[DeTomaso] Distrubutor Gear Chewed Up
Thomas Tornblom
Thomas.Tornblom at Hax.SE
Fri Jun 2 17:55:54 EDT 2006
Hookay, just off the phone with Crane tech, and I seriously recommend
anyone installing a Crane roller cam, solid or hydraulic, to check that
there is enough clearance when installing the timing gear.
They have checked, and ALL their roller cores are made like this, and
they recommend running a fully threaded bolt.
I have also measured the thickness of the Rollmaster timing gear, a
CS3085, with a Torrington thrust bearing, and it is almost identical to
the old cast iron manley timing gear I used before, and also almost
identical to the old Ford silent gear.
Anyone using a stock Ford or ARP 154-1002 Cam bolt kit is very likely to
have problems with this. Particularly if you are not installing the
eccentric, and particularly with the ARP kit, as the ARP washer is just
0.12" thick, while the stock Ford washer is 0.23". With the ARP kit
there is no way that the timing gear will be properly clamped, eccentric
installed or not.
I did not get through to them that I believe their cores are wrong. That
will probably take someone with better arguing skills.
They did not recommend drilling out or modifying the cam. They said that
that would throw it out of balance, which seems like a pretty daft
argument to me. I would be drilling in the center of the cam, where
balance would have no effect at all, and it is not like I would remove
any significant amount of material. The cam would likely have to rev
around 100 krpm before balance would be a factor at all.
I have BCC:ed them on this mail I would like to suggest that they change
their cores to accommodate more clearance. I urge them to buy an ARP
154-1002 Cam bolt kit, which is very likely to go into many engine
builds, and also a Rollmaster CS3085 timing gear set, which is probably
one of the best timing sets on the market, and try to get that to work
with their roller cam cores. I don't think they will get the ARP bolt to
work with any timing gear.
If they still believe that one should use a fully threaded bolt, then I
suggest that they add one to each cam, or recommend some brand. I also
suggest that they add a warning notice to their cam installation
instructions.
I will most likely use the Allen head bolt I bought yesterday, together
with the thick Ford washer. It has just a 0.4" non-threaded section. The
only thing that makes me slightly uneasy is that it is a Taiwanese bolt,
F K E, but it appears to be a solid bolt, and I bought at a shop that I
believe steers clear of junk.
Cheers,
Thomas
Asa Jay Laughton wrote:
> Okay, so bolt it on with the fuel pump eccentric in place and see if
> that makes a difference. If so, then just run with the eccentric in
> place. It's light enough and as long as you aren't running a fuel pump
> off it, there won't be any load.
>
> Asa Jay
>
> Thomas Tornblom wrote:
>
>> Daniel C Jones wrote:
>>
>>> Thomas,
>>>
>>> I've not seen that problem but I've not seen my cam, either. I had it
>>> directly sent to Dave Williams. Dave, let us know what you find when
>>> you assemble the engine.
>>
>>
>> Crane is investigating the problem, including chasing up the blue prints.
>>
>> They said they see three potential causes:
>>
>> 1) The blueprints for the core are wrong
>> 2) The vendor making the cores did a mistake
>> 3) The guy at crane finishing my cam did a mistake
>>
>> The tech guy at Crane checked around the tech department, and they had
>> had no such problems from other customers, or so they say.
>>
>> My problem may be aggravated by the fact that I'm not installing the
>> fuel pump eccentric. Using the stock Ford bolt and washer, plus the
>> eccentric would potentially avoid the problem, or at least hide it.
>>
>> I can imagine it will be a hit or miss with the combination of bolt
>> and washer, timing gear brand, using the fuel pump eccentric or not.
>>
>> I am contemplating drilling the threads about 1/2" deeper into the
>> core, with the cam still in the block. I would prefer not having to
>> remove the timing gear again as it is new and is really tight.
>>
>> Anyone know how hard these cores are? Would a plain drill bit in a
>> power drill work?
>>
>> Anyway, Crane said they would get back to me today.
>>
>>>
>>> Dan Jones
>>>
>>
>> Cheers,
>> Thomas
>>
>>>
>>> On 6/1/06, Thomas Tornblom <Thomas.Tornblom at hax.se> wrote:
>>>
>>>> Speaking of steel roller cams, I just ran into an unforeseen problem
>>>> today with my new Crane hydraulic roller cam. The threads for the cam
>>>> gear bolt starts way too early, which makes the unthreaded part of the
>>>> bolt shank bottom out before clamping the gear properly.
>>>>
>>>> It was just by sheer luck that I noticed. I got a box with random arp
>>>> bolts from Summit today, and one of them was a new cam bolt. The
>>>> supplied washer is slightly thinner than the stock washer, and when I
>>>> tried to bolt down the gear, the bolt wasn't even close to reach the
>>>> washer before it couldn't be threaded anymore.
>>>>
>>>> I compared it to the old cast iron flat tappet Crane cam, and the
>>>> threads starts about 0.78" down the hole, and the bolt can be threaded
>>>> almost to when the bolt head reaches the cam, if no gear is in
>>>> place. On
>>>> the new cam the threads starts 0.31" down the hole.
>>>>
>>>> Using the old bolt I get about 1/4 turn after the bolt touches the
>>>> washer before the bolt bottoms out in the cam core.
>>>>
>>>> Is this a common problem, and are there any special short bolts for
>>>> this?
>>>>
>>>> Thomas
>>>>
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>
--
Real life: Thomas Törnblom Email: Thomas.Tornblom at Hax.SE
Snail mail: Banvallsvägen 14 Phone: +46 18 290 290
S - 754 40 Uppsala, Sweden Cellular: +46 70 261 1372
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