No acceleration at all, but runs great?? At the end of my rope. .

[InthePits.net]

Just like a train wreck you know whats gonna happen but ya cant look away.

[youngengines]

I never saw valve spring pressure at max lift. I run around 380lbs on our limited sportsman engines that have flat tappet cams and turn 7500rpm. I wouldnt be so worried about the seat pressure.

[rodb63]

Update on Ford N-heads lost acceleration

Guys, sorry its been a while since my last post. I haven't raced since my last one in early may whwere we still had no acceleration. I found out that the N-head valve seat area is hardened only about .015 deep (I may be off memory there a bit in my number). Anyway it was pretty shallow and after talki9ng with my head guy this explains the "intake seat" beating since that material was probably soft from machining through the hard surface. This would suggest there isn't valve bounce, just beating on a soft seat?
I spent the last 3 nights up until after midnight on the boat making changes, (like all you have done at one time or another) and getting up early for work, I'm a little foggy but I"m updating results best I can.
OK, Anyway after a lot of thought, and reading through every post on here, I decided to focus more on the boat and see what the ____ could be wrong, like binding the prop shaft or ???
My shaft is so loose per my choice and rattles around easily thinking I'd have more speed. My strut bushings are made of an oil impregnated plastic, and I'm told the shaft could rattle/vibrate and creat harminics and slow me down. OK new bushings made yesterday and put in late last night.
2nd, I put my old shaft back in, 3rd, I changed the way my thrust bracket is braced, even though it was the same when it was fast, I changed it to reflect a more EVEN pressure on brkt itself. I know a hydroplane is a bit polish to this board and I'm rambling a bit, but I want everyone interested in this thread to know I"m trying my VERY HARDEST to get all my power back. I have a good feeling that my changes are good but as for acceleration who the heck knows.
I will post again later tonight with an address for video streaming for anyone who would like to watch this race on the computer. The last race they streamed on the web sucked according to my Dad, but I"ll post it anyway if I can get it exact so anyone bored over the weekend can check it out.
As for the guy who mentioned these new N-heads don't flow like the old ones, I"m talking over 100 hp loss, and if you are right? I'll throw my tools all over the place, and flip a coin I hope thats not it. I am a FORD guy, and I think FORD DID do everything to mess these heads up, ok no whining on my part. I"m gonna get after it this weekend after a good nights sleep. I"ll report back.
I can't thank everyone on this enough. Anyone wanting pictures of the boat, shoot me your e-mail and I"ll gladly share, pretty cool really.
Rod

[rodb63]

No vacumm ?!?!?!?!?! Please read

We just had a race, out of 5 boats I got lucky and pulled off a 2nd for the weekend, We found something. First of all after the changes I made to the boat, still no acceleration. I was introduced to a Knowledgable Ford guy and I"ll get right to the point. When warming up the engine Sunday AM, he put his hands over my 600 HP carb and said "there is no vacumm here at all". I have been running at 1400 degrees EGT on my left front Cylinder for 2.5 seasons (EGT guage was just calibrated) , he said I"m probably not pulling any fuel in.
I am getting a vacumm Guage in the next few days and tapping a fitting in (no ports on this 600 HP). 600 HP by rule.
Dang after all this time could I be THAT low on vacumm? 2 engines? I tested for leaks back in 09 according to my notes. This cam thats currently in now has never gone fast, but in 09 I used the old cam that DID go fast years back and still the same NO acceleration.
What the heck can cause good dyno pulls and no vacumm at all at 2000 RPM?
Cam?
I( will report back asap with vacumm guage results. Where is the best place to tap into the Victor Jr intake? Right into the body part below the carb and spacer? Or on one of the ports?
Thanks guys, I just can't see this thing leaking, in 2 engines? 2 carbs? 2 different cams? Tried them all.
I can say that I have been not only running at 1400 exh gas temps, but no matter what my jet size, up to 92! I can't get color on my plugs at all. OR very little,. always looks lean. The guy told I'm NOT pulling fuel into the engine.
We just ran top end at 7100 RPM, not missing a beat as usual, just no real tq at all. Still no acceleration.
THANKS!
Rod

