1974 GTE 351W Engine |
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Mantis
New Member Joined: 19-July-2018 Location: Colorado Status: Offline Points: 20 |
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Posted: 04-August-2018 at 12:04PM |
This is my post to discuss and detail my work on the engine
for the 74 GTE.
The engine in the GTE is a 351W-2V, pretty vanilla for the
year. The engine appears to have 113k on
it, so not bad for a 351W. That said, it
sat for ~18 years, so there is no telling what is gunked up, dried out, or
brittle. She is running pretty well now,
with us putting about 200 miles on it since we got it. We have done a full tune up with cap, rotor,
plugs, wires, and coil. I tried tuning
the carb, but I think it needs a rebuild.
That said, the GTE is running pretty well with ~13 seconds from 0-60; which
is right about what was expected from the factory. I know that any good engine discussion starts with what the
owner has in mind for the car and by extension, the engine. Our plan is to keep the GTE more of a mild-mannered
personal luxury car it was intended to be originally. That said, nothing says we can’t try and
unlock some of the potential of the 351W that was locked away under the smog
compliance requirements. I am not
looking for a high revving horse power monster, I am looking for more of a low RPM
torque motor with a smooth idle that runs regular grade gas fine. Random thoughts in no particular order: I do not really plan to put tons of money into an engine. After reading a ton on the 351W, I plan on keeping the stock
intake and 2V 2150. This because many say
they did a decent job for low end torque and that the 2150 is a good 2V carb. I am also keeping the heads as they “SHOULD” be
decent castings that, again, are designed for low end torque. I believe that there are some good gains to be had from a
decent cam. My current thought is to
look at something like a Comp Cams 252H. I am really not sure about how far I go in a
refresh/rebuild. I could go as short as
just a cam, or go all in for a rebuild.
The engine is pretty solid, but I am reluctant to put a small effort in
when the full build will help refresh old seals and gaskets. If a full build, I am not sure about pistons. The reason I say this is that from what I
have been able to determine the engine has an 8.8:1 compression. While not great, I think it is close to what
I would want for a regular gas engine. I
may consider boring to 30 over and trying for some pistons to get me to around
9.0:1, but I am still researching that. The good news is I do not have to rebuild anytime soon. I have the carb kit inbound and I am going to
tackle that first. Any input or thoughts from you guys is welcome. |
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Kevin
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72FordGTS
Admin Group GTS.org Admin Joined: 06-September-2005 Location: Ontario, Canada Status: Offline Points: 5802 |
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Staring with a carb rebuild is a great idea. You can also play around with the distributor timing too, maybe try a bit more base timing, or play with the curve a bit too. Dual exhaust and headers are also easy power adders. 351W have probably the cheapest header options for these cars. You could stick with quiet mufflers if you aren't looking for the performance sound.
I was in similar situation to you with my engine, a high mileage strong runner, but wanted to boost the power. I ended up doing exhaust, switched to a 4-bbl carb, eliminated all emissions controls (minimal on a '72) did some ignition tuning and it made the engine run stronger, but I wanted more. I was considering doing a cam, but then decided I might as well do an entire rebuild rather than put a new cam with all old parts. Mind you I went overkill on my build, but with a 351W, you could do a decent budget built. Ford only rated these engines at 8.0:1 compression form the stats I have. It'd be nice to rebuild, and get some new pistons to bump the compression up to around 9.0:1 and then run a cam like that 252H with a new timing set. With the compression, cam, exhaust, and ignition work it should run much stronger. I'd say stick to the basics, like I mentioned in the first paragraph if you don't want to rebuild the engine. But if you are up for a rebuild, then bump the compression and go with a mild cam. That's my two cents... |
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Vince
1972 Ford GTS Sportsroof - Survivor, One Family car GTS.org Admin |
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MrSmog
Senior Member Joined: 21-January-2016 Location: Ky Status: Offline Points: 1407 |
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never heard of a 1974 GTE? the older cougars had a GTe version but didn't know they brought that back in 74?
