Starting to understand why building engines may be best left to the professional

[Barry_R]

Thanks Barry. I'm scrambling around to pick up a good used dial indicator (easy part) and an extension to reach down to the lifter. Question to those who have done this - is a 6 inch extension enough to reach down to the top of the lifter? I think the push rods are 8 plus inches.

6" extension should get you there. You can use a piece of welding rod, coat hanger wire, anything stiff enough to run the dial indicator up and down. You just have to find a flat spot on the lifter or put something on the end of the wire so it doesn't go in the oil hole.

Won't argue about the lifter compressing possibility.
Won't argue about the importance of open and close events.
I usually do ICL and follow up with the open/close as a cross check using the same setup - they better match.
I will say that if you see 6 or 7 degree variances in ICL measurement you have issues with measurement setup or the cam itself.

As far as an extension you can just as well get a piece of wood dowel from the Home Depot....as long as it slips through the intake hole...

[Yellow Truck]

I'll be checking out a nearly new Mitutoyu dial indicator ($40) this morning, and I think I'll pony up for the extension ($20). I know you can do it with welding rod or a dowel, but given the chances of doing this wrong I think I'll at least give myself the chance of doing it right!

I don't think I'll try to take the read from the valve since I'm using hydraulic lifters and the springs are pretty stiff. I assume that taking it directly off the lifter will give a pretty good read since the dial indicator won't put up much resistance to the lifter. Taking the rockers off to get to the lifter is not too big a price for getting this right.

I picked up a piston stop, but I'll have to order a degree wheel, seems no one carries them here in Calgary. I will also confirm TDC on the harmonic balancer while I'm at it and make sure it isn't moving around (given the timing drift I've seen).

[scott foxwell]

I will say that if you see 6 or 7 degree variances in ICL measurement you have issues with measurement setup or the cam itself.

Asymmetric lobe...actual centerline can be that far off from what you measure.

[Yellow Truck]

I've been scrambling around to make sure I have the bits I need to do this. I have the front of the engine down to the crank and spacer and should be able to do this on the long weekend. I plan to remove the water pump and rocker assembly on the passenger side to do this (no 7 inch degree wheel available in Calgary on short notice, and I don't want to rely on paper and cardboard).

I'd like to confirm what I'm checking. I was planning on finding TDC with the piston stop, then watching the #1 intake lifter position move from the base circle up to 0.050 inches and note the position on the degree wheel. According to the cam card that should occur at 9 degrees BTDC. Then I will watch for it to fall to 0.050 inches, which according to the cam card will happen at 45 degrees ABDC. I see the max lift is .3370 and it should occur at 108 degrees ATDC, but I don't expect that to be as specific a measurement as the other two since there is a little flattening at the top of the lobe.

I planned to do the same on the exhaust but looking for 0.050 of lift at 52 degrees BBDC and the same at 8 degrees ATDC, with max lift of .3380 at 112 degrees BTDC.

Any shift from these values indicates the cam is incorrectly installed and may be the cause of some of the issues I'm experiencing.

Do I understand this correctly? If not, please correct me before I do something I'll regret.

Unrelated comment - I don't know much about cams, but I understood a lobe separation of 106 to 109 mean more overlap, and 110 to 118 meant less, but this cam seems to have 17 degrees of overlap (the intake opens 9 before TDC and the exhaust closes 8 after TDC). I tried to map out the relationship between cam events and crank rotation - I hadn't done it before since we just installed to the cam card.

[My427stang]

Looking at your numbers, you have a cam that is 234 @ .050 intake and 240 @.050 exhaust, 110 LSA on 108 ICL

Right off the bat, that seems installed a little late and a little bit larger than I'd probably use in a truck.  Not enough to drive you crazy, but a little later than I would want it unless you are running a bit more compression than you should. That being said, it's not far off what I run in my 445 truck, but my truck doesn't do any work anymore and I installed mine earlier (advanced) for a bit more vacuum and low end

Regardless, your method is correct to check valve events if those came off your cam card

So, you are doing the right thing.  If you also post the advertised (.006) valve events, and your compression ratio, we can give an estimate of how far forward you can advance it, but remember, as Barry said, you are also looking for gross errors.  Either the cam is not what you think it is, or you are installed later than the expected 108.
 

[Yellow Truck]

Thanks Ross. My truck doesn't do any work either. I just like wasting gas and rubber in it.

The C/R should be around 10.03 to 1. I know the cam is a bit over the top, but that was what I was aiming for. The .006 numbers are 288 and 290.

