Budget ohv engine build

[Cov1500]

As a side project I am going to build an ohv engine that will eventually find it's way into my Toledo. It will probably be a 1500 with a single carb (modified 1-1/2" or 1 3/4" SU) with stub stack and original AC delco air filter case (purely because I like the look of it) and pipercross air filter.

I am wondering what other combination of readily available original parts (from other models if necessary) would give the best all-round engine? I am not looking for all out power or expensive machining operations.

[Carledo]

There is an old saying, "If I was you , I wouldn't start from here!" The BEST Triumph OHV engine to work with is the "small crank" 1300, preferably one from a MkIII Spitfire,or failing that, a pre 1970 13/60 Herald. Its stronger lighter, better lubricated and more free revving than any 1500. Its also harder to find these days cos lots of other people know this too!

Steve

[Cov1500]

As I've just sprayed the airfilter case I thought I'd post a picture with the filter and stub stack. I have modified this slightly as I wasn't keen on the contour. Haven't included the modified carb as it is on the car, but it has been altered along the lines suggested by David Vizard.
The inlet manifold has the casting numbers 309104 V3178, I'd like to know if this is the same as the one used on the Kipping 1500?

[cliftyhanger]

I did a budget build on a herald engine a few years ago. I had a slightly tired 1300 out of the car I was scapping, and one with a noisy crank in the new car.

pulled both engines apart, I ended up with 7 matching standard pistons in good condition, and an odd one. Bizarre. 8 conrods.
I head that somebody had lightly ported at some stage, one totally standard. One good cam and followers, the other not. 2 oilpumps, but I used a good sh 1500 pump. I good crank in standard size.

I built the engine up and did some minor blueprinting using the digi kitchen scales, i mixed rods and pistons until I got a set of 4 with a combined weight within 1g of each other.
I had jumble bought new big ends, mains, and bought new thrusts, got 2x +5 in there. Honed the bores and used new jumble bought rings, and likewise gaskets (payen of course)
Total cost including filters was about £25! and the engine was superb, I did 20K plus much of that rallying and autosolo/autotesting, and got lent to friends for motorsport too. Only regret was not sopurcing a mk3 spit profile cam, that would have been a good upgrade.

You can do these engines pretty cheaply if the crank will accept new bearings and the bores just a hone. Single carb is not a bad thing either, Thomason did some articles on his standard spec spit 1500 that he won a couple of championships with and he used a single HS4 during the week, twins at the weekend. Little difference in power and economy (from rolling road back to back data) but the HIF44 was the kipping choice, and prettu sure it was a std dolly 1300 manifold (better design than the herald type)

[Jon Tilson]

If you use that single carb manifold with the OE 1500 style exhaust manifold then it may well foul underneath and not seal
against the head face.

I suspect Thomason and various Spit aficionados would already have ditched the OE manifold and gone 4-2-1, which would have stopped
that happening.

Ive never been in Thomason's spit but I cant see it having the hair trigger throttle response that the twin SU manifold gives and is
worth at least 2 car lengths in any traffic light burn out....the single setup gives a longer path.

Interesting idea though....and you do get a better air filter.

Jonners

[grahamc]

IMG_0129resized.jpg (80.99 KiB) Viewed 2072 times

[I've gone down this route for my MK3 Spitfire - it has a 1500 engine with a single hif44 carb on a modified 1300fwd inlet manifold - the standard air filter case holds a K&N filter element - with the hif44 you don't need a substack. You definitely cannot use a standard 1500 exhaust manifold due to lack of clearance on the single carb manifold so I went with the original manifold from the spitfire / dolomite 1300 range. I've also fitted the 1500 overdrive box and diff to lower the revs. Originally I had a hs4 on a standard dolomite log type manifold and it did strangle the engine slightly from about 3500 - 4000 revs up, but the torque and miles per gallon were great. With the hif44 I can't tell any difference from the twin carb setup other than a better tick over as my carb spindles had worn.

[Cov1500]

That's very much along the lines of what I was expecting. I hope to pull the 1500 (fwd) engine before the weekend, obviously there would be a lot of parts required to convert it to rwd format, so I may need another donor engine anyway. The exhaust manifold on this engine is a cast 4 into 1 (possibly the same as 1300?). The cylinder head is unusual in that it has the large exhaust valve, but I don't know if this is a good thing! It may be possible to use a 1300 head to raise the compression ratio?
I would be interested if anyone has any info on lightest/best flywheel/clutch and what the best standard cam is (other than a mk3 spitfire - is there a similar big journal grind?)

[cliftyhanger]

Fit a low compression (8.5:1) 1300 head to give you about 9.8:1 on a 1500 block.

If you use a spit 1300 head you will end up with too high a CR for anything but a race(ish) cam. Which is hopeless on a road car.

Canleys can supply mk3 profile big journal cams, or go to newman cams direct? Bear in mind many (most?) used cams are beyond their best when inspected...

Have you thought about ignition yet?

And once built the all important session on the rolling road. I have seen "well set up" cars get HUGE gains on the rolling road. ie 40% gain on an excellent 1200 herald (won masterclass at the TSSC event 15 years ago, all built as std spit 1200 engine and tuned. The rollers showed the "correct" needles were far from it!) and my own car form 70 to 91bhp. You just can't do it at home.....(unless you are a genius with years of experience tuning and modifying)

[Cov1500]

Ignition wise I was thinking of just matching the distributor to the 'source' camshaft and using electronic ignition. I will look into getting a mk3 grind cam. If I go this route I think I'll have to go to a 1 3/4" SU.

I did see that someone has used a ford ecs ignition module. I was wondering if the outputs of this could be merged and used to trigger a conventional coil (to keep the period look rather than use a coil pack. If this is possible a trigger wheel could be bolted on place of the front mounted starter ring.....) The distributor could then be used for distributing the spark.

[cliftyhanger]

The ecs module will not (99.99% certain) have the correct advance curve.
If you are wanting power, then some things you just have to get right. A series of " it works" means you end up with a heap of disappointment.
Simplest is to get a dizzy with the correct curve for the cam as you have suggested. Next up is a 123 or megajolt or nodiz. None cheap, all very good though. Don't try reinventing the wheel, it rarely works nearly as well as tried and tested routes. Sad but true (and so many people have the T shirts, I have a drawer full of them)

[Cov1500]

Does anyone know if the oil pump, sump, engine front and rear engine plates, flywheel etc are interchangeable between the 1300 and 1500 blocks?

[cliftyhanger]

yes to sump, pump.
Flywheel can be, holes in teh same place etc but earlier 1300 flywheels had smaller crank bolts. You can get spacer tubes if fitting a 1500 fly to 1300 crank, the other way round you can drill the 1300 fly at home.....
Plates, I "think" they are the same, though I have a suspicion there may be a few odd differences......check carefully.

[Cov1500]

just a quick update. I have (nearly) finished stripping the 1500 engine. So far, so good. Main bearing are just going down to copper in places but not obvious signs the crank is damaged. Big end journals look OK too. Need to separate the pistons/ rods to check little ends, fingers crossed they will be OK. Cam looks OK as well. Going to take one of the piston rings and check the gap top/middle/bottom of the bores to see if there is any excess wear but they seem fine.

Hopefully it'll be a case of just new seals/bearings/piston rings/gaskets and a light hone for the bore to redo the bottom end.

2 very stubborn studs yet to be removed. Anyone have any clues as to the significance of the 'P' painted on the block?