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I am in the process of building a 71 429 SCJ for my jet boat. This engine has D00E R heads and D0VE A block (4-bolt main) along with the stock 429 crank. I am looking at using Sealed Power flat-tops and crane Extreme marine came #XM278H12 cam with magnum roller tip rockers.
What is the recommended piston to cylinder clearance for use on a jet. My cooling system has a pressure regulator set for 15# and I am using a gate valve to regulate volume.
Thanks for any advice as I don't want to screw up this engine for obvious reasons.
Let me know ford guys. :)
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Use the piston manfacture's clearance recommendation. Typically the clearance would be .004" to .006" for a forged piston but may vary from mfg. to mfg.
[ June 02, 2003, 03:49 PM: Message edited by: 058 ]
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058 it seems you know a lot about ford big blocks, do you know where I can find A flat with a 385 series motor in it? will you be a cfw on father day?
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058,
I've read several posts regarding setting them up slightly loose for use with a jet due to possible low incoming water temps causing cold seizing. Is there any truth to this?
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That is a very good ford block not many of them around.Oh heads are good too.
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waterloged:
058 it seems you know a lot about ford big blocks, do you know where I can find A flat with a 385 series motor in it? will you be a cfw on father day? I'm going to try to make CFW on Sat. only without boat. Just going to do a quick day trip so I can be home Sunday, Father's day for my daughter. I don't know where you can find a BBF powered flat as there aren't too many of them around, seems there is another engine thats a bit more popular...although I have no idea why. :D Locating mounts is the biggest problem with building your own Ford powered flat but thats about the only way you can have what you want. Thats what I've done, bought empty hulls and built my own engines and used mounts that I bought prior to getting the boats. Just curious, why do you want to go against the tide and run a Ford? If you're like me its because I bleed Ford blue. Perhaps we can hook up at CFW and talk Fords quietly otherwise we may get thrown in the water or kicked out, you know how testy those brand X guys can get. :D
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thedroid:
058,
I've read several posts regarding setting them up slightly loose for use with a jet due to possible low incoming water temps causing cold seizing. Is there any truth to this? Droid, There is some consideration to cold cylinders with hot pistons and some clearance should be added just for insurance. I would rather live with a little piston noise on cold startup than to stick a piston when you're into the throttle. Depending on piston mfg. stick with the high side of their recommendation, I think you will be safe with that but I should point out a lot is going to depend on your tuneup. If you lean the engine out the extra clearance isn't going to do you much good, you just might stick a piston anyway. As with any H.P. engine turning much higher rpms and WOT is going to require extra care upon setup and tune to insure that the engine lives a long and happy life.
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058,
It's also my understanding that bbf engines like big carbs, like 850 cfm+ as well as a fair amount of timing, all in at 3500 w/34-36 degrees of advance. Any advice on this.
Thanks
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Fords do like airflow. An 850 is about the smallest carb I would consider for any modified BBF. Although I have had very little experence with jetboat engines and their lower peak rpm I still see some hard running jetboats with 1050 or 1150 Dominators so the old carb sizing formulas are rather obsolete, at least for Fords.
