Help me brainstorm...
5 Year Member
Joined: May 2013
Posts: 1,251
Likes: 263
From: San Antonio, Texas
The 112 lobe separation will run a little rougher than a 114 would.
Also, I skipped right over the comment about the egr still leaking a little into the intake. Cut a pice of aluminum out of a soda can and cut it to the same size as the egr gasket. Punch out the the bolt holes but not the port hole. This will completely block off the egr and stop the leak. That will help because you've got unmetered air leaking in now and that can cause a lean condition if it gets worse.
When the valve springs were installed were shims put in to get the correct installed height? Were the springs checked for possible binding at full lift?
The first thing I would do is completely block off the egr, disconnect the battery to reset the ECU, then hook it back up and see if it runs any different. Then check for any leaking or broken vacuum lines or any other vacuum leaks. Also, use some good non residue electrical cleaner to clean of the MAF.
Also, I skipped right over the comment about the egr still leaking a little into the intake. Cut a pice of aluminum out of a soda can and cut it to the same size as the egr gasket. Punch out the the bolt holes but not the port hole. This will completely block off the egr and stop the leak. That will help because you've got unmetered air leaking in now and that can cause a lean condition if it gets worse.
When the valve springs were installed were shims put in to get the correct installed height? Were the springs checked for possible binding at full lift?
The first thing I would do is completely block off the egr, disconnect the battery to reset the ECU, then hook it back up and see if it runs any different. Then check for any leaking or broken vacuum lines or any other vacuum leaks. Also, use some good non residue electrical cleaner to clean of the MAF.
Thread Starter
Senior Member
Joined: Oct 2013
Posts: 149
Likes: 13
The 112 lobe separation will run a little rougher than a 114 would.
Also, I skipped right over the comment about the egr still leaking a little into the intake. Cut a pice of aluminum out of a soda can and cut it to the same size as the egr gasket. Punch out the the bolt holes but not the port hole. This will completely block off the egr and stop the leak. That will help because you've got unmetered air leaking in now and that can cause a lean condition if it gets worse.
When the valve springs were installed were shims put in to get the correct installed height? Were the springs checked for possible binding at full lift?
The first thing I would do is completely block off the egr, disconnect the battery to reset the ECU, then hook it back up and see if it runs any different. Then check for any leaking or broken vacuum lines or any other vacuum leaks. Also, use some good non residue electrical cleaner to clean of the MAF.
Also, I skipped right over the comment about the egr still leaking a little into the intake. Cut a pice of aluminum out of a soda can and cut it to the same size as the egr gasket. Punch out the the bolt holes but not the port hole. This will completely block off the egr and stop the leak. That will help because you've got unmetered air leaking in now and that can cause a lean condition if it gets worse.
When the valve springs were installed were shims put in to get the correct installed height? Were the springs checked for possible binding at full lift?
The first thing I would do is completely block off the egr, disconnect the battery to reset the ECU, then hook it back up and see if it runs any different. Then check for any leaking or broken vacuum lines or any other vacuum leaks. Also, use some good non residue electrical cleaner to clean of the MAF.
As far as the valve springs are concerned, I don't know as they came installed from summitracing.com. TFS Track Heat 170s, 61cc chambers. I was told by a performance engine builder that he has personally taken off, and measured, the seat pressure of those springs and that they measure at 140# (it's been awhile and I am retarded so if my terminology isn't correct, he essentially told me it would be a waste of money to buy a spring kit). Could I have been led astray here? Sure, but he had nothing to gain from it.
Vacuum lines: All brand new, high heat silicone.
MAF sensor/housing: Have two, tried both, no change.
5 Year Member
Joined: May 2013
Posts: 1,251
Likes: 263
From: San Antonio, Texas
Do you know the part number for the heads? I was looking at the specs for them on Summit and there are a few different ones.
You said yours are are the 61cc model. On summit the only ones that show as coming assembled are the
Trick Flow® Twisted Wedge® Track Heat® 170 Cylinder Heads for Small Block Ford TFS-51410010-M61
Here's the link to the page. http://www.summitracing.com/parts/tf...view/make/ford
But in the specs overview I saw this info.
Also I've bolded the part in the other info section
So, with the 1.6 rockers you're using, combined with the info above, you might have the valves tapping the top of the pistons. And the seat pressure says 125, not 150.
You said yours are are the 61cc model. On summit the only ones that show as coming assembled are the
Trick Flow® Twisted Wedge® Track Heat® 170 Cylinder Heads for Small Block Ford TFS-51410010-M61
Here's the link to the page. http://www.summitracing.com/parts/tf...view/make/ford
But in the specs overview I saw this info.
Notes:
Trick Flow twisted wedge pistons are required for use with these heads to allow for piston to valve clearance with camshafts over .550 in. lift. Heads are drilled to accept 1/2 in. head bolts. Valve cover rail is raised .350 in. over stock.
