Pistons
February 18th, 2018, 11:29 AM
#3
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Location: St. Paul, MN
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February 18th, 2018, 11:53 AM
#4
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February 18th, 2018, 01:46 PM
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February 18th, 2018, 02:37 PM
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Cutlassefi has good stuff and is highly respected and knowledgeable on this site.
February 18th, 2018, 02:40 PM
#9
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You will need a good local shop for boring and new pistons. You are into more than just a simple rebuild. I have seen the name of a shop in St. Paul mentioned by one of the members, but know nothing about them. I have a 455 out at a shop in Forest Lake.
Cutlassefi has good stuff and is highly respected and knowledgeable on this site.
Cutlassefi has good stuff and is highly respected and knowledgeable on this site.
February 18th, 2018, 02:58 PM
#10
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Do you have a local shop for machine work ?
February 18th, 2018, 04:42 PM
#11
Pistons are a solid investment . even on a mild/stock build. I would make it so if you wanna turn the which up you can easily do so. Having a good set up pistons and careful planning on the block machining will yield a nice stock / mild build but also give room for growth.
If you want my cheap alternative. Find a nice used set of speed pro flat tops. the regularly go for like 200 bucks used. Not the greatest piston but they are forged and will work but its not as light or efficient as the new designs.
If you want my cheap alternative. Find a nice used set of speed pro flat tops. the regularly go for like 200 bucks used. Not the greatest piston but they are forged and will work but its not as light or efficient as the new designs.
March 14th, 2018, 05:31 AM
#14
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Don't disappoint yourself with a cast piston. $650 sounds like a lot, but it will make for a MUCH better engine...otherwise you're left with a 50 year old Speed Pro design that weighs 200g more
March 14th, 2018, 06:08 AM
#15
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Agreed and their is free horsepower in the modern ring pack Mahle pstons that Cutlassefi sells. Not only that they will have better quench and provide a pump gas friendly compression ratio. Mark also sells cams as well, the stock cam is super tiny and useless to make any power.
March 17th, 2018, 10:57 PM
#17
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That would be .030" over bore. It's a standard "next size up" for a rebuild. Be sure to verify the piston height as many aftermarket cast pistons are shorter than the factory pistons, which results in very low compression ratio. Factory is 1.612" height and most aftermarket cast pistons are .020" or more short; whereas most forged pistons are the correct height.
That doesn't make any sense. The camshaft doesn't have anything to do with the piston top.
Which cam?
What are the specs for lift and duration?
You need to match the cam to the compression ratio for optimum performance.
That doesn't make any sense. The camshaft doesn't have anything to do with the piston top.
Which cam?
What are the specs for lift and duration?
You need to match the cam to the compression ratio for optimum performance.
Last edited by Fun71; March 17th, 2018 at 11:04 PM.
March 17th, 2018, 11:01 PM
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March 17th, 2018, 11:04 PM
#19
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March 17th, 2018, 11:25 PM
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For the actual compression ratio, you need to measure the combustion chamber volume in the heads, the distance from the top of the piston to the top of the block deck, the volume of the piston dish, and the head gasket thickness. Combine this with the camshaft intake valve closing spec and you get an idea of the cylinder pressure, which can then give you an idea if it will be acceptable for a given gasoline octane rating.
If you post up as much info as you can, we will be able to give feedback as to how "pump gas friendly" the build might be.
If you post up as much info as you can, we will be able to give feedback as to how "pump gas friendly" the build might be.
March 18th, 2018, 05:19 AM
#21
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You don’t have to get anything from me but DONT GET ANYTHING from Mondello in Paso Robles. You’ll be sorry.
The piston I offer yields a compression ratio of between 9.25-9.5:1 or so depending on deck and Cyl Head cc. Perfect for a street build.
I finished my project engine, I’ll post the results and you can see for yourselves how this piston helped make more power.
The piston I offer yields a compression ratio of between 9.25-9.5:1 or so depending on deck and Cyl Head cc. Perfect for a street build.
I finished my project engine, I’ll post the results and you can see for yourselves how this piston helped make more power.
March 18th, 2018, 07:38 AM
#22
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Mark's(Cutlassefi) Mahle pistons have 10cc dish's, taller compression height for better quench and a very modern 1mm ring pack plus are way lighter than the ancient technology Speedpro forged pistons. Talk to Mark about a cam as well.
March 18th, 2018, 12:10 PM
#23
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Just to clarify. Several people have been burned by Mondello since Lynn took over. Mark isn’t pushing his product because he sells it. He knows his stuff and chances are it will be a less expensive option AND potentially a less expensive lesson. We’re all not just stroking Mark because we enjoy it. He has been an invaluable asset to this forum as well as the Oldsmobile community.
March 18th, 2018, 04:58 PM
#25
If you want pump gas friendly I would run as much as you possibly could ( 9.5 imo) . 9.5 should be fine even with 91 octane. it gives you more options for cam and you will make more power. But DONT and I mean DONT buy from mondello in paso robles. That guy f**ks all the newbies who don't know better.
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