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californiajohnny
Moderator Group Joined: 05-October-2013 Location: winlock, wa Status: Offline Points: 14606 |
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he means gran torino elite...
i'm a firm believer in completely rebuilding an engine vs rering and rebearing one, complete is just more consistent and reliable! the 525 cam is basically a stock replacement cam maybe a tiny bit over stock but not much difference that's noticeable i'd say go with what cam they offer in the 260 -268 range noticeable increase in torque and a gain in mileage without a crazy lumpy idle new timing chain set to zero (some smog motors had retarded cam timing) and a dual plane aluminum intake with 4 bbl carb, and good headers with 2 1/2" dual exhaust will make a nice difference (it did on my 74 351W ) |
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JOHN
74 GRAN TORINO S&H CLONE 74 VETTE CUSTOM 90 S10 BLAZER 4X4 LIFTED 77 CELICA CUSTOM 75 V8 MONZA SUPERCHARGED 79 COURIER VERT. SLAMMED 75 VEGA V6 5 SPD 70 CHEV C10 P/U 68 MUSTANG FB CONVERSION |
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Mantis
New Member Joined: 19-July-2018 Location: Colorado Status: Offline Points: 20 |
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I was remarking to my wife how it is funny how I can be thinking of something, but it gets mentioned by others. What I am referring to is exhaust. I was telling her that a good start would be installing a good exhaust.
I was waffling on whether I go 2.25 or 2.5. I have read opinions both ways, but I was not sure if a 2.5 would be a bit to large. I am leaning towards 2.25 system with turbo mufflers (not sure on brand yet) and an H pipe. I was considering an X pipe, but read where the H is a better choice for low end power. I appreciate the cam feedback, I will keep researching. I know that a 4V carb and intake is a viable option to improve performance, but I thought that the benefits come at higher RPMs and I am not wanting to build that direction. |
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Kevin
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Rockatansky
Senior Member Joined: 30-July-2010 Location: On The Road Status: Offline Points: 6059 |
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Comp 252 is much more efficient than a dog stock cam, but you may find it lacking highway legs? i've recommended the 252 before but today i'm feeling the 260H over the 252H for the slightly higher rpm range (1200-5200 vs 800-4800), starting at 1200 it's still well below stock TQ converter rating. you'd need to use a diesel TQ converter to take advantage of the 800 rpm low end! and it's still going to be happy with stock rear gears but i think you'll welcome the little bit more over it being missing? 113k miles on the stock cylinder bore? if you were to pull the heads and see the ridge at the top i'm pretty sure you'd want to bore it, new piston & rings ... and if the heads have never been worked on they're going to need guides and a valve job for sure too. do you know about stock Ford valves? they suffer head separations and destroy the engine at will, there's no way to predict when it will happen but it does, a lot. my 1st recommendation if you don't do anything else is to replace the valves with decent quality 1 piece stainless steel units and fresh valve springs appropriate for the cam. after you know what sizes everything are check out https://www.alexsparts.com/ great prices for good parts ;) |
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72 GT Ute
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Mantis
New Member Joined: 19-July-2018 Location: Colorado Status: Offline Points: 20 |
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I am not convinced in any solid way on the compression ratio for the 351W in 1974, but I am leaning towards the 8.7:1. I am not trying to argue, just my research suggests otherwise. And I should confess that I love debating these things. Data point 1: Supposedly in this book on page 38, it lists the compression ratio for the 351W and says that 60.4cc heads have 8.7:1 compression ratio. I plan on buying some SBF books to try and learn more. Data point 2: If you read through casting numbers for 351W heads here, there are C9, D0, and D1 castings listed, nothing else that would go into a 1974. That suggests that the worst head you would get in a 1974 would be 1971 heads. The 69-71 heads all had the same basic specs with 1.84/1.54 valves and 60.4cc chambers. I get that they could have changed the pistons, but I have read in more than a few places that it was the higher compression through 1976. After 1977 they used the 302 spec heads with the smaller valves and 69cc chambers and all bets are off. I am not insisting that I am right, but I would love to get more definitive information.
Edited by Mantis - 05-August-2018 at 9:54AM |
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Kevin
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Mantis
New Member Joined: 19-July-2018 Location: Colorado Status: Offline Points: 20 |
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Wow, great info on the cams, I will have to think about the 260H. Thank you! I will have to admit that I am learning about SBF engines and I am grateful for your helping me learn what I do not know. I am reading a bunch trying to fill the gaps, but there is a TON of information out there.
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Kevin
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Rockatansky
Senior Member Joined: 30-July-2010 Location: On The Road Status: Offline Points: 6059 |
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as far as pistons i've seen everything from 2 eyebrow reliefs to eyebrows, 2 & 4 eyebrows in a shallow dish with a bevelled outer edge to a full 'bathtub' dish, and i have no idea where to find the volume data for each variation? if you're really curious pull a spark plug, get a boroscope and have a look inside. they have a boroscope accessory for phones now!
