running, even at cold water temps. Made attempt to resolve this by replacing the relay to no avail. ECTS resistance checks out also so not at all clear what is happening here.

The other bigger problem is the sound from inside the engine. I reasoned it might have been mal adjusted rockers arms. A quick trip to pull-a-part netted a valve cover I cut open so I could adjust while running. As I adjusted the first one and compared the sounds I knew that was not the problem. After some conversation with Fred32v I decided to finish up adjusting the other side, listen underneath, then pull the plugs, check compression and see if the sound was there with a free spinning crank.

Remarkably putting my hand on the oil pan while running I could feel the knock near the 5-6 rod journals.

Then I did a compression test. Ugh there was one at 50, two at 85, another at 130 and the others were 155 and up. This is not going to be good for a performance test. Our replacement valves helped but we must not have them seated properly. This engine has to come out.

In the meantime I started locating parts. I am going to see Tony soon as he has many of the parts I need from his engine rebuild, and I located a guy with a spare bottom end in pieces for $75 which I plan to get this weekend.

Kinda bummed the chance to get this thing on the street and/or on a track is basically done for the season.
[quote="Basement Paul"]Is that a mint rocketship on the hood?? :shock:
-BP[/quote]

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MostMint
Posts: 1790
Joined: Thu Jul 21, 2005 12:11 pm
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Re: 89 Corvette Mostmint #39

Postby MostMint » Thu Nov 01, 2018 9:53 am

Upon further thought going to redo compression test with oil in cylinders to isolate between valve or ring compression problem.

Deciding also maybe get a mule engine and swap over the tray and intake could get back online quickly. Would like 245 hp to get true performance test so have some learning to do about heads and cams. Like why does the TBI version in Suburban make 210 hp and the Vette makes 245hp
[quote="Basement Paul"]Is that a mint rocketship on the hood?? :shock:
-BP[/quote]

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Maverick
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Re: 89 Corvette Mostmint #39

Postby Maverick » Thu Nov 01, 2018 10:21 am

Probably not telling you anything you don't already know but, a leak down test will tell you if the compression leaks are intake valves, exhaust valves, rings and/or head gaskets. A simple test to nail it down without swapping parts.
Maverick

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MostMint
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Re: 89 Corvette Mostmint #39

Postby MostMint » Mon Nov 05, 2018 7:33 pm

The fuel line rusted out from the inside
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Should read 1.1 something
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parts is parts
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I went on a parts acquisition odyssey last weekend I now have a short block, and extra crank rods and pistons and other stuff. I am also getting another running engine and possibly a TPI intake and heads from a Camaro.

Tiresmoker suggested I run the trans through the gears before pulling the engine. I moved the rayostat off the shifter boot and now I can’t get it to start. I wondered if I moved the knob and tried to check it but the range I am getting is nowhere near the resistance I need. I tried my VATS bypass but no success yet. It resists.

At this point I have to give up on the likelihood I will get to any track and just focus on getting it running and basic street tests for now.
[quote="Basement Paul"]Is that a mint rocketship on the hood?? :shock:
-BP[/quote]

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MostMint
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Joined: Thu Jul 21, 2005 12:11 pm
Location: planning a race

Re: 89 Corvette Mostmint #39

Postby MostMint » Sun Nov 11, 2018 8:02 pm

I was able to get the VATS bypass to work successfully. The Vette ECU needs a 30 hz signal which required an additional ground wire to be connected.

Once again Fred32v came by. This time we put the backup engine on a stand, then were able to start the car and confirm the transmission will go through all the gears. We then proceeded to remove the wounded engine from the car. We managed to spill some oil draining the spare engine other than that this was a fairly clean job.

