I can't wait to see the spreadsheet. Have you tried spacerplates under the carb to see if there is any difference? Does it seem that the Edelbrock carbs build better low/mid power and the Holley carbs better mid/high power?

 

The information you are providing is terrific! I've been trying to get my 400 powered dirt tracker ready for this season and the work you are doing is showing me the power potential is there.

Thanks again,

-rgsracer

 

We broke #5 piston. From what we can tell, we have some extra heat and detonation. We are guessing the cause is from using the Vac. advance dist. We set our ign. for full advance by pulling the vac. line and reving the ewngine to about 3500 rpm. That is where we have our 30.5 full advance. I think we got the problem when we are running the 600 Holley, we are pulling about 1.2 # of vac. I'm thinking this is pulling the advance some more than we originally set it for. Second Minn. gas I've heard is blended for cold and running this straigh 87 oct fuel is not the best for dynoing either. We are fixing the engine as we speak. We plan on running the Weiand intake again with the 650 holley. with a 89 oct. fuel and then we will be calling it quits. I want to make sure the engine is OK to sell before we pull it off. I would like to play some more but we have a few racers that are waiting for dyno time.
We'll post the Weiand results again and see if they changed from the original tests.

 

Did it crack the skirts? If so did both crack? How high did you run the rpm's up to?
I crack all 8 pistons, TRW forged, in mine but I ran it almost or at float way to many times. To many to even guess. I never installed a tach, idiot me, but I am guessing 6500-7000 rpms. My cam says float is at 6400.

 

5500 was max. RPM.
#1 and #2 ring land has a crack. I noticed a little blow by, so we stoped and did a cranking compresion check. All were at 165-170 but 1 at 110. So we pulled it. A little melted aluminum around the top of the head of the piston.

 

Sorry about the bad news Tim.

Thanks for your contribution here. I'm also interested in the final spreadsheet when you get it done.

So do you still think that this CR is ok on 87 octance with less ignition advance??

 

One thing to keep in mind. Usually an engine on a dyno is either idleing or wide open under load. I don't feel bad, the idea is to find what works and what does not. I really feel we would need to pay attention to the ign. advance. I was trying to run 9.7-9.8 compression ration on bone stock fuel. I think we were %95 of the way there. Slow the curve down in the advance, don't run a 600 carb. I'm thinking a 650-700 carb is just fine.

It sure pulls hard. I'm tempted to run some of our 110 fuel, just to see what happens.

 

I think the dyno is tougher on the engine than if the engine were in vehicle. On the dyno, the engine actually DEVELOPS that horsepower. In a vehicle this rarely happens except under all out racing conditions.

Also I expect that it's hard to detect knock with the dyno except on an engine with knock sensors. The only engine dyno I've ever been around was a 6-71 Detroit Diesel many years ago. They gave us hearing protection and I wondered what that was for. I had been around these engines when they were revved up in the chassis and the noise was no big deal. Once they loaded the engine, I understood why they gave me the hearing protection. Also the exhaust manifold turned red INSTANTLY. If running one of these engines is anything CLOSE to what I experienced in the Detroit Diesel dyno room, then I expect it is exciting and a parts breaker.

As Tim says he has learned alot, and lucky for us he is willing to share what he is learning with us.

Thanks Tim.

Have a great day,
Doc

 

Cracked lands is consistant with too much spark advance/detonation. I know Tim is trying to get as much out of 87 Octane fuel as possible, but I would not even try to run an engine like that on less than 89 Octane.

BTW, I calculate the DCR to be 7.88:1. I suppose that 7.9:1 DCR is the limit for 87 Octane fuel with quench.

 

The CR limit is a variable with other variables involved. It will depend on advance curve, fuel mixture, fuel octane and load.

BTW Tim, you might want to reinforce the dyno room walls before you crank up the timing and run the 110. That is not to imply that the engine will come apart, but that you want to make sure you have some hearing left after that run.

Good luck,
Doc

 

Not sure where you live but here in Ohio we can get 92,93 & 94 octane pump gas depending on the station. I really liked BP & Citgo 93 and Sunoco Ultra 94. A mixture of race gas and pump gas would be a good test. If you really want to make some power, VP makes Ultimate 4 (U-4) for four stroke motorcycles. It give a 250cc 2 - 3 more HP. It has extra oxygen in it and an octane of 92 I think. You may find with the 110 that it will make less power than 92 - 94 pump gas. I'd love to have a dyno and get to play around testing. Thanks for letting us all live through you!

 

Well we installed a new piston, buttoned everything up, and fired it up. We installed the Weiand this time. Here's the conditions this time.
Did not touch the dist. from before, we only disconnected the vac line so we would not get any more "extra" advance. We only ran the holley 650. We did change to 91 oct. fuel. So the question is we have better HP and Torque from the original pulls. Why? A looser engine? Better fuel?

Corrected HP 388-393-387-390

Corrected Torque 451-458-449-452

Our test have always been with a 1" open hole spacer.

We had a "Super Sucker" aluminum spacer so we tried it also.

Corrected HP 393-394

Corrected Torque 458-458

Are they worth $100?

We are officially done with this engine project. I appreciate everbodys involvment, input and encouragement. I hope this has been a learning project
for many people. We have gotten some engine sales and parts sales from this project, and I apprecitate that very much. When we list it for sale we will give you guys a heads up. To be honest I have been very impressed with this engine and combination. Realize this is my first 400 I have built from the ground up. We specialize in SB Ford dirt circle track engines, so this was a change. Next I would like to build a 4.250" stroke 400.

Again I would like to thank people like Dan Lee and Dale Carmine for allowing us to borrow their intakes. Thes guys unselfishly shipped their intakes not asking me to cover freight charges. That's money out of their pocket they shared with us. There is a lot of information we gained having 3 manifolds to compare side by side.

Also to Comp Cams, Kevko Racing Pans and Angus racing for their contributions to this project.

And a big thanks to Ford Truck Enthusiasts
for having a media such as this web site to bring and share engine ideas.

Thanks again to everyone.

 

Thanks for all your efforts Tim. It was well worth it.
I would like to see plots of the pulls on your website, or at least one representative pull with each intake. Also I would like to know the manifold vacuum with each intake and the same carb.

 

danlee,

It sounds like it's a little too late to gather that data.

I would like to know the specific cam that he used. When you go to his site, there is a long list of cams in his cam selection section but I never saw which one he chose.

Have a great day,
Doc

 

The soft ware for the dyno gathers and keeps all the information. So I will have to go back to each run and pick the infor I want. I am thinking of a spreadsheet that has RPM across the top and Torque, HP and Vac. on the side. Possibly group them per manifold.