'99 ohv 4.0 cam build

[jd4242]

I didn't run any numbers but that is substantial. Your right, i just looked up some SOHC piston specs and they are thinner than i thought. And that would take me forever in die grinding and measuring. So those are not looking like an option lol. Funny how quickly things can change. Wonder if anyone makes aftermarket first gens that are stronger than orginals. I'll do some looking around and get back.

Its been years but I have a lot of info laying around somewhere. Sohc pistons are nice but most people that use them run them with the larger cc first gen heads.personally they scare me because of my stuck valve issue before.if your dead set on them you could do custom copper thick head gaskets which is good for nos applications but is very pricey

 

[Dono]

Tough to know what 'stronger' really means.
If your going first gen, aftermarket new pistons are probably lighter and stronger than factory. I think the alloys have changed.

I know my aftermarket 2nd gen oversized pistons were lighter than my stockers. Im hoping stronger in the dish area also.

Glad to hear the voice of reason was heard. You just can't argue with factual numbers.

The sohc seems to make its extra power with the head design, and the 'slightly' higher compression. I doubt the pistons themselves are really much stronger. I mean, look at the power the stock ohv pistons are taking. The issues were having is with the wear on our old bottom ends from miles, not the pistons breaking down. My blow by issue was probably mostly wear, and rings loosing their tension.

I say go first gen piston. Anything else is quite a bit more work.

 

[QueenCitySleeper]

Ok cool, good stuff here. From what ive found we have the best knowledge of this motor on the internet. Something like this perhaps?

http://www.enginepartsstore.com/servlet/Detail?no=1512

 

[jd4242]

just for a reference if you run 95+ heads with stock bore and stroke with sohc pistons you come out to 13.06:1
some specs if you wanna run it,my numbers for 2nd gen piston is smeared but looks to be -23cc
1gen pistons-------2nd gen----------sohc
-17.5cc----------- -23cc ----------0 flat

95-98tm-------90tm
48cc----------60cc

stroke
3.307

stock bore (3.950)

felpro headgasket,very close to OE
.050 compressed is around .035 to .040


as for pistons these are what i would run if i was you.these are .020 over,what i run
http://www.summitracing.com/parts/slp-wh570p50mm/overview/make/ford

make sure you use the HD felpro head gaskets too.
the right side is 545SD; left side is 544SD

 

[QueenCitySleeper]

How do the sealed power pistons compare to the Keith Black?

 

[Dono]

No clue, I used sealed power.
It would be cool to find a way to do a side to side comparison between them.

 

[jd4242]

No clue, I used sealed power.
It would be cool to find a way to do a side to side comparison between them.

There is over on rps.KB are good piston but I have heard they have had problems with ring gaps.the mutual feeling is that the sealed power speedpro are better pistons.sealed power does make two different pistons.the speed pro are better

 

[QueenCitySleeper]

Thanks for all the info. The Sealed Power Speed-Pro are a steal compared to the KB. Yea I looked on rps and didnt find as much as I was hoping for. I havent been able to find anywhere that the Speed-Pro have failed. They should hold a 200 shot? Guess the next question would be if the crank and rods would hold assuming everything is balanced.

 

[jd4242]

I would throw a sohc oil pan on.everything else I would think would be fine.people have sprayed 120shots on basically a stock motor, all stock bottom ends.200 will take a GOOD tune and a two stage or a progressive rate kit.think thats what they are calling them, where it starts of at like 75 and slowly increases up to 200 depending on rpms.

 

[Dono]

The one common belief is that the bottom end of our motors are tough as nails.

Are you thinking of loosening up the bore size for a bit more clearance on piston to bore? Apparently the added heat can be an issue. Also ring gap?

I wouldn't think it would be an issue on our motors. They are not exactly high reving monsters.

 

[QueenCitySleeper]

Yes i will do a sohc pan. Progressive nitrous tuning. It adds fuel and nitrous while simultaneously pulling timing according to how you tune it. thats what I would want for a shot of that size. NOS sells a two stage controller that supports up to a 250 shot for $250. It will be a pricey setup, but thats definitely the right way to do it.

 

[QueenCitySleeper]

I want to avoid having the block machined. I have a good motor, the cylinder walls looked like glass. I might hand hone but I dont really want to bore it. Im gonna need all the strength I can get if I dont go with a first gen block.

 

[Dono]

Yeah, I'll be hurting from the costs of machining for a while. The other side of it is....it's all apart, and do you want a failure?
You sound pretty good with measuring, so I'm sure you will measure up the cylinders for wear before making a final decision.

 

[jd4242]

I would highly suggest boring to .020 and have the pistons there when its done.there has never been an issue with the blocks until you bore over .050 then you need a first gen block.the speed pro have a coating to help with heat.I have had juice on every car except my accord and my rule of thumb is.for a stock not forged motor but tuned for NOS is,20-25hp per cylinder depending on the size of the motor. I tend to go25- 30 so then if it blows I rebuild and up the shot.i have never blown a motor with those numbers.200 is not unreasonable at all for a built motor and the size of ours.I was planning on a 150 shot before I did the sc and that was with out the sohc pan or head studs.

 

[Dono]

I'm looking forward to this. It just might convince me to bottle feed. Definitely not to the extent you are going to though.

 

[jd4242]

I'm looking forward to this. It just might convince me to bottle feed. Definitely not to the extent you are going to though.

50shot and use w/m in the gas jet.what I plan nowwith a sc and good tune we could see huge gains and safe.

 

[Dono]

Probably cools the combustion chamber right down.
So, more tuning after 50 shot is installed?

 

[jd4242]

Probably cools the combustion chamber right down.
So, more tuning after 50 shot is installed?

O yea.cool the blades, case..everything.yea you would be able to add boost and timing with that small of a shot when combined with w/m.may only be a 50 shot but willing to bet after all is done you could gain easily 50-75hp to the ground and ""pretty safe""

 

[QueenCitySleeper]

Im looking forward to it. But that is a little ways away unfortunately. But Ill keep searching for new ideas with your guys help. Today I pulled the exhaust out and loosened my trans bolts. Ill try and get the new rear main seal in tomorrow. It looks like Im leaking from other areas on the motor though. Hopefully the new seal will stop most of the leakage. Im losing so much oil, I cant afford to keep adding the way I am. If it still leaks badly Ill have to pull the intake off and check my cam sensor and valve covers for leaks. In the meantime we need to get these SC OHV's running at their best

 

[Dono]

Check where your oil filter housing assembly bolts to your block. I had a leak from there. Couldn't tell till the motor was out. It's worth having a close look, you never know.