[DeTomaso] Hydraulic lifter pressure hole location

[Doug Braun]

Under the edge by that amount.

Doug

-----Original Message-----
From: detomaso-bounces at realbig.com
[mailto:detomaso-bounces at realbig.com]On Behalf Of Daniel C Jones
Sent: Monday, May 24, 2010 2:52 PM
To: DeTomaso Forum
Subject: Re: [DeTomaso] Hydraulic lifter pressure hole location


Do you mean that your under the chamfer edge by 0.015" or above the
lip by the same amount?

Dan Jones

On Mon, May 24, 2010 at 4:41 PM, Doug Braun <doug at silicondesigns.com> wrote:
> Dan,
>
> I'm running the Crane 36532 hydraulic roller link-bar lifters so I agree
> that in theory I shouldn't have a problem.  But being the type that likes
to
> double check everything in an engine build I took some measurements.
 These
> measurements show that the top of the lifter pressure holes rise to
between
> 0.015" and 0.040" of just entering the chamfered area of the lifter bore.
> The 0.015" measurement is the worst one I found.  The question is, is this
> normal and/or OK to run with?
>
> Doug
>
> -----Original Message-----
> From: detomaso-bounces at realbig.com
> [mailto:detomaso-bounces at realbig.com]On Behalf Of Daniel C Jones
> Sent: Monday, May 24, 2010 12:55 PM
> To: DeTomaso Forum
> Subject: Re: [DeTomaso] Hydraulic lifter pressure hole location
>
>
>> What's the recommendation on how close the pressure hole on a hydraulic
>> roller lifter can get to the top of the lifter bore and still be safe?
>> As you go with a cam with taller lift, the hole gets closer and closer to
>> coming out of the bore.  I talking about how close the hole can safely
get
>> to the edge of the chamfer at the top of the lifter bore where
pressurized
>> oil will just begin to leak.  I want to check this on my new stroker
motor
>> to be safe.
>
> It varies from block-to-block and depends upon the size of the chamfer
> at the top of the lifter bore but, on many blocks, the oil feed is exposed
> at maximum lobe lift.  Some manufacturers (like Comp) will reduce the
> base circle of the cam so the OEM type lifters can be used.  As a rule,
> irregardless of how much lift that a camshaft has, the lifters generally
> all stop in approximately the same location at the top unless the base
> circle is deliberately reduced which can cause problems at the other end
> of the lifter bores.  With a reduced base circle cam, the OEM lifters
> will usually be safe at maximum lift but some blocks will have
interference
> problems with the dogbones.  A local shop has a fixture to machine the
> block for clearance but it can also be done by hand.  Comps link bar
> lifters have the oil feed (and associated band on the lifter) in the same
> place as the OEM lifters so have the same problems at max lobe lift.
>
> The Crane/FRPP link bar retrofit hydraulic roller lifters have the oil
> feed placed lower on the lifter body and do not have the max lift problem.
> Erson also makes a couple of link bar lifters (one a less expensive street
> version and the other a more expensive race version) but I've not been
> able to verify them for fit.
>
> Dan Jones
>
>
>
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