Stroker Buyers Beware - Pro Comp stroker kits  

Cobraed
  • Cobraed
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Post #1 post 26th July 2007 - 09:36 AM
For any one looking at buying a stroker kit for either a Ford Cleveland or a Holden v8. I have had a couple of customers bring me in one of each these kits for balancing and we have found the following.
The Ford pistons had vertually no skirt so would not provide enough ring support for a good seal and longevity. the weight difference between the lightest piston and the heaviest piston was 6.2 grams which is a lot of material to remove from a piston to make a matched set. no other work was don on the kit and it was sent back.
The holden crank has had a extra piece added to the end counterweights which required grinding so that it fitted into the block plus removing extra material from the block. To balance this crank will require fitting mallory metal at both ends so add about $300.00 to the balance cost. The pistons and rings supplied were incorrect in that the rings were 0.061" and the ring grooves were 0.079" so check these as soon as you get the kit. The piston also has had a Ford valve relief machined intothe piston.
If you are looking at one of these kit be prepared to spend extra on machining and balancing.

--------------------
Australia land of the free. You can think and say what you want but the government still controls what you can do
SG1
Post #2

What were the kits worth just as a matter of interest?

Cobraed
Post #3

I believe they go for about $1500.00

MADcunz
Post #4

great information!

Salad Fingers
Post #5

All Pro Comp gear is shit.
Really shit.
Even their electric dissy's fall appart.

Cobraed, have you guys balanced many SCAT kits?

Cobraed
Post #6

Scat and eagle are not a problem just check when you buy the kit as to whether it is internal or external balance

SIKUNIT
Post #7

I'd rather stick with the tried and proven gear, and spend the extra few bucks when buying.

Havent heard 1 good thing about the RPM USA gear.

EAGLE have release a new line of kits recently, waiting to hear some feedback on those, had much to do with them Ed??

Mookie
Post #8

Thats interesting to know.

I dunno if anybody has ever read "peterson 4x4 and off road" its a US 4x4 mag they have 4 pages procomp ads in there

if i haddn't read this i would have bought that for sure

Cobraed
Post #9

The pro comp stuff is for the lower budget and is not in my opinion suitable if you are going to give it a good thrashing. The big problem is that whilst it is cheap to buy by the time you put it all together it isnt much cheaper then buying the better quality stuff. ie Scat, Eagle or Harrop.
Havent had a lot of the new Eagle stuff in but what I have seen is pretty good. If you look at whats used in some of the crate motoers it is usually Eagle but some of the shops up here dont like it and prefer Scat. As far as I know both are manufactured in china and finish machined in the USA. I find that the Eagle cranks have a tuffer journal surface so are better suited to mudracing than the scat. When buying a stroker kit you should also check the supplier is giving you H series bearings as the chamfer in the standard bearings can come in contact with the larger radius on the crankshaft. Anthing else you need to know if buying a kit just ask

MADcunz
Post #10

Where do you work Cobraed? Sounds like you have a bit of knowledge!

Cobraed
Post #11

Winnellie performance. Been doing it for two bloody long, about 20 years.

ROLLER
Post #12

yeah its engraved in the concrete right in front of the glass doors.... just so you don't forget tongue.gif

chevyman
Post #13

having an engine building shop on the Gold Coast myslef i totally agree. these stroker kits are rubbish. i had a customer bring me one to build an engine with and we measured and checked balance. totally junk. you cant go wrong with a C,O,M.E, engines kit. never had a problem.

lx355
Post #14

QUOTE(Cobraed @ Jul 26 2007, 09:36 AM) [snapback]1281277159[/snapback]

For any one looking at buying a stroker kit for either a Ford Cleveland or a Holden v8. I have had a couple of customers bring me in one of each these kits for balancing and we have found the following.
The Ford pistons had vertually no skirt so would not provide enough ring support for a good seal and longevity. the weight difference between the lightest piston and the heaviest piston was 6.2 grams which is a lot of material to remove from a piston to make a matched set. no other work was don on the kit and it was sent back.
The holden crank has had a extra piece added to the end counterweights which required grinding so that it fitted into the block plus removing extra material from the block. To balance this crank will require fitting mallory metal at both ends so add about $300.00 to the balance cost. The pistons and rings supplied were incorrect in that the rings were 0.061" and the ring grooves were 0.079" so check these as soon as you get the kit. The piston also has had a Ford valve relief machined intothe piston.
If you are looking at one of these kit be prepared to spend extra on machining and balancing.


