Combustion chamber comparison

[travis]

A02217EE-870D-4F02-8D57-762ECAEE556C.jpeg

B18096CF-14D7-46A4-9CB2-70384CB412E3.jpeg

Top pic is the 69cc E5AE chamber, bottom pic is the 62cc E7TE chamber. How much more detonation prone is the bigger chamber going to be?
Getting whatever compression I need is the easy part. I’ve seen too many engines with open chambers like this that pinged like mad even with very moderate compression

[ProPower engines]

I would use the pic on the right.
That said I have seen a mod a guy here posted some years back that cut a small slot from the quench pad center towards the exh. valve to help with cooling and swirl.
I have done this to a few problematic engines and the light throttle ping disappeared. I am only talking about
.050 wide and about.020 deep seemed to do the trick
O sometimes do it for extra insurance on some marine stuff

[travis]

I would use the pic on the right.
That said I have seen a mod a guy here posted some years back that cut a small slot from the quench pad center towards the exh. valve to help with cooling and swirl.
I have done this to a few problematic engines and the light throttle ping disappeared. I am only talking about
.050 wide and about.020 deep seemed to do the trick
O sometimes do it for extra insurance on some marine stuff

I seem to remember reading something about that...I’ll have to look into it. Unfortunately the smaller chamber heads are junk...exhaust seats are beat completely out of them in several holes and I used them for some practice porting. I wish I would have compared the 2 side by side before spending 25+ hours porting the E5AE’s

[Carnut1]

Long ago I got my hands on a 302 carbed limo engine. Flat tappet cam and the big chamber heads. So what was the logic of the bigger chamber lugging a barge around?

[travis]

Long ago I got my hands on a 302 carbed limo engine. Flat tappet cam and the big chamber heads. So what was the logic of the bigger chamber lugging a barge around?

To drop the compression so low that it won’t ping? These big chamber heads came off my ‘87 F-150 351w. Factory rated 8.1 compression, 195@.050 cam, 2 1/4” single exhaust, tiny iron 4bbl intake with a 585 Holley...and they had the nerve to call this an H.O. The only real difference between this engine and the 2bbl engines was the intake and carb. Supposedly this was worth some 70hp...the 2bbl engine was 139hp, and the H.O. was laughingly rated at 210hp.

[Carnut1]

I believe that was the logic. Those sad heads can still be fine for the street with some work done to them.

[Schurkey]

I have seen a mod a guy here posted some years back that cut a small slot from the quench pad center towards the exh. valve to help with cooling and swirl.

A search for "somender-singh" would yield more text than you could read. Might start with https://somender-singh.com/

[ClassAct]

A02217EE-870D-4F02-8D57-762ECAEE556C.jpeg

B18096CF-14D7-46A4-9CB2-70384CB412E3.jpeg



Top pic is the 69cc E5AE chamber, bottom pic is the 62cc E7TE chamber. How much more detonation prone is the bigger chamber going to be?
Getting whatever compression I need is the easy part. I’ve seen too many engines with open chambers like this that pinged like mad even with very moderate compression

IMO, one is just the same as the other. The little bit of quench you gain with the smaller chamber is negligible at best.

If it's detonating it's not that chambers fault.

[Carnut1]

I believe the ports are the same as E7's so the flow will be similar with similar porting. Over 200 cfm would make a good running street mill.

[travis]

I believe the ports are the same as E7's so the flow will be similar with similar porting. Over 200 cfm would make a good running street mill.

I thought they was the same too, but put them side by side and the E7TE is better in almost every way...especially in the bowls. The E7TE’s also have a much smaller smog bump in the exhaust port that is closer to the flange and MUCH easier to grind out.

[PRH]

I would “expect” the smaller chamber to have better detonation resistance, at the same CR.
It’s makes for a double quench situation.

before spending 25+ hours porting the E5AE’s

Yeowza!!

That’s a solid 20hrs more than I could bring myself to spend on porting for that type of build.
You must really like “lightening” those oe ford heads.

You really shouldn’t let something as basic as exhaust seat recession be the cause for passing on a set of cores.
I put exhaust seats in just about all the old iron I work on.

I had a set of some version or ford 289 heads here last year where some of the exhaust seats were receded real close to a 1/4”.
Some of, if not the worst I’ve seen.
Had some Pontiac 670 heads that were just about as bad last year too.

[travis]

You must really like “lightening” those oe ford heads

I did for a moment. The moment passed

[PRH]

Sounds like those E5’s wore you down.

Gotta pick your battles....... and choose wisely the jobs that are “25hr worthy”.

[ProPower engines]

Long ago I got my hands on a 302 carbed limo engine. Flat tappet cam and the big chamber heads. So what was the logic of the bigger chamber lugging a barge around?

Mostly because companies will by the car as a 4 door then the extention work is done. They never thought about using just the base model car's performance to haul an extra 4000 lbs of extention.
We had several over the years come into the wrecking yard that were crashed hard and the early limo's conversions just had the basic feature package that included an engine that was not really up to the task of hauling that barge down the hyway.
A local limo company that had a fleet of caddy's also had some Ford LTD conversions in the fleet said they were only used in the city as they sucked fuel bad on long hyway trips and the engines did not last long when used for hyway trips.
And the carbed version would just suck in the power dept. even the early injected engines would have lacked power
but the main reason was to save ential cost on the car purchase by ordering an option stripped base model back then.

[ProPower engines]

I have seen a mod a guy here posted some years back that cut a small slot from the quench pad center towards the exh. valve to help with cooling and swirl.

A search for "somender-singh" would yield more text than you could read. Might start with https://somender-singh.com/

Thats the same basic idea. An angle slot cut in the quench pad towards the exhaust valve.
There shows a guy with a file in the you tube vid. of the Singh character's mods but the same idea applies.
I have tried it on some open chamber heads and the results were impressive. I tried this on some
ford 460 heads used for marine applications by mercruiser on their 3.7 Lt 4cyl. engines that use a single 460 head.
Detonation issues that plague these engines were eliminated to the point where the compression at 9.5-1 was gone where
Mercury marine just used a thicker head gasket to reduce the detonation issues these engines have.

About to do the same deal to some 400 M series Ford heads and see how that goes.