What to look for in rebuilt gt40p
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=42001
Printed Date: April-29-2024 at 7:05am
Topic: What to look for in rebuilt gt40p
Posted By: outerbanked
Subject: What to look for in rebuilt gt40p
Date Posted: September-29-2017 at 6:57am
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I have not looked for heads locally. I read the hot rod gt40p how to guide and realized most of what they were discussing was for heads too fancy for what I need (1987 sn2001, family boat used for ski, wake). I have read enough to get a general idea when I upgrade the cam (cam research) http://www.correctcraftfan.com/forum/forum_posts.asp?TID=5627 Performer intake, quick fuel m600 (if my rebuild and spec-to-80319 of my blistered 80551 fails to preform). My plan was to chase down where my compression was going . If exhaust I would try to spin valves (it has run rich for awhile since the carb needs work). Engine is 1500 hrs. I neglected to do a wet compression test. These are warmed up, plugs out, throttle at idle, but cranked until it would raise no more. Oil pre is 20-25 at idle on mech guage (sender was out and new to me boat) 1: 115 2: 105 3: 125 4: 145 5: 126 6: 128 7: 120 8: 126 Has anyone ever ordered from these guys? Do I need the max lift of .560 valve springs? Seems many have said too much spring press will ruin a cam. I have assembled a remanuf engine 20 years ago, but never built my own. My thought was if the above plan shows weak heads, to pull the heads, inspect the cylinder walls, then decide if I can make it another year with new hwads, or if I need to repair this lower end or find a remanuf longblock to throw in and then one day build the orginal block up slowly. Thank you. https://m.ebay.com/itm/351W-FORD-GT40P-4-BAR-PAIR-OF-CYLINDER-HEADS-F77E-1-2-HEAD-BOLT-HOLE-/263172641468 This is for 2 rebuilt heads These heads have 1/2" head bolt holes WCC Heads are thoroughly cleaned and inspected Pressure tested and/or magnafluxed to ensure no cracks or leaks in casting Guide work performed / replaced with new guides or liners as needed Three Angle Valve job performed We also pull a vacuum on each valve to insure A perfect seal between the valve and the seat All valves are reground or replaced with new valves as needed CBN milled to ensure straightness and correct finish All machine work performed on the latest state of the art equipment All parts are thoroughly cleaned and inspected before assembly Heads are assembled with new valve seals and brass freeze plugs VALVE SPRING UPGRADE AVAILABLE MAX LIFT .560 ADDITIONAL COST OF $120 SEND MESSAGE WITH ORDER AND WE WILL BILL YOU SEPARATELY THRU PAYPAL NO CORE CHARGE |
Replies:
Posted By: outerbanked
Date Posted: September-29-2017 at 7:21am
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https://imgur.com/a/NtIoD I had to cut the garage door tracks and remove the door moldings. Will not work for everyday parking, but will work for winter. |
Posted By: 8122pbrainard
Date Posted: September-29-2017 at 7:49am
https://imgur.com/a/NtIoD" rel="nofollow - Link ------------- /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 < |
outerbanked wrote:Posted By: Duane in Indy
Date Posted: September-29-2017 at 7:57am
Another alternative for the heads would be going to a set of Flo Tek heads that Speedway Motors sells. They are machined in Evansville Indiana. They are aluminum and have 58 cc chambers. I am running them on my engine and have been satisfied with their performance and the fact that you will shed 40 pounds. Dollar for dollar they are a good value. Something to think about.    ------------- Keep it as original as YOU want it 1978 Mustang (modified) |
Posted By: SNobsessed
Date Posted: September-29-2017 at 10:44am
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A leak down test will tell you what is wrong & is a lot easier than pulling heads for inspection. ------------- “Beer is proof that God loves us and wants us to be happy.” Ben Franklin |
Posted By: outerbanked
Date Posted: September-29-2017 at 1:36pm
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SNobsessed, I agree, my plan was a leakdown and listen first, followed by spinning the exhaust valves [if I'm lucky]. My post was not clear on that. I have been looking at heads and intake and will look at the flo tech. I have a lot more research time than "work on boat by myself" time. Thank you. |
Posted By: KENO
Date Posted: September-30-2017 at 12:40pm
