lowering compression

[ken 0]

Well to start with I had bad miss information when I built my Cleveland. I relied on on an old Chilton manual for compression (my dumb ass mistake) . The book said it it was 11.495 when it was only 10 to1. I know custom cam is one way or the pistons. Id rather not do the pistons because there custom and not a standard bore (.4400) $1300. Does anyone know about using Cometic gaskets to lower compression.I read on one site that would only make a minimal difference. I've also read that a 351 C shouldn't be bored over .30 due to thin cylinder walls.I would like to get back to 10 to 1 or 9.5. The problem is in hot weather the engine gets to hot and whats to die at a stop. I'm running as large a radiator as i could stuff in in there with waterless coolant and twin sucker fans and one pusher. Also the timing is correct. Any input would be appreciated.

[barnett468 418]

you can get you all the custom 4032 material pistons you want for around $650.00 for 8 from race tech. 2618 material will cost a little more.

in general, waterless coolant is not as efficient at cooling as plain water or regular 50/50.

 

we need WAY more info.

What heads do you have?

What cc are the heads?

what volume is the top of your pistons?

did you set the timing curve to the optimum level?

does your engine ping?

what gas are you using?

what water pump?

exactly what t stat and t stat setup. the cleveland is different than the windsors.

exactly what radiator do you have?

what is your elevation?

how hot is your hot weather?

does it have any problems in cool weather like 60 degrees or less?

exactly what fans do you have?

 

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[ken 0]

I’ll tell you what I know.

1. 64cc heads iron

2. What volume pistons?

3. Timing optimum yes

4. Pining only when lugging the motor when hot.

5. Pump gas with octane booster.

6. The correct Cleveland stat with skirt

7. Champion alluminum radiator with matching sucker fans and one pusher fan

8. Elevation about 50 ft

9. Portland Or mild climate

10. Water pump is a flow kooler

 The motor has about 300 miles on it. Everything is new motor, trans rearend, front end, steering gear.. you name it, it’s new. I went with the waterless coolant after watching Jay Leno’s garage. I have only previously only put 2000 miles on it in the last twenty years ( have had the car 40 years). I don’t intend to let it sit around anymore. I thought there would be less corrosion using the waterless product.

[barnett468 418]

ok great.

the piston "volume" is the size of the dish or dome including the valve reliefs.

if the fans came from champion they are the lower end of air flow per size/diameter and i for one wouldn't use them even if they gave them to me. spal is one of the best fan mfgs and they have many to choose from. stock USED original ford fans from a v6 contour, or taurus, or lincoln are also some of the best.

based on your reply, it doesn't sound like your compression is excessively high. if it was, it would ping most of the time when accelerating even with octane booster, unless you happen to also be using 95 or higher octane gas.

 

if you have .041" thick gaskets, you could go to .060" thick ones but i would use thick intake gaskets. you may also have to slot the holes on the intake slightly. increasing the gasket thickness by .020" will lower your compression by around .5 but this should not be done on heads that have a quench pad.

 

did they zero deck the block?

do your pistons have a raised dome?

how did you set the timing curve and the vacuum advance if you use one?

when it gets hot does it get hot in traffic or on the highway or both?

if you have a numerical temp gauge, how hot does it get?

champion makes a few different rads, so how many rows deep and how wide is it and is it a cross flow?

your bore is .040 over?

what cam do you have?

do you have headers?

where is your float level set at?  if the float level is high, it will cause stalling at idle when hot and sometimes erratic idle or stalling after stopping moderately quickly.

 

[Alan_Mac 48]

You might want to try 100% gas (no ethanol). What is your timing set at?   With 300 miles the motor, it could be tight.  When my motor was rebuilt it had a big overheating problem. I installed Maradyne dual fans with the shroud that fits a 24" radiator. (~2800 cfm) and it solved the problem.   