Why does everyone seem to have such a bad opinion about these kits. I have had one in my car for a while. The crank was one piece, the pistons were hypatec brand made by Precision international who also do dart equipment, i believe. It had chev rods which i assume are stronger than holden rods. The kit came to me external balanced and slotted straight into the block after i had done all regular clearencing. The car hauls ass, i mean it really puts you back in the seat. The wheeels spin at an instant etc. The only problem i have had with the engine relates to compression which is due only in part to the heavily shaved heads and the fact that the block may have been decked more times than it should have. But i was advised this prob would be fixed by o-ringing.

As for piston skirt lengths, i was reading an article recently where they spoke to bill mitchell the guy who makes the harcore 454 small block stroker and other guns from the states. Anyway the article said that because of the throw of the crank on all these new large strokers it is a requirment that skirts have to be much shorter to clear, now while in the past this would have been a problem advances in the manafactuireing process have fixed this. Indeed this was a very inciteful areticle, the adress to which is

http://engine-builder.com/ar/eb30748.htm

I am not trying to questions peoples experience in the industry, those of you in said industry would no doubt have more knowledge than myself, i just feel that these kits are always given a bad name but i have had one for two years or more know and the kits itself does not give me any troubles.

I do have a question though, would not the material in these cranks, given that they are made with what i would hope are more modern casting methods and utilising advancments in metal composition, be stronger than a standard 308 crank, which i have read in street machine and other reputable magazines of the sort, can handle upto 600 horsies.

Just a bit of objective reasoning for you all.

SIKUNIT
Post #15

The reason this thread was started was because a mate of mine purchase the said kit, took it to the machine shop to be balanced where it was found to be twice as much work and effectively double the $$ to be balanced.

Before it even went out to be balanced, the engine builder found 16 thou end float, which turned out to being the supplier providing the incorrect bearings.

Then the ring's were the wrong size for the piston glands, slopping around. Agisn, the supplier was at fault.

Why would you waste your time with a cheap, nasty kit, when you can spend a little more and be supplied with the correct parts and have less labour involved??

Needless to say he's kicking himself now.

Yes it may work out alright, but why go through the BS when you can buy a kit for the same amount as you would have spent on the said kit, and have less drama's??

Cobraed
Post #16

The quality of the materials is unknown, if your your engine is still going thats great, you may actually have a CAT stroker kit which was the earlier version sold by SSS which apart from needing mallory metal to balance the crank actually fitted into the block.

lx355
Post #17

Yeh i did get my kit from sydney speed. They had it external balanced and charged 200 as i bought the whole kit from them. They did not add mallory they just added weight to the balancer and took some from the flywheel. At the time i bought my kit the better brands were still highly priced. I'm not saying that if i were doing it now i would by one of these kits, if i were i'd probably got to High Performance World for a nodular iron eagle kit internally balanced.

Sixes350
Post #18

Then again ive had some gear sent from a reputable company and was totally wrong too. New type Gen3 bearings sent for the Iron 350 Chev! Not happy!

I had my original motor balanced at Winnellie Performance and was damn happy with the work.

RBNT
Post #19

Buy an RB.

vh-holden
Post #20

QUOTE(RBNT @ Aug 29 2007, 07:18 PM) [snapback]1281381117[/snapback]

Buy an RB.


and a dress.

Cobraed
Post #21

The Harropp cranks, or Eagle cast cranks or come cranks are all good and balance well. The rod and piston combinations are all there to suit your budget, ACL, SRP, Probe etc the only one I personally dont like are the HYPERTEK and the KB. They are VERY HEAVY unsure.gif The KB pistons are also very sensitive to ring gap and dont mind breaking thru the crown if the ring gaps are a little on the tight side. For me the best value for money in a Holden 355 stroker package is the Harrop crank (lighten it up for best resulte) either Scat or Eagle 5.7" chev journal H beam rods and SRP or Probe pistons, use total seal file fit rings and this combination will handle a good shot of gas or a decent blower overdrive. It also balances up and fit into the block with no problems. There is nothing wrong with the COME cranks but in my opinion they are a bit overpriced for what they are. thumbsup.gif

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