help post 95ci stage 3 build - Harley Forum

cmbereznoff@qwest.net · #1 08-09-2009, 05:49 PM

Help!!!!

OK, here is the version of a epic story.

Equipment:
2002 FLHT, stage three rebuild:
1550 ci SE Cast High Compression Pistons P/N 22661-99A
Heads ported, polished, oversized Valves (1.90 Exh can’t remember intake size),
Rocker boxes clearanced for 600 lift and oversized valves
SE valve springs
SE adj push rods
Headquarters Black ops lifters
Headquarters 0039 575 lift Cams
“new style” HD cam plate with high flow oil pump
CV 40 mm carb, complete high performance rebuild currently with .200 and #48 jets
Vance and Hines high flow Air Filter
Rinehart True Duals
TwinTech Ignition Module and TwinTech coil

generally runnibg at 5-6000 feet elevation (MSL)

Ok here is the problem:

After the rebuild, front deck height showed front piston -0.005 below deck and rear +.005 above. This caused obvious piston impact on rear cylinder when using a Cometic 0.030 head gasket. Went to a stock HD 0.045 gasket. No more impact “appreciated”.

Initial run of bike showed a lot of pinging at 2500-3000 rpm under load, bike ran hot. Adjusted ignition curves from mid point recommended starting settings of #5 advance and #7 slope setting on TwinTech igniton. Eventually adjusted ignition curve slope all the way back to 0 ( not degrees just the setting 0-9 available ) and Advance to 0 ( not degrees just the setting 0-9 available ) after many other trial combinations. Seemed better to the point I and mechanic felt 500 mile break in would be safe / OK with the 0 advance 0 slope setting at 60-70 ambient air temp.

During the break in the environmental temps were in the 70s and not much problem noted. However, when the environmental temps hit 85-90 degrees, back came the "ping / clack". Now, noise is present only under near or wide open throttle and under full load, up hill, 4-5th gears, 2400- 3000 rpm. OK, 500 miles have past. I can run it up in the rpms and load the engine. Exhaust tip deposits at very limited in amount and a light grey. Plugs look perfect, tan to light grey. Engine seems to run hot? ( temp). Runs unfreaking unbeliable above 3500 rpm, great torgue on low end.

Next "cure" was to go from the installed 195 and #45 jets to 200 and #48 jets in an attempt to run less lean, thus cooler and avoid pre-detonation. I also installed HD deluxe oil cooler, changed oil from "Dino" oil 20-50w, to Amsoil 20-50w, tired 93 octane.

Engine ran better ( ?), front wheel lifts off the ground shifting from 1-2 or 2-3rd about 5000 plus rpm shifts ( maybe it would have before but 3000 rpm limit was not broken. STILL "PINGS" at 2400-3000 rpm under WOT and load ( up hill ). Maybe clacks is a better word. I have never heard any "pings" above 3200rpm all the way to 6200 rpm. Makes me question that predetonation is an issue.

Now I am thinking that the "pings" I am hearing ma be the rear piston slapping the head due to piston/rod elongation when the engine is hot with associated piston/ rod stress elongation and not really pre-detonation.

I am I crazy about this assessment?

I am thinking that I need to measure the squish bands and adjust the head gasket and or base gasket thickness.

I have the data link software to upload new ignition curve maps but none seem avail on the net for carb models. I am at the point of scrapping the whole tamale and starting over with new heads and cylinders ( yuk).

ANY thoughts about this will be greatly appreciated.

frisco-rigid · #2 08-09-2009, 07:02 PM

Hi CM

Umm, who installed those heads without checking clearance first.?

Geeeze, soo much..

First--- the Pinging/detonation is caused by Hi-Comp, timing AND/OR A/F..
But you already know that..
At your Altitude 10.5 to 1 is about like 9.5 to 1 everywhere else..
Research and you'll find the exacxt formula..
Then when you installed .045 Head gaskets you Lowered the comp even more..
Then you fattened it up and adjusted ign,,,geeeze, you've done everything I woulda done but it still pings..

I've never gotten Rod-Elongation from heat,, that I know of, who sugg'd that to you.?