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72 GT Ute
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MrSmog
Senior Member Joined: 21-January-2016 Location: Ky Status: Offline Points: 1407 |
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funny you mention this, just tried it with zero success. when the image was clear i was so close to the piston, couldn't tell what type it was. I must need to find a better borescope, any tips to find one for this?
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Rockatansky
Senior Member Joined: 30-July-2010 Location: On The Road Status: Offline Points: 6059 |
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what are you using the phone accessory thing? no personal experience here but Harbor Freight has a couple just make sure the knob fits through the plug hole, you have the big 18mm's?
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72 GT Ute
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Mantis
New Member Joined: 19-July-2018 Location: Colorado Status: Offline Points: 20 |
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So, what are people's thoughts on 2.25 vs 2.5 dual exhaust on a fairly tame 351W?
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Kevin
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californiajohnny
Moderator Group Joined: 05-October-2013 Location: winlock, wa Status: Offline Points: 14606 |
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i went from stock manifolds and 2" dual exhaust to shorty headers and 2 1/2" dual exhaust and it made a difference runs smoother and got rid of some minor inconsistent little quirks in how it ran! the smallblock fords were fairly restrictive on the exhaust compared to most other engines
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JOHN
74 GRAN TORINO S&H CLONE 74 VETTE CUSTOM 90 S10 BLAZER 4X4 LIFTED 77 CELICA CUSTOM 75 V8 MONZA SUPERCHARGED 79 COURIER VERT. SLAMMED 75 VEGA V6 5 SPD 70 CHEV C10 P/U 68 MUSTANG FB CONVERSION |
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Rockatansky
Senior Member Joined: 30-July-2010 Location: On The Road Status: Offline Points: 6059 |
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i wouldn't go to much effort or expense for such a mild power level, 2.5" is usually better for performance oriented applications but believe it or not even such a small increase will change the low end characteristics
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72 GT Ute
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72FordGTS
Admin Group GTS.org Admin Joined: 06-September-2005 Location: Ontario, Canada Status: Offline Points: 5802 |
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No worries at all, I was just stating that several sources I have list this engine as being "advertised" at 8.0:1. I agree with you that the heads are the 60.4cc heads as I don't think they switched to the larger 69 cc heads until 1977 like you said. However, it was my assumption that the pistons changed while the heads remained the same to lower the compression. In any case it may be a moot point, because as we know, the advertised compression ratio and real world were often different. And no doubt, if you do tear down this engine, I think we all agree a compression boost would be of benefit for your goals.
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Vince
1972 Ford GTS Sportsroof - Survivor, One Family car GTS.org Admin |
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Rockatansky
Senior Member Joined: 30-July-2010 Location: On The Road Status: Offline Points: 6059 |
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actually, if you want it to run on regular the stock CR and the small cam will work well, bumping it up to 9:1 with the small cam gets the DCR into mid-grade or possibly premium territory. raising the static compression ratio just to control it with less DCR is kind of pointless, at the end of the day the DCR (actual chamber pressure / octane requirement) tells you how efficient or sluggish the engine will be
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72 GT Ute
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72FordGTS
Admin Group GTS.org Admin Joined: 06-September-2005 Location: Ontario, Canada Status: Offline Points: 5802 |
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Rock, you know way more than me, but if this engine has a 8.0:1 compression, you wouldn't boost that at all? I get the whole DCR thing, but the 1970 351-2V engines ran 9.5:1 advertised compression and they ran on regular, and used the same cam as a 1974 351-2V. This was my logic behind it anyway. I was thinking that his car would do well with a 9.0:1 and the 260H, which seems like it'd be a good combo for lots of low end torque and a good boost over a stock engine.
As for exhaust, I would think 2.5" would be overkill. The 2.25" would be fine, even 2" duals would probably be okay too. My dad installed 2" duals many years ago on my car and it was a good improvement over the stock single exhaust, with no loss to the bottom end.
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Vince
1972 Ford GTS Sportsroof - Survivor, One Family car GTS.org Admin |
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Big Bird
Senior Member Joined: 25-August-2013 Location: New York Status: Offline Points: 4194 |
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Look into the specs/parts used for the 94-96 Lightning. 351W in a vehicle of similar heft.
What Ford did moved them around pretty good. Might be a good starting point. IIRC the cam used was a 70s Torino part. (Not even a roller cam).
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"What we do in full frontal view, is more honest than your cleaned-up mind."
