Hot Rod Forum : Hotrodders Bulletin Board - Reply to Topic -- Hot Rod Forum

Register FAQ Search Today's Posts Unanswered Posts Auto Escrow Insurance Auto Loans
Hot Rod Forum : Hotrodders Bulletin Board > Tech Help> Engine> 5600 rpm stutter
User Name
lost password?   |   register now

Thread: 5600 rpm stutter Reply to Thread
Send Trackbacks to (Separate multiple URLs with spaces) :

Register Now

In order to be able to post messages on the Hot Rod Forum : Hotrodders Bulletin Board forums, you must first register.
Please enter your desired user name (usually not your first and last name), your email address and other required details in the form below.
User Name:
Please enter a password for your user account. Note that passwords are case-sensitive.
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:
Please select your insurance company (Optional)


Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.

Additional Options
Miscellaneous Options

Topic Review (Newest First)
08-02-2012 06:52 PM
5600 rpm stutter

I tried to find a cam similar to yours on Comp CamQuest. It would seem your missing about 50 HP. That cam produced 411 hp @ 5500 and 438 lbs of torque @ 4500 rpms. The cam is XR284H, 2300-6500 rpm range, lift .507/.510, duration advertised 284/296* Now on those dyno reading if they were an avg hp and torque these are similar 232/283.
08-02-2012 02:47 PM
wadedog so that sounds fairly close but does that mean my engine has something wrong and should be faster with the components it has now or is running correct with these parts cam etc..

I was hoping the engine when built with these parts would have made it closer to 450 hp at the flywheel but maybe i had unrealistic hopes.
08-02-2012 09:56 AM
5600 rpm stutter

the results of a 3500 lb. car is: Your HP computed from your vehicle ET is 318.92 rear wheel HP and 354.35 flywheel HP.
Your HP computed from your vehicle MPH is 305.83 rear wheel HP and 339.81 flywheel HP. Something must be way off on that dyno!
08-02-2012 05:59 AM
wadedog not sure of weight but i would say around 3500

my 60 was 1.758
1/8 was 7.912 mph 86.26
08-01-2012 08:38 PM
5600 rpm stutter

You can check this website that cobalt327 referred me to. It has many calculators. Wallace Racing HP Calculator For 1/4 Mile . See how close you come to the dyno readings.
08-01-2012 12:48 PM
wadedog well with the stutter gone my car runs good but i'm not sure if it is running the best it can but maybe it is and the dyno numbers are messing with my head and maybe those numbers are wrong.

I ran a best of 12.498 at 106.63 at the track.

383, 373 gears,3000 stall, 750 holley,mt drag radials.lunati voodoo cam kit 638-60105
07-31-2012 10:41 PM
Accel Plugs and Taylor wires

I have read reviews on both of these products. It seems Accel used to make good products years ago. Do a search on best brand of spark plugs. I also read a thread on this website where a guy was using Taylor wires and was having issues with performance. Turned out to be a bad set of Taylor wires. Check them closely at night time for arcing. Maybe if you want better performance try a solid lift cam kit with matching springs. Maybe less money spent than carrying it to dyno shop. Look at the specs. on this: Howards Cams 112312-08S at Summit Racing.
07-31-2012 09:52 AM

go for the beehives with less mass it will allow your valvetrain to atain its max rev range and then some and it will do it alot quicker due to its lighter mass lunati and or comp cams make A1 quality beehive setups.

PS have you physically checked your springs to make sure one of you springs or any part of your valve train has not broken or loosened up ie rocker not torqued properly just a hunch
03-27-2011 07:14 PM
kc8oye given my experience with Accel brand products.. I would get rid of those plugs right of the bat, and get a set of basic copper plugs in there.

I used accel plugs once.. had all kinds of problems.. pulled them back out and found several that had failed in various manners. swapped them out for some basic AC Delco R45TS (chevy 350) and engine ran 100% better.
03-27-2011 06:10 PM
cobalt327 Yeah, that sure sounds dodgy, him not giving you a straight answer about the springs. And there's the possibility the springs that were removed may have been fine- after breaking in the cam w/lighter springs. You should have gotten the original springs back anyway- I suppose he kept them to sell to the next guy.

You can get the necessary tools to measure with for not much money. Eric mentioned cheap calipers and just a caliper will do most if not all of the measuring you need to do considering you don't need 0.00001" accuracy. Even splurging for a snap gauge set isn't a lot of money, considering you don't need Starrett-quality tools to do what you need to do, although good tools are a good investment if this will be something you are going to be doing more of.

