[DeTomaso] rocker arm alignment

Fri Sep 21 06:48:33 EDT 2012

yes, the joys of aftermarket parts.
the CHI heads required different length pushrods.  plus I used roller lifters, which are longer than stock lifter, changing the necessary length of the pushrods.  And the rocker studs have to be long or extra long (forgot exactly which) to keep the rocker tip centered on the valve stem.  I worked with dave storlein of proting dynamics, a CHI expert.  when I thought to ask him these questions, he was very knowledgeable and helpful (although I had to think of the questions to ask - a lot was figuring it out after I ordered the wrong part from summit racing)   Justin

> Subject: Re: [DeTomaso] rocker arm alignment
> From: bd8134 at gmail.com
> Date: Fri, 21 Sep 2012 00:23:39 -0400
> CC: cengles at cox.net; will.kooiman at gmail.com; detomaso at realbig.com
> To: justingreisberg at hotmail.com
> 
> I had Manley valve guides with 3/8" pushrods on CHI heads and each one was misaligned.
> http://www.poca.com/index.php/gallery/?g2_itemId=38025
> 
> The pushrods were too short, the new pushrods moved the rocker arm further up the rocker stud and that resulted in the studs being too short.
> Not enough threads left for the nuts to grip.
> http://www.poca.com/index.php/gallery/?g2_itemId=38032
> 
> Maybe I should have tried the comp cams guide plates.. :-)
> 
> On Sep 20, 2012, at 9:11 PM, Justin Greisberg <justingreisberg at hotmail.com> wrote:
> 
> > 
> > i just bought the manley pushrod guideplates which fit my 3/8" pushrods on CHI heads perfectly. i appreciate the info from everyone, but that was an easy solution for me. i still have those comp cams guideplates sitting somewhere collecting dust justin
> > 
> >> From: cengles at cox.net
> >> To: justingreisberg at hotmail.com; will.kooiman at gmail.com; detomaso at realbig.com
> >> Subject: RE: [DeTomaso] rocker arm alignment
> >> Date: Wed, 19 Sep 2012 21:24:38 -0500
> >> 
> >> Dear Justin,
> >> 
> >> 
> >> If the guide plates don't fit properly or adversely affect the
> >> valve train geometry, then very experienced engine builders tell me that the
> >> answer is to cut the offending guide plates in two and then adjust where
> >> they need to be for that particular engine and then *weld* them in the
> >> proper position. I thought it was a bit extreme when I first heard it, but
> >> after four engines and the pictures from Sean, I believe it.
> >> 
> >> 
> >> Amateur engine builder, Chuck Engles
> >> 
> >> 
> >> -----Original Message-----
> >> From: detomaso-bounces at realbig.com [mailto:detomaso-bounces at realbig.com] On
> >> Behalf Of Justin Greisberg
> >> Sent: Wednesday, September 19, 2012 3:47 PM
> >> To: will.kooiman at gmail.com; detomaso at realbig.com
> >> Subject: Re: [DeTomaso] rocker arm alignment
> >> 
> >> 
> >> on my CHI heads with rocker studs and harlan sharp rocker arms, there was no
> >> option to move the rocker arm sideways at all. if the guideplates dont fit,
> >> then there is no adjustment. the guideplates themselves might need a slight
> >> right/left adjustment on the rocker studs, before you tighten the studs.
> >> BUT it is well known that some of the aftermarket cleveland guide plates do
> >> not fit properly. summit now lists a bunch of guideplates for the
> >> cleveland, including some from AFR that I have never seen. justin
> >> 
> >>> Date: Tue, 18 Sep 2012 22:46:38 -0500
> >>> Subject: Re: [DeTomaso] rocker arm alignment
> >>> From: will.kooiman at gmail.com
> >>> To: justingreisberg at hotmail.com; detomaso at realbig.com
> >>> 
> >>> That looks like an adjustment problem.
> >>> 
> >>> If you loosen the rocker studs, you can adjust the rockers left/right 
> >>> by moving the guide plate.
> >>> 
> >>> I would only cut/reweld the guide plate after I've confirmed that the 
> >>> ones I had could not be adjusted. For that matter, if it's off so bad 
> >>> you can't adjust them, I'd get another brand of guide plates. They 
> >>> are pretty inexpensive.
> >>> 
> >>> Also check that the pushrods do not rub anywhere - through their full 
> >>> travel. It is pretty common for them to bind on the rocker arms or on 
> >>> the heads themselves (the holes cut through the heads for the pushrods).
> >>> 
> >>> Just my opinion, but I wouldn't take it back to the builder. This is 
> >>> an easy fix, and you'll do it better than he will - since it's your baby.
> >>> 
> >>> 
> >>> 
> >>> On 9/18/12 6:06 PM, "Justin Greisberg" <justingreisberg at hotmail.com>
> >> wrote:
> >>> 
> >>>> 
> >>>> Important:
> >>>> when using pushrod guides for clevelands, I found the same thing. I 
> >>>> think the traditional crane or comp (I forgot which) guide plates 
> >>>> just do not fit properly. I found some other brand, I am sorry I 
> >>>> forgot which, which was much better. I talked to some engine 
> >>>> builders and they confirmed the same thing. I think the comp cams 
> >>>> were not good and the manleys fit well. I see summit now sells trick 
> >>>> flow brand as well, which was not available when I built my engine. i
> >> was using 3/8" pushrods.
> >>>> I also found the pushrod length for CHI heads plus harland sharp 
> >>>> roller rockers was very much shorter than standard to get the rocker 
> >>>> over the center of the valve stem. an adjustable pushrod length checker
> >> was
> >>>> essential in adjusting the valvetrain. justin
> >> 
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