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I've had no problems with the GT-40P heads with the normal springs and a cam with a little more lift than stock (in the .460 range) Never dealt with the place you refer to, but Dreaming on this site has recently gone through some engine issues and dealt with a place in Spokane and he liked what he got. Here's a link to one of his threads, he's probably an easy drive from you since he's in Tacoma and could tell you his experiences. You could send him a PM. http://www.correctcraftfan.com/forum/forum_posts.asp?TID=31100&title=where-to-start-with-this-engine-rebuild" rel="nofollow - link Since the 351 has "free spinning valves" from the factory, I'm not sure what you expect to get from an "exhaust valve spin". It doesn't have positive rotators but they are described by Ford as free spinning. |
Posted By: MrMcD
Date Posted: September-30-2017 at 2:48pm
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Dreaming ordered his rebuild from S&J in Spokane. There is also a shop in Spokane named Motor Works. Either one could rebuild a set of heads for you if needed or do the entire engine. They can rebuild your engine or give you an exchange. Dreaming would have a better idea of what they would charge. I think he upgraded his when ordered. There is also a large re-builder in Bellingham WA. Yamato I believe is the name. Any of these are professional shops that work on schedules so you will get your parts back when they say they will if time is an issue. I just did a valve job helping out a friend, a Jeep 4.0L, we dropped off the head on a Tuesday morning and got it back Friday afternoon, had it running again on Saturday. Not a big deal if you only need a valve job. We used a local machine shop that did all the things advertised on the ebay site you listed. That is all standard rebuild items they are listing that any competent shop will give you. ------------- |
Posted By: MrMcD
Date Posted: September-30-2017 at 2:50pm
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Duane, good looking engine, can I ask how much power/speed you picked up with the new Aluminum Heads? ------------- |
Posted By: Duane in Indy
Date Posted: September-30-2017 at 3:19pm
Mark, Good question but hard answer.. I did a complete engine rebuild at the same time as the head swap. Bored, pistons, cam, port/polish, carb, intake. Total blueprint job. At the same time I re-gelled the deck and hull. New stringers with out foam. Got rid of a lot of weight. Follow my "Mustang 17 Rebuild" thread in the general section sometime. Pre rebuild I was only getting about 45 mph. Now pushing 60 mph. gps @ 5400 rpm. I feel confident that the heads play a big part. Remember with these relatively low rpm, high torque engines you want small chambers (compression), small ports and small valves to produce the effects that we are looking for . Just the opposite of drag race high rpm motors. JMO, others may vary. Duane  ------------- Keep it as original as YOU want it 1978 Mustang (modified) |
Posted By: MrMcD
Date Posted: September-30-2017 at 4:23pm
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Thanks for the update Duane. Wow. 60 in a Nautique is rarified air for sure. I swapped heads on my 78 351W 25 years ago. Similar update, I used a set of 289 Hi Po heads, smaller chamber size for more compression, I think I was at 10.5, had larger valves and fully ported and polished. It really woke up that 351. I did not have GPS but did see 50+ MPH in the 78 Ski Nautique. Mine would just start to porpose on smooth water wide open. I know it would gain about 200 RPM after the speedo hit 50 so maybe 53-55. Not 60 for sure. I used a 13 x 14 on it back then. 60 mph is pretty cool. ------------- |
Posted By: outerbanked
Date Posted: October-02-2017 at 4:48pm
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Keno, too much you tube and not enough manual reading I guess. I now know that valves spin. I had seen a video of someone cleaning up exhaust valves by presurizing the cyl and spinning the valve. This was done without valve grinding paste, and with the cyl head installed. Seems too magic now, but at the time.. My mind starts to hunt for a solution to a problem I do not have. I am not able to hop out my back door and start up the boat, nor drive it to work like a project car. I still have not had the time for a leakdown test to tell me where the air is leaving the system. Thanks for the responses. |
Posted By: Shep72
Date Posted: October-04-2017 at 2:03am
| I used eBay. Seller was windycityengineandparts gt40p heads with 1/2" bolt holes. $475 +$134 shipping. I didn't like one of the heads he sent and he sent another with return shipping for the one I didn't like. Cam was a barebones by Lunati. I did upgrade to dual springs recommended for my cam. Did some shimming to get proper spring compress height and a couple of rockers for proper preload. (Common on rebuilt heads). So far I have zero complaints. Also did the dui ignition in place of pro tech. |