dmoffitt

2.8 (3.0 crank, custom rods, worked pistons to lower compression to approx 8.4)
lindsey's "stage 3" (big-valve, lighter springs/retainers) head
lindsey intake manifold, stock throttle-body
sfr 4:1 header
kokeln "street" turbo (considering upgrading to something a touch bigger)
had a digital MAF on there, but now i'm going with either link2 or tec3.

i don't plan on needing more than 7k rpm nor do i think that would be wise considering a stroked engine, but i would like to make the most of what i've got, so tell me, do you think the stock camshaft is adequate, or should i be shopping for another (and if so, what)? TonyG had mentioned a while back that one of the JME cams might be better suited, either the PHT CS-19 for 944T or maybe PHT 8SR/S3-14 for 944T ?

dmoffitt

oh yeah - and i've got 73lb/hr injectors and will be soon installing a new fuel rail, sx fpr, damper, pump, cell, lines etc... so fuel isn't a concern

TonyG

First off... if you have a 2.8 using a 3 liter crank, why do you have "worked pistons".

Are they stock pistons that have been machined down and you are using a stock rod length?

You have a lot of variables to contend with, and you need to know EXACTLY what is going on before you install a higher lift cam due to potential clearance issues (piston-to-valve).

TonyG

dmoffitt

they are stock pistons which were "fly-cut" - simply to lower compression, and to aleviate worries should i suffer a t-belt failure. as i didn't do the work nor have it done locally where i could personally oversee it, i really don't know 100% what is going on in there but i could ask dave or mike. the 3.0 crank was from andy (944turbo), the rods are Pauter, no they aren't stock length, they're designed for use in a 2.8 stroker setup.

that help?

TonyG

dmoffitt

I'm still not clear.

You need to get all the exact details of what has been done to your engine before you consider a different cam.

Are your valve sizes stock?

TonyG

dmoffitt

nope. the head on the car is one of lindesy's "stage 3" heads (quite large valves, i'd say about as big as you could go on a 2V head). ported, flows 252 cfm according to them.

i apologize if i seem vague, while i'm learning fast about engine building, i didn't do this myself and bought all of it almost a year ago at this point...

basically, dave and mike @ lindsey racing (and their engine builder(s) / machinist i'd assume) took a low-mileage running 2.5L block, tore it down, honed the cyl. walls, replaced every seal, gasket, the water pump, oil pump, balance shaft bearings/seals, rod bearings, all of the bolts/studs/fasteners, put in the Pauter rods and a crank i bought from Andy Albert (3.0, lightened, knifed, balanced, x-drilled, very very worked, brand new) to make it into a 2.8 stroker. we fly-cut the pistons to both lower compression plus at the time i was paranoid about this being an interference engine and i was informed that it would help aleviate the chances of valves and pistons coliding should i suffer a timing belt failure (although i don't know to what extent, esp. now that the valves are a different size, but thats my ignorance shining thru as usual). i'm trying to think if there are any other details i could share... if you had specific questions i could forward them to dave/mike and get back eventually w/ answers, but that's about all i can remember off the top of my head.

TonyG

dmoffitt

I would not use anything different than what you are using now unless you are preparred to do a clay mockup to verify with 100% accuracy the existing clearances.

Way too many things have changed (especially the intake valve sizes) that could easily result in a cam that can run the valve either too close to the piston or actually result in the valve hitting the piston.

For instance... you cannot on a stock bore/stroke/piston 951 bottom, use a Milledge "middle cam" using larger than stock valves without specific valve reliefs cut into the tops of the pistons. (which is exactly why I am using stock valve diameters.... I didn't want to pull the pistons to have them machined just to go to larger valves).

TonyG

TonyG

dmoffitt

I looked at your home page and see the pictures of the Pauter rods and pistons.

It looks like valve reliefs have been cut into your pistons but DO NOT assume that they are big enough.

Typically the person that cuts the pistons will do a mock up with a light valve spring and the valves on one cylinder, with clay on top of the piston. Then they slowly rotate the engine by hand though a couple of revolutions. Then remove the head, and measure the indentations made by the valves into the clay.

It's this measurement that tells the story about clearance that exists and if more is necessary, and exactly where the additional clearancing needs to be made.

This is an area where you do NOT want to be guessing or taking other peoples word for it....

TonyG

dmoffitt

stock's sounding better and better to me thx tony!