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pjsmetana
07-06-2009, 08:02 PM
I re-did my compression test with the 30wt oil in the chamber. Almost a 10psi jump in 1,2, and 4, and almost a 30psi jump in cyl 3 (the cylinder I was @ 70psi on before). I could go with just replacing the rings... but since I'm gonna be in there... heck with it! Lets go for some performance! and keep it mostly streetable.

So here starts my 1st stage. Planning. I expect to start this about a month after I move, so Start time of 4 months from now would be perfect. I'll post in stages as the time for each part of my build comes.

So, heres my 1st set of question on this:

What should I get?
I know what parts are needed, but I'm not savvy on brands for British engines that have been proven reliable.

What compression ratio should I shoot for?
I read that my compression ratio is 7.5:1 stock, and clearly thats too low.

Square build: Over, even or Under? (Stroke or revv for those who arent up on squares)
I don't know how high of RPM the transmission can handle, but I REALLY like rev happy high RPM engine sings (even if that means narrow power band). Although I do plan to get the Ford or Toyota transmission, so it probably don't matter.

Should I forget building the 1500 and get a 1300 and build that?
I hear the 1300s are much more rev happy and great for racing... but I still want this streetable. I need to be able to sit in traffic and not overheat or rattle to death. Right now I have that, but I don't have much power at all.

Maybe someone has done this all already and has a listing of Cam lobes, Valves, head mill specs, crank specs, brands, and so on that they could share?

70herald
07-07-2009, 12:25 AM
take a look at this first:

https://www.totallytriumph.net/spitfire/engine_building.shtml

You should take a look at what has already been done to your engine first in order to decide how to proceed. If the 1500 block still has standard pistons, and the bores are in reasonable shape you could just have it bored out to the next size. With the 1500 the first real improvement you need is to have the rotating bits properly balanced.

Trevor Triumph
07-07-2009, 12:42 AM
We, my wife and I, took the her 1500 engine to a shop- they milled the block, cleaned, ground, and polished the crank. They balanced the the new 9:1 pistons and connecting rods. We added a European intake manifold and HS4 SUs from TSI, added an electronic ignition, and bought a four into one header. The car runs well- freeway speeds and some grunt to get up hills.

pjsmetana
07-07-2009, 05:54 AM
70herald - that link is fantastic! Thanks.

billspit
07-07-2009, 07:52 AM
The 1500 has more torque and is a better street engine than a 1296. But, it doesn't like to rev so you won't be playing Speed Racer.

NOTE...Putting 9:1 pistons in the engine doesn't result in 9:1 compression. It also takes the European cyl head to do that. What I did was have my head shaved about .050. I was shooting for 9.3:1. No idea how close I got. I too got a European exhaust and intake. Still working on the carbs though. I got HS4s from Hap Waldrop that likely came off an MGB. Curto says I need different float chambers so I'm kinda stuck right now.

The 1500 has the mildest cam of the Spit line. I went with a 270 cam from BPNW. Also got their better quality lifters. The small crank 1296 has a very good cam grind to it so I've been told. The deal is you don't want a big cam in a 1500 unless you are racing.

For bearings I went with King Trimetal bearings. Too hard to find the CORRECT Vandervell bearings any more. Big problem is the thrust washers. Most folks think the brand most available now are crap. I would now try the special ones that appear on this web site in references.

As for overheating, build it, run it and keep an eye on the temp. Add a good puller fan if needed. Flush the old rad as a precaution (professionally). Griffin Radiator can make you a custom rad for not a whole lot of money in copper and brass.

Andrew Mace
07-07-2009, 08:33 AM
The small crank 1296 has a very good cam grind to it so I've been told.True, so long as you're talking "early" US Mk3 or home-market spec. cars with the FD series engine. The FE (1969-70 US-spec. emissions) engines had a much less desirable camshaft.

billspit
07-07-2009, 11:38 AM
Small crank = FD. Large crank = FE.

I think.

Andrew Mace
07-07-2009, 12:43 PM
Small crank = FD. Large crank = FE.

