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maguey123

302 to 351c, help a young fella

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Hey fellas, I bought a "351"c for 250$ was originally 600$ but I got there and was seized so got it for $250 and unseized turns out to be a 302, I am underway of making a 351 and have bought my crank from a local guy for $250 and now need a grind. I'm only a uni student so trying to keep the budget down. I'm chasing alot of low down torque as this is for a f350 not falcon (been reading some threads and you guys have alot of knowledge on engines).

 

Spoken to the local engine builder and he recommends the 351 crank with 302 rods combo (he'll order the pistons in for me cheap, sadly will have to buy new rings tho so much for budget build) but I plan on using the 302 heads for the more efficient burn and more torque, currently bored 40 though over and the cam that came with it I can't identify, this engine was rebuilt before I bought it, still has hone marks. The only identification I can find is posted in the photo. I'd like to know as this will help me determine to keep the 302 heads or go for the 351 heads. 

 

With 58cc heads a 40thou thick compressed gasket and -3cc pistons, havnt taken into account deck height I'm getting a 12.05:1 static cr. I'd like to run on atleast 95. Happy to die grind some of the head chamber if necessary.

Screenshot_20210405-180436_Gallery.jpg

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PC314 Dynotec cam.?  Very standard.  

 

Budget, ....hmmm....   302 rods in a 351, needs special pistons. ACL used to make them, not sure anymore.  Been a while since I've seen anyone use them, nowadays if you're after a torque monster, stroker kits are the way to go. $$$$

With a high compression ratio, you may have to run 98 Premium to stop it pinging. Up to $1.80 a litre..! 

New cam means new lifters, more money.

Rings are cheap and easy.  Buy a good standard volume oil pump, and double row timing chain.

 

Not trying to put you off, just think about where you want to spend your limited budget. A fresh, slightly warm cam in a 351 with stock crank and rods, will give you thousands of trouble free kays, with flat tops, and 302 heads. Spend some money on the heads, EG: valve guides, stellite seats, double springs etc..... 

 

Welcome on board, by the way. Good to see you have interest in an old Effie. 👍

 

 

 

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Old mate said he'll order them in wholesale for me and the price of 351 rods are about 250-300 a set and the hypatech pistons on eBay to suit the 302 rods are 483 so I imagine he can get them for 300ish direct and new rings are the go. I use 95 or 98 now anyway as the current 302 in it I built over Christmas but just not overly happy with it. Uts probably not happy with me tryna push around 3.2t. I mainly use it for work as I have a motorbike for a daily to and from uni.

 

The cam thankyou! I tried pc314 but couldn't find anything but dynotech it comes up straight away! 

 

Stage 1 (PC314) or CM314D
208* I & 208* E @ .050"
.484" I & .484" E lift
1500-4000 rpm
 

 

The timing chain is double row and is still very tight.

 

Cheers mate, bought my first when I was 14.

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Cool.

 

302's aren't very economical (in my humble opinion) as they are basically a de-stroked 351. The Yanks have never even heard of a 302 Cleveland. Mind you, they only had the Clevo for a few years, 71-73 Mustangs, F -trucks, etc... We had them from XW to XE, basically 1970-1984 ish.  

 

Let us know what you decide, do a little research, and add up some dollars.  Keen to see the old girl, if you have any pics.?

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Yea hard finding info if I forget to add the cleveland key word ahaha.

 

I've been doing research and speaking to afew fellas I know, getting the calculation for the dynamic comp ratio is difficult, every site I try says a different answer. So far all of them have been over 9.5 tho! Need to get it down. I've bought the full gasket (learnt yesterday not felpro but rockets own "proformance gasket" brand) set from rocket and I have just emailed them to try and find the compressed thickness of it. I'll cc everything tomrrow arvo hopefully to try and get more accurate.

 

Using felpro specs and 58cc head volume I can get a 10.7 static, not sure if the pistons come in a dished version, if not I might be doing some lathe work!

 

I'll add a pic tomrrow!