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We also got to the bottom of the oil pressure sensor leak - it appears to be an internal leak of the sensor itself my guess it trauma from prior owner rebuild attempts.
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Oh and by the way the speedo was working so my earlier repairs must have been OK
[quote="Basement Paul"]Is that a mint rocketship on the hood?? :shock:
-BP[/quote]

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MostMint
Posts: 1790
Joined: Thu Jul 21, 2005 12:11 pm
Location: planning a race

Re: 89 Corvette Mostmint #39

Postby MostMint » Thu Nov 15, 2018 9:34 pm

[quote="Basement Paul"]Is that a mint rocketship on the hood?? :shock:
-BP[/quote]

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MostMint
Posts: 1790
Joined: Thu Jul 21, 2005 12:11 pm
Location: planning a race

Re: 89 Corvette Mostmint #39

Postby MostMint » Sat Nov 24, 2018 8:27 pm

After some deliberation I decided to put Loren's engine in the car without a rebuild. So we started down that path. That engine is a 4-bolt main so my newly created windage tray will not work without additional fabrication. Nonetheless we can use the factory windage tray. This engine used to have one and it still has the factory bolts. While apart we looked at the bearings. Mains are .030 under and rods are .010 under. We're thinking this was rebuilt once before. Beside the bearings the windage tray bolts are in the wrong place and the #4 intake valve seat was machined incorrectly.

While changing the valve seals today we used air to keep the valves up and noticed the #4 intake valve leaking. This required removing the head where we discovered the valve seat problem. I plan to send this to a machine shop to get this one seat corrected.

The bores look good and the valve seat I checked looked very good.

The mains we checked showed some copper which I was willing to live with til I started thinking about it more. With the valve problem I will spend the extra time and $40 to change out the bearings.

Also learned that the truck balancer pulley has the wrong depth, the truck flexplate is larger diameter than the Vette, the truck harmonic balancer is larger diameter than the Vette, and the truck oil pan is smaller than the Vette pan. Unfortunately the reduces the # of spares I can get from the truck engines.

Did some research on the camshafts.

Was able to locate specs for the Vette cam and the 96 engine (Evan's) roller cam.
Also - for reference here are some cam specs:

Corvette stock roller cam L98 10066049
Lift (w/1.5) .415"/.430"
Int/Exh Dur@.050" 207'/213'
LobSep 117'

1996 L31 truck roller cam (Evan's engine):
Intake lift- .414" Exhaust Lift- .428"
Intake duration @.050"- 191 Exhaust Duration @ .050" - 196
Lobe Centerline- 111
I confirmed the lift with the dial indicator

1995 truck flat tappet cam (Loren's engine)
I had to do measurements to get specs for this. At .373 intake and .399 exhaust this cam is no good it has to go.

With this information I decided to replace the flat tappet cam with the truck roller cam. At this point the cam, lifters, dog bones, and spider are installed.

Nothing easy with this project right now.

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[quote="Basement Paul"]Is that a mint rocketship on the hood?? :shock:
-BP[/quote]

User avatar
MostMint
Posts: 1790
Joined: Thu Jul 21, 2005 12:11 pm
Location: planning a race

Re: 89 Corvette Mostmint #39

Postby MostMint » Thu Dec 06, 2018 12:11 am

So the head went back on and the valvetrain. These ports on the truck heads are odd and I think they stink but I resisted spending a lot of time redoing them I want this thing running.

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[quote="Basement Paul"]Is that a mint rocketship on the hood?? :shock:
-BP[/quote]

User avatar
MostMint
Posts: 1790
Joined: Thu Jul 21, 2005 12:11 pm
Location: planning a race

Re: 89 Corvette Mostmint #39

Postby MostMint » Thu Dec 13, 2018 7:11 am

Update:

Last Friday Tom, Joey and Kurt helped and we got the engine assembled and back in the car. We also removed a bunch of connectors from the wiring harness as they were no longer needed. On Sunday I made progress connecting everything back up to the engine. Finally on Monday evening I had a chance to start it.

Through these work sessions we learned:
* why the Vette uses a smaller harmonic balance - the larger one hits the subframe.
* fitting the engine to the transmission and motor mounts is tricky. We will want to devise an easier path
* the Vette uses three bolt holes that the prior application did not. All of them required tapping to clean out the rust etc. This would have been much easier to do on the engine stand
* truck heads have straight plug holes, using them with the Vette headers puts the plug really close to the heat shielding
* I tried grounding a couple of the A/C wires but the fan still runs when the engine is running

I have done some research and I think I know what I need to do to get the fan off. All the A/C switches are closed when fan assist is not needed, which means the circuit has to be complete to ground. I can bypass all of it by grounding the correct wire into the ECU. That is next. Some care required finding a ground on a fiberglass car!
[quote="Basement Paul"]Is that a mint rocketship on the hood?? :shock:
-BP[/quote]


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