Randy 1979 T-Bird 2005 F-150 STX RCSB 4.6, 3.55 LSD How the Heck does a REGULAR CAB SHORTBED weigh over 5200 pounds? |
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Rockatansky
Senior Member Joined: 30-July-2010 Location: On The Road Status: Offline Points: 6059 |
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i don't know about that Hahaha ... here's the calc for 252H at 8:1 (52* intake valve close) Static compression ratio of 8:1 Effective stroke is 2.99 inches Your dynamic compression ratio is 6.98:1 Your dynamic cranking pressure is 136.64 PSI 9:1 with 252H cam. safe for premium but not too sure about regular Static compression ratio of 9:1 Effective stroke is 2.99 inches Your dynamic compression ratio is 7.83:1 Your dynamic cranking pressure is 159.01 PSI here's the calc for the 260H at 9:1 (56* intake valve close) DCR is climbing up to what is considered a very safe range for pump premium but will it run on regular? Static compression ratio of 9:1 Effective stroke is 2.91 inches Your dynamic compression ratio is 7.65:1 Your dynamic cranking pressure is 154.23 PSI here's any typical factory cam including the CJ cam that closes the intake at 76* ABDC, more CR, more cam and a significant loss of DCR from the 8:1 252H Static compression ratio of 9:1 Effective stroke is 2.42 inches Your dynamic compression ratio is 6.53:1 Your dynamic cranking pressure is 125.01 PSI now set the cam back 4* to post emissions valve timing to 80* BDC intake valve close Static compression ratio of 9:1 Effective stroke is 2.31 inches Your dynamic compression ratio is 6.28:1 Your dynamic cranking pressure is 118.61 PSI i wish the chart extended down into the regular fuel & 6.xx:1 DCR's Edited by Rockatansky - 12-August-2018 at 6:29PM |
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72 GT Ute
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72FordGTS
Admin Group GTS.org Admin Joined: 06-September-2005 Location: Ontario, Canada Status: Offline Points: 5802 |
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Thanks Rock, that's great info. I can see how the DCR is getting up there with some of the small cams. I looked up the stock 351W-2V cam specs if you want to do the calculations to compare. 1970-72 351W Cam: Valve Lift: .418/.448 Intake Duration: 256 opens 11 BTDC closes 65 ABC Exhaust Duration: 270 opens 68 BBC closes 22 ATC 33 degrees overlap 1973-74 351W cam Valve Lift: .418/.448 Intake Duration: 256 opens 15 BTDC closes 65 ABC Exhaust Duration: 274 opens 68 BBC closes 26 ATC 41 degrees overlap Compression Ratings by the factory were: 1970: 9.5:1 1971: 9.0:1 1972: 8.6:1 1973-74: 8.0:1 |
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Vince
1972 Ford GTS Sportsroof - Survivor, One Family car GTS.org Admin |
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Rockatansky
Senior Member Joined: 30-July-2010 Location: On The Road Status: Offline Points: 6059 |
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did they happen to give a lift spec for the closing points? Bubba's page shows that Ford used .004" lift for the opening points and .006" for the closing points, maybe just a couple degrees difference to actual seat so i'll add 2* no world shaker factory 9.5:1 motor Static compression ratio of 9.5:1 Effective stroke is 2.66 inches Your dynamic compression ratio is 7.46:1 Your dynamic cranking pressure is 149.21 PSI factory 8:1 motor, over a full DCR number softer! notice they added 4* to the durations to gain 8* overlap but the IC & EO stayed the same, seems counter-inuitive for emissions Static compression ratio of 8:1 Effective stroke is 2.66 inches Your dynamic compression ratio is 6.32:1 Your dynamic cranking pressure is 119.63 PSI Edited by Rockatansky - 12-August-2018 at 6:27PM |
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72 GT Ute
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MrSmog
Senior Member Joined: 21-January-2016 Location: Ky Status: Offline Points: 1407 |
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I know a 1976 351w was 8.2-1 and ran damn good in a early 70 maverick with a 100 shot of nitrous I'd be surprised if that 74 motor was any higher then 8.5-1, you might want it to be higher but I seriously doubt it. I think the lightnin 351ws were like 8.8-1.
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72FordGTS
Admin Group GTS.org Admin Joined: 06-September-2005 Location: Ontario, Canada Status: Offline Points: 5802 |
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No, there is no mention of the lift spec for the closing points. The best I can do is assume Bubba's info is correct for these specs too.
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Vince
1972 Ford GTS Sportsroof - Survivor, One Family car GTS.org Admin |
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