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Phill
09-04-2016, 12:57 PM
My engine is a 1300cc twinport that I bought of ebay last autumn. I have tried to start the engine but it is suffering from very low compression on three of the cylinders and no compression on the fourth. Squirting oil into the bores and re-testing results in better compression and a low reading on the one that was zero when dry. Also when the engine is turning over oil fumes are coming out of the oil filler suggesting to me that the engines compression is going down into the sump. As a result I suspect the fault lies with the piston/rings rather than gas escape through faulty valves in the cylinder head.

My question is if I replace the pistons and barrels with 1600cc versions is this a straightforward swap or do I also need to swap or modify the heads to accommodate the larger pistons?

MicksRedNova
09-04-2016, 01:10 PM
My engine is a 1300cc twinport that I bought of ebay last autumn. I have tried to start the engine but it is suffering from very low compression on three of the cylinders and no compression on the fourth. Squirting oil into the bores and re-testing results in better compression and a low reading on the one that was zero when dry. Also when the engine is turning over oil fumes are coming out of the oil filler suggesting to me that the engines compression is going down into the sump. As a result I suspect the fault lies with the piston/rings rather than gas escape through faulty valves in the cylinder head.

My question is if I replace the pistons and barrels with 1600cc versions is this a straightforward swap or do I also need to swap or modify the heads to accommodate the larger pistons?

Phill
Heads are the same so a barrel and piston set is an easy swap.
It may be that your rings are gummed up causing compression loss, a fairly easy fix with the heads a barrels off. My suggestion would be remove the heads and barrels - about an hours work - and inspect for cracks, scoring and free movement of rings. If there is no significant wear or damage (including valves) then slap it all back together and run it as a 1300 to get you going. If the engine is unknown there could be other issues that become apparent when its running that may make investment in 1600 kit not cost effective.
As its easy to drop the engine later to do the upgrade I'd leave it till then.

Mick

Phill
09-04-2016, 06:15 PM
Good sound advice as always Mick. Good to know the heads are the same so no modification required, but I will probably follow your advice and see if I can fix the engine utilising existing components - then all being well ugrade at a later date.

Peter
10-04-2016, 01:07 PM
Only the 1200 is different, being smaller in the crankcase opening and shorter stroke, (64mm), the 1300, 1500 and 1600 are all interchangeable as well as the 161cc kit of course :wink:

There are a few different heads with various valve sizes. (in MM) single and twin port of course. but all the same stud PCD apart from the smaller 1200.

1192cc In 31.5 Ex 30.0
1285cc In 33.0 Ex 30.0
1493cc In 35.5 Ex 32.0
1584cc In 35.5 Ex 32.0

Mine are 044 heads with stainless swirl valves of 40 x 35.5 :whistling:

If you strip it down to the crankcase and have the means go for the steel crankcase thread inserts for the cylinder studs, they have been known to pull the threads out.

Scorpion
11-04-2016, 02:37 AM
If you strip it down to the crankcase and have the means go for the steel crankcase thread inserts for the cylinder studs, they have been known to pull the threads out.[/QUOTE]


Funny you should say that Peter. just found that exact problem. yet another one to sort out before stoneleigh. :@

ratrog64
11-04-2016, 11:49 AM
I'm not sure if you have them there, but here in the states we have repair studs. Perfect for that one stripped out stud. It is slightly larger and it cuts its own threads as you turn it in. If you have multiple pulled studs I'd go with machining and new case inserts, but if its just one or 2, the repair stud is just the ticket.

Peter
11-04-2016, 11:53 AM
They are great for a one or two off if you're flipping the car on but long term I would go for the kit with all 16, drill and tap. Took all of an hour to do.

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ratrog64
11-04-2016, 02:13 PM
If the motor is apart already case inserts are the only way to go. If the motor is together and you are just doing the pistons and cylinders the repair stud is a simple solution for that one or two pulled studs. I have had repair studs in motors for more then 10 years and never had an issue. A few motors I was also not very nice to (baja bugs and sand rails).

Scorpion
12-04-2016, 01:54 AM
If the motor is apart already case inserts are the only way to go. If the motor is together and you are just doing the pistons and cylinders the repair stud is a simple solution for that one or two pulled studs. I have had repair studs in motors for more then 10 years and never had an issue. A few motors I was also not very nice to (baja bugs and sand rails).

Thanks for that. just found em on the interweb. not having had a nova with a vw engine i was a little in the dark on how to go about repairing it. got that bit sorted, now just the rest to do. cheers.

Scorpion
12-04-2016, 01:55 AM
They are great for a one or two off if you're flipping the car on but long term I would go for the kit with all 16, drill and tap. Took all of an hour to do.

Sent from my Vodafone Smart 4 turbo using Tapatalk

cheers peter.