A valve spring compressor would be the biggest investment, you might check w/the parts stores to see if they have a loaner.
03-27-2011 12:26 PM
wadedog thanks for the reply's, I know this is a long thread and I am very appreciative of all the help i have gotten .

the wires are taylor 8.5 spiro pros ,the plugs are accel 0784 u grooves.

Yes Im pretty mad about not being told what springs i bought, I bought the heads used with good springs but didn't know the specs on them either and the shop replaced them because he said they were too stiff and put a set on from his shop and i never got a receipt for them but i paid for them !
later when i asked what they were he said "don't worry about it, it's not the springs ,it's the lifters causing the problem"
that turned into a heated argument because i said i had a right to know what i bought but it ended in a stalemate and loss of a friendship i thought i had.

maybe your right Cobalt that i shouldn't test it at high rpm again right now, it's been on the dyno this way so i figured it was ok to test at the track.
i'll have to pull the covers and buy some tools to measure everything.
03-27-2011 03:15 AM
Originally Posted by wadedog
sorry don't know your answers , my builder isn't saying what springs he used and I haven't measured them or have the tools to do so. I don't think I have a problem with bigger diameter springs. I don't know what my heads will accept,sorry.
Pretty hard to make any kind of direct part # recommendation without some idea of what will fit in there, but basically you would be looking at 125-140 lbs seat with 300-340 lbs open. You're going to have to get in there with a pair of calipers and at least get a diameter and use the depth finder on the caliper to get a decent idea of installed height.

You can get a functional digital 6" caliper off Ebay for as low as $12 or so, I paid $16 for a 10" that I carry in the truck just for general use when I'm out and about helping friends or at a swap meet. They may not be totally accurate to the .001" like an expensive one, but if it is within .002"-005" it's close enough for this type of work.

Howards Cams/Competition Products at has a very good selection of valvesprings at real good prices, you should take a look there.
03-27-2011 03:13 AM
Originally Posted by wadedog
sorry don't know your answers , my builder isn't saying what springs he used and I haven't measured them or have the tools to do so.

I don't think I have a problem with bigger diameter springs.
I don't know what my heads will accept,sorry.
What do you mean, "my builder isn't saying what springs he used"? Are you saying you asked and he refuses to tell you??

A short primer on dealing w/service providers:

YOU are the "boss", in that you are paying the freight. This doesn't mean you can boss anyone around or be an a-hole, however it DOES sure as hell mean you have the right to expect an honest answer to any reasonable question!

Be polite yet firm. If you feel that you're being lied to or are getting the runaround, either decide to take your business elsewhere, or be content paying him to be his beech. I would strongly suggest the former rather than the latter.

If the dynamics are such that you cannot or will not be able to face up to this guy, it may well be too late for you to step up now, but let this be a lesson in how to proceed when dealing w/the next shop- the shop I hope you take the work to next.

If these are RHS aluminum heads, they will surely accept a larger spring than the stock 1-1/4" diameter springs, so that part should not be an issue.

Measure the width of a retainer- that'll tell you what size the springs are unless they're "beehive" or conical. In that case, the sides of the springs will not be parallel- which will be readily apparent by just looking at them. A beehive spring will be fatter in the middle, a conical spring will have a bigger retainer than the spring seat or sometimes vice versa (spring w/a larger seat end than the retainer end).

I wouldn't take the engine back to high RPM until the spring issue- if one exists- is resolved. The risk is dropping a valve, which will be a very costly bit of bad luck. If this machine shop is refusing to tell you what springs are being used- it is for a reason. And the reason is NOT to hide the fact they installed a good, high quality spring- of that I can assure you.

All that's required to test a spring for pressure is to remove one and hie it off to a machine shop that has a spring pressure tester. Some shops may have the tool for testing spring pressure on an assembled head, so ask what they're set up for.

Give them the installed height- that will give you the seat pressure. Then, subtract the valve lift of the cam from the installed height. That will give you the open spring height where the open pressure can then be measured.

The spring can also be measured for coil bind height, and the spring rate in pounds per inch can be determined as well. This should be routine stuff for any half way decent and/or 'performance' shop.
03-27-2011 02:50 AM
sqzbox I'm kind of getting in on the tail end of this but what kind of plug cables are you using? and what heat range plugs?
03-27-2011 01:03 AM
wadedog sorry don't know your answers , my builder isn't saying what springs he used and I haven't measured them or have the tools to do so.

I don't think I have a problem with bigger diameter springs.
I don't know what my heads will accept,sorry.
This thread has more than 15 replies. Click here to review the whole thread.

Posting Rules
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

All times are GMT -6. The time now is 08:35 AM.

Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0 PL2
vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
Copyright 1999 - 2012. All Rights Reserved.