[lanky 44]

Semi-off topic but I wanted to mention some, not all, inline 4 contours had the exact same fan setup as the v6's. Why some do and some don't I'm not sure.

If it were me, since you said the engine gets too hot at idle I would start with cooling because that's the easiest to tackle first. 

[ken 0]

yes the block was zeroed

the pistons are not domed

the cam is a comp cam #32-246-4

its a 24inch four core radiator not a crossflow with two 1500 cfm suckers. I also have a taurus sucker fan but it doesn't cover the full surface. Thats why I opted for the twin fans and shroud.

the bore is 4.044

stock exhaust with flow masters headers coming soon

it gets hot both in traffic and highway

Temp gage is an idiot light and generally it will peg all the way over

I have to assume the float is set right along with the timing. Im not a fine tune guy, i have a mechanic for that. 

[barnett468 418]

2 hours ago, ken said:

yes the block was zeroed

the pistons are not domed

the cam is a comp cam #32-246-4 

its a 24inch four core radiator not a crossflow with two 1500 cfm suckers. I also have a taurus sucker fan but it doesn't cover the full surface. Thats why I opted for the twin fans and shroud.

the bore is 4.044

stock exhaust with flow masters headers coming soon

it gets hot both in traffic and highway

Temp gage is an idiot light and generally it will peg all the way over

I have to assume the float is set right along with the timing. Im not a fine tune guy, i have a mechanic for that. 

xlnt. ok, will be back in a short while.

 

 

[barnett468 418]

ok, your compression is around 10.7 if your pistons are flat on top, which is a little high but not horrifically high.

do your heads have a quench pad?

your cam and stock exhaust combined together are likely causing part of the heat problem, and if you install headers, it should reduce the heating problem some.

never, ever, trust an idiot lite or orig gauge. get an infra red gun or better yet a real temp gauge and use that at least until the problem is corrected.

.044" over is probably contributing to the problem a little as well but i wouldn't worry about that at the moment unless the block has a core shift or thin spots from rust inside the water jackets, and the cylinder thickness can only be checked with the heads off.

a cross flow rad would help reduce temps some and a multi pass rad will reduce them even more but the multi pass rads are a bit pricey.

i would also try 2/3rds demineralized water and 1/3rd green prestone anti freeze and 1.5 times the recommended amount of DEI radiator relief and a 16 lb rad cap.

your 1500 cfm fans are unlikely to flow 1500 cfm. i would use a contour dual fan if it fits better than a taurus.

i would also convert the t stat to a brass milodon 180 or 192 and get a bypass plate or modify your original plate with a plug of some kind and drill a 1/8" hole in the center of the plug. the milodon will flow more water and will not close from the increased pressure created by the high flow water pump.

also, if the head gaskets are installed backwards, it will over heat the engine.

 

Less than optimal advance can cause an engine to run hotter than it otherwise would, however, more advance often means more pinging if it already pings even if the engine runs a little cooler with more advance so this type of thing is a bit of trial and error, however, if more advance makes it run cooler but also makes it ping more, you can increase the advance via the distributor vacuum can instead of thru the centrifugal system of the disatributor.

 

IGNITION TIMING

Disconnect and plug the distributor vacuum advance line going to the carb.

Rev the engine to around 2500 rpm then advance the timing 4 degrees and listen for an increase in rpm. If there is a noticeable increase that you can definitely hear, and the engine still runs smoothly, the mechanical advance is less than optimal.

 

 

 

 

 

 

[ken 0]

I misspoke about the pistons, and I don't know the shape. They are Arias #M596012. I tried but couldn't find it on there site. My paper work from my machinist say's 11.5. No Quench pads. I guess i should have been clearer. I changed out the old radiator for the new one it got better, but eventually it would still heat up. At the same time my mechanic changed to a 160 thermostat, not sure which one. i will check the float again and the vacuum advance. i will do this next week when i get my driveline back from being shortened.