Something to consider--
Putting it under high or full load at 2400-3000 R's, especially in 4th & 5th gear, might be inviting that Ping/Deton.. Keep the R's up.. Since you Don't hear any "Pings" after 3200, ah, maybe that's telling you something..
When I "get it on" I wind it up.. Even easy cruising thru town I keep 2800 and if I demand ANYTHING,,, I drop a gear..
I run my 93", 120" and 127" in the 116* Phoenix Valley summer heat with no deton.. But,, I would get Ping/Deton with improper tuning AND the wrong gear..

I don't know if this helps at all---
In my Hi-Comp 120" and 127* motors I run 5*+- at idle with a fairly slow curve to Full advance of 28* at 2200 Rpm +-..

tommyglide · #3 08-10-2009, 01:19 AM

Greetings, I have a somewhat similar build in an 07 96" motor. Under 3000 rpm the pinging increases seemingly proportionately with the ambient temperature, especially pulling hard up a hill. Bad enough at 75 degrees but at 85 or above there is alot of racket going on. Spark is good, afr is good, so I just avoid running below 3000 when I need lots of power and life appears to be reasonably good. I hope your motor works out for you.

cmbereznoff@qwest.net · #4 08-10-2009, 01:34 AM

I wish I could recall the exact reference for the elongation quotes, but alas no more.
I do recall reading that a stock 5.500 inch lenght piston can elongate by as much as 0.050in. Back in my physics and chemistry days I remember that each metallurgic composition demonstrates individual linear coefficients of expansion ( DL = aLDT) under a given heat.
Aluminum and it's alloys have a linear coefficient of thermal expansion of 11.7 -13.7 ( 10 to log-6 in./in.*/°F ) This would give us a change in length of a 5.5in piston, of 0.014in under a 200 degree change in temp from ambient temp of 70 deg F to operating temp of 270 deg F ( as an example using a coefficient of 12.7)

Given a piston is a "cylinder" with some restriction to side to side expansion, it seems logical that there would be an greater expansion in the length of the cylinder under a heat load. The rod would also expand under it's own coefficient of expansion as well as the holes in the rod, increasing the effective rod/piston length beyond the 0.014 mentioned above. So the 0.050 in increase mentioned above does seem quite high, but not out of the realm of possibilities when all factors are taken into account. The inertial forces of a piston swinging on the end of a lever ( rod) at 3000 rpm at say 300 deg F would seem to induce some stress elongation, but I have no references for that. I am certain some physicist could do the calculations.

Keeping the revs up is a solution. It is just that I am so obcessive regarding an engine that performs well under all loads and rpm's, the rpm specific pre-detonation, if that is what it is, drives me a little more nuts.

tommyglide · #5 08-10-2009, 01:44 AM

Is the engine actually designed to run well and strong at that particular rpm, or are we asking a little too much out of it? On another post frisco had some good points about lugging and crank pin damage but if you want 110 and 110 at 2800 rpm you may need a little luck for any engine longevity.

cmbereznoff@qwest.net · #6 08-10-2009, 01:46 AM

good point !

frisco-rigid · #7 08-10-2009, 03:18 AM

Hey CM

Allota arithmatic there.. But it doesn't matter cuz motors are built with all that in mind..

Don't forget,,, pistons and rods are Not the only components expanding & elongating with heat--- the Barrels/cylinders are elogating at the same rate, actually more..

Hmmm, I'm still Obsessed with Jennifer Beals in Flash Dance but that doesn't get her to perform for me under my load which I'd prob Pre-detonate anyways..!!

milindh · #8 08-10-2009, 05:24 AM

CM

I think you're over thinking this thing here. If your engine's "pinging" clears up as the rpm's go up you don't have a clearance problem. That would get worse. The build on your TC is not so different from my FXR4 Evo 80"er. Very similar actually. And it doesn't like the under 3000 rpm in the upper gears. It will ping and rattle if I lug it and 2500 rpm in 4th and 5th is lugging it. Even 3000 rpm is not so sweet. Your bagger, being another 125-160 lbs heavier, would bog it down even more. I don't know just how much adjustment there is on your ignition system but you might be able to get some of that pinging out of there with an advance curve that wasn't all in at the wrong time. I dunno. Or you could just retard the overall timing a couple degrees but then you'd lose some of that great top end. Or... you could just ride it and keep the r's up.

Tn.Heritage · #9 09-23-2009, 03:58 PM

Do yourself a big favour and put it on a dyno and get this thing tuned before you damage the pistons, bottom line is your not tuned right, I know thats what you don't want to hear but it's the truth, get er tuned and have fun.