[rodb63]

Problem found looks like. NO Vacuum

At this last weekends race I found I have very low vacuum, I drilled and tapped into the Voctor Jr. Manifold right below the top (.5"). Here are the results.
Keep in mind my engine won't idle below 2000 RPM thats why I think the leak is below. I did the spray trick all over the carb spacer and intake with WD40 AND starting fluid.
Its sealed well.
At 2000 RPM I showed 9 Vacuum.
2500 RPM 11 Vacuum
3000 RPM 13 Vacuum
3500 RPM 15 Vacuum
4500 RPM 16.5 Vacuum.
I think its either leaking on the underside of the manifold in the lifter valley, or possibly a cam issue? My spark plugs have always looked lean with no signs of ouil on them, and running a dry sump with a #10 pulling from the lifter valley. If the leak is below through the lifter valley into the intake, wouldn't my plugs show oil on them or something besides a total lean look?
Thanks in Advance,
Rod

[rubbinsracin]

maybe the motor combo just doesn't like the cam grind that it has?

[rodb63]

I know this is a possibility, and what really bugs me about this is I put back in the old flat tappet cam to try it a year ago and it did the same thing. Thats why I'm praying its a leak.
What I"m saying is the bigger cam is a .580 lift after lash, and the smaller one is about a .555 lift after lash. Both about 270 duration at .050 lift. I know theres more to it then those numbers but the bigger cam NEVER went fast although Dynoed better accross the board by about Avg of 20 HP and Tq.
The smaller cam was a rocket from 2003-2005. Anyway we are running the smaller cam as I"m about to put the fresh engine in after picking it up Saturday. I'm using this current engine now to get all this data, and tonight I will remove the intake looking for an internal vacuum leak. I read where if I just roll the starter over with the throttle plates closed, it should read 3-7 vacuum, if its zero its probably a leak.
I plan to put the manifold back on with no gasket looking for rocking or using a feeler guage etc. then hopefully measure putty squished by the intake with gasket to see if its not laying flat like it should. Using no gasket though should tell me from what I read.
Thanks!!! I will report tomorrow or Friday on the intake internal leak.
Question, my plugs have ALWAYS looked REALLY lean the last 2 years, if its lean, can I STILL be leaking into the intake through from the lifter valley? Keeping oil out but leaking air there? NO signs of oil on the plugs, thats what is killing me, plus my builder is REALLY good about all this.
I"ll report back, Thanks a million.

[rubbinsracin]

with all of your problems you have had maybe you should take this guys way out.....lol

http://iraffiruse.net/post/490027496

[rodb63]

Internal Vaccum leak most likely

Last night first I turned over the engine with the starter only. I read where it should pull a small amount of vacuum, and if it was Zero it may be an internal leak. It read Zero as I turned the engine over for about 10 seconds.
I thjen removed the intake, to fine most of the Lower areas of the gasket wet with oil, also this same area on the intake manifold. After cleaning all the gasket material off I put the manifold back on metal to metal I could not tell if it was a bad fit or not. using a straignt edge everything passed, and I put one of those gravity angle finders on all 4 surfaces and all read 45 degrees. I will say though I put a feeler guage and could easily slide .018 under the top part of one bank and bottom of the other.
I'm going to take a razor blade to all surfaces tonight then with new gaskets from my builder tomorrow I"ll to the putty thickness test using washers the same thickness as the gasket. (Current gaskets are .062
QUESTION. If there is a gasket problem is the answer to use a thicker gasket? Is .090 or .120 thick ok?
*** Can I use Silicone of some sort on the entire gasket surface? I know some silicones don't like gas, but for now can I finish my season using a sealer of some sort?
Bottom line It looks like this is the culprit, but I won't know until I stick the other engine in and get these Gaskets SEALED and run it.
Thanks guys. I think with all your help we finally found the power loss. VACUUM.
Rod