I think.

Sorry, no. Both those (and the ultra-rare FF blocks, found in US-spec. Herald 13/60s destined for Puerto Rico) are small crank. FH, FK and FL are large-crank engines. There are probably others, such as those found in the 1300 fwd sedan, but the F-series from Spitfires are most common in the US.

tomkatb
07-07-2009, 02:04 PM
I did what Trevor did. 9 to 1` compression pistons. Shaved the head a bit. Quality 3 axis valve job. Balanced pistons. Crank reworked. Dual HS4's and 74 exhaust manifold.

Car runs much, much better. The shop that rebuilt it has built many. He discouraged me from hot stuff. He said the crank cannot take it. The last 100hp motor he built lasted 30 days. He quit racing his because of this. He went to Midgets.

On my engine the cam was shot and there was crank knocking.

It is a different car now. Enough power to be fun. It will now turn 4500 rpm happily.

Larry

billspit
07-07-2009, 03:46 PM
Small crank = FD. Large crank = FE.

I think.

Sorry, no. Both those (and the ultra-rare FF blocks, found in US-spec. Herald 13/60s destined for Puerto Rico) are small crank. FH, FK and FL are large-crank engines. There are probably others, such as those found in the 1300 fwd sedan, but the F-series from Spitfires are most common in the US.

You are obviously much more knowlegible about these engines than me. I thought the engines on the later Mk 3s had the bigger crankshaft and used the single Stromberg intake. Same as went into the Mk IV. Am I wrong about this too?

Andrew Mace
07-07-2009, 04:02 PM
You are obviously much more knowlegible about these engines than me. I thought the engines on the later Mk 3s had the bigger crankshaft and used the single Stromberg intake. Same as went into the Mk IV. Am I wrong about this too?Sorry, but I think you are -- about the crank, that is. :frown:

But yes, the 1970 US-spec. Mk3 did go to the single Stromberg for emissions purposes.

pjsmetana
07-07-2009, 05:53 PM
I started a really rough build plan on a notepad while on break at work. What I'm missing most of is the stock specs, like Bore, Stroke, Cam Durations, chamber volume, so on. Anyone have the list of stock specs as such?

Don_R
07-08-2009, 07:58 AM
Pete,

This is the info from my motor heratige disk.

Bore 2.9" 73.7mm
Stroke 3.44" 87.5mm

Valve timing
Inlet open 18 degree BTDC
close 58 degree ATDC

Exhaust open 58 degree BBDC
close 18 degree ATDC

Should be a 9.0:1 compression motor


Hope this is of help to you

pjsmetana
07-08-2009, 10:14 AM
Should be a 9.0:1 compression motor



Are you sure? Everything I've read about this year 1500 engine (US spec) says 7.5:1 due to emissions.


How much can I mill the head without needing shorter push rods? is .050 too much? Seems like that would be borderline.

Anyone have the displacement formula available to post here? I know its something like

((Head Chamber Volume + Cyl Volume BDC)-(Head Volume + Cyl Volume TDC))x # of Cylinders = Displacement

But I cant find it in my notes... silly me

Don_R
07-08-2009, 12:00 PM
Pete,

According to the info I have. The U.S. cars had a 9.0:1 and Canada cars had a 7.5:1

Possibility exists that they listed the info wrong.

IMHO .050 should be no problem. The adjustment on the rocker should have enough room to make up the change.

I am looking into the same thing you are. I have a big bearing 1300 and am looking into what i can do for a rebuild. The motor need more power, 48 HP just ain't cutting it.

Don_R
07-08-2009, 12:23 PM
Pete,
From a discussion over at the NASS page.

