Sealed power H621P
Printed From: CorrectCraftFan.com
Category: Repairs and Maintenance
Forum Name: Engine Repair
Forum Discription: Engine problems and solutions
URL: http://www.CorrectCraftFan.com/forum/forum_posts.asp?TID=37691
Printed Date: October-07-2024 at 2:19pm
Topic: Sealed power H621P
Posted By: 93xs2003@gmail.com
Subject: Sealed power H621P
Date Posted: November-17-2015 at 7:22pm
| Could anyone tell me the piston head volume of a sealed power H621P piston? I haven't been able to find a published volume. |
Replies:
Posted By: MrMcD
Date Posted: November-17-2015 at 9:30pm
|
FMECat.com will give you the listed specifications but the volume is not listed. I checked the last printed catalog from 2005 and it does not list the Volume for that part number.. I will see if I can get it if you are not in a hurry. |
Posted By: 93xs2003@gmail.com
Date Posted: November-18-2015 at 6:18pm
|
I got it from sealed power: "the dome volume for the H621P piston is -18.0cc. From The Federal-Mogul Motorparts Garage Gurus Product Support Team" Thanks, |
Posted By: 8122pbrainard
Date Posted: November-18-2015 at 6:31pm
|
Steve, You better tell us what you are up to with the pistons!!  ------------- /diaries/details.asp?ID=1622" rel="nofollow - 54 Atom /diaries/details.asp?ID=2179" rel="nofollow - 77 Tique 64 X55 Dunphy Keep it original, Pete < |
Posted By: MrMcD
Date Posted: November-19-2015 at 2:56pm
|
Sealed Power pulled the print on that piston for me this morning. They say it is -18.9cc. Very close to what the Tech group gave you.. H621P dish volume = -18..9cc FYI: The design engineer told me he would choose a dish any time he can. A dished piston helps the flame ball and gives a faster and more complete burn than you get with a flat top and far better than a dome top piston. He says testing shows they can give up 1/2 point in compression and make more power with a dish. If you want high compression choose small chamber heads with a dish. |
Posted By: 93xs2003@gmail.com
Date Posted: November-19-2015 at 6:15pm
|
It's a 92 prostar / 351W / GT40 heads / powerslot / ~1400 hrs There are hairline cracks in the waterjacket of the head. Plugs were very rusty when purchased last fall, this set was new this spring. So the leak has been there for a while, and while I haven't seen any water, rust on new plugs suggest it has been actively leaking this summer. No water in oil. No water on plugs tips. Engine is out. Internals were very clean. Block is off to machine shop. Will use GT-40P heads Cam research cam (0.490In/0.490Ex/218In-222Ex@0.050/112LSA) H621P pistons Stock intake / exhaust Undecided on distributor |
Posted By: 8122pbrainard
Date Posted: November-19-2015 at 6:52pm
Just don't put one of the EI conversions in it!!  ------------- /diaries/details.asp?ID=1622" rel="nofollow - 54 Atom /diaries/details.asp?ID=2179" rel="nofollow - 77 Tique 64 X55 Dunphy Keep it original, Pete < |
93xs2003@gmail.com wrote:Posted By: MrMcD
Date Posted: November-19-2015 at 10:37pm
|
The H621P is a Hypereutectic piston, have your machine shop bore it to the bore size shown on the piston box. IE: 4.030 for a 30 over. These pistons don't grow as much as a standard cast or a Forged Piston so they do not need more clearance added as many machine shops will want to do for you. They will offer better fit which gives better ring seal and if you increase the bore size beyond what the oversize is you will give some of that advantage away. The factory builds the clearance needed into the piston and gives you the needed block size on the part number outside the box. If you plan to add Nitros, a Turbo or a Supercharger you may wish to add extra clearance to your bores. |