[barnett468 418]

Ok unfortunately your 160 t stat is now open all the time rendering it non functional. You need a 180 or 192 but in your case this alone will not fix the problem. You can call arias and ask them what your pistons are but as long as they do not have a dome that is still useful info but more accurate info would be better but it is not 11.5 compression if they do not have a dome.

 

Are you saying that it ran cooler with the new rad when you first installed it but it eventually started running hotter with no other changes? If this is the case, did the weather get hotter at the same time?

[ken 0]

Yes it ran cooler longer with the new set up. I can tell when the the thermostat is opening and closing. I can watch the idiot light get up to 3 quarters and then drop back down. I have a gage but haven’t put it in yet. It goes in the consol where the ashtray would be, and the consol needs to be rebuilt. It’s fine sitting and idling for long periods of time. We checked it out with a inferred laser pointer. As it warms up the hard stops tend to kill the motor. So I will double check the float.

[barnett468 418]

1 hour ago, ken said:

1. Yes it ran cooler longer with the new set up. I can tell when the the thermostat is opening and closing.

2. I can watch the idiot light get up to 3 quarters and then drop back down.

3. I have a gage but haven’t put it in yet. It goes in the consol where the ashtray would be, and the consol needs to be rebuilt.

4. It’s fine sitting and idling for long periods of time.

5. We checked it out with a inferred laser pointer.

6. As it warms up the hard stops tend to kill the motor. So I will double check the float.

1. this did not answer my question completely, therefore, i don't know exactly what is going on with it.

2. you must mean gauge, not light, but that is useful info.

3. i would still install it and duct tape it or wire tie it etc to keep it from flopping around.

4. so if you drive it and the gauge goes to 3/4's while driving, does the gauge go back down if you then stop for a couple minutes?

5.  how long was it running for before you checked it with the infra red gun?

where on the engine did you point the infra red gun?

how hot did it say it was?

where was the needle on the stock temp gauge when you checked the temp with the infra red gun?

6. ok, based on that condition only, it strongly suggests that the float level is too high.

if your carb has brass screws in the side of the float bowls, set the gas/float level so it is around 1/8th inch below the inspection hole immediately after turning the engine off. i check the level with the engine running but this makes a bit more of a mess. either way, put a wad of paper towels or something below the inspection holes to try and keep the gas off the intake. also, wrap a piece of paper towel around the float adjustment screws every time you loosen them, otherwise, it will likely spray gas all over for a second which can be...unpleasant.

If your carb has clear inspection plugs, tell us what the level currently is then lower it until the gas is just 1/4 up the inspection window.

 

.

[barnett468 418]

Do you have a photo of the pistons or the paper arias gave you?

.

[ken 0]

I finally gave up on getting ahold of arias and called my machinist. He Told me arias is no more, and that the owner had passed. He said they were 1.33 domed piston with valve release. After our long conversation suggested to change the pistons out for 9 to 1. He said if I ran race gas the problem would go away, but that’s not practical. The car has always run hot even stock. I think I’ll check out race tech down the road, but will attemp the carb and vacuum advance suggestions you made. Thanks for all the input. If I had to do it over again I would have bought a crate motor. Thanks again

[barnett468 418]

37 minutes ago, ken said:

1. I finally gave up on getting ahold of arias and called my machinist. He Told me arias is no more, and that the owner had passed.

2. He said they were 1.33 domed piston with valve release. After our long conversation suggested to change the pistons out for 9 to 1.

3. He said if I ran race gas the problem would go away, but that's not practical.

4.The car has always run hot even stock.

5. I think I’ll check out race tech down the road, but will attemp the carb and vacuum advance suggestions you made.

6. Thanks for all the input. If I had to do it over again I would have bought a crate motor. Thanks again

1. i talked to arias this morning but they may not have records if you got the pistons a while ago.

2. well, 9 to 1 is a bit low with that cam but you still likely need headers or a smaller cam.