73 Large Valve head

Chamber cc Just over 51cc
Milled the head .100"

New chamber just over 41CC

Andrew Mace
07-08-2009, 02:01 PM
...and some information regarding compression ratios of the "1500" engine (mistakenly cited as 1492cc when it should read 1493cc), in a chart from TriumphSpitfire.com (https://triumphspitfire.com/enginenumbers.html). This chart seems to confirm what I've long heard: that for the 1976 model year ONLY, compression ratio for US-spec. engines was 9.0:1; otherwise it was 7.5:1 for the "Federal" 1500 engines.

pjsmetana
07-08-2009, 05:36 PM
...for the 1976 model year ONLY, compression ratio for US-spec. engines was 9.0:1; otherwise it was 7.5:1 for the "Federal" 1500 engines.

What was different about the '76 engine compared to the rest of the 1500s?

If its simple as domed pistons, then this project will seemingly be a breeze.

So far heres what I've decided to get done:

-Mill the head (.050-.100, however far I can go and maintain stock rockers and pushrods
-Shotpeen the connecting rods
-Have the crank polished and check it for straightness (and Shotpeen, Nitride, Tufride, or Cryogenically freeze it)
-replace all bearings and low end bolts
-gapless rings (from totalseal.com)
-Larger bore, not too much larger, just to whatever the next available size up is to match pistons (I'd love to match the stroke @ 87.5mm but thats probably WAY overkill, so I'll probably aim for 75-80mm or so)
-Triumphtune Fastroad cam, the 83 or 89 depending on grind height, as shorter will mean I can mill the head a wee-bit more
-1.475" intake valve, and head machined to match, with 3 angle grind
-Change my carb from the single Weber DGV to twin Weber DCOE 40's, twin SU 40's, or maybe the Mikuni's if I can find a decent price
-Have the block chemically dipped, and possibly cryo, so on
-light weight flywheel (I know this don't add power, but Ive had one in the past on a diff car and I loved the difference in how the engine felt)

Looking at possibly the change to a Duplex timing chain as well. I hear I can get the double-wide chain gears off a TR6 and they will match. Can anyone confirm this?

Also thinking of going with an electric water pump. Computer or thermostatically controlled depending on price. Sounds worth it for roughly a 5% gain. Does anyone have this?

Does any company out there make a stronger than stock crank at a decent price? I was thinking about calling Eagle up for this, as I've had their X-beam rods before and I was quite pleased with them.

I hear I can/should ceramic coat my valves and exhaust port. Does this make any effect on the ability to lap the valves properly prior to installation?

Andrew Mace
07-08-2009, 07:50 PM
...for the 1976 model year ONLY, compression ratio for US-spec. engines was 9.0:1; otherwise it was 7.5:1 for the "Federal" 1500 engines.

What was different about the '76 engine compared to the rest of the 1500s?

If its simple as domed pistons, then this project will seemingly be a breeze.I think that was it, but I'm not as well versed on the 1500 engines.



-gapless rings (from totalseal.com)I can't tell you much of anything about the rest of your list (other than to maybe get a copy of the Competition Prep. Manual), but I can vouch for the TotalSeal rings. Years ago, I overhauled a .020-over, "race-prepped" 1147cc Spitfire engine, due to the fact that the rings on the #2 cylinder had broken, turning the engine into a great oil fogging machine. :frown: Fortunately, there was no damage to piston or bore, so I was able to hone the cylinders and reuse the pistons. I bought a set of Grant rings from TRF and sent them to TotalSeal for conversion. Decent price, quick turnaround...and great performance after a quick break-in!

Don_R
07-08-2009, 08:13 PM
Pete,

The talk on the NASS pages about the 76 1500 engine came to the consensus that the difference was using the flat top pistons and the head was milled .050"

Several different heads were measured including a european head and the measurements seem to confirm the theory. A stock 7.5:1 head being 3.10" thick and the 9.0:1 head being 3.05" thick.

The milling counts for 4CC and the dished pistons have a 6.7cc recess. The net change should being the motor up to 9.3:1 or so. Close enough for the factory to claim a 9.5:1 ratio.

mikecyc72usa
07-08-2009, 09:39 PM
This is what I've heard, but it doesn't answer one question: Were the pushrods the same length as on other years? Or were there 1976 specific pushrods?

