Advice needed on Delta Cam regrind issue. (1 Viewer)

[Stubby]

Got the cam for my 2F back from Delta Cams, and measured the cam rise for each lobe (total height at top of lobe minus base circle). I measured all of them multiple times because I was getting some odd numbers. This is my first experience with a regrind, so I'm not exactly sure of what the tolerance should be on the cam lift.

These are my actual measurements......with an advertised cam rise of .284", should I be concerned about the amount of variation between lobes, and that most of them are well below spec?

Lobe #	Total height @ top of lobe	Base Circle	Cam rise
1	1.411	1.126	0.285
2	1.455	1.180	0.275
3	1.457	1.177	0.280
4	1.465	1.176	0.289
5	1.464	1.190	0.274
6	1.459	1.182	0.277
7	1.463	1.184	0.279
8	1.455	1.176	0.279
9	1.461	1.185	0.276
10	1.458	1.177	0.281
11	1.454	1.178	0.276
12	1.460	1.189	0.271

 

[Malleus]

If your measurements are correct, that cam wasn't ground. I could do that by hand with a sanding block. I'd say they owe you a cam.

 

[Stubby]

If your measurements are correct, that cam wasn't ground. I could do that by hand with a sanding block. I'd say they owe you a cam.

Checked my micrometer against a gage block, and triple-checked the measurements. I was REALLY hoping that I was wrong, but I agree with what you said. I could have done better with an angle grinder.

Looks like I'll be having an interesting conversation with Ken at Delta Cams tomorrow. Damn.....

 

[Malleus]

I couldn't find my 2F engine manual, but my 3F says the tolerance on the cam is ±0.05-mm, or ±0.002-inch, and there is a minimum height. FWIW.

 

[Stubby]

I couldn't find my 2F engine manual, but my 3F says the tolerance on the cam is ±0.05-mm, or ±0.002-inch, and there is a minimum height. FWIW.

Yeah, they're way outside of that spec.....and the base circle for #1 really concerns me. It's almost the same size as the cam billet, where the others are still noticeably proud.

I really wish there was another option for a "performance" 2F cam besides regrinding. Although, maybe this was just a new guy doing the work and he isn't a first round draft pick. We'll see tomorrow when I call them with the numbers.

 

[Skreddy]

Any pics? Showing where and how you’re measuring. I’ve never used delta but know lots of people that have and never had issues, that doesn’t mean they can’t/don’t happen.

But if accurate, that ain’t good. At least not right.

 

[rkymtnflyfisher]

This is interesting, I had mine reground at Delta in like 2015 or so. I never took any measurements when I got it back, at least I don't remember. Luckily I haven't had any issues at all.

 

[fjc-man]

If you’re ok with a “stock” grind you can get a Melling camshaft through summitracing.com The part number is MC803. Maybe you can get something more to your liking if you deal with them direct.

 

[Steamer]

the base circle for #1 really concerns me.

This is just me thinking with limited cam knowledge and, this doesn’t explain the rises being out of spec, but responding to your concern of the smaller # 1 base circle.
Isn’t the base circle dictated by how much needs to come off the top of the lobe to get through any wear that was present?
In other words, the more that needs to come off the lobe top, the smaller the base circle will be to get the correct rise.
If my thinking is wrong on this maybe someone could splain it to me?

I had mine reground at Delta in like 2015 or so. I never took any measurements when I got it back,

Same here. Delta in 2009. Never occurred to me to measure it. I'm only now realizing that I could have.

Also to Stubby: I wonder if measuring the rise with a dial indicator and V-blocks would yield the same numbers.

 

[Malleus]

Found my 2f manual (while I was looking for something else).

MEASURE with dial indicator
Camshaft runout
0.15-mm/0.0059-in

MEASURE with micrometer caliper
Cam limit:
IN 38.0-mm/1.496-in
EX 37.9-mm/1.492-in

Journal oil clearance
No. 1
47.955-47.975-mm
1.8880-1.8888-in
No. 2
46.455-46.475-mm
1.8289-1.8297-in
No. 3
44.955-44.975-mm
1.7699-1.7707-in
No. 4
43.455-43.475-mm
1.7108-1.7118-in

MEASURE with dial bore indicator
Bearing inner diameter oil clearance (in cylinder block)
STD
0.025-0.075-mm
0.0010-0.0030-in
LIMIT
0.1-mm/0.004-in

HTH

 

[Stubby]

Any pics? Showing where and how you’re measuring. I’ve never used delta but know lots of people that have and never had issues, that doesn’t mean they can’t/don’t happen.

But if accurate, that ain’t good. At least not right.

No pictures, but I'm using a 1"-2" micrometer, measuring the largest point from top of lobe to OD of base circle, then repeating that measurement perpendicular to lobe to get the base circle OD. Subtract the two values to get cam lift.

I can see me being .001 or .002 off due to measurement error, but the numbers I'm getting are WAY off. I even checked with a pair of digital calipers to see if I was going crazy.....the calipers and micrometer measurements yielded the same numbers.

 

[Stubby]

This is just me thinking with limited cam knowledge and, this doesn’t explain the rises being out of spec, but responding to your concern of the smaller # 1 base circle.
Isn’t the base circle dictated by how much needs to come off the top of the lobe to get through any wear that was present?
In other words, the more that needs to come off the lobe top, the smaller the base circle will be to get the correct rise.
If my thinking is wrong on this maybe someone could splain it to me?


Same here. Delta in 2009. Never occurred to me to measure it. I'm only now realizing that I could have.

Also to Stubby: I wonder if measuring the rise with a dial indicator and V-blocks would yield the same numbers.

To get the higher lift without welding the lobe, you have to grind the base circle smaller. My problem is that the #1 lobe is almost the same diameter as the cam billet itself. That may not be a bad thing, as long as the lifter has clearance and can still spin.

Measuring with a dial indicator and v-blocks would be the most accurate, but for just those two measurements, a micrometer should be more than sufficient.

Once I talk to Delta Cams today I'll post up again with what they say.

 

[65swb45]

…and now it’s Wednesday night.

 

[Stubby]

…and now it’s Wednesday night.

Got tied up with stuff and forgot to post.

Ken agreed that the tolerances were way too large, and asked me to send my cam back to him so he could inspect it and find out what happened. It went out yesterday and should arrive in Tacoma on Monday / Tuesday. Probably be this time next week before I have any new information.

 

[Malleus]

I'd love to see his plan to get them in spec. The limit, according to the FSM is 1.490-ish; none of your lobes is even close to that. No. 1 is 0.080 off that limit.

Maybe he's going to stretch your valves?

 

[65swb45]

Personally, I have to wonder how many cores they get in that are beyond a standard regrind.

 

[Stubby]

I'd love to see his plan to get them in spec. The limit, according to the FSM is 1.490-ish; none of your lobes is even close to that. No. 1 is 0.080 off that limit.

Maybe he's going to stretch your valves?

Regrinds require making the base circle smaller, so the FSM limits don't really apply any longer. You just have to turn the adjuster on the rocker arm down farther to get correct lash.

 

[Stubby]

Personally, I have to wonder how many cores they get in that are beyond a standard regrind.

As long as the bearing journals are good, and there's not much runout, lobes that are shot are simply welded up and reground. They had to do that to a few of the lobes on my cam when I first sent it to them.

 

[Stubby]

Heard back from Ken at Delta Cams yesterday afternoon. He put my cam up in v-blocks, zeroed on the base circle, then measured lobe lift with a dial indicator. Measuring it that way, the lobes were from .279" .283" (within tolerance). When we talked about the discrepancy when measuring with outside micrometer, he said that the "old British tooling" that they use does introduce some runout on the base circle, but the lobe is the important part, so they haven't put effort into resolving that issue.

So, bottom line is the grind is good.....if I had a set of v-blocks, I would have measured it that way myself, but it's at least good to know why there was a discrepancy with the mic.

 

[rainingagain]

Hmmm...the base circle also has tolerances and is an important part haha. Runout there is no good but I suppose it can be remedied with lash adjustment on these engines.

This sort of tells me not to use Delta Cams for anything high performance or anything with a hydraulic lifter honestly. Just sayin.