8000 rpm with a flat tappet cam and solid lifters

Posted By: Sb Valiant

8000 rpm with a flat tappet cam and solid lifters - 12/18/12 12:58 PM

I was just wondering has anyone ever been to 8000 rpm with a flat tappet cam, solid lifters and roller rockers and of course and good oiling system. Or has anyone been up around this rpm that bracket races for the most part????

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Posted By: Sb Valiant

Re: 8000 rpm with a flat tappet cam and solid lifters - 12/18/12 01:01 PM

Can anyone give me hope that this is possible or forget it and go straight to full roller?

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Posted By: Streetwize

Re: 8000 rpm with a flat tappet cam and solid lifters - 12/18/12 01:55 PM

My old 340 W2 peaked at 7800RPM and wasn't uncommon to hit 82 or even 8400.....this was in the late 70's and early 80's with old school TRW slugs that weighed a ton. Big Isky Solid Flat tappet and a 4 speed....and No Scattershield!!

Posted By: Guitar Jones

Re: 8000 rpm with a flat tappet cam and solid lifters - 12/18/12 02:00 PM

I did it for years with a stock stroke 340 and W5's. Valve springs were key though and the second it hit 8500 it would knock the adjusters on the rockers loose. I was running about 420 psi over the nose of the cam, more than Hughes wanted me to but his springs would float at 7500.

Posted By: therocks

Re: 8000 rpm with a flat tappet cam and solid lifters - 12/18/12 02:23 PM

My 440 with solid cam and flat tappets I was shifting at 72 to 7400.I set the limiter back to 6800 now.It still was pulling hard at 7200.Rocky

Posted By: MR_P_BODY

Re: 8000 rpm with a flat tappet cam and solid lifters - 12/18/12 02:55 PM

I will ASSUME its a small block... yes 8000 is doable...
I use to run my 340 W-2 to 8000+ but as said.... springs
are the weak link on a solid flat tappet

Posted By: Triple Threat

Re: 8000 rpm with a flat tappet cam and solid lifters - 12/18/12 04:58 PM

The question is why?

Posted By: Oyvind Mopar

Re: 8000 rpm with a flat tappet cam and solid lifters - 12/18/12 06:02 PM

Nascar engines ran with flat tappets. 10000 rpms+. They also use roller rockers. What should be the problem? A roller can give more midrange torque, but technically the flat tappet is the simplest to use for high rpms. Go ahead!

Posted By: qwkmopardan

Re: 8000 rpm with a flat tappet cam and solid lifters - 12/18/12 06:18 PM

Quote:

The question is why?

Reliability and cost. With a flat tappet you can get cam, lifters, springs, and a nice steak house dinner with money left over for what a set of roller lifters cost.

8000 rpm not a problem at all either, especially with a small block. try to get the intake valve 110 grams or less, Use a hollow lifter, [not the solid chunk of iron lifters], Mopar perf. lifters are hollow. 5/16" .08 wall pushrods. 150#/160# seat and 380#/410# over the nose held in place with 10* tit. retainers. If it is in your budget, put titanium intake valves and lighten the exh valves to less than 90 grams and you can reduce the springs to 130# seat and 350# open. My demon is set up with tit. intakes. With 4.88 gear I went through at 7800rpm. Have 4.56 gear now and only sees 7400rpm but slowed aprox. .05

Keep plenty of lube on cam while adjusting valves. If possible put intake on very last, even after motor is in car and tq conv bolts are in. Lube cam one final time, put on intake and make sure it starts right up. Also don"t make the mistake of running engine for 30 minutes at 2500 rpm as at a steady rpm, be it idle or 6000rpm the lifter rotation slows or stops. Just no steady RPM while you set the timing and button up all other loose ends. Then load it on the trailer, take it to the race track and beat on it, avoiding any idling for the first several hours of run time.

418.c.i. sm. block mopar--production heads and block--solid flat tappet cam--3050#--9.68 at 136mph--1400 runs and counting

Posted By: dogdays

Re: 8000 rpm with a flat tappet cam and solid lifters - 12/18/12 07:32 PM

Only one gripe with the above poster: Use the largest diameter pushrods you can get to fit. You can go to a thinner wall and they will still be stiffer in column loading than the 5/16". Check out Comp Cams article on pushrods.
The deal is this: Pushrods see quite high loads and their length/diameter ratio is poor, putting them in a special class called column loading. Also, their ends are not fixed so they can rotate in any direction around their ends. If they start to flex, all that cam motion that you paid for will be lost in the pushrods.

R.

Posted By: Guitar Jones

Re: 8000 rpm with a flat tappet cam and solid lifters - 12/18/12 08:39 PM

Quote:

Only one gripe with the above poster: Use the largest diameter pushrods you can get to fit. You can go to a thinner wall and they will still be stiffer in column loading than the 5/16". Check out Comp Cams article on pushrods.
The deal is this: Pushrods see quite high loads and their length/diameter ratio is poor, putting them in a special class called column loading. Also, their ends are not fixed so they can rotate in any direction around their ends. If they start to flex, all that cam motion that you paid for will be lost in the pushrods.

R.

I can agree with this somewhat. I used 7/16 Crane .090 walls in my 340. In the 408 I used .120 wall 5/16 as recommended by Trend. It helped greatly with clearance issues also.

Posted By: 1DGEMAN

Re: 8000 rpm with a flat tappet cam and solid lifters - 12/18/12 09:31 PM

340 LC Stock eliminator engine routinely went to 7800.

Posted By: Sb Valiant

Re: 8000 rpm with a flat tappet cam and solid lifters - 12/18/12 10:28 PM

That's what we have are some trw domed pistons suposely 13:1. Also an 8 bolt old school crank I am not sure what it is but it's not a callies or newer style crank. A buddy of mine bought the spare crank I had that was an 8 bolt that was the same exact thing and he identifyed it as an moldex crank which is a big old heavy crank. The cam is post to be a 606 lift flat tappet cam of some sort that I don't know. I would like to get some new stuff just to know what's in the engine. This is why we are going through the motor this winter to find out the real answers!!!! I hear a few people that don't run a windage tray. My question is why???

Posted By: Sb Valiant

Re: 8000 rpm with a flat tappet cam and solid lifters - 12/18/12 10:34 PM

I couldn't have said that any better and thanks for the info qwkmopardan!!!

Posted By: Sb Valiant

Re: 8000 rpm with a flat tappet cam and solid lifters - 12/18/12 11:38 PM

Are you talking about hughes racing engines? If so I would like to know your opinion wether there products are good enough for this type of rpm? Maybe they have improved since then?? Or maybe you didn't get a good enough spring? I have no idea.

Posted By: Cab_Burge

Re: 8000 rpm with a flat tappet cam and solid lifters - 12/19/12 02:57 AM

Don't spin it that high with stock rods

If you do you may live to regret it

My friend did, he spun a rod bearing in a original T/A motor with a big solid lifter cam and a bad electric tach

We found that the electric tach was off by 1000 RPM at 7200 RPM later by installing a mechanical tach, electric tach said 7200 RPM and the mechanical Stewart Warner read 8200 RPM at the same time in third gear in a 4 speed car

Posted By: LA360

Re: 8000 rpm with a flat tappet cam and solid lifters - 12/19/12 03:22 AM

The old A/Street Super Stock class here in Australia used to run flat tappet camshafts routinely to 9500rpm. The modified street class in Super Stock still does similar RPM with their flat tappet camshafts.

Why do you feel you need to turn your engine to 8K? Are the heads and bottom end up to it??

As I have said previously, put your engine on the dyno and find out where it's at, it could actually save you some $$$ and time. At the moment you're just walking around in the dark.

Posted By: WHITEDART

Re: 8000 rpm with a flat tappet cam and solid lifters - 12/19/12 03:57 AM

408 with 360-1 245rp flat tappet 630in 652ex- 270 272 @50 likes to be shifted at 7500 been past 8200 many times.. but im using a top shelf piston and rod combo. I have ran this package since 2005 .. only down side is keeping the valve spring right . to much spring you kill the cam.. to little spring you float the valve .. the car runs 10.00 132mph 3100lb with me in the seat and pump gas

Posted By: D-50

Re: 8000 rpm with a flat tappet cam and solid lifters - 12/19/12 11:52 PM

Quote:

408 with 360-1 245rp flat tappet 630in 652ex- 270 272 @50 likes to be shifted at 7500 been past 8200 many times.. but im using a top shelf piston and rod combo. I have ran this package since 2005 .. only down side is keeping the valve spring right . to much spring you kill the cam.. to little spring you float the valve .. the car runs 10.00 132mph 3100lb with me in the seat and pump gas

What is your 1/8 mile ET ,Sorry for the Hijack..

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Posted By: WHITEDART

Re: 8000 rpm with a flat tappet cam and solid lifters - 12/20/12 12:48 AM

1.33 60ft 6.28 108mph . this combo has more in it but the car does not have a full cage. so 1o.oo has been the dial .. this is at 3000 ft .. I have thought that at sea level with a good tuneup 9.80 but not sure.

Posted By: D-50

Re: 8000 rpm with a flat tappet cam and solid lifters - 12/20/12 12:58 AM

Thanks,Just wondering what mine would run in the 1/4 mile.I still have not done much tuning on mine yet either.Our 60 ft and mph are about the same,I think mine is spinning mid track.