3. The pinging problem would go away but it would still run hot, since it ran hot previously.

4. How do you know that if you never had a numerical gauge on it?

5. Hopefully they will help at least some.

6. No prob, and crate engines are sometimes not great quality, and reputable builders are often the best way to go, but if I was building someones engine and they handed me domed pistons, I would calculate the compression before assembling it and let the customer know if it would run on pump gas or not.

 

.

[1969_Mach1 333]

I don't know what you use for octane booster.  But in interim, until you make any changes to lower the compression ratio, you might try adding something like Torco Accelerator to your fuel. https://torcoracefuel.net/products/torco-accelerator 

It won't help the heating issue, but might reduce the detonation.

[Rsanter 152]

Let me mention something stupid or simple....

could re radiator be clogged? When you rebuild an engine it can often loosen thing in the water passages but not enough to come out of the block. Then after some run time it will come loose and can clog the radiator. I have seen this happen more than once.

whenever I rebuild an engine I always run a gano filter in the top radiator hose for a while and it always ends up with debree in it.

 

if race gas will solve the problem then I would get some and start running that or at least in a blend. Then see how that works

 

if the pistons have a bit of dome to them I would trim the pistons a bit to lower the compression. I have done that several times to fine tune the compression we wanted

[1969_Mach1 333]

I use to run a bend of 110 octane race fuel with 91 octane pump gas back when I could easily find the race gas at local motorcycle dealers.  I didn't have detonation issues, but with 10.7:1 CR the motor ran much better.  Since the race gas is no longer easily available for me I switched to using Torco Accelerator.  With the Torco Accelerator mixed to get 95 octane the motor runs as good as when I used the race gas and pump gas mix.

As far as Ken's overheating issue, I wondered if there is an easy way he can determine if the head gaskets are installed correctly?  It would at least rule out that possibility.  I've seen those heating issues happen on a Windsor (not mine) with head gaskets improperly installed.

Yes, the heating issues could definitely be the items barnett was looking into.  Did I miss something, what carb is on that motor?

[ken 0]

I will give Torco a try. The radiator is not clogged. As far as trimming the pistons, i would rather replace than go down that road. If i decide to change them it will probably be 10-1, that way it will leave room for a fat head gasket if that doesn't help enough. its a holley 650 i believe. I traded my mechanic my edelbrock 600 for it.

[barnett468 418]

3 hours ago, ken said:

I will give Torco a try. The radiator is not clogged. As far as trimming the pistons, i would rather replace than go down that road. If i decide to change them it will probably be 10-1, that way it will leave room for a fat head gasket if that doesn't help enough. its a holley 650 i believe. I traded my mechanic my edelbrock 600 for it.

what octane booster were you using? most boosters don't boost the overall octane by much. if the torco doesn't help enough, one of the best octane boosters is tel which is real lead additive. you can get it on ebay. below is some info.

http://www.wildbillscorvette.com/octanesupreme01a.htm

boostane is one of the other top boosters and they make a street version and professional version. the pro version increases octane more and will even increase hp if you tune for it.

https://www.lsxmag.com/tech-stories/fuel-cooling-ignition-tech/the-big-fuel-test-boostane-adds-24-rwhp/

https://www.lsxmag.com/tech-stories/fuel-cooling-ignition-tech/big-fuel-test-part-5-e85-versus-winner-crowned/

torco has additives that will settle out of it but when the car is moving they should get mixed back in ok.

 

 

the 650 holley will be a little bit small when you put headers on it but it is far simpler carb than an eddy. if yours has vacuum secondaries, you can try different secondary springs to see if you can increase performance. the white spring is the most common one people upgrade to.

.

[RogerC 136]

Recommended Required reading,

351C Performance Tuning and Re-Building.pdf

[ken 0]

Just been using what’s been avialable at my local auto parts store. VP racing fuels octanium. My thoughts too on the carb being a bit small.

[Machman 0]

Flow cooler. I had the same issues. Stock water pump.