[My427stang]

I'd likely advance that cam to 105/106 ICL with that compression and aluminum heads in that application.  Could even go 104 if you have decent fuel, especially with the good chamber.  FYI even a couple degrees change will increase vacuum and part throttle drivability.

That being said, 108 ICL is likely not the problem, but when you do find the cause of low vacuum, cranking the cam forward will only help.

FYI it's not THAT big of a cam, like I said, I run similar, but it's on the big side for a truck by traditional standards

[machoneman]

Ok well first off.... no one starts off as an engine builder.  They own a series of progressively less shitty vehicles until they have mastered getting horribly worn out engines tuned well enough that they can function well enough to get them to work in the morning, many of these lessons are learned at 4am and hour before you need to leave.  After ten years you have enough money to build a stroker or other high performance engine.  If you skipped the important years..... your learning curve has to be steeper.

Drew
[/quote]

I just saw Drew's reply and that of Brett's just afterwards. I've seen a few fellows with zero or near zero engine building experience try to build a killer or even hot engine for the very first time. Things did NOT go well!

As Drew well stated, coming up through junk engines, bad running beaters, slapped together 1st top end jobs, then cam swaps, then later complete engine assembly and learning, often the hard way, is the way to go.

[Drew Pojedinec]

*except Mr Lykins, just cuz he likes to be contrary


Thankfully Paul has some great minds helping him work this out.  Thankfully he also started with a hydraulic roller cam, a SFT would have been a problem by now.
Keep the faith, you are getting there.

[Yellow Truck]

Bob - I started with shitty stuff when I was a teenager, then took 40 years off.

Luckily I have friends who help, and this forum, which is invaluable.

I now have all the bits, so time to get started. I have to spend tomorrow with my brother in the rehab unit at the hospital, where he will spend the next couple of months in intensive speech and physical therapy. His wife needed a day off, so tomorrow I'll shadow his therapy sessions.

[Yellow Truck]

Ross - thanks again. I have access to run of the mill Shell 91. There are a couple of 93 octane fuels around but they all have ethanol, Shell is the only pure gasoline premium. I'm not sure why, but I've been advised to go with the lower octane and avoid the 10% ethanol mixes in the older engine.

If I understand what you are suggesting - I should consider moving the cam so the ICL is in the 104 to 106 position on the degree wheel. Since ICL is hard to nail, that means moving the 0.050 events 2 to 4 degrees advanced. Of course it is possible I will find we misplaced the cam and ICL is not at 108.

[My427stang]

Ross - thanks again. I have access to run of the mill Shell 91. There are a couple of 93 octane fuels around but they all have ethanol, Shell is the only pure gasoline premium. I'm not sure why, but I've been advised to go with the lower octane and avoid the 10% ethanol mixes in the older engine.

If I understand what you are suggesting - I should consider moving the cam so the ICL is in the 104 to 106 position on the degree wheel. Since ICL is hard to nail, that means moving the 0.050 events 2 to 4 degrees advanced. Of course it is possible I will find we misplaced the cam and ICL is not at 108.

Yes, that is what I am saying

Additionally, I am saying that I think you WILL find something other than that though, a 108 ICL would not cause all your heartache with a 445 and 10:1 compression.  I just think after you find the issue, a 2 degree advance of the cam, from where you thought it was, would be beneficial

[Yellow Truck]

Ok, I've been out messing with it. I see the TDC mark is about 4 degrees retarded compared to the pointer on the timing cover. I'll confirm that when I have the balancer back on, but it does suggest that the timing light is exaggerating the amount of ignition advance.

I am seeing 0.050 of lift at about 10 degrees ATDC, the cam card calls for it to occur at 9 degrees. The closing 0.050 occurs around 48 degrees, the cam card calls for that to occur at 45 degrees. Given that my measuring skills are sub par, and I don't have much iron up top to grab with the magnetic base I think I'll put it away and check it again tomorrow. I will also set up and check the exhaust events.

Having said that, I'm not seeing any gross error. Seems we didn't screw up the install. I am surprised that when cranking with the all the plugs out it is stiff for about 90 degrees, then leaps ahead as if compressed air was driving it. I only have one set of rockers off, but I wouldn't expect that to have much impact with the plugs out.

[Yellow Truck]

Rather than modify my previous post, since I've already owned up to being a little weak on taking measurements, I'm looking at the cam card and the intake should be open 9 degrees BTDC, and I'm seeing it open 10 ATDC. I think I need to do it again.

[My427stang]

Looking forward to the results

FYI, if your mark turns out to be 4 degrees off on the balancer, I'd be looking to see what moved.