Overheating on cam break in. Glowing Exhaust

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nosigma
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Re: Overheating on cam break in. Glowing Exhaust

Post by nosigma »

Update:

Thermostat
I checked the T Stat over the weekend. It does not have a weep hole, I reported earlier that it had an 1/8" hole. I am going to drill one.
I hung the thermostat into a pot of water with a thermometer in the water. I brought the temperature up and down from 180 to 212 several times. Opening began at 195 to 198 (its a 195 deg T Stat). It was fully open by 205-210. Closing began around 200 on the way down and was fully closed by 195. There was a little hysteresis, call it +/- 3 degrees but there is definately nothing wrong with the T Stat.

Cam Timing
I just finished checking the cam. Its a hydraulic cam, I had to pull the roller rocker and I could not use a dummy spring under the rocker to keep the push rod and lifter seated under pressure greater than the dial indicator and the weight of the push rod and lifter. Despite this after multiple measurements I got the same answer. The intake was .050 below max lift at 69 degrees ATDC and was .050 below max lift (after passing through maximum lift) at 155 degrees ATDC. This gives an intake center line of 112 degrees ATDC installed. The cam is ground with a 110 degree intake center line. The cam is retarded (opening later) by 2 crank degrees. I can not believe that two degrees of cam retard is going to cause the problem.

So far the only problem has been the radiator cap, which is not going to lower the temps. I am taking the radiator in to be rodded out (brass and copper). I did this back in 03 when built the triple weber motor and it Never overheated on me, but its safe to check.

Anyone have an RPM/Ignition advance curve I can look at for one of these motors?

John
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Re: Overheating on cam break in. Glowing Exhaust

Post by SilverXJ »

nosigma wrote: Cam Timing
I just finished checking the cam. Its a hydraulic cam, I had to pull the roller rocker and I could not use a dummy spring under the rocker to keep the push rod and lifter seated under pressure greater than the dial indicator and the weight of the push rod and lifter. Despite this after multiple measurements I got the same answer. The intake was .050 below max lift at 69 degrees ATDC and was .050 below max lift (after passing through maximum lift) at 155 degrees ATDC. This gives an intake center line of 112 degrees ATDC installed. The cam is ground with a 110 degree intake center line. The cam is retarded (opening later) by 2 crank degrees. I can not believe that two degrees of cam retard is going to cause the problem.
Why couldn't you just have measure off the pushrod w/o the rocker on? What method did you use to find true TDC? If your results are correct, 2* most likely wouldn't cause this issue
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Re: Overheating on cam break in. Glowing Exhaust

Post by nosigma »

Two problems with measuring off of the rocker....

First the rocker does not push straight up, it comes up an an angle so you dont get a clean measurement. The push rod end of the rocker travels in a arc around the shaft so it moves up AND towards the valve. This would make for an inaccurate measurement on a solid lifter engine or on a hydraulic lifter motor.

On a hydraulic lifter motor the valve spring causes the lifter to collapse a significant amount and then it expends again as the cam comes back on the base circle. the lifter does not collapse in a identical way all the time as a result you cant get a consistent or accurate measure of the crank angle .050 either side of max lift. By pulling the rocker the lifter is not fighting the valve spring and does not collapse.

I probably should not have whined about removing the rocker. It takes about 10 minutes to reset the rocker. I just hate doing it since I live in mortal fear of setting it up loose and throwing a lash cap, having it fall into the lifter galley and destroy the motor. Had it happen once but the cap stayed in the head.

John
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Re: Overheating on cam break in. Glowing Exhaust

Post by SilverXJ »

I understand why you can't measure off the rocker especially on a hydraulic lifter engine. However you made it seem like you did measure off the rocker and I was just wondering why you couldn't measure off the pushrod instead.

Are you running lash caps?
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Re: Overheating on cam break in. Glowing Exhaust

Post by nosigma »

I did measure off of the push rod. Sorry for the confusion.