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A cheap and simple combo tow combo I've often advised people on is one i used to have in the 351 in my customline, it was nothing special but the combo is the key, I used what was essentially a re ring and bearing stock 351 short engine and pair of 302 cc heads with the chamber layed out slightly (i can't remember how much but I ended up with 10.5:1 static comp) a comp 268h and valve springsto suit, torque power dual plane air gap intake, 600cfm edelbrock and a pair of exhaust manifolds (i did later run some yella terra bolt on roller rockers, they didn't make any more power but they made valve float happen about 700rpm later and valve spring retainers lasted longer, ideally I should of put decent retainers and collets in that engine but I had a large bucket of stock retainers I kept in the boot, and I got so good at changing them on the side of the road that I could do a pair in 15 minutes) it made 235hp and around 385 ftlb at the tyres through a c10 with a 2200 stall and 3.5 gears, it made peak torque at 2k rpm and fell flat on its face at 5500rpm, the car was amazing for towing and ran a flat 14 at Heathcote and would shred tyres with 6 people in the car in top gear at 2500 rpm, I like the 268h for budget builds as it doesn't require a high stall, bolt on rockers can be used with it (machining clevo head for screw in studs can get expensive) and it is designed to be a rv cam so it make bulk torque at low rpm, its a cam that doesn't require extra machine work on the heads so that saves a ton of budget

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........waiting for a bite from [mention=244]gerg[/mention] 
Ok you got me bear

All good advice here... I can vouch for that cam being a baby one. Good midrange punch with the narrow LSA, easy on rockers and springs with such low lift. I have that exact spec cam in my 302 but advanced 4 degrees (to give it better low down torque) but yes as mentioned, will nose over very sharply just after 5k. I would gather that you'd get 250 HP at the treads with this cam on a 351. My 302 got 196hp through a manual, on a mainline dyno (not as "happy" as other dynos generally)

40 thou is getting iffy on a clevo, most will advise never to go past 30, and on blocks this old, to get them sonic checked. It's extra expense, yes, but no point in doing even a light freshen-up if it's going to split a bore.

12.5 comp doesn't sound right to me. I know it will go up a bit with closed chambers vs open, but I think it's more like 10.5. You need to add in deck height, as most hypereutectic rebuilder pistons sit down the hole quite a bit so you add that to the effective chamber volume. Also piston dish has to be added.

I have noticed that mine likes E10 the most out of all the fuels. It hates 91 (pings its arse off). 95 and 98 it runs ok, but drinks shitloads of each. We have to remember that fuels these days are 100% designed for fuel injection, and in the fuel companies' eyes, carburettors don't exist. Mine loves heaps of timing so I think a bit more comp will be ok. Mine sits at about 10:1 with a 0.025" head skim. If going up in cam size, comp will be even less of an issue for you.

http://www.wallaceracing.com/cr_test2.php

Have a play with that compression calculator. It's from a Pontiac specialist website but it works and their other calculators are pretty useful too. The dynamic comp calculator is great, this is what you build your engine around (using cam specs).

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Thanks for all that, with the cam being small wouldbit still be enough for the 302 heads or do I need more bleed off? My 302 is currently at 40 thou and goes okay thus engine I'm tearing down was rebuild built and at 40 thou so no point for me to chase another block. I have been playing with that site but does it use ivc at 050 or 006. Thanks

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Thanks for all that, with the cam being small wouldbit still be enough for the 302 heads or do I need more bleed off? My 302 is currently at 40 thou and goes okay thus engine I'm tearing down was rebuild built and at 40 thou so no point for me to chase another block. I have been playing with that site but does it use ivc at 050 or 006. Thanks


Most cam companies quote cam timing at 0.050" lift because that's the point where any appreciable flow starts to occur. Before that, it's negligible and 0.006" specs are only given to take into account pushrod and rocker flex, oil clearances, etc . Also to demonstrate the amount of cam ramp up; the 0.006" duration will be a lot longer than at 0.050" if it's a stock-type, flat-tappet grind. You'll notice on hydraulic rollers that the advertised vs 0.050" figures are much closer because the ramps can be made much more aggressive.