There are numerous heads that came on the 1300 and 1500 engines, and they are all interchangeable, but that doesn't mean you should interchange willy nilly or you can end up with too high or too low compression or trade down to smaller valves. If you are keeping your basically stock North American market engine setup, then no point in looking for another head--just tidy up the one you have. But if you want to do a little more and will be improving the flow into and out of the head (better carbs and intake manifold, and a decent exhaust), then finding a "big intake valve" head from a world market late 1300 engine will yield 8.9:1 or so on a 1500 with dished pistons--an upgrade that'll require no messing with the bottom end to change to flat-top pistons. Shave about 0.040" off this same head, and voila--approx. 9.5:1 compression, which will do fine on ordinary premium pump gas and a reasonable ignition map and not knock. There are a few other "big intake valve" heads to choose from, but for most you'll also need to switch to flat top pistons to help raise the compression enough to help. But as has been said, without some other mods, this upgrade would yield little improvement.

The combustion chamber volumes of your 75 and 78 heads (I suspect stamped (not cast) with part numbers TKC 1409 and TKC 3239, respectively) are the same (on the order of 45cc per cylinder per head chamber only--not counting the deck clearance volume and piston dish volume). This and the dished pistons make a 1500 engine 7.5:1 vs. 9.0:1. If you decide to use the 75 head with the air ports, remove the little air injection tubes before you plug the holes to improve airflow.

This was posted by Paul Geithner some time ago somewhere, and I saved it for reference. Hope it helps!

pjsmetana
07-10-2009, 11:04 AM
Thanks guys! Lets keep this going, as I'm quite sure I wont be the last one to do a rebuild like this.

Don_R
07-12-2009, 10:28 AM
Pete,
Some more of the engine discussion on the NASS forum

The big journal cranks, while heavier, are also stiffer and stronger than the small journal cranks.
The real problem is the big journal rods, they are apparently made from the heaviest metal known to man.
Typically they they run 775-800 g (for a 48 HP motor!!!!)

The solution is straightforward, lighter rods, flat top pistons, the usual port'n'polish, cam, headers, dual SU's.

Turns out that the stock big journal rod are 1.875 stock.

You can find (on eBay) ex-Nascar H beam rods that use the very common 1.850 bearing, weighing about 500g, for about $200/set of 8. Each rod is capable of supporting 75-125 HP at 8K RPM.

So turn the journals to 1.850, and use the H beam rods


The stock Spitfire rods are 5.75 C-C, and the deck height is 8.75".

So you can use SBC 5.7 rods and stock 1500 pistons with a 1500 crank, or if you go with a 1296 crank, use 6.00 H beam rods, and 1500 pistons, they pop up about 0.020", so you might not even have to skim the head.

Why would you choose the 1296 over the 1500?

So you can turbocharge it and run higher revs, of course!

The longer rods yield a bit better mechanical advantage in a motor, which equals more torque.

The advice to fix up the oiling system is dead on, but you should also put 0.050" restrictor sleeves into the cam bearing galleries. This helps to maintain oil pressure/flow to the mains and rod bearings.

With these mods, even a 1500 can rev reliably to 7500 RPM.

billspit
07-12-2009, 05:55 PM
With these mods, even a 1500 can rev reliably to 7500 RPM.


You sir are the first person I've ever heard say that!

I'm going to bookmark your information.

Now a stupid question. If you turn the crank that much, do you have to get it nitrided? I've read that turning cast iron causes it to harden anyway.

Never mind, My math skills are usually turned off on the weekends. It isn't that much.

pjsmetana
07-12-2009, 05:58 PM
Groovy Don, thanks! I keep on reading more and more about how the 1500 engine is the way to go. Right now I'm looking into bore options. I think I might be asking Michael Oritt (when he gets back) about the bore on his Elva's engine. It's a 1500 bored to 1600. His race engine seems really reliable, which should prove fantastically fun on the street, if I go with similar specs.

Don_R
07-13-2009, 07:25 AM
Just trying to do my part in helping you spend your money, Pete. :thumbsup: