DCR Top End Modifier

[ACR Turtle]

http://www.srtforums.com/forums/showthread.php?t=298881

A friend of mine had DCR build him a short block for his SRT-4. He is running the AEM setup and a big turbo. While on the dyno they could not get the car to make over 18 psi over like 6800 rpms. After a call to Darrell's shop he said we are aware of the problem and have the solution coming out shortly. It turns out the is too much oil coming to the top of the motor and causing a valve float situation. With this new part it restricts oil flow and allows more rpm and boost obviously for more power. An SRT on the forums had a similar issue and with this part was able to fianlly tune the car to the tune of 700 hp.(video on the forums)

My question is this, have any of the hybrid guys run into this situation? Are you guys even trying to turn your engines this high?

I ordered one for my SRT, because its supposed to help even stock cars. We'll see.

[speeduphoria]

Kevin Davis said he experienced valve float at 7300rpm and up. This is w/ crane springs and 2.0 cams AFAIK

[russ jerome]

I datalogged most all runs and a 2.2 shortblock/2.4 head spins
happily past 7k RPM. I had that adjustable oil control valve I
made to feed the head, kept my head oil pressure "just" high
enough to keep the low oil pressure light on at low rpm idle.

Have to look but my better runs were shifted at 7200rpm and
a few 7400 shifts mixxed in. I know that 6900rpm in 3rd and
2.60 final drive is realy too fast to sustain on any WI freeway.

[kedavis]

Quote:

Originally Posted by speeduphoria Kevin Davis said he experienced valve float at 7300rpm and up. This is w/ crane springs and 2.0 cams AFAIK

That was a mistake on my part I put solid lifters in and the crane 18's and man this thing wont rev over 7200.Well guess what the dis2 limiter was set at dahh you guessed it 7250 it now pulls hard to 8000 rpm feels like a whole different car.The ble lifters have built in oil restrictors in each lifter they are super quite too havent had a chance to make it the track again yet.Ive got too many limiters on this damn car Ive got 2 on the sds and 2 on the msd I still feel stupid though.

[guidsm]

I sure the DCR modifier cancel the squirt in the head...like we do on our conversion.

[speeduphoria]

exactly
what size restrictor did you use for the oil feed?
also any idea what your oil pressure is in the head at idle or max?

basically everyone uses a restrictor in the external oil feed, what size ? depends

The stock one is too large @~.142" so some use a .098" restrictor
I would like some info on hot idle oil pressures(at the head of course), max oil pressure(head) and oil weight

I think the only restrictor on the srt4 engines is the gasket (~.132" hole)

[guidsm]

I have run whitout cancelling the squirt port under the cam cap...result: too much oil in the head...and oil pressure lost at high rpm. NB: i have used a rectrictor at the head input..same size that the one in th CB.

Next mod will be....

[whywoody]

I used an 1/8 drill bit,so .125''. I haven't had oil pressure loss problems,but I don't rev mine as hard as some,only sometimes to 6k.I blocked all the bleeds in the cam caps,and for drain backs I use two #12 fittings monted as low in each corner of the rear of the head as I could.
Oil pressure is normaly hot 20psi at the crank and 16psi at the head.I have seen it idle at the head as low as 8psi when stink hot after long hard trips on hot days,or really warm city driving.Cam journals looked fine last I looked.
This was using Mobil 1,0w50.I drive year round,so I see ambient air temps around -35c to +35c.

[speeduphoria]

woody any idea what a max hot pressure to the head?

[whywoody]

Quote:

Originally Posted by speeduphoria woody any idea what a max hot pressure to the head?

Sorry,I have the gauge in the engine bay.I could make a longer hose and watch it for you,might take a few days for me to get the chance,but you have me curious now!
I don't know why I don't know this....what else have I overlooked!!! lol
I was more worried about idle pressure when I put it together..

[Garret]

Doing the same 16v head oiling mod to my buddy's 412 WHP SRT4

[speeduphoria]

Quote:

Originally Posted by Garret Doing the same 16v head oiling mod to my buddy's 412 WHP SRT4

What exactly are you doing? pluging the block feed and running external? Or just a restrictor?

[Garret]

cancling the oil squirting

[DblTrbl]

Questions:

What is the purpose of the squirters? Don't they lubricate the top of the lifters?

Also, how does the amount of oil in the head affect valve float?

Does air in the head oiling system affect lifter operation?

Do the squirters allow air to escape since they are the highest point in the oiling system?

[ACR Turtle]

Quote:

Originally Posted by DblTrbl Questions: What is the purpose of the squirters? Don't they lubricate the top of the lifters? Also, how does the amount of oil in the head affect valve float? Does air in the head oiling system affect lifter operation? Do the squirters allow air to escape since they are the highest point in the oiling system?

Its not a squirter, its a restricter. The way it was explained to me was that it goes into the head and keeps the oil pressure to the lash adjusters down. Evidently at upper rpms there is too much presure and the lash adjusters are overpressurized causing a valve "float" situation.