ShopTalk Forums | Aircooled VW Tech & Restoration Help

I have built a 1600 cc Engine based on a new crankcase, Chromoly 69mm crank, race bearings,race rods 5.4" CB, Ingle 200 Cam ( stage 2) Lightweight Lifters, cut to measure pushrods, Mahle P & C , 1.25..1 Rockers, CB 44 1396 Heads, 55cc chambers, 40 X 35 Valves-- 0.60mm Deck Heights ( tight I know) . Straight cut cam gears. The engine is showing only around 100 psi on compression check--will not run --attempts to fire on No 2 cylinder only. Carburetors are Weber Style 40s with 130 mains & 52 Idles hand balanced on the bench & run well on an alternative 1600 standard engine.

Stripped down the engine again suspecting cam timing etc --but no such luck--cam timing is spot on --no joy--rebuilding again but a little puzzled as can't find the real problem. Everything is brand new in this engine .Any input from anyone gratefully accepted--deck height is far too tight of course --but I can sort that easily--however my CR will drop and its not as expected

Just a passing thought, if you're using Bosch plugs made someplace other than Germany try some NGK's for your application. Ainokea

Thats far too simplistic its nothing to do with ignition--found the problem in any case misground exhaust cam lobe

A 7.2:1 static compression ratio with a long high RPM cam probably won't run much better ground right.
.060 is about right if you are running a V8 with a 4+" bore to 7500 all day long, with some margin for missed shifts.
What kind of rev limit/usage do you expect? What do the heads flow?
Why do you think .060 deck is remotely a tight deck?
(Admittedly, I burned my little blue book a long time ago)

Google had no luck on an Ingle 200 cam, or "ingle camshafts" for that matter.
Similar to a Sig Erson 200 by chance? Have a cam card?

Drop the main jets to 115 for a 1600cc

OvalFast wrote:Thats far too simplistic its nothing to do with ignition--found the problem in any case misground exhaust cam lobe

ONE misground cam lobe will not make it try to start on one cylinder only.Should fire on 2 at least.Keep looking

Have you checked the ignition system. A bad cap, rotor, if you are using points and condenser try replacing them.

Check your ground by using a jumper straight from the ground on the battery to the block.

Do a dry fire by pulling a plug one at a time then putting a plug on its spark plug and grounded against the engine block/case then turn the engine by hand to see if the plug fires. I've had new plug wires and plugs out of the box that were bad before.

Very basic things to try if you already haven't; you might not find anything but then you never know what you are going to find.

.6mm = .024".

1mm (.040") is the minimum safe piston deck IMO. I've taken apart comparatively mild 1600SP offroad engines (limited to a single stock carb and virtually incapable of exceeding 5000 RPM) which were built with .040" deck after only a couple of races and found frightening signs - .016" less would be foolhardy.

From a distance it's all just speculation, but I'd start concentrating on why it's such a lousy air pump - 100 psi cranking compression is abysmal. First thing I'd look at is the accuracy of the indexing of the straight-cut cam gears by verifying the valve action matches the cam card. If you don't have a cam card, at least confirm that it's not far from "split-overlap" (a few degrees advanced from there is common with some grinders, but I know of nobody who builds in any retard - and retarded cam timing would be consistent with low cranking compression.)

Marc is correct on checking things like the cam timing out. Here is the site for Engle VW cams if that might be of any help: http://vwparts.aircooled.net/VW-Engle-Cams-s/1012.htm.

Yes, I agree with Marc that the clearances need to be checked also.

I am not sure on this but could the cam have been installed on the gear wrong which could affect the cam timing or is it possible that the gear is off?

With what I think you are saying I would go back to basics on this. I think I would find top dead center for cylinder #1 of the crank, make a marker for indexing and start checking things like the cam timing from there.

If one valve was wrong then check the others. After a valve job a lot of guys hand lap the valve into the set.

If you have a compressor then you could use it to see if the valves seat by blowing air into the spark plug hole (you would need an adapter) and see if it hold pressure or not. In this case you would check the carb and the crankcase vent for blow-by.

I hope this helps.

I have to stop posting at 4AM, I repeatedly read that as .060" deck.

I ran .023" in a 1700 T4 for several times the mileage T1 engines usually last, but limited to stock redline.
On a high revving motor, .050 is a better plan.

Piledriver wrote:...I ran .023" in a 1700 T4 for several times the mileage T1 engines usually last, but limited to stock redline.
On a high revving motor, .050 is a better plan.

Yes, a Type IV has a much stiffer bottom end and you can get away with less - even without head gaskets.
On a Type I with a smallish bore and normal piston-to-cylinder clearance I'd stay at .050" or more for high-RPM use on any motor that was planned to be left together for a long time...more clearance means more piston rock at TDC, and a larger bore means the piston will come closer to the head when it rocks, so for bigger/looser motors even more is wise...but there should never be a need to exceed .060" in any case.

For this combo I'd recommend .050" minimum...the static C.R. will drop by ~.4 (depending upon where you're at now), if that's all that big a deal for you the heads could be kissed ~.025" to get it back up. That'd also make the ideal pushrod length unchanged.

Problem solved chaps many thanks for all input installed an Ingle 100 kept the deck height, in fact, reduced it slightly, no issues or concerns there --fly cut the cylinders heads to achieve 50 ccs was 55ccs CR 7.8..1 pressures 140 PSI all ok runs well--fully balanced CB Chromoly crank was installed as were race 5.4" rods cylinders shimmed accordingly - reduced the jets to 120s & 50 s seems good for now. The original lack of cylinder pressure definitely down to camshaft being well off on exhaust grinds-- worse on 1-3 than 2-4 by quite a margin--never saw that before. Cheers job done -engine installed & flying. Thank's Marc also v good your points noted

Someone asked about 60 thou , not thou I was measuring mm s actually 0.55 mm & it runs high rpm at that figure that's why I said a bit tight--I'll re-shim as heads now flycut to 50ccs giving me some leeway to adjust CR yet maintain clearance shooting for 1mm if the maths work out

if and when you pull the heads to adjust your head to piston clearance, please take pictures. we think the piston will touch the head at 0.55mm [.02165in].