Wrong pistons

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MoparAnglia

MoparAnglia

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As mentioned in another thread, I am building a 390 stroker, which was to include Hughes' Exclusive Icon stepped dish(-18cc) pistons. I was planning on using RHS/Indy heads from IMM with a skim to 60cc which would give 10.3 comp with a .040 gasket and zero deck.

I sourced the parts through my local engine builder who assured me he could get the Hughes' pistons from KB/Icon.

Well, they sent the wrong pistons (846 flat tops), he's balanced the whole assembly and even going to a 67cc chamber I'm staring down the barrel of 11:1. Our fuel is equivalent to your 91 octane and I was planning on going with a big hydraulic roller anyway, but how big to bleed off the excess squeeze?:eek:ops:
 
If you could use a aluminum head it will help.
11:1 is fine-- if you use a big enough cam.
How big of a cam????

I would hope your engine builder could answer the question of how much cylinder pressure you will have.

Light cars have a little more room for this, but it should not be a guessing game.
Make sure your right.
It's not just the cam size--------It's the whole combination.

I have to ask a question.
Why would the engine builder balance the wrong set of pistons?????
I would have sent them back and charged the shipping to the company that sold them to you.
 
you said the desired pistons are -18cc, so they stick out of the block?

The RHS-heads are closed chamber so i think that won´t work??

Michael
 
T67POWER said:
If you could use a aluminum head it will help.
11:1 is fine-- if you use a big enough cam.
How big of a cam????

I would hope your engine builder could answer the question of how much cylinder pressure you will have.

Light cars have a little more room for this, but it should not be a guessing game.
Make sure your right.
It's not just the cam size--------It's the whole combination.

I have to ask a question.
Why would the engine builder balance the wrong set of pistons?????
I would have sent them back and charged the shipping to the company that sold them to you.
Click to expand...

Hadn't nailed the cam specs down yet but [email protected]" is a good starting point. A closing point of 72ABDC is giving 8.25 dynamic.

I've contacted the supplier, I'll see what he comes back with.
 
Yeah, I know they're not cheap but that doesn't bother me. Its just opening up the quench distance seems a crappy way of doing things.
 
Yeah, because once the quench is gone, that pup will probably spark knock at 9.5 on 91 with iron heads. Lemmie ask a stupid question. Knowing the dramatic difference in power, why hydraulic? Sinch you're already gonna have to run an adjustable rocker, why not go solid roller? The cost is the same...maybe a little cheaper but the power difference is great.
 
Tis a good question, just cos its a driver really. A hot, cramped, smelly, noisy driver but a driver nonetheless. It may see track time half a dozen days a year (maybe a bit more initially just to play with the suspension settings), but I want to be able to use it as and when I feel like it. Its still a question I'm asking myself though!
 
Stroker makes a good point. Run a solid roller. Polish the chambers and coat the piston tops for detionation resistance. Keep an eye on your distributors timing and a ear on the engine knocking/pinging.
 
Okay, off at a slight tangent then but a quick look at Comp's street rollers reveals a gap - there's no XR292R, and the 286 seems a tad mild for this application.

Who's running what and what peaks are they producing rpm-wise?

Also, I'm not sure if side-stepping oil system mods is viable. Didn't Crane do a 'drop-in' Solid roller set-up a while back?
 
There wa a issue with the drop in lifters...st first, in which a few places have corrected since then. It was with the hyd. roller cams lifter having the oil band pop out of the lifter boss exposing the oil and dropping oil pressure.

Mechanical/solid lifter issues are with the link bar. They were not a drop in and required grinding which not all the blocks could handle.

This issue has been addressed by most companies.

You can call Comp Cams up and have them custom grind you a cam of any style. This cost no more than a off the shelf cam.
Hugesengines(.com) has a bunch of "MoPar" cams that you'll probably like alot.

Click this--> http://www.hughesengines.com/Index/index.php
 
Speak with the guy, Brian, you plan on getting the heads from.
 
rumblefish360 said:
There wa a issue with the drop in lifters...st first, in which a few places have corrected since then. It was with the hyd. roller cams lifter having the oil band pop out of the lifter boss exposing the oil and dropping oil pressure.

Mechanical/solid lifter issues are with the link bar. They were not a drop in and required grinding which not all the blocks could handle.

This issue has been addressed by most companies.

You can call Comp Cams up and have them custom grind you a cam of any style. This cost no more than a off the shelf cam.
Hugesengines(.com) has a bunch of "MoPar" cams that you'll probably like alot.

Click this--> http://www.hughesengines.com/Index/index.php
Click to expand...

Okay, I was aware that Hughes, Comp etc. had dealt with this, as I recall it was due to the random chamfers present at the top of some lifter bores.

I was thinking more of oil system mods such as tubing the galley or bushing the lifter bores to suit running the solid lifters. I'll look into it and most likely speak to Brian at IMM as I figured I'll not go wrong matching the cam to his RHS heads.
 
LOL, yea.... I'd imagine he'll set ya up well.
 
so you'd recommend solid roller for street use? at what lift/duration does it pay to go solid roller vs hyd roller?
sorry to the OP, but I am strongly considering going with the hughes drop in hyd rollers (for my street car), but am still debating.......
 
Seems like a ton of expense when the gasket will solve the issue. Talk to your machinist. He should be helping defer the cost of fixing the issue he created. I would not go solid roller, or hydraulic roller. I'd get the right pistons, have the shop credit you the full amount for the pistons they got wrong, and then balanced, you pay to have it rebalanced, and stick to plan. But that's me.
 
kielbasa said:
so you'd recommend solid roller for street use? at what lift/duration does it pay to go solid roller vs hyd roller?
sorry to the OP, but I am strongly considering going with the hughes drop in hyd rollers (for my street car), but am still debating.......
Click to expand...

Alot depends on the intended use of the car/engine and at what point you yourself think it will pay off in terms of more performance for what your doing. Regular hyd. cams can get very large and provide enuff of what your looking for to propel the car very fast.

IIRC, MoPar has a Hyd. cam listed @ 312 duration to run into the 10's....again, IIRC.
 
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