I am running lash caps since I am using stock valve stem diameter for better flow (yes it is one of the things I tested back in the day) and the lash caps give me slightly larger area for the roller side to side. The hardened roller rides on the hardened lash cap instead of the slightly softer valve stem material. Less wear on the tops of the valve stems. The stem sits deep inside the valve locks (a whole bunch of valve-locks-cap-spring trades led to that). The lash caps keep the roller well above the top of he locks. ,The lash caps also let me fine tune the installed height of the valve stem (all within .002, a lot of hand grinding careful measuring) while cutting the seats all to precisely the same geometry instead of cutting them to various depths to get equal stem heights. There are slight casting differences along the length of a head. I also raised the roof of the combustion camber .100 to keep the CR down so I could run large quench are pistons with a smaller dish on the old motor that this head was on. Raising the roof required additional depth on the seats to get the valves back into the roof of the chamber. Hence all the valve geometry was up for grabs at that point. For what its worthI also moved the intake valve about .040 closer to the exhaust to unshroud it from the camber wall which gave a nice increase in low to medium lift flow that added noticeably to the total flow between the .050 valve lift points (just off the seat to almost back on it). Total flow during the time the valve is open is the goal not just a huge number at maximum lift.

A whole bunch of compromises, trades and design went into getting that head just right. I went through 3 on the grinding and flow bench before I was happy with this one. I want to take extra special care of it. Not sure what I will do when the head goes.

I took the radiator in to have it de soldered, boiled, rodded and assembled. The shop I use to use for this no longer does the work in house and the staff was totally ignorant. Apparently they were the last ones around here who rebuild radiators. Sounds like I am heading down to Richmond to get it done. DC is a paper city.

John

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Re: Overheating on cam break in. Glowing Exhaust

Post by CobraMarty »

Do you have the valve ad spring specs and any flow numbers on you head?
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Re: Overheating on cam break in. Glowing Exhaust

Post by nosigma »

The flow bench results can be found on the sticky: http://www.jeepstrokers.com/forum/viewt ... ?f=5&t=226. I hit 264 CFM at 0.50 lift intake with the smaller valves. Never got it measured after the big valves went in (with chamber relief and moving the intake .040 closer to the exhaust for additional unshrouding). Peak numbers were less important to me than low and mid lift numbers to maximize area under the curve. The air comes in at all lift values, not just at maximum lift.

The valve springs are triples with Harland sharp rollers. I can not seem to find my original build notebook from 2003 (disturbs me greatly) so I cant say which valve springs I used. I would not recommend what I used anyhow. Way too much custom machine work, locks, keepers and lash caps. Its worked out great but I would NOT suggest anyone copy my valve train, way to much money and work. Holds together over 7000 rpm on a missed shift but given the crank-cam harmonics I keep it at 6000 and below. I ran this same head on my triple weber 258 (264 with overbore) and it was fabulous.

John
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Re: Overheating on cam break in. Glowing Exhaust

Post by nosigma »

I wont say for certain that the overheating is fixed but it sure looks like it right now.
I found nothing wrong with the cam timing, radiator or cooling fans. The only problem I saw was a weak radiator cap which wont let it run any cooler, it just depresses the boiling point.
Here are the changes I made:

1) Installed a new radiator cap tested good to 13lbs. The old cap released at about 5 lbs (see earlier posts).
2) Installed the HESCO adjustable fuel pressure regulator, set to 44 lbs from HESCO
3) Installed the home made MAP voltage sensor, set to 5.5V.

Finished the last 5 minutes of cam break in with the MAP sensor switched to the stock position (or so I thought)
AFR at 2000-2500 ran around 14.3 so there was really no change here.

Then engine did get up to 220-230 but no higher during the last 5 minutes at 2000-2500.

Took it for a short drive to start ring break in but ran into a couple of problems:

1) As the throttle opened up from about half to full the engine stumbled hard and leaned out bad, saw 25:1 on the AFR. As long as I kept the the throttle opening under about 1/2 the AFR stayed in the 13-15 range.
2) The clutch does not release fully. In gear with the clutch down if you rev the motor the car pulls forward.
3) There is a very noticeable vibration at higher rpm's which sure feels like clutch again. I suspect the input shaft bearing in the trans may be bad or I ate another pilot bushing. I sure hope this isnt it because that the problem I started with 3 years ago lead me to tear down a perfectly good motor and build this on.
4) The fuel pump makes one heck of a squealing racket. Not happy about that at all. This is pretty low on the list right now, better isolation is probably the answer.