Trick Flow twisted wedge pistons are required for use with these heads to allow for piston to valve clearance with camshafts over .550 in. lift. Heads are drilled to accept 1/2 in. head bolts. Valve cover rail is raised .350 in. over stock.
Trick Flow® Twisted Wedge® Track Heat® series cylinder heads are capable of producing 600+ hp on naturally aspirated engines--they're the winningest heads in NMRA racing. Twisted Wedge® Track Heat® heads so dominated that the NMRA saddled them with a weight penalty! Twisted Wedge® Track Heat® heads include all of the features of the famous Twisted Wedge® series heads, plus higher-rated valve springs (125 lbs. of seat pressure at 1.780 in. installed height), 10 degree machined steel super locks, and manganese bronze guides to support camshafts with up to 0.600 in. of lift when used with the proper pistons. Track Heat® 170 heads with Fast As Cast runners are perfect for dual-purpose street/strip cars and for racers looking for the best combination of performance and value. These heads feature cast intake and exhaust runners with Twisted Wedge® CNC-ported profiles. You get near-CNC-ported power and performance for the price of ordinary cast heads. Twisted Wedge® Track Heat® series heads work with most OEM and aftermarket intake and exhaust manifolds/headers. The heads are ready for installation straight out of the box. They come with stainless steel valves (the intakes are backcut), 1.460 in. dual valve springs, locks, retainers, ARP 7/16 in. rocker studs, and guideplates. Bare cylinder head castings are also available.
Thread Starter
Senior Member
Joined: Oct 2013
Posts: 149
Likes: 13
Do you know the part number for the heads? I was looking at the specs for them on Summit and there are a few different ones.
You said yours are are the 61cc model. On summit the only ones that show as coming assembled are the
Trick Flow® Twisted Wedge® Track Heat® 170 Cylinder Heads for Small Block Ford TFS-51410010-M61
Here's the link to the page. http://www.summitracing.com/parts/tf...view/make/ford
But in the specs overview I saw this info.
Also I've bolded the part in the other info section
So, with the 1.6 rockers you're using, combined with the info above, you might have the valves tapping the top of the pistons. And the seat pressure says 125, not 150.
You said yours are are the 61cc model. On summit the only ones that show as coming assembled are the
Trick Flow® Twisted Wedge® Track Heat® 170 Cylinder Heads for Small Block Ford TFS-51410010-M61
Here's the link to the page. http://www.summitracing.com/parts/tf...view/make/ford
But in the specs overview I saw this info.
Also I've bolded the part in the other info section
So, with the 1.6 rockers you're using, combined with the info above, you might have the valves tapping the top of the pistons. And the seat pressure says 125, not 150.
If my pistons were tapping the valves, wouldn't I be looking at all kinds of performance issues and, perhaps, catastrophic failure? Not just a shudder at idle?
5 Year Member
Joined: May 2013
Posts: 1,251
Likes: 263
From: San Antonio, Texas
Ok cool.
I have seen it happen where the valves were lightly tapping the valves without causing a catastrophic failure. It tweaked some of the valves just enough to cause them not seal 100% but not have popping through the intake. And it caused a rough idle along with a lower vacuum reading and less power output than it should have. But if you checked the clearance and it was good, cool.
I'm kind of at a loss at this point. You listed the new parts in the first post. Were those parts put on when the initial work was done? Have any newparts been put on since this problem started?
I have seen it happen where the valves were lightly tapping the valves without causing a catastrophic failure. It tweaked some of the valves just enough to cause them not seal 100% but not have popping through the intake. And it caused a rough idle along with a lower vacuum reading and less power output than it should have. But if you checked the clearance and it was good, cool.
I'm kind of at a loss at this point. You listed the new parts in the first post. Were those parts put on when the initial work was done? Have any newparts been put on since this problem started?
Martin
Joined: Jan 2011
Posts: 3,036
Likes: 260
From: Lehi, Utah
Take another look at Comp Cams website for 302 cam specs. None of the cams with idle to 5500 rpm will have specs anywhere near your cam. A cam that idles decent will have minimum LSA of 114 to 116 and max lift of .500. I'd bet your vac at idle is 6 to 8 hg.
I went through similar problems with a cam that had LSA of 112 and finally ended up pulling it in favor of a more idle friendly cam. When the specs on a cam state power band of 1200 to 6000 rpm, it also means that cam will not run well at 700 rpm idle. A cam that's not idle friendly will produce problems , and not just at idle.
I went through similar problems with a cam that had LSA of 112 and finally ended up pulling it in favor of a more idle friendly cam. When the specs on a cam state power band of 1200 to 6000 rpm, it also means that cam will not run well at 700 rpm idle. A cam that's not idle friendly will produce problems , and not just at idle.
Thread Starter
Senior Member
Joined: Oct 2013
Posts: 149
Likes: 13
Take another look at Comp Cams website for 302 cam specs. None of the cams with idle to 5500 rpm will have specs anywhere near your cam. A cam that idles decent will have minimum LSA of 114 to 116 and max lift of .500. I'd bet your vac at idle is 6 to 8 hg.