So to answer your question, you'd enter your specs at 0.050" lift (if you have them handy). You can calculate the intake valve closing event at 0.050" from the other calculators on that page (assuming the cam is a symmetrical pattern), inputting LSA, etc.

After a lot of reading about dynamic comp, an ideal figure for a street engine is around 8:1, getting up around 8.5 for a well-prepped, closed-chamber engine, up to 9:1 with an alloy head and racey fuel. Going too high in comp is an exercise in diminishing returns. Once you get up to the ideal, going higher only causes more problems for very little gain in HP.

In my opinion, you should start with a camshaft and build the engine around it.

If you want to use the cam you pulled out, make sure you keep every lifter in order so they're going back on the lobe they ran on. If you've mixed them up, throw the whole lot in the bin. One wiped lobe will mean a full engine pulldown to get all the shavings out. Trust me on this one, I've wiped 2 cams in 70,000km.

If going for a new cam, Thom's recommendation is sound, as well as some offerings from Elgin (low-end and OEM spec cams) which some folks on here have used and have had good results with. I've used Crow and Precision's house brand (forgotten the name) but to be honest, I wouldn't mind an upgrade soon as I was a bit disappointed at the HP I got from the 208/208 I'm running. Great torque, just falls on its face after 5000.

Some good rules of thumb:

* Stock rockers and springs don't like lifts much above 0.5"

* If you want to take your engine past 5000, or upgrade the cam, or go up in lift, you need to upgrade the valvesprings.

* a narrow LSA will give a narrow powerband, a wide LSA will give a wide powerband. That's why towing cams have a pretty tight LSA. They're made for midrange.

* The small parts will be what cost the most. The engine itself is pretty simple. Carb, coil, dizzy, plugs, leads, gaskets, nuts, bolts, water pump, alternator, all add up.

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You guys are so knowledgeable, I loving it, I am aiming for the 8.5, I kept all the lifters with a number in the bottom according to their position.

 

The cam is a dynotec pc314 which is the same as a crow cam 21602, it has the 208 and 208 as well, this is abit small but it's I the range I would like, I never really rev past 4k (if that aha) I've always driven diesels and hurts me to rev that high.

 

If I can't get the comp low enough I might get some small dishes machined into the pistons, I have decided to get the 351 rods as it'll be a cheaper alternative to new pistons and rings when these pistons are still good and the rings are still good too. 

 

Been struggling to find a place to do a crank grind for a reasonable price, local place wanted 880 plus gst and cleaning fee but a fella on a Facebook group has kinda got me sorted with a 300$ for crank exchange for crack test, grind, and polished! Hopefully doesn't fall through!

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You guys are so knowledgeable, I loving it, I am aiming for the 8.5, I kept all the lifters with a number in the bottom according to their position.

 

The cam is a dynotec pc314 which is the same as a crow cam 21602, it has the 208 and 208 as well, this is abit small but it's I the range I would like, I never really rev past 4k (if that aha) I've always driven diesels and hurts me to rev that high.

 

If I can't get the comp low enough I might get some small dishes machined into the pistons, I have decided to get the 351 rods as it'll be a cheaper alternative to new pistons and rings when these pistons are still good and the rings are still good too. 

 

Been struggling to find a place to do a crank grind for a reasonable price, local place wanted 880 plus gst and cleaning fee but a fella on a Facebook group has kinda got me sorted with a 300$ for crank exchange for crack test, grind, and polished! Hopefully doesn't fall through!

Yeah it sucks that engine reconditioning has become a niche industry, as opposed to the old days when a vehicle would go through 2 or 3 engines in its life and there were plenty of mobs around that would do that work. Nowadays, the only machinists/builders left can pretty much name their price.

 

$880 is an insane amount. There's probably a couple of hours max in that job, I've worked at a reco place and the crank grinder would pump out cranks all day long.

 

Also, consider just carving a bit out of each chamber where the quench area meets the open bit. You could take outba few ccs there. Costs you nothing and no piston thickness to worry about.

 

Sent from my CPH1920 using Tapatalk

 

 

 

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