How can I tell if I have a stock head or non jet valve head.
Posted 25 August 2019 - 06:19 PM
Posted 25 August 2019 - 06:27 PM
Posted 25 August 2019 - 06:38 PM
Known to crack cyl head right across the e seat due to metal bushing/sleave pressed in to close to valve area (gets hot). I wouldn't waste my time w it if that's what it is. Just buy new head from Engine Machine Service in Niles OH.Inspect all your parts from old head and swap it over w fresh valve job.
Edited by croquest87, 05 September 2019 - 01:19 PM.
Posted 25 August 2019 - 08:33 PM
Posted 25 August 2019 - 08:43 PM
Posted 25 August 2019 - 09:15 PM
If your not sure about the parts, Engine Machine Service can build the head for you. Randy, goes by "Dad" on here is the one to talk to. Great guy and will take care of you.
Posted 04 September 2019 - 07:57 PM
87' Serbia Black ESi-R- SOLD
Posted 05 September 2019 - 12:35 PM
Both work. The mechanical setup needs periodic adjustments/attention. Some folks feel they are better for sustained high-RPM operation as the auto-lash pills can have the oil squeezed out by the valve springs if there isn't sufficient time for the oil pressure in the rocker arm to re-fill the adjusters. For normal street driving (even with a heavy right foot) the auto-lash setup is more than sufficient. I did a couple hours at Willow Springs many years ago and had no issues with my 88's auto-lash setup.
Jet valves: remnants from when the 2.6 engine had a carburetor. Many ChryCo cars and Mitsus used the 2.6 engine this way, they generally had "MCA-Jet" stickers on the car or on the top of the engine. MCA-Jet was the jet valves. They are small valves next to the intake valves and opened by the same rocker arm as the intake valve (there is a round "ear" sticking sideways from the rocker end to do this). Inside the cyl head, where you'd expect to see valve head itself, you'd instead find a steel cylinder-shaped plug. The jet valve feeds this plug that has a 90 degree passage in it; that 90 turn shoots the jet valve air along the edge of the cylinder to promote additional "swirl." Swirl helps air+fuel stay mixed for a cleaner and better burn, especially in the carb days since carbs often didn't mix the air and fuel perfectly. Swirl also helps get the air+fuel mix more evenly distributed inside the cylinder... again for a cleaner and better (i.e. more powerful) burn. Throttle body fuel injection mixes better than carbs so the jet valves are not as essential on StarQuests. Modern port fuel injection is better yet - spraying the fuel directly at the intake valve - so it goes right into the cylinder and doesn't have a chance to "un-mix" while traveling through the intake manifold.
Since you have the head off the car, look at the side where the intake manifold attaches. You'll see a narrow channel running around the intake openings... that is the air channel feeding the jet valves.
As for the busted exhaust manifold stud: any decent machine shop can repair that. The cause: look at the exhaust manifold - notice how the 4 runners end in one beefy plate that bolts to the head? As the exhaust manifold heats up, thermal expansion makes the metal want to move. Some runners are longer than others though so they'll expand even more. That beefy plate limits them however forcing the whole manifold to bend; that bending in the beefy plate is what rips apart the stud. Limiting the movement means something else "has to give" because the metal IS going to expand... typical result is cracks in the #1 and especially #4 exhaust manifold tubes. If your manifold doesn't have any cracks - great - you are lucky. To fix the issue: cut the "webbing" between the 4 ports in that beefy plate. Make about a 1//8th gap between the ports. That allows the ends of the tubes to move left/right with thermal expansion. You'll see the bolt holes are bigger than the studs - there is already allowance for some motion. Once the webbing is cut it is likely the face of the manifold (where it attaches to the head) will move a bit and will no longer be consistent across the 4 openings. A machine shop will have to re-machine this area flat. No big deal. Just be careful when making the cuts as the manifold probably has a lot of internal stress in it right now - when you are 99% through a cut don't be surprised if the metal moves and grabs your cutting blade!
Posted 05 September 2019 - 08:13 PM
Posted 12 September 2019 - 09:10 PM
Posted 12 September 2019 - 09:29 PM
Posted 13 September 2019 - 05:02 AM
Posted 13 September 2019 - 06:31 AM
Here is some good info for you also complete schematic couple of posts down so you can get better picture .Notice that timing chain tension is from oil pump plunger w small guide pushes against the chain during operation. There is a mechanical adjuster for balance shaft chain(completely separate).
Edited by croquest87, 13 September 2019 - 06:45 AM.
Posted 13 September 2019 - 09:58 AM
Posted 13 September 2019 - 12:48 PM
Edited by croquest87, 13 September 2019 - 12:50 PM.
Posted 22 September 2019 - 07:57 AM
Posted 22 September 2019 - 10:52 AM
Edited by croquest87, 22 September 2019 - 10:53 AM.
Posted 22 September 2019 - 03:23 PM
Posted 22 September 2019 - 08:08 PM
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