[rubbinsracin]

when we put our gaskets on, heads and intake, we spray them with this:

http://www.google.com/products/catalog?hl=en&biw=1440&bih=744&q=spray+on+copper&um=1&ie=UTF-8&tbm=shop&cid=7438551903716389274&sa=X&ei=DWL7Tdr6AcPAtgeZ9JHDDg&ved=0CEEQ8wIwBA

we notice when we had to pull a head off because we dropped a valve a few years ago that the gaskets were all gold. and our motor guy told us that he does it to every motor he builds. anything from a street application to a full race motor. sure gaskets are supposed to do their job, but why not use this too?

[rodb63]

Thank you!

Thanks Rubbin, I've been looking for something that gas won't eat through.

PERFECT!!
Rod

[rodb63]

I think we have an explanation

Guys, after 2.5 seasons I think we have found whats been slowing us down.
Vacuum.... when I first checked vacuum after putting a fitting in my intake, it read 9 inches at 2000 RPM, then 11 at 2500 and 13 at 3000.
After doubling up my intake gaskets (to .120) using black silicone to glue them together over night with a small amount of weight, I then put those on using that copper sealant, but the paint on stuff with the round ball applicator (like the red form a gasket), that along with using the SPRAY copper sealant on the carb and spacer gaskets, we went to the following. 13 inches of vacuum at 2000 RPM, 15 inches at 1500 and 16 at 3000.
Keep in mind my cam has a 270 duration at .050 lift so come cams and my head guy said 10 inches of vacuum at 2000 RPM sounded about right, just a foot note.
Last night I did a leak tesl with a thick alum plate and an air fitting where the carb bolts on and pumped in 10 psi of air. I sprayed soapy water and all the spacer gaskets were leaking except the top one (has the most pressure I assume, and I had this plate tightened down a lot more than my carb. This tells me not to use the copper sealer on the carb gaskets, but it did work well on the (doubled) .120 intake gasket both sides. The intake had good crish on both sides as before using the .060 gasket it had only .005 crush on one side.
QUESTION, should I use very little silicone on my (cardboard type) carb/spacer gaskets spreading it with my finger thin ... OR ... try the nitrile rubber gaskets and which ones?
I've read a lot of you racers say any gaskets and do not use sealersealer, well its not an option, it leaks, I watched it. My surfaces are all flat, really. I do use 2 spacers, a 2" 4 into one, and a tapered spacer because the engine is 6.5 degrees in a hydroplane
Some of you have really stepped up and gave some great advice, I will do my best to get back to you soon and personally thank you.
My next race is July 9-10, and I'll report what happens.
Thanks again,
Rod NM 5

[Dirtrunner35]

With the engine running, take a bottle of propane with a hose on it and go around the intake gasket and carb spacer, if the rpm's go up, there is your leak.

[rodb63]

Thanks Dirt,
I've never tried the propane before, but this time it better not leak as I'm using a thicker gasket (1262R) and sealing my carb gaskets or trying the nitrile rubber ones.
Anyone have an opinion on the rubber gaskets? I know whats said about the usual paper ones.
Thanks. Wish I was racing this weekend, but one more week.
Rod

[rubbinsracin]

we use the regular paper type on ours and have no trouble. but i bet the rubber ones would give you a somewhat better seal, as long as you dont squish it to much and cause it to crack/tear. are you using the plastic carb spacers or are the metal ones? we were required by our sanctioning body for a year to switch to plastic spaces if we wanted to run a 2" spacer. we did and found that they warp and squish way to much after heat cycles and were leaking all over with them. so we switched to the 1" metal spacer we were allowed and it worked a ton better.

in short. get rid of the plastic and go with a metal spacer if at all possible.