I went through similar problems with a cam that had LSA of 112 and finally ended up pulling it in favor of a more idle friendly cam. When the specs on a cam state power band of 1200 to 6000 rpm, it also means that cam will not run well at 700 rpm idle. A cam that's not idle friendly will produce problems , and not just at idle.
I went through similar problems with a cam that had LSA of 112 and finally ended up pulling it in favor of a more idle friendly cam. When the specs on a cam state power band of 1200 to 6000 rpm, it also means that cam will not run well at 700 rpm idle. A cam that's not idle friendly will produce problems , and not just at idle.
Maybe to many trucks?
Joined: Oct 2012
Posts: 641
Likes: 29
From: In the backwoods
So, since I built the top end of the 5.0 in my truck, I have had a random engine shimmy/shudder/shake/whatever. Ive been trying to track down the cause but have been unsuccessful. Here is a video of another engine that looks to have the same "shudder" mine does:
Safe Trans Am WS6 ENGINE Shake ?? Big Cam/heads/bolt ons etc - YouTube
Have any of you ever seen anything like this? It is completely random and inconsistent. Some shakes are more violent than other. Whenever the engine shudders the rpms dont seem to change nor does the exhaust note change.
Engine mods: tfs 170 61cc track heat heads (thermactor air function turned off in tune), custom ground ed curtis cam, 1.6 probe roller rockers, moss ported lower intake, jba shorty headers, magnaflow y-pipe, dronemaster 40, 3:73 frpp gears. Also turned off in tune: knock sensor function, and egr function. Truck put down 225/267 to the wheels. Poopy numbers if you ask me but when you consider the 205/275 they came with from the factory (to the flywheel) I guess its not terrible.
Some more details and things that have been suggested on other forums:
Fuel pump/fuel trims: This would have shown up in the A/F on the dyno, no?
Spark/miss: New plugs (gapped at .050) and wires, new tfi and coil, original distributor.
Motor mounts: Maybe?
Bad balancer: Not likely from a reliable source (holla at my boy qdeezie).
EGR: Still leaking exhaust gases into upper, despite being turned off in computer. Thoughts?
Anyway, trying to eradicate this engine shudder but havent been able to. Ideas please? No codes, cylinder balance test passes on first go.
If I dont have it figured out by mid-May then its going back to the tuner, and maybe he can uncover something with his data logs. In the mean time, Im bored and like tinkering, so lets figure this out =).
Thanks fellas.
Safe Trans Am WS6 ENGINE Shake ?? Big Cam/heads/bolt ons etc - YouTube
Have any of you ever seen anything like this? It is completely random and inconsistent. Some shakes are more violent than other. Whenever the engine shudders the rpms dont seem to change nor does the exhaust note change.
Engine mods: tfs 170 61cc track heat heads (thermactor air function turned off in tune), custom ground ed curtis cam, 1.6 probe roller rockers, moss ported lower intake, jba shorty headers, magnaflow y-pipe, dronemaster 40, 3:73 frpp gears. Also turned off in tune: knock sensor function, and egr function. Truck put down 225/267 to the wheels. Poopy numbers if you ask me but when you consider the 205/275 they came with from the factory (to the flywheel) I guess its not terrible.
Some more details and things that have been suggested on other forums:
Fuel pump/fuel trims: This would have shown up in the A/F on the dyno, no?
Spark/miss: New plugs (gapped at .050) and wires, new tfi and coil, original distributor.
Motor mounts: Maybe?
Bad balancer: Not likely from a reliable source (holla at my boy qdeezie).
EGR: Still leaking exhaust gases into upper, despite being turned off in computer. Thoughts?
Anyway, trying to eradicate this engine shudder but havent been able to. Ideas please? No codes, cylinder balance test passes on first go.
If I dont have it figured out by mid-May then its going back to the tuner, and maybe he can uncover something with his data logs. In the mean time, Im bored and like tinkering, so lets figure this out =).
Thanks fellas.
If not I would be thinking slightly dirty injectors.
Has it always done this since you built the top end?
If so I would suggest cam.
Just throwing this out their but if it is the cam not getting enough vacuum can you put an external vacuum pump to make up for it?
Trav
Thread Starter
Senior Member
Joined: Oct 2013
Posts: 149
Likes: 13
Did it act up while on the dyno?
If not I would be thinking slightly dirty injectors.
Has it always done this since you built the top end?
If so I would suggest cam.
Just throwing this out their but if it is the cam not getting enough vacuum can you put an external vacuum pump to make up for it?
Trav
If not I would be thinking slightly dirty injectors.
Has it always done this since you built the top end?
If so I would suggest cam.
Just throwing this out their but if it is the cam not getting enough vacuum can you put an external vacuum pump to make up for it?
Trav