The motor does produce a bunch of power and pulls real hard up to 3500 rpm which is as high as I have had it. Very happy with the power I have seen so far. Just need to clear up the other stuff.

More on the glowing exhaust after dark. The vibration and clutch stuff I will put into my original High RPM vibe thread thats been dead for a couple years.

John
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Re: Overheating on cam break in. Glowing Exhaust

Post by nosigma »

Oh yeah, I checked engine codes after I got back. There were 3:
Code 12: Memory cleared in the last 50-100 starts (no concern)
Code 33: AC clutch relay circuit open or short (no concern since the AC is not wired up or fully installed)
Code 14: MAP voltage too high or too low. Probably not a problem since the MAP voltage when switched into the adjustable MAP sensor is 5.5V. While I drive it with the stock voltage I did have the switch set to the Adj MAP voltage position during testing so the code was generated an stored.

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Re: Overheating on cam break in. Glowing Exhaust

Post by Cheromaniac »

nosigma wrote:1) As the throttle opened up from about half to full the engine stumbled hard and leaned out bad, saw 25:1 on the AFR. As long as I kept the the throttle opening under about 1/2 the AFR stayed in the 13-15 range.

4) The fuel pump makes one heck of a squealing racket.
Sounds like problem 4) might be causing problem 1). A fuel pump that squeals is usually on its last legs before it dies altogether.
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Re: Overheating on cam break in. Glowing Exhaust

Post by heavy equipment »

Are you using the single multi-groove belt? If the water pump is turning the same direction as the crankshaft, it'll turn backward and move very little coolant. The only time I've had a glowing manifold on a naturally aspirated gas engine it was caused by retarded ignition.

Good luck!
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Re: Overheating on cam break in. Glowing Exhaust

Post by nosigma »

The water pump turns the opposite direction of the cranshaft. Crank turn clockwise. Water pump turns counter clockwise.

Fuel Pump: That would be very short life (like 20 minutes) for a fuel pump, though it squealed after its first start up so maybe it was bad from the factory (Airtex). After I change the oil will test the fuel pressure at idle and see if I am getting close to the 44lbs that HESCO says the FPR is set at.

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Re: Overheating on cam break in. Glowing Exhaust

Post by SilverXJ »

Airtex isn't the best brand to say the least. Check fuel pressure while driving.
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Re: Overheating on cam break in. Glowing Exhaust

Post by heavy equipment »

Carquest and, I think, NAPA have gone to Bosch electric fuel pumps. For me, Bosch pumps last several times as long as Airtex. They do cost a little more, but the work and annoyance they save is well worth it.
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Re: Overheating on cam break in. Glowing Exhaust

Post by nosigma »

I was a bit leary of the Airtex but the price was decent (you get what you pay for) and it was easy to find the pressure and flow specs for an outside the tank unit. Since the motor is in a Rambler I didnt want to go through the grief of moding the fuel tank for an in tank pump and sump.

Any suggestions from any one on which model Bosch pump (if they have an external).

I did read a thread about a Ford truck electric fuel pump but I could never get a part number for it or even a model/engine size/year.

I picked up a FP gauge today. Since the hood is still off it will be easy to fab up a bracket so I can see the gauge while driving.

I dont think that overheating is an issue any longer. It stayed cool at an idle and when driving, though I only have a few minutes on it. Until cooling rears it ugly head I am going to focus on tuning. I am trying to build up a table of driving modes, control scheme (open, closed) sensor involved and sensors that trigger changes between open/closed modes along with trigger values for the OBDI. No single good source, but the information is on this site in dribs and drabs. I feel a lot more helpless here than I ever did with the triple Weber 45DCOE set up where I had lots of adjustments (idle, main, airs, fuels, emulsions, chokes) and a distributor that I could recurve. I just need to get use to a new way of doing business (FI).

John

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