I did have a head I bought off a friend on my truck that had port and bowl work and a 3 angle valve job. The head gasket would blow after about a year so I took it off and put my old one back on. After seeing him over the weekend I asked him about the 3 angle valve job and he said he still had the tools to do it with. He told me he could still do it with his drill press there in his garage. He use to run race cars on the dirt track here locally and did a lot of his own motor work.

I can tell a difference from the original head I have on now and the one I bought off of him. The performance is not quite the same. I'm thinking of taking it to the head shop and have them true it back up. My friend told me he had taken .020" off of it when he worked on it.

How much more can be taken off the head surface before it effects the push rod length? It would only probably take about .010" to true it up.

My friend told me if I wanted to have the tools to do the 3 angle valve job i could have them. He also has the tools to put in replacement valve guides.

Looks like I might just try my hand at some head work. I've got 4 extra heads to play around with.

 

couldnt you just get spacers under the rockers to make up for the milled head? instead of needing new push rods.

 

I don't know I've never tried to do anything like that before.

 

You can get shorter pushrods, they're not too expensive, (about $30 for the full set). They're 0.060" inches shorter.

It'll have to wait until the head is installed, (or at least held down with the HG you're going to use in place), but when the lifters are EMPTY, bring each cylinder to TDC on the intake stroke and measure the clearance between the valve and the rocker arm with a feeler gauge.

You're shooting for 0.150". If it's less than 0.125", you need shorter pushrods. If it's greater than 0.175", you need shorter pushrods.

 

Are you checking the clearance with the nut on the fulcrum tightened down all the way? That's with no oil in the lifters right?

abondened bronco, did you get your truck all straightened out? I guess if you like working on them it can always be better can't it.

 

Yeah, this is with everything in place and the rocker arms fully adjusted. You'll probably want the head bolts tightened down (not necessarily torqued) so it doesn't move around. It's better if it is torqued, but if you want to remove the head after you check lengths, then tightening the bolts just enough to keep it in place is good enough. And yeah, no oil in the lifters so the push rod can bottom out.

The Bronco's doing alright, I guess. The Comp 260 cam I put in it shredded a lobe after 200 miles, which really sucked. On the other hand, I came across a really good deal on a used 300 for $50 so I swapped it in. Turns out it runs really well and has great compression, so I'll use it to get me around for a while while I fix up my other engine.

 

It is getting harder to find a good running 300 six anymore. I was lucky with mine. I picked up and old 78 ford truck that had a good one in it for $150. Still going strong. Have to resort to rebuilding one if I want to have another good one.

Thanks for the info on how to check the valve train, that will come in handy later when I try the head out again.

 

Yeah, I definitely lucked out on this one. $50 and the guy dropped it off at my house. Compression was all between 150 and 155 front to back. Lots of valvetrain clatter, so I need to clear that up.

When I measured my valvetrain, the one thing that really screwed me up was not making sure it was on the intake stroke. My book even specifically stated intake. If not, the measurements will be off by quite a bit. Not sure why the clearance between the rocker and valve top would be different on one stroke vs. the other, but...

 

Did you like the comp cam you had? Is this a common problem for some failures?

I have another 300 six motor that is suppose to only have like 40,000 miles on it. I got it for $75 from and friend that got it as a extra motor when he bought a truck. I pulled the head and it is still on the original bore. Thinking of going thru it and changing the cam and putting my modified head back on it.

 

I didn't actually get to use it for all that long, but I liked how it performed.
Apparently, though, there's quite a forum dedicated to complaining about Comp's failure rate. I think if I get another one, I'll go with someone else. It's too bad.

Nice find on the motor you have. If everything's nice and tight, that'd be great to throw that head on it and have a low mileage engine in your truck. All in all, I think it took me only two days from start to finish to swap engines.

 

Regarding the milled head....you might also check with Felpro to see if they offer a thicker head gasket to offset the height reduction saving you the cost ofreplacement pushrods, although that would reduce any benefit you may have wanted from milling the head (which typically raises compression ratio)...just an option.

With regards to the valves...yes, grind & resurfacing the valves is something that can be effectively done in a garage...I would recommend a 4 angle valve grind- that is actually what the oem's have used for many years and what most machine shops do anyway....

With regards to cams...

Parkerizing is the final step that some big name cam companies will not even offer, and a crucial step to help break the cam in (a heated acid bath that microscopically etches the metal surface and adds a very thin layer of graphite coating which allows the cam lube to hang onto and penetrate into the cam surface during cam break in); or by technical definition…..
• Parkerizing (also called phosphating and phosphatizing) is a method of protecting a steel surface from corrosion and increasing its resistance to wear through the application of an electrochemical phosphate conversion coating (en.wikipedia.org/wiki/Parkerizing)
• A thermo-chemical application whereby a nonmetallic, oil-absorptive coating is applied to the outside surface of the camshaft. This protects the cam lobes during the break-in period. (APE - Cam terminology)

Here's the problem as I see it.....

1. Comp has by appearance - seems to be a company that has experience more cam lobe failures than most and places the blame on the low ZDDP in the oils. Is it a factor yes, but I highly suspect that they are also using Chinese cam billets & they do not include Parkerizing their cams unless you specifically request and pay additional money for it.

2. Companies like summit who offer their own brand name cams, I don't know and I doubt they will tell you, but knowing summit's pricing structure, I will bet their cam billets are Chinese based as well.

3. Considering the cam has such critical importance to the engines performance and life, to me it makes sense to use a cam grinder who will talk with you directly- even modify the cam grind to fit your needs even better and to address the possibility of cam lobe failure with the new oils. With regards to price...the difference is nil- especially considering its cheap insurance to know exactly who is machining such a critical part for your engine. And remember, advertized lift/duration/lobe separation is just that- advertized and not the specific grind including ramp profile that is used on the cam.

That is why I highly recommend Iskenderian & Crower...both are family owned, been grinding cams for decades, and both will even re-grind your oem cam if possible- saving you even more $. Isky may be the only cam grinder today who still checks every single valvespring befor it leaves the shop!

As you are probably aware, many of the cam mfgs in the past few years either sold, closed their operations to re-open elsewhere (typically with new staff) or .......

In addition to Isky & Crower, I use to very highly recommend....
Sig Erson & Crane...

Both became part of corporate entities, eventually leading to periodic quality issues and closing their doors- I think Crane re-opened, but with a different staff. Typically the staff is very, very young and well- requires a learning curve.

If you do a search on the net, Harvey Crane has posted a little summary of the history of the people who made the cams at Crane, his opinion of what happened and the eventual outcome of several of the staff.

While there are some cam failures cause by start-up/break-in error, cam lobes that are of a street type profile should not be completely worn out in 10,000-30,000 miles- and while just about every cam mfg recommends adding ZDDP (and sells) to the oil, I still highly suspect Parkerizing is not done by some and the billets are of Chinese origin with inferior properties.

Given the criticality of the component- IMHO, I don't like speaking to a catalog parts sale person- they really don't know any more about the cam than what they are reading- companies like Summit, while their bulk purchase agreements are great for price, when it comes to making an engine breathe, there are so many variable including elevation, humidity, fuel blends/available octane, most cam mfgs will vary a "core grind pattern" to match the external impactors in addition to the internal impactors- which today IMHO makes the different between and engine that runs well, to one that just seems to run a little bit better, smoother and gets better mileage than expected.

 

I've looking into the Crower cams for the 300 six but have had difficulty finding anyone that carries one. Don't want one that is radical just give a little better performance. Somethine from 1500 rpm to 4500 rpm. I rarely get above 3000 rpm.

 

Call them on the phone, the family owned businesses typically do not list all the cam profiles they have, only the ones that are the most popular.

 

In Comp's defense, they also sell more cams than anyone else so there are more potential opportunities for failure.

And in my experience people are much more inclined to blame someone else when they make a mistake breaking in an engine than say, "I'm an idiot. The break-in instructions specifically said not to use double or triple valve springs during break-in but removing and reinstalling the springs seemed like a PITA" or "I just ran the engine at a constant rpm rather than constantly varying between 2,000 and 3,500 rpm."

Not saying Comp is above criticism, but there are plenty of people who run a Comp cam with no worries. Maybe their QC is subpar but then again people do make mistakes when they rebuild/hop-up engines. Even people who do it well for a living.

 

Beechkid: That was some good reading about cams. I'll stick with Isky. After checking online for 'comp cams lifter failure', and finding many many complaints of lifters failing within 500 miles, I got afraid.

Regarding push rod length: With the adjustable type rocker head, I found it very helpful when checking the geometry, to use a roller rocker and the 'witness mark method.' I simply covered the end of the valve tip with a felt tip pen, bolted on the roller rocker, and cranked over the engine. I then removed it and could see where the contact was. On a correctly set up head, the roller should make contact at the 1/3 of the way to dizzy side, then cross over center to the 1/3 of the way to the intake side of head. Where it hits tells you longer or shorter p.rods.

Even though I took .020" off my block, and .020-.030 off the head, I ended up having to use .060 longer p.rods because the sbc valves I